Download document 8032427

MAKING YOUR JOB EASIER: Sample Collection Guidelines Linda Shell, DVM, DACVIM (Neurology) Veterinary Education and Consulting I.
Minimize lipemia a. Prefer fasting: less chance of lipemia b. Lipemia = normal for up to 8-­‐10 hours post meal c. Lipemia = triglycerides; hypercholesterolemia does not produce lipemia d. Lipemia can induce hemolysis e. Some animals lipemic no matter how long they fast f. Lipemia avoidance: heparin 100 IU/kg IV and collect blood 15 minutes later g. Labs may use clearing agents on lipemic serum h. Ask clients to fast their pets overnight: 8 hours is good enough for most. II.
Minimize hemolysis a. Fast the animal; lipemia induces hemolysis b. Use minimum amount of alcohol to raise vein c. Use large vein and large needle large needle d. Use vacutainer e. If using syringe/needle, avoid excessive back pressure on syringe f. Remove needle from syringe and stopper from tube; allow blood to flow from syringe into serum tube g. Use appropriate amount of anticoagulant (excessive amount = hemolysis) h. Mix without excess agitation i. Prompt centrifugation once clot forms; don’t centrifuge before clot forms! j. Gelatinous serum: loss of AT III; presence of acute phase proteins like fibrinogen; centrifuging before sample clots. III.
How lipemia and hemolysis can affect test results a. Generally machine-­‐dependent so every lab is different! b. Lipemia may elevate these: TP, TBilirubin, albumin, globulin, glucose calcium, phosphorus, and bile acids. c. Lipemia may decrease these: lipase, ALT, AST, AP, amylase d. Hemolysis can affect variety of results: i. causes leakage of RBC constituents into serum/plasma = increased K, creatine kinase, AST, ALT, P. ii. causes dilution of serum constituents = decreased Na and Cl iii. causes color interference = variable effects on bilirubin, TP, AST, creatine kinase, albumin, lipase, BA, AP, Ca, creatinine iv. causes some chemical interactions = decreased CO2, decreased thyroxine, and decreased insulin. e. Both lipemia and hemolysis can affect bile acids. Check with your lab as affects can vary. 1
IV.
Blood collection tubes and procedures a. Lavender: EDTA as anticoagulant; used for hematology. b. Red marble with serum separator gel: no anticoagulant; used mainly for serum chemistries. Avoid using it to collect serum for endocrine testing, drug levels. c. Red tube: no anticoagulant; used for serum chemistries, endocrine tests, and drug levels. d. Blue: citrate as anticoagulant; used for coagulation studies. e. Green: heparin as anticoagulant; used for plasma/whole blood chemistries. Plasma samples should be centrifuged to separate plasma from cells. Decant plasma layer into a separate tube and label it as ‘plasma’. f. Allow blood collected in red top or red marble top tubes to sit at room temperature to allow clotting (approximately 15-­‐30 minutes), and then centrifuge to separate serum from other blood constituents. g. Serum may be used immediately, but should be refrigerated if there is a time delay in analysis. h. Never store whole blood in the freezer, as it causes irreparable cell damage. i. If you use vacutainer, fill tubes as follows: blue top, non-­‐additive red top, serum separator tube, green top, purple top. j. If you use needle/syringe, most labs recommend filling serum before EDTA. If you do fill the EDTA tube first, be careful to avoid contaminating other tubes filled afterwards. k. If EDTA contaminates serum tube, the K and Ca results will be very abnormal looking (very high K and very low Ca). V.
Collection for coagulograms and von Willebrand’s factor a. Require blue top (citrate) tube b. Imperative that blood comes in contact with citrate as soon as possible (delay= inaccurate results) c. Avoid trauma, clots, hemolysis d. Get enough! Inappropriate amount of blood = false results e. If no vacutainer, use syringe method but check with your lab for their specific instructions: Draw an exact amount of citrate into a syringe as follows: i. 0.2ml citrate + 1.8ml of blood = 2.0 ml total sample ii. 0.3ml citrate + 2.7ml blood = 3.0 ml total sample iii. 0.4ml citrate + 3.6ml blood = 4.0 ml total sample VI.
Urine collection and analysis a. Collection technique influences how the sample results are interpreted. b. Which collection technique to use is determined by veterinarian and what disease process he/she needs information about. c. If a free-­‐catch sample is needed, often times, a first morning, mid-­‐stream, sample is preferred, as it tends to be the most concentrated and precedes the morning meal. Random samples may be used for evaluation too. d. A cystocentesis collection is often done for routine visits because of convenience. It is also preferred for sick patients. In general, it is easier to interpret results of a cystocentesis sample collection. e. A cystocentesis collection is preferred for urine culture/sensitivity. 2
f.
Disadvantages to cystocentesis collections: hitting blood vessel which contaminates sample with RBCs; hitting colon which contaminates sample with bacteria. g. If owner’s complaint is hematuria, a free catch sample may be preferred. But sometimes in cases of hematuria, we want to look at both a cystocentesis and a free catch sample. h. Use a sterile, opaque, airtight, labeled container; ideally 6 ml minimum. If culture/sensitivity is anticipated, put some aside in a sterile container before you start analysis (to avoid contamination). i. IF looking for crystals, confirm type on a freshly collected, un-­‐refrigerated sample within 60 minutes of collection. j. If sample isn’t analyzed within 60 minutes of collection, refrigerate it and try to get it analyzed in next 12 hours. k. Warm all refrigerated urine samples to room temperature prior to analysis to minimize artifacts caused by cooling of the sample l. Potential artifacts associated with refrigeration: i. In vitro crystal formation (especially, calcium oxalate dihydrate) increases with the duration of storage. ii. A cold urine sample may inhibit enzymatic reactions in the dipstick (e.g., glucose), leading to falsely decreased results iii. Specific gravity of cold urine may be falsely increased because cold urine is denser than room temperature urine m. Potential artifacts associated with prolonged storage at room temperature and their effects: i. Bacterial overgrowth: increased urine turbidity, altered pH (increased pH if urease-­‐producing bacteria are present or decreased pH if bacteria use glucose to form acidic metabolites), decreased concentration of chemicals that may be metabolized by bacteria (e.g., glucose, ketones), increased number of bacteria in urine sediment and therefore altered urine culture results ii. Increased urine pH: may occur due to loss of carbon dioxide or bacterial overgrowth; can cause false positive dipstick protein reaction, degeneration of cells and casts, and alteration of the type and amount of crystals present. VI. 3
Fecal Collections and results a. Always use fresh feces. Older feces may contain eggs, oocysts, and larvae that have developed beyond their diagnostic stage. b. Using 1 gram sample increases fecal egg recovery. c. Freezing will kill or damage eggs/parasites. d. Free living mites and grain mites: non-­‐pathogenic e. Rhabditiform larvae: free living nematode, old sample with larvated hookworm eggs, strongyloides. Later two are pathogenic. f. Coprophagy of other animals feces results in “parasites” that “pass through” i.e. non-­‐pathogenic for dog or cat so no treatment necessary: Eimeria (coccidia of rabbits, rodents), Strongyle eggs (horses), Anoplocephala (tapeworm of horses, deer, rabbits), Nematodirus (trichostrongyles of ruminants). MAKING YOUR JOB EASIER: THE URINALYSIS Linda Shell, DVM, DACVIM (Neurology) Veterinary Education and Consulting Urine Specific Gravity (SG) 1. Measure of the ratio of a volume of urine to the weight of the same volume of distilled water at a constant temperature. 2. Indicator of concentration of dissolved materials in the urine 3. Indicator of kidney function. Alteration in the concentrating ability of the kidneys is an early indicator of renal tubular damage. 4. Measure via refractometer, not dipstick pad 5. Always good idea to get urine sample at same time of chemistries/CBC. Dipstick Information 1. Interpret in conjunction with urine sediment findings and collection method. 2. Note the expiration date and general condition of strips; use well-­‐mixed, room temperature urine samples 3. Leaking from one pad to another is a problem! 4. Protein: The urine dipstick is the most readily available test of urine protein (detects albumin and globulins) but is also the least reliable. a. Both false positives and false negatives occur. b. A trace or 1+ reaction is considered normal with a specific gravity greater than 1.035. c. Highly alkaline urine (>8) can produce a false positive result d. Transient, physiologic, or nonpathologic proteinuria has many causes: strenuous exercise, fever, seizures, and venous congestion of the kidneys 5. Glucose: Glucose is freely filtered by the glomerulus and is reabsorbed in the proximal tubules. Renal threshold for exceeding the tubular reabsorption occurs at blood glucose levels of 180 mg/dl in dogs and 280-­‐300 mg/dl in cats. a. Transient and stress-­‐induced hyperglycemia in the cat can result in glucosuria. b. Cats with cystitis may give a false positive reaction. c. Glucosuria warrants automatic look at serum glucose because the most common cause of glucosuria is hyperglycemia due to diabetes mellitus. d. Many causes of glucosuria without concurrent hyperglycemia: Current one to ask owner about is *Chicken jerky treats* made in China! 6. Ketonuria: Ketonuria without glucosuria: excessive lipid catabolism (starvation, fasting, anorexia), high fat diet, or possibly impaired liver function. a. Ketonuria without glucosuria in an otherwise normal patient is not likely significant. b. The stix detects acetoacetate or a combination of acetoacetate and acetone, depending on the brand. 7. Bilirubinuria: The stix and tablet methods detect conjugated bilirubin. a. Test pad may give false negative results if exposed to air or light for long periods of time or if urine has dark color (hemoglobinuria) which masks changes on stix. 4
b. Normal cats do not have bilirubinuria: a positive reaction is significant. c. Dogs have a low renal threshold. Therefore, trace, 1+ or 2+ bile results are frequent in normal dogs with high urine specific gravities. e. Causes: hepatic disease, bile duct obstruction, hemolytic diseases. 8. Occult blood: Detects myoglobin, hemoglobin, and/or intact red cells. Normally five or fewer RBCs per hpf occur in normal urine (proestrus is exception). a. Normally myoglobin and hemoglobin are not present in urine. b. Hematuria is most common cause of positive occult blood; confirm by finding RBCs in urine sediment. If no RBCs are found in sediment, look at the patient's hematocrit and plasma color: if plasma is red or pink (and proper venipuncture technique was performed), then hemoglobinuria is present and indicates hemolytic anemia. c. Myoglobin is a protein found in muscle. Myoglobinuria is usually seen in dogs with rhabdomyolysis. Serum creatinine kinase should be elevated. 9. pH: Normal 6.0-­‐7.5; some list a wider range of 5.0-­‐8.5 a. Run off from adjacent pads can affect pH results. b. Alkaline urine: recent meal, ingestion of alkali (bicarbonate or citrate), UTI with urease-­‐producing bacteria, renal tubular acidosis, vegetable source diet, alkaline fluid therapy, metabolic and respiratory alkalosis. c. Acid urine: meat or milk protein diets, catabolism of body protein, acidic fluid therapy. e. A pH meter must be used if pH level is critical in the evaluation of a patient. 10. Urobilinogen: Useless in veterinary medicine because reagent strips can’t accurately measure it. 11. Leukocytes: Insensitive and produces false negative results in the presence of pyuria. 12. Nitrite: Designed to detect the presence of gram negative bacteria, but has very limited value for detection of bacteriuria. False negatives are frequent Sedimentation Information 1. Generalizations: a. Sediment of urine collected by cystocentesis or catheterization may contain RBCs from trauma b. Voided samples often contain cells & bacteria from the genital tract & caudal urethra c. A high urine SG will cause cells in urine to shrink while low SG can cause cell swelling to occur. d. Centrifuge 5-­‐10 mls at low speed for about 5 minutes; pour off supernatant except for about 1 ml e. Resuspend sediment in 1 ml of supernatant. Put drop on microscope slide/coverslip Exam on low power for casts & epithelial cells; high power for cells, bacteria. f. Casts and crystals are best visualized on the unstained preparation; cells, organisms and sperm are best seen on the stained preparation. 5
2. 3. 4. 5. 6
Cells a. RBCs crenate (shrivel) in concentrated urine and swell and lyse (appearing as colorless rings or ghost cells) in dilute urine. b. WBCs: Greater than 5/hpf indicates inflammation. They degenerate in old urine and may lyse in hypotonic or alkaline urine. c. Squamous epithelial cells are common in urine samples. They are large, thin, flat with angular borders & large nuclei. Origin: distal urethra, vagina, vulva, prepuce. d. Transitional epithelial cells originate in the bladder, ureters, renal pelvis, and proximal urethra. They may occur in clumps, especially if the urine was collected by catheterization. Increased number suggests inflammation. e. Renal epithelial cells originate in the renal tubules; they may represent tubular degeneration. Crystals: Can be within normal limits a. Identify crystals in uncontaminated fresh urine sediment, preferably at body temperature. b. Formation is dependent on the amount of the substance in the urine, the solubility of the particular crystal type, & is affected by pH & specific gravity of the urine. c. Acidic urine crystals: Calcium Oxalate (hypercalcemia, steroids predispose), Amorphous Urates, Sodium Urates (liver disease; Dalmatians), Uric Acid, Calcium Sulfates, Cystine (Newfoundlands) d. Alkaline urine crystals: amorphous phosphates or struvite e. Bilirubin crystals can be normal in dogs especially in concentrated urine d. Medication crystals: sulfonamides Casts: Cylinders of material that formed from a matrix of protein secreted by the renal tubules. Casts are fragile; easily destroyed with improper preparation of sample a. Although a few casts may be seen in normal urine, the presence of casts in urine samples usually indicates tubular damage. b. Casts dissolve in alkaline urine, so identification/quantification is best done with fresh urine samples. c. Hyaline casts lack cells or cell debris and least indicate renal tubular damage. d. Granular casts have granules of degenerate WBC, RBC, and/or epithelial cells and are either coarse or fine. Indicate tubular degeneration & severe kidney damage. e. Waxy casts are wide and smooth, with sharp margins and blunt ends. f. Fatty casts are lipid material incorporated into a protein matrix of the cast. Bacteria: a. Bacturia without pyuria usually indicates some error. Gram stain can confirm bacteria. b. Possible lab errors: Contamination of an old urine sample with bacterial or yeast etc. Overgrowth or growth of an organism in one's stain used for urine sediment. c. Possible errors if collected via free catch: Bacteria from surface of the vagina or prepuce. d. Possible error if collected via cystocentesis: Bowel puncture. These bacteria may not grow if sample is cultured because they die quickly (need anaerobic environment). MAKING YOUR JOB EASIER: Red and White Blood Cells Linda Shell, DVM, DACVIM (Neurology) Veterinary Education and Consulting 1. Quick PCV/TP test a. PCV or hematocrit is quick/easy way to evaluate red cell mass b. Look at plasma in the microhematocrit tube. i. Plasma is normally clear and colorless. ii. yellow = bilirubin. With normal PCV, liver disease may be present. With anemia, destruction of RBSs may be present iii. red = RBC lysis from either collection & handling process or from intravascular hemolysis. Can confirm intravascular hemolysis if hemoglobinuria is present. c. Evaluate buffy coat with the naked eye & under the 4x objective of the microscope. If there is an obvious double layer, there may be a significant leukocytosis (the upper layer is platelets, the lower layer is leukocytes). Buffy coat layer size can give you indication of excessive numbers of WBCs or very low numbers of WBCs. d. Pink layer to buffy coat suggests an increase in reticulocytes; anemia is expected.
e. Determine plasma protein using a refractometer. 2. Remember the order in which blood is put into collection tubes varies with vacutainer vs. needle/syringe collection. Don’t contaminate serum tubes with EDTA! 3. Quick scan of blood in EDTA tube: Clumping or autoagglutination of the EDTA blood will sometimes be seen with immune mediated hemolytic anemia (IMHA) 4. Rapid slide agglutination test (SAG): Add one drop of fresh blood with one drop of 0.9% saline and mixing them together on a slide. The presence of gross agglutination in face of anemia supports the diagnosis of IMHA. If agglutination is not observed grossly, check for it under the microscope. 5. Common changes seen in the RBC line a. Agglutination is noted as three-­‐dimensional clumping of RBCs. Confirm with a saline agglutination test. Caused by surface-­‐related antibodies that result in tightly bound cross-­‐linking of erythrocytes. Differentiate from rouleaux, loosely attached organized linear arrays of RBCs (stack of coins). b. Polychromasia is due to polychromatophils, immature RBCs that are typically slightly larger than adult ones & have a slight blue stain due to the presence of RNA. May be sign of bone marrow responsiveness ("regeneration"). c. Spherocytes appear as smaller than normal RBCs with increased density and no central pallor compared to normal RBCs. They represent extravascular hemolysis due to partial phagocytosis by macrophages recognizing surface attached immunoglobulins. An immune-­‐mediated extravascular hemolytic process is likely if they are present in significant numbers. Zinc toxicosis is another rule out. d. Acanthocytes are characterized by 2-­‐10, blunt, finger-­‐like projections on the RBC surface. They indicate "lipid-­‐loading" & investigation into causes of changes in 7
cholesterol:phospholipid ratios in the plasma (liver disease, underlying metabolic disturbances) and possible splenic disease is warranted. e. Target Cells or codocytes are RBCs with excessive cell membrane to cytoplasmic content ratio commonly associated with "lipid-­‐loading" by similar mechanisms as seen with acanthocytosis. f. Hypochromasia is due to hypochromatophils, RBCs with decreased cytoplasmic content of hemoglobin. They are pale thin cells typically smaller than normal RBCs. Seen with chronic blood loss situations & developing iron deficiency. g. Schistocytes are irregular fragments of RBCs caused by mechanical injury. Can be associated with DIC and "microangiopathy" such as occurs with fibrin accumulation in small blood vessels/capillaries. Increased turbulent flow of blood through large vessels (caval syndrome with Heartworm disease) or within the heart (endocarditis) can result in similar findings. h. Metarubricytes are nucleated RBCs. When found in low numbers relative to high numbers of polychromatophils, they may indicate a strongly regenerative response by the bone marrow. But if found without associated polychromasia, bone marrow stromal damage (infiltrative bone marrow disease, endotoxemia/septicemia, hypoxia, heavy metal toxicity [acute lead toxicity] is likely. i: Heinz bodies are small, projections on the surface of the RBCs that represent denatured/oxidized hemoglobin due to oxidant injury. Causes: acute onion toxicity in the dog; acetaminophen toxicity in the cat as well as other underlying metabolic disturbances. j: Inclusions or parasites include Babesia, Mycoplasma (Hemobartonella), Cytauxzoon, Ehrlichia, distemper viral particles. 6. Common changes in WBC line a. Atypical lymphocytes: Describes varied changes within lymphocytes e.g. eosinophilic cytoplasm, changes in nuclear texture, angular nuclei, prominent nucleoli, large abundant cytoplasm. Nonspecific indicator of disease (seen in increased numbers in both infectious and noninfectious conditions). Significance remains controversial. b. Reactive lymphocytes: Cells with dark blue cytoplasm and darker nucleus. Noted in chronic infection. Not abnormal at all, but simply reflect normal function of the immune system. c. Döhle bodies: Normal if seen in low numbers of neutrophils in cats. Cytoplasmic inclusion of ribosomal matter. R/O chronic bacterial infection and viral diseases. Associated with toxic neutrophils d. Toxic neutrophils i. +1 toxicity: Döhle bodies only. ii. +2 toxicity: Döhle bodies and diffuse cytoplasmic basophilia that results from the retention of cytoplasmic RNA iii.+3 toxicity: all of above in addition to foamy cytoplasmic vacuolation iv.+4 toxicity: all of above in addition to giantism and/or nuclear lysis e. Hypersegmented neutrophils: 6+ lobes of nucleus; chronic infection, steroids, pernicious anemia f. Vacuolization: septicemia, toxic diseases, storage diseases, prolonged sample storage. 8
g. Toxic granulation: large cytoplasmic basophilic granules; infectious diseases h. Sideroleukocytes: Neutrophils or monocytes with hemosiderin inclusions or stainable iron in cytoplasm. Seen occasionally in dogs with IMHA or intravascular hemolysis. i. Smudge or basket cell: degenerative WBC's that have ruptured. May be an artifact if blood is held too long before making the smear; also associated with leukemia. Other degenerative changes: pyknosis, karyolysis and karyorrhexis 7. Common changes in platelet line: Adequate numbers of platelets essential for formation of hemostatic plug. Life span: 5-­‐7 days in dog; fewer days for cat. Clinical signs of low platelets: petechial or ecchymotic hemorrhage. Must look at platelet number as well as observe slide for platelet estimate. Clumping of platelets is common problem which results in a falsely low platelet count and a misdiagnosis of thrombocytopenia. b. Platelet clumping vs. true thrombocytopenia. Validation of decreased platelet numbers is essential with a blood film review. If platelet count is low and yet estimated platelet number is adequate, platelet line is likely normal. c. Giant platelets: increased rate of production of platelets at the bone marrow level usually in response to a peripheral demand for platelets. Normal for Cavalier King Charles dogs! d. Increased platelet number. Usually don’t get too concerned until platelet count reaches 800,000 and is repeatable. If repeatable over several weeks/months, if no other cell line is abnormal, and if platelets appear normal in appearance, the veterinarian may start looking for causes of secondary thrombocytosis. Remember that physiologic thrombocytosis is transient due to exercise or epinephrine release so it is best not to take blood from a pet who has just been exercised or involved with stress situation. 9
MAKING YOUR JOB EASIER: SERUM CHEMISTRIES Linda Shell, DVM, DACVIM (Neurology) Veterinary Education and Consulting LIVER EVALUATION I.
Alanine aminotransferase: ALT/SGPT. Hepatocytes are the major source of this enzyme so this enzyme increases when liver cells are damaged. The pancreas, cardiac, and skeletal muscle also release this enzyme on a smaller scale. II. Alkaline phosphatase: ALP or SAP. This enzyme is present in bone cells, especially osteoblasts in young animals, and in the liver. Very common to see it elevated in patients under 1 year of age and in older patients too. III. Albumin: Is made by liver hepatocytes. It makes up 30-­‐50% of total protein and maintains osmotic pressure within the vascular space. Decreased production by liver or increased loss via kidney or GI tract can result in hypoalbuminemia. Vasculitis and Addison’s disease are two other possible causes of low albumin. IV. Aspartate aminotransferase: AST/SGOT. This enzyme is found largely in hepatocytes, but some is made by pancreas, kidney, cardiac, and skeletal muscle. So it is not liver specific. Increases will parallel ALT increase if caused by liver disease. V. Cholesterol: Primary source is hepatocytes; may be low with end stage liver disease. May be elevated with Cushing's Disease and hypothyroidism. VI. Bilirubin: Increased levels of bilirubin in conjunction with a normal PCV suggests biliary obstruction (hepatic or post hepatic). Increased bilirubin can also be seen in hemolytic anemias as a byproduct of hemoglobin degradation. VII. BUN: While elevated values are traditionally associated with renal disease and dehydration, very low values can be seen with end stage liver disease because the liver makes urea nitrogen. KIDNEY EVALUATION I.
Blood Urea Nitrogen: BUN Is produced from amino acid breakdown performed by the liver. Excreted by the kidneys. Renal azotemia does not occur until 75% of nephrons are no longer functioning; therefore, by the time BUN is only mildly increased, there has been a significant decline in renal function. Elevated with dehydration and with gastrointestinal bleeding. II. Creatinine: Byproduct of muscle breakdown. Better indicator of GFR than urea nitrogen as it is not affected by renal tubular reabsorption, diet, protein catabolism, or hepatic function. Excreted by the kidney. PANCREATIC EVALUATION I.
Amylase: While the primary source is the pancreas, elevations can be seen with decreased excretion via kidney as well as increased production by GI tract. Not specific for pancreas. Function is to break down starches and glycogen II.
Lipase: Primary source is the pancreas but elevations can be seen with renal and gastrointestinal diseases. Function is to break down fatty acids of lipids. Not specific for pancreas. 10
I.
II.
III.
IV.
V.
ELECTROLYTE EVALUATION Potassium: Both abnormally high and abnormally low values are important in terms of disease states. Decreased values are associated with prolonged anorexia, certain drugs (e.g. furosemide), chronic kidney failure, post-­‐obstructive diuresis, diarrhea or vomiting. Increased values can be found with Addison’s disease, some drugs (NSAIDs, Beta blockers, ACE inhibitors, heparin) acute kidney failure, urinary outflow obstruction, and pseudo Addison’s (whipworms, severe GI diseases in dogs). Calcium: Most of calcium in the body is in bones! Calcium is carried by albumin in the serum. So it is common to see low calcium level when the albumin is below normal. Both high and low values are important in terms of disease states. High calcium levels can cause pu/pd. Low values may cause tetany, muscle tremors, seizures. Phosphorus: Most of phosphorus is also in the bones. Phosphorus is carried by RBCs in the blood. Very low levels of P can cause lysis of RBCs. High values can be normal in animals under one year of age, but in older animals high values are often associated with chronic renal failure. Sodium: Both abnormally high and abnormally low values are important in terms of disease states. Low values can be seen with GI disease. High values can result from excessive intake (salt block, homemade play dough) and can cause seizures or coma. Chloride: Highs and lows are usually tied to sodium values. High chloride values with normal sodium level are typically seen with animals on bromide because of bromide ion is picked up on colormetric tests for chloride determinations. Chloride level in body is actually normal in such cases. OTHER TESTS I.
Globulins: Total protein level minus albumin = globulin level. High levels indicate antigenic stimulation or antibody production. May have to do protein electrophoresis to determine if globulins are due to infectious/inflammatory problems or neoplasia (lymphoma, multiple myeloma) II.
Glucose: If elevated, check urine glucose to confirm diabetes mellitus. Serum elevations without glucosuria could be stress related. If hypoglycemic, sepsis, insulin-­‐secreting tumor, Addison’s, and liver failure are possibilities. III.
Triglycerides: Frequently elevated after eating. Serum will be lipemic. Some diseases result in high triglycerides: diabetes mellitus, pancreatitis, hypothyroidism, Cushing’s disease, cholestasis, and idiopathic hyperlipidemia. Summary I.
Hemogram, chemistry, and UA are excellent screening tests for organ function. II.
Sample collection and handling is very important because results can be skewed by lipemia, hemolysis, type of collection, storage, etc. 11
MAKING YOUR JOB EASIER: Selected Common or Newer Laboratory Tests Linda Shell, DVM, DACVIM (Neurology) I.
Serum Bile Acids (BA) a. BA are stored in the gall bladder & released into the intestinal tract. Most BA are actively resorbed in the ileum and carried to the liver where they are re-­‐
conjugated and excreted as part of the enterohepatic circulation of BA. b. No need to run BA if there is elevated bilirubin; elevated bilirubin tells you there is liver dysfunction and it can falsely elevated bile acids. c. Samples should be non-­‐lipemic and non-­‐hemolyzed; 6-­‐12 hour fast. d. About 15-­‐20% of dogs have a higher fasting than post-­‐prandial BA value; using random BA sample or single BA sample isn’t optimal e. Normal BA results don’t necessarily rule out hepatic disease. f. Higher fasting result than post prandial result: i. handling or misidentification error ii. lab error iii. sporadic contraction of gall bladder and small intestine in fasted state g. Low pre and post prandial values i. Prolonged fasting ii. Intestinal malabsorption iii. Increased intestinal transit time through bowel (diarrhea) II.
Urine Bile Acids a. In theory, urine BA would be better test as they are measuring concentrations over a longer period of time and are not subject to pre and post sampling & gall bladder contraction b. Normal results do not exclude underlying liver insufficiency. c. Collect 2 ml urine within 4-­‐8 hours of eating (optimal) III.
Protein C Activity test: (PCA) a. PC is a short-­‐lived anticoagulant protein that modulates inflammation and apoptosis. Synthesized in the liver. b. Significantly reduced in dogs with severe liver dysfunction including shunts. c. Subnormal PCA was found in 98% of dogs with shunts but only 30% of dogs with MVD. Therefore low PCA concentrations may offer a noninvasive method to help differentiate PSVA from MVD in some dogs. d. Sample is collected in a special citrate anticoagulated vial. IV.
TLI: trypsin-­‐like immunoreactivity a. Trypsinogen synthesized exclusively by the exocrine pancreas b. Species-­‐specific ELISA: cTLI and fTLI c. Highly sensitive & specific for diagnosis of exocrine pancreatic insufficiency (EPI) when a reduced value is obtained. d. Elevated values may indicate pancreatitis or gastrointestinal disease if renal function is okay. e. 12 hour fasted sample f. Not affected by pancreatic supplements 12
V.
PLI: Pancreatic Lipase Immunoreactivity a. Pancreatic lipase is a more specific marker for the pancreas than serum lipase. b. PLI is significantly decreased in dogs with EPI c. PLI is increased in dogs (approximately 80% sensitive) and cats (approximately 70% sensitive) with pancreatitis. d. Specificity: High so not supposed to have many false positives (???) e. Need fasted serum sample VI.
Serum B12 (cobalamin) and folate a. Fasted serum sample required. b. Tests may help decide if GI disease is present. c. Folate absorbed in duodenum; B12 in ileum d. Low B12 levels will require B12 supplementation. e. Low folate levels suggest severe duodenal or jejunal disease; supplementation required. f. High folate suggest some small intestinal bacterial overgrowth in which case antibiotics may be used. g. Combination of low B12 & high folate: more suggestive of idiopathic "SIBO" than just increased folate alone. In SIBO, bacteria synthesize folate & bind B12. h. Combination of high B12 & high folate: high dietary intake or supplementation VII.
Fungal disease tests: a. Antigen tests are more specific for the disease state than are antibody tests. b. Presence of antibodies signify exposure but not necessarily disease whereas presence of antigen signify disease. Only about 30% of dogs with blastomycosis have serum antibodies at time of diagnosis! c. Blastomycosis Antigen Test (Miravista labs) i. If diagnosis cannot be made by identification of Blastomyces dermatitidis organisms by cytology, culture, or histopathology of suspected lesions, look for antigen, not antibody, in serum & urine. ii. Urine is preferred sample. iii. Dramatic decline in serum antigen concentrations 30 days after the initiation of treatment with itraconazole. iv. Urine antigen concentrations were maintained at 30 days but declined after 60 days of treatment v. Assay is known to cross-­‐react with other systemic mycoses in humans including Histoplasma capsulatum (histoplasmosis), Coccidioides immitis (Valley fever), and Penicillium marneffei. d. Histoplasma Antigen Test (Miravista labs): Cross reacts with blastomyces. e. Coccidioidomycosis Antigen Test (Miravista labs) has not been studied in the dog. Currently the antibody assay offered by Dr. Pappagianis at the School of Medicine, University of California, is the recommended test. f. Aspergillus: MiraVista Diagnostics provides an Aspergillus antigen test for use in dogs, but it is currently not validated for use in this species. Antibody-­‐based tests are available through commercial labs 13
VIII.
IX.
ACTH stimulation test a. Used to diagnose Addison’s disease as well as Cushing’s disease b. Do not perform if dog has had prednisone within last 24 hours. c. In cases of suspected Addison’s where steroids are needed, dexamethasone can be given for acute treatment and it will not interfere with ACTH stimulation test. d. Advantages of ACTH stim to diagnose Cushing’s disease: Quick. Can run other tests (e.g. bile acids) at same time. e. Disadvantages of ACTH stim to diagnose Cushing’s: More costly due to purchase of synthetic ACTH. More false negatives. More likely to miss adrenal tumor. Can’t discriminate between the 2 types of hyperadrenocorticism. Low dose dexamethasone suppression test a. Can’t use it to diagnose Addison’s; is used to diagnose Cushing’s disease. b. Advantages: More positives (but also more false positives). Less expensive. Can often discriminate between pituitary dependent vs. adrenal dependent types. c. Disadvantages: Affected by stress of hospitalization (can’t take radiographs, do other tests during the 8 hours this test is conducted). Takes all day to perform. Can’t have recent administration of corticosteroids. X.
14
FIPV/coronavirus testing a. Antibodies: FIPV is a mutation of the feline enteric coronavirus (FECV). There is no FIP antibody test (commercial laboratories offer "FIP-­‐antibody titer" tests but these are actually reporting FECV titer). i. None of the so-­‐called antibody tests for FIP are diagnostic. Positive titer refers to the presence antibodies; it does not indicate a diagnosis of FIP. ii. Is there any value in performing routine antibody titer screening for FIP/corona? Probably not. A negative titer result can’t rule out FIP while a positive result can’t rule it in. b. The reverse transcriptase-­‐polymerase chain reaction (RT-­‐PCR) assay for FECV antigen can be done on effusions, serum, plasma, and feces but it does not distinguish between FIPV and FECV or any other feline coronaviruses. i. Cats with benign (so-­‐called) FECV can have circulating coronavirus in their plasma, but that's NOT necessarily an indication of FIPV. ii. However, if m-­‐RNA can be identified in macrophages, that is diagnostic for FIPV because only the FIPV replicates inside cells. c. RT-­‐PCR technology can be utilized to identify m-­‐RNA (messenger RNA) of replicating feline coronaviruses inside circulating monocytes of infected cats. Unfortunately, false-­‐positive test results can occur. This test is done at Auburn University, College of Veterinary Medicine-­‐Molecular Diagnostics Laboratory. d. Peritoneal and pleural effusions analysis: i. FIP fluid is light to dark ‘straw-­‐colored. Has a sticky, viscous consistency, high protein content (5 to 12 g/dL) & high spec. grav (1.017 to 1.047). ii. Cytologically, FIPV fluid is relatively hypocellular consisting of neutrophils and macrophages, with occasional mesothelial cells. iii. An Albumin:Globulin ratio FIPV fluid > than 0.81 is highly predictive for ruling out a diagnosis of FIP. iv. A globulin fraction > than 32% of the total protein (in FIPV fluid) is highly predictive of FIPV. Summary of Some Common Laboratory Results and Interpretation Questions 1. Platelet clumping is most common cause of a low platelet count. If both number & estimate are low, thrombocytopenia is likely. 2. How do I prevent platelet clumping? Get "clean stick". Use jugular vein if possible. Immediately place blood into EDTA tube. Use correct fill line. Gently invert tube 8-­‐10 times. If clumping still occurs, draw blood into a heparin-­‐flushed syringe before putting sample into EDTA tube. Alternatively, blood can be collected directly into a citrate (blue top tube). 3. Lipemic serum sample? Overnight fasting usually works. Or 24 hr fast. Some dogs have metabolic problem though & are lipemic no matter how long the fast. 4. How to prevent hemolysis? Fasting helps. Avoid prolonged venous occlusion. If syringe draw, take needle off & let sample run down side of tube. Allow sample to sit for 20 min before centrifuging. If you centrifuge before blood clots, hemolysis & decreased yield occurs and in some cases a ‘jelly fat clot’ appears. Use a well-­‐balanced centrifuge to avoid excessive vibration. Promptly separate RBCs from serum. 5. What happens if I can’t get enough blood to fill EDTA tube? Under filling may cause falsely low PCV & low MCV, falsely high refractometric TP, poor staining & morphology of cells 6. The K and Ca results are very abnormal but the animal looks okay. Most likely sample was contaminated with EDTA; even a small amount may affect calcium & potassium levels. If you use vacutainer, fill tubes as follows: blue top, non-­‐additive red top, serum separator tube, green top, purple top. If you use needle/syringe, most labs recommend filling serum before EDTA. If you do fill the EDTA tube first, be careful to avoid contaminating other tubes filled afterwards. 7. I saw struvite crystals in-­‐house but lab reported another crystal type. What happened? Storage time & temperature have significant impact on types of crystals. Increased storage time & decreased storage temperature were associated with significant increase in calcium oxalate crystals in 1 study. Urine samples should be analyzed within 60 minutes of collection to determine crystal formation/type. What if I can’t analyze urine in-­‐house? Collect via cystocentesis & spin a portion of it. Make a fresh sediment smear & air dry it. Send the smear to lab with rest of urine in a RTT for cytological analysis. 8. Lab reported bacteria in urine but culture was negative. Why? Small particles look like bacteria. Without a Gram stain, there is no way to tell difference. What if Gram stain was positive and yet culture was negative? If sample was collected by cystocentesis, needle may have accidentally hit colon; those bacteria can be picked up in urine/Gram stain but can’t be cultured because they require an anaerobic environment. Look at entire UA and clinical history signs before ordering urine culture. 15
Improving the client education and in-clinic care of
neurology cases.
Linda Shell, DVM, DACVIM (Neurology)
Small animals with neurological signs often require labor-intensive supportive care as the
nervous system is allowed to heal. While all sick animals can have complications, those
with neurological disease are more predisposed because of the nature of the disease
process as well as because of the common use of corticosteroids in the treatment of many
neurological disorders. Complications are common and can be avoided if we are aware
of what can happen and if we take preventive steps. Common complications are:
Aspiration pneumonia secondary to seizures or being recumbent
Pneumonia or atelectasis secondary to recumbency and/or aspiration
Urinary dysfunction secondary to paralysis
Urinary tract infections secondary to paralysis and corticosteroid use and/or catherization
Decubital ulcers secondary to prolonged recumbency, muscle wasting, and corticosteroid
use
Muscle atrophy secondary to disuse or primary peripheral nerve or muscle diseases
Joint stiffness secondary to paralysis and disuse of joints
Monitoring on a daily basis:
1. Urinations: how many, how much. Bladder size q 4-6 hr
2. Bowel movements: how many, how much, color (watch for melena or blood if
patient is on NSAIDs or corticosteroids)
3. Temperature: q 12 hr to look for early signs of pneumonia, infections
4. Appetite
5. Attitude
6. Neurological signs: static, improved, worse. Any movement to limbs? Any sign of
voluntary tail wag?
7. Bath needed? Keep clean & dry!
8. Evidence of skin irritation = decubital ulcer
SEIZURES
1. Definitions
a. Seizure: abnormal electrical activity of brain waves
b. Seizure classifications: may alternate between partial and general, with
duration ranging from seconds to minutes.
i. Partial: involve part of body: intention tremors, rapidly running in
circles, hypersalivation, exaggerated chewing motions or an acute
change in consciousness or behavior.
16
ii. Generalized: involve the whole body with a loss of consciousness.
Lateral recumbency, running or paddling limb motions, stiff limbs,
chewing motions involuntarily urinate or defecate.
2. Causes of seizures: DAMNIT
3. Seizure vs. epilepsy: one time event vs. repeated events over time
a. Primary epilepsy
b. Secondary or acquired epilepsy
4. Historical information:
a. Distinguish the event as a seizure, not syncope, narcolepsy, or collapse
b. Environmental concerns: indoor vs. outdoor (how well observed is patient,
could seizures have occurred in past?), toxin exposure potential (xylitol,
mycotoxins, antifreeze, ), kids/stairs (trauma)
c. Presence of systemic or neurological signs before or after seizure
d. Signalment
e. Drug history
f. Littermate or parent history
5. Nursing care during/after seizure
a. During seizure, if possible, keep patient sternal with the head angled down
to prevent aspiration. May elevate head after seizure.
b. May cradle head and neck to prevent traumatic injury in some cases.
Avoid getting in way of teeth
c. Establish IV access for administration of drugs
d. Administer oxygen if necessary immediately after seizure (flow by)
e. Keep environmental stimulation to a minimum as patient may be
disoriented, hypersensitive, and possibly aggressive after a seizure.
f. Evaluate blood glucose to rule out hypoglycemia
g. Post ictal changes should be separated from the actual seizure: dilated
pupils, salivation, vocalization, vomiting
h. Note duration of seizure activity, duration of post ictal stage
i. Inquire about pre-ictal signs
j. Are any post ictal signs localizing/asymmetric?
6. Client education
a. One seizure with normal interictal state and blood work may not warrant
any further work up or treatment. Depends on complete
history/examination.
b. Intact females should be spayed since estrus can lower the seizure
threshold resulting in increased seizure activity during estrus.
17
c. Since seizure thresholds are influenced by genetics as well as
environment, all suspected primary epileptics should be spayed or
neutered.
d. Epileptics should not be allowed to roam freely, since if they miss a
treatment dose they may be prone to having "withdrawal" seizures if
phenobarbital was used as the primary antiepileptic drug.
e. During the seizure, owner should not put their fingers in the pet's mouth.
They should however make sure pet is on the floor so that the pet will not
fall off bed or couch and experience more trauma
f. Owner should be warned of side effects of any drugs used to prevent
seizures.
7. When to start antiepileptic drugs: varies with patient, owner, history.
a. Usually 3 to 4 seizures/year would be concern enough to start drugs but
we have to assess the interval between the seizures, how severe the
seizures are, how easy/difficult it may be to medicate the patient
FAITHFULLY.
b. Benefits and risks should be discussed with the client since most animals
on anticonvulsants will require medication for life and dose adjustments
or changes in drugs may be necessary as tolerance or side effects develop.
8. What to monitor once antiepileptic drugs are started:
a. A seizure log or diary should be kept by owner and it should be evaluated
1-2x/year by veterinarian; more often if seizure activity is occurring more
than once every 6-8 weeks.
b. A baseline hemogram, chemistry profile, and urinalysis are recommended
before starting antiepileptic drugs and repeated at least annually.
c. Depending on which antiepileptic drug is administered, serum levels may
need to be done.
d. Some recommend annual bile acid testing if phenobarbital is used.
9. Stopping antiepileptic drugs:
a. Abruptly stopping administration of antiepileptic drugs is usually not
recommended.
b. Phenobarbital is barbiturate and is addictive; therefore abruptly stopping it
can result in withdrawal seizures.
c. Since bromide has a very long half-life, it can be stopped abruptly because
the blood levels decrease slowly over time (self-weaning process).
18
d. Weaning is safer even if the antiepileptic drug is not addictive because as
drug level is reduced, it gives us a chance to see if seizures are going to
return.
e. Weaning is not usually attempted until there is clear evidence that pet has
been seizure-free for 6 months or more. However if seizures were in
clusters or severe in nature, it is better to wait longer than 6 months to see
if seizures will recur.
f. If seizures occur during the weaning period, the pet should be placed back
on the antiepileptic drug at the level that originally controlled the seizures.
g. Those pets that usually have a successful weaning from anticonvulsants
are usually those that had seizures due to an underlying disease process
that was successfully treated (e.g. rickettsial vasculitis, brain neoplasia,
hypoglycemia).
h. It is very unusual for primary epileptics to be successfully weaned from
anticonvulsants. Generally, I do not recommend to attempt weaning cases
where primary epilepsy is suspected.
10. Commonly used antiepileptic drugs:
a. Phenobarbital: Side effects include polyuria, polydipsia, polyphagia and
weight gain, sedation and lethargy (these might wear off over a few
weeks). Phenobarbital has the potential to cause liver and bone marrow
failure, especially if serum levels are high or if high doses are used.
Serum levels are monitored to look for signs of liver failure and toxicosis.
Once phenobarbital has been administered twice daily x 2 weeks at a
consistent dose, a drug level can be taken at any time (peak and trough
levels are not necessary unless the veterinarian is concerned that the dog
is metabolizing the drug differently than it should be).
b. Potassium bromide: Has same side effects as phenobarbital. Some dogs
have gastrointestinal side effects especially if a ‘loading dose’ is used.
Behavioral changes can occur. Since this drug is metabolized via kidneys,
it is a good one to use if liver disease is present in an epileptic. Serum
levels are monitored to avoid reaching toxic levels.
c. Zonisamide (Zonegran): Newer; bid. On generic label so finally
affordable . Sulfa-derived drug so idiosyncratic reactions can occur but
are very rare: vasculitis, IMTP, IMHA, bone marrow dyscrasia,
hepatopathy, dry eyes. Can be used alone or with phenobarbital, bromide,
or levetireacetam. Toxic dose not known so don’t *have to* monitor
blood levels. Mild GI effects and sedation in few dogs.
d. Levetireacetam (Keppra): Newer; tid. On generic label so finally
affordable. Little to no drug interactions. Excreted mainly by kidneys.
19
Toxic dose not known so considered very safe even at much higher doses
than what we start out at. Mild GI effects and sedation in few dogs.
e. Diazepam (Valium): Oral administration not effective in dogs (but is so in
cats). Injectable form can be used rectally at home after a seizure. Can be
used IV or as CRI to stop seizures in the hospital. Do not leave it in
plastic syringe or exposed to light.
HEAD TILT AND NYSTAGMUS
1. Location:
a. Outside brain: inner ear and vestibular nerve from ear to brain stem.
Prognosis usually good if etiology can be determined and appropriately
treated.
b. Inside brain: Vestibular nerve cell bodies originate in caudal brain stem,
underneath cerebellum. Prognosis guarded because of location
2. Causes:
a. Outside brain: inner ear infection, trauma (ear cleaning and medications),
vasculitis (rickettsial diseases), hypothyroidism
b. Inside brain: neoplasia, granulomatous meningoencephalitis, fungal
encephalitis, protozoal encephalitis, migration of parasites (Cuterebra)
3. Historical information: history of otitis externa? Signs of hypothyroidism? Age
(old dog vestibular syndrome very common; idiopathic feline vestibular
syndrome also common but not age associated)? History of ear cleaning?
Presence of other neuro signs? Onset sudden or slow?
4. Hospital observation and nursing care
a. Sudden onset: signs usually improve within few days if origin was outside
brain so may monitor in the hospital to determine progression of signs.
b. Sudden onset: animal may not be able to walk. May roll. May need
sedation and padded cage. May urinate and defecate in cage.
c. Appetite commonly affected in first few days. Vomiting can occur so
watch for aspiration pneumonia signs (monitor temperature closely; listen
for soft cough/hack; ausculate lungs in quiet room). May need anti-nausea
drugs. May have to hand feed and water.
d. IV fluids may be needed but IV line can be twisted/ripped out if patient is
rolling
e. For information about managing recumbent patients, see the next section
on Paralysis.
f. Head tilt is usually toward the side of the lesion. Right tilt = lesion on
right side
20
g. Nystagmus: Has a fast and a slow phase; fast phase is AWAY from side
of lesion usually. Type of nystagmus and whether or not it changes or is
positional helps us to decide lesion location in some cases.
i. Horizontal
ii. Vertical
iii. Rotary
h. Other nervous system signs can be present. Guidelines:
i. Obtunded, comatose, severely depressed: more likely related to
brain lesion
ii. Horner’s syndrome (miotic pupil, enophthalmus, ptosis) more
likely related to ear lesion
iii. Facial paralysis (excessive drooling on one side; inability to
blink/close eye; droopy upper lip) can occur with brain and ear
lesions but more commonly found with ear lesions in my
experience
iv. Head tremors when food/water bowl is approached = brain lesion
LIMB PARALYSIS
1. Definitions:
a. Ataxia
b. Paraparesis
c. Paraplegia
d. Tetraparesis or quadriparesis
e. Tetraplegia or quadriplegia
2. Causes: Trauma, disc herniation, vascular accident (fibrocartilaginous embolism),
neoplasia, infections, congenital malformations, degenerative diseases
3. History: Determine acute vs. slow onset because rule outs will vary
4. Complications of paralysis
a. Atelectasis & accumulation of lung secretions occur in recumbent animals.
i. Turn the patient q 2-4 hours from left to right lateral side to sternal.
ii. If atelectasis or pneumonia is present, prop the patient sternally or
position it with the most normal functioning lung down to improve
ventilation.
iii. Postural drainage can also be accomplished by positioning the
patient in a head down posture (20 degrees from horizontal) for 1530 minutes every 4 hours to increase mucus drainage and prevent
tracheal plugs.
iv. It is important to supervise patients closely during treatment in
order to intervene if the patient becomes stressed or secretions
inhibit the airway.
b. Pneumonia is treated with appropriate antibiotics and coupage.
21
c. Decubital or pressure sores are usually localized to bony prominences and
are primarily caused by pressure. Tissue ischemia and necrosis results in
ulcerative lesions that are difficult to eliminate once started. They can be
avoided by using ‘soft’ bedding such as sheepskin, foam or air mattress,
trampolines, or bandaging techniques.
i. Small dogs may do well on a raised grate covered with synthetic
fleece, which allows urine to pass through.
ii. Larger dogs need more padding, such as an air mattress, water bed,
or waterproof thick foam mattress.
iii. Any bedding must be cleaned regularly to avoid prolonged contact
with body wastes.
iv. Absorbent, waterproof pads can also be place under the animal's
hind quarters to absorb urine and prevent saturation of the bedding.
v. Frequent bathing (with thorough drying) may be necessary to keep
the skin clean and dry in order to prevent urine and/or fecal
scalding.
vi. A ‘doughnut bandage’ can be placed over bony prominences or
existing decubital ulcers to prevent further pressure damage. Such
devices may relieve pressure and allow good air flow to enhance
tissue recovery.
vii. Topical antibacterial creams may be used to control infection.
viii. Surgical intervention may be required for severe ulceration or
delayed wound closure.
ix. Frequent turning of the patient and appropriate bedding are the
most important prevention measures of a nursing care for
recumbent patients.
d. Over distension of bladder can result in permanent atony of the detrusor
muscle.
i. Keep accurate and up-to-date records of the patient's ability to void.
ii. The bladder should be palpated to gauge size even if there is urine
present in the cage as the patient could have urinary overflow as a
result of distension. Urinary overflow is commonly mistaken for
voluntary urination.
iii. Assisted emptying of the bladder may be necessary to prevent
leakage and urine scald, reduce the risk of urinary tract infection
(UTI) from retained urine and to prevent bladder wall
overstretching
iv. The bladder should be assessed every 4-6 hours as a general rule,
but the urodynamics of each patient vary on a case-to-case basis.
22
v.
vi.
vii.
viii.
For example, using prednisone or IV fluids could warrant bladder
assessment and possible evacuation more frequently.
Urine evacuation can be done via manual expression, intermittent
aseptic catheterization, or placement of an indwelling urinary
catheter attached to a closed collection system. If the bladder
cannot be expressed without minimal stress to the patient, a urinary
catheter should be placed. If a closed urinary system is used, the
prepuce or vaginal area around the urinary catheter should be
swabbed every 12 hours with dilute Nolvasan to prevent bacterial
growth. Culture the patient's urine via cystocentesis after removal
of an indwelling urinary catheter to test for any infection
The volume of urine produced, along with time, color, turbidity
and smell should be recorded.
Urine scalds can be prevented by ensuring the patient is dry at all
times. Longhaired patients can have fur clipped around the
perineum and hind limbs and, if necessary, barrier creams applied.
Elizabethan collars should be used when patients are unattended
e. Urinary tract infections are frequent in patients who cannot empty their
bladders.
i. Watch for changes in urine color and odor
ii. Keep the bladder empty
iii. If using catheter to empty bladder, practice sterile techniques.
iv. Intermittent urine cultures may be helpful to detect infections early.
5. Sterile adhesive dressings may help to protect a surgical site from gross
contamination of feces/urine. Daily assessment of the site should be performed to
check for signs of swelling, redness, and discharge or seroma formation.
6. Nutrition: Although recumbent patients will have a low energy requirement, the
trauma & stress increases their metabolic rate.
a. Food should be highly palatable and, if necessary, energy dense for
patients that have a reduced appetite.
b. Support recumbent patients in an upright or sternal position before feeding
to reduce the risk of aspiration. Patients with neck pain or post-cervical
surgery should have their food and water in elevated bowls. Recumbent
patients need to be able to reach their food and water.
c. If patients are reluctant to eat, making a fuss over them may stimulate
eating. Comforts from home (food, bedding, toys) may tempt the patient.
d. Make sure that daily food intake is recorded.
7. Massage therapy is helpful on many levels.
a. introduces and accustoms the patient to its caregivers.
23
b.
c.
d.
e.
f.
has some calming and soothing effects
helps to control venous stasis and promotes lymphatic drainage.
warms up muscles before physical exercise
improves joint and muscle function.
can be used on other parts of the body, not just the affected area,
especially in recumbent patients.
8. Passive ROM exercises can help improve or maintain flexion and extension of
joints, improve flexibility of muscles, tendons and ligaments, and enhance
awareness of neuromuscular function. They may also provide sensory input to the
spinal cord.
a. Rehabilitation of a paralyzed limb is typically focused on maintaining
joint range of motion until voluntary motion returns.
b. Perform 2-3x day, 10-30 repetitions.
c. Can perform even if patient is in abdominal or pelvic sling.
9. Early supported standing via abdominal or pelvic sling or cart can help preserve
function of the front legs in paraplegic animals.
10. Outdoors for mental boost! Some patients will respond to visits outdoors,
especially as they gain ability to voluntarily urinate.
24
Neurological signs and diseases that you can put a name on by the
signs or history
Linda G. Shell, DVM, DACVIM (Neurology)
Canine Epileptoid Cramping Syndrome (Spike’s disease)
This poorly characterized problem in Border Terriers has a variety of signs: staggering, dizziness,
exaggerated stretching, unusually slow and/or methodical posturing or walking, trembling, abdominal and
lumbar muscle contractions, borborygmus and apparent intestinal pain, falling over, struggling to rise but
unable to do so. Dogs are cognizant, responsive to stimuli. Current thinking is that it is a seizure;cases
often respond to antiepileptic drugs.
Frequency of episodes varies from 1-2 x during the animal’s lifetime to several times per week. In some
dogs, signs are progressive in frequency and duration. Age of onset: Apparently any. But 2-6 years
seems to be the average.
Dancing Doberman Syndrome
This peripheral neuropathy of unknown etiolog has only been described in Doberman pinschers thus far.
Age ranges from 6 months to 7 years. Signs are first observed in one hind limb and consist of flexion of
the limb while standing. Similar signs then usually develop in the other hind limb, resulting in "bicycle"
type motions when dog is standing: one hind leg flexes, is put down, and the other one flexes. Pain is not
present. Oddly enough, pelvic limb spinal reflexes are often increased, rather than decreased, as one
would expect for a peripheral neuropathy. Over months to years, clinical signs usually continue to
progress to encompass proprioceptive deficits and paraparesis. In one case that was followed for 5 years,
quadriparesis developed suggesting that the disease may progress to the thoracic limbs as well. There is
no treatment and signs do not resolve.
Sleep-associated Movements
Alternating phases of brain activity occur during sleep. The first stage of sleep is characterized by low
frequency electrical activity, i.e. slow wave sleep. This is followed by rapid eye movement (REM) sleep. In
people, REM sleep is characterized by rapid eye movements, irregular breathing, increased blood
pressure, and loss of muscle tone. However, the brain is highly active, and the electrical activity recorded
in the brain by EEG during REM sleep is similar to that recorded during wakefulness. REM sleep is
usually associated with dreaming in people. Slow wave sleep alternates with REM sleep in cycles lasting
about 20 minutes.
During REM sleep, animals will often groan or whimper slightly and move or twitch their limbs or face.
This may occasionally be confused with a seizure or other abnormality. If the movements are sleep
related the patient will wake up normally when it is awakened.
In some animals, the movements during sleep are abnormally excessive, even violent to point where the
patient is propelled from chair, bed, or across the floor. Some have excessive running movements of the
limbs. Some may attack inanimate objects or whatever is in their path if they are moving forward. In
contrast to a seizure, the patient can be aroused during these episodes and wale up with no confusion or
incoordination. We think that these signs are similar to a sleep disorder in people called REM behavior
disorder. Clonazepam is often successful at reducing the problem in affected dogs and people.
Fly Biters
Fly-biting behavior (snapping at an imaginary fly) is seen especially in Cavalier King Charles spaniels,
miniature Schnauzesr, and greater Swiss mountain dogs. Some affected dogs seem to be following
objects with both their eyes and ears. Fly-snapping behavior has traditionally been thought to be a form of
psychomotor epilepsy but it may also be a form of obsessive-compulsive disorder.
Seizure: Finding pre-ictal and post-ictal stages (lethargy, disorientation) would suggest seizure activity.
25
Definitive diagnosis is based on finding EEG abnormalities or a positive response to anti-seizure
medications. A thorough neurologic exam is also important to identify any focal brain lesions that would
indicate the need for imaging and CSF analysis to rule out a progressive brain lesion. These are likely
complex partial seizures or seizures originating from the visual cortex. In people, visual cortical seizure
activity can cause spots of light or other visual hallucinations.
Compulsive disorder: Fly-snapping is considered to be compulsive if the bouts are frequent and
disruptive to the animal's functioning, when they continue for prolonged periods of time, when they are
associated with anxiety, and when there is no aura or other symptoms compatible with a diagnosis of
psychomotor epilepsy.
Metronidazole Toxicity
Since metronidazole is postulated to act at GABA receptors in the cerebellum and vestibular systems,
overdosing can cause head tilt, rolling, ataxia, and head/limb tremors. Doses of greater than 60mg/kg/day
have been associated with “toxicosis” in dogs, but even doses as low as 30mg/kg/day have been known
to cause CNS signs. Seizures can also occur and seem to be more common in cats administered doses
of greater than 48mg/kg/day.
Discontinuation of the drug usually produces a rapid improvement, but recovery is faster (13.4 hours
compared to 4.25 days for non-diazepam treated dogs) when diazepam is administered for 3 days at a
dose rate of 0.2-0.6mg/kg q8hr. The exact mechanism by which diazepam exerts its favorable effect in
reversing signs is not known but it is postulated that diazepam competitively displaces metronidazole
from the benzodiazepine sites on the GABA receptors.
Chiari Malformations (Syringomyelia, Caudal Occipital Malformation Syndrome)
Chiari malformations are developmental disorders of the occipital bone mesoderm, most likely genetically
transmitted. Chiari malformations, first recognized in the Cavalier King Charles spaniel, are now being
recognized in many different toy breed dogs. Dysplasia of the occipital bone results in crowding of the
structures in the caudal fossa with an end result of herniation of the cerebellar tonsils & compression of
the underlying brain stem. Abnormal cavities filled with liquid (likely spinal fluid) develop within the spinal
cord: syringomyelia. Spinal fluid also accumulates within an enlarged central canal: hydromyelia.
Oddly enough, often the primary initial clinical sign is scratching at the neck or shoulder area. This is
believed to result from compression of the decussating spinothalamic tracts within the spinal cord by the
syrinx. As the lesion progresses, other signs such as ataxia, weakness and neck pain develop in some
patients. Diagnosis is by MRI of the caudal fossa and cervical spinal cord. Initial treatment for mild cases
has been glucocorticoids and/or gabapentin. Foramen magnum decompression procedure may allow the
discontinuation of life-long steroids.
Limber Tail (Cold Tail)
This is a condition in which working dogs (Pointers, Labrador Retrievers, coonhounds, beagles, golden
retrievers) suddenly develop a flaccid tail. The tail either hangs down from the tail base or is held out
horizontally for several inches from the tail base and then hangs straight down or at some degree below
horizontal. Sometimes the hair on the dorsal aspect of the proximal tail may be raised. Affected dogs may
resent palpation of the area 3-4 inches (8-10 cm) from the tail base.
Some affected dogs have a history of prolonged cage transport, a hard workout the previous day,
swimming, or exposure to cold or wet weather. Mild elevation of serum creatine kinase may be found
early after onset of clinical signs. There is histopathologic evidence of muscle fiber damage.
Most dogs recover spontaneously within a few days to weeks. Anecdotal reports suggest that antiinflammatory drugs administered within 24 hours after onset hasten recovery. Other conditions that have
been confused with "limber tail" include tail fracture, spinal cord disease, and impacted anal gland.
Myxedema Stupor and Coma
Myxedema coma is an uncommon and severe form of hypothyroidism. A concurrent illness or
26
predisposing factor (infection, central nervous system depressants, stress, trauma, cold exposure,
diuretics) may result in decompensation of untreated chronic hypothyroidism. A reduction of oxidative
processes and slowing of metabolism in all body systems causes lethargy progressing to stupor, coma,
and if untreated, death.
The typical signs of hypothyroidism are accompanied by some combination of myxedema (nonpitting
edema of the face and jowls); obtundation, stupor, or coma; hypothermia often without appropriate
shivering (rectal temperature may be very low; 70-80); bradycardia (heart rate may be as low as 20-30
bpm); hypotension; and hypoventilation. Because of the life-threatening nature of this illness, a
presumptive diagnosis should be made and appropriate therapy instituted pending results of thyroid
function tests.
Treatment consists of levothyroxine (a single IV dose that is 3-5 times the standard oral dose is usually
recommended, followed by standard oral doses). Supportive care consists of passive warming. Fluid
administration should be judicious because of impaired free water excretion.
Hypothyroidism should always be an initial rule-out for hypothermia without obvious cause. If the
hypothermia is present without efforts to shiver, hypothyroidism should be suspected until proven
otherwise.
Ventroflexion of Neck
In cats, this clinical sign has several different possible causes: myasthenia gravis, thiamine deficiency,
polymyositis, hypokalemia, organophosphate toxicity, hyperthyroidism, hereditary myopathies (Burmese,
Devon Rex), hypocalcemia, and portosystemic encephalopathy, polyneuropathy, hypernatremic
polymyopathy, ammonium chloride toxicity. Overall, cervical ventroflexion is a sign of generalized
neuromuscular weakness in cats.
The chin usually rests near the thoracic inlet, with the eyes positioned dorsally to maintain a straightahead gaze. The cat may have a slight protrusion of the dorsal aspects of the scapulae when weight is
placed on thoracic limbs. The gait is often stiff and a crouched, wide based stance is often seen in pelvic
limbs.
Feline diabetic neuropathy
In poorly controlled diabetic cats, a distal symmetrical peripheral neuropathy may develop with
progressive paraparesis and a plantigrade gait (dropped hocks). Usually both hind limbs are affected, but
some cases are unilateral. Clinical signs may progress to also involve the thoracic limbs. The reported
clinical incidence of neurologic signs is 8% although the true incidence may be much higher.
Strict glycemic control reverses the clinical signs of neuropathy in some, but not all, cats. The reason that
some cats don’t improve is not known.
Other rule outs for dropped hocks: trauma to gastrocnemius tendon/muscle, lower lumbar spinal cord
lesion, other neuropathies.
Feline Hyperesthesia Syndrome
Feline hyperesthesia syndrome is an unusual condition because the demonstrated behaviors may
actually be triggered by different factors (fleas, behavioral disorders, myositis, seizures, etc). These
behavioral changes can include those mimicking estrus or biting at the tail, flank, anal or lumbar areas
often accompanied by vocalization, running, jumping or apparent hallucinations. Affected cats often have
noticeable dorsal skin ripples that may occur spontaneously or may induced by grooming or petting.
Extreme cases may exhibit paddling, involuntary urination and defecation, changes consistent with
seizure activity. Some cats will exhibit a range of self-mutilation from excessive licking, to plucking
(trichotillomania), barbering, biting, and chewing that lead to skin lesions. Thus signs overlap with
behavioral, neurological, and dermatological systems. It is sometimes difficult to distract the cat from the
behavior.
It is important to eliminate flea allergy, painful spinal or muscular problems, and dermatological causes as
27
etiologies before considering the possibility of a seizure or behavioral disorder. Environmental and social
stresses have been associated with feline hyperesthesia and range from readily apparent skin conditions
(including food allergy, atopy, or fleas) to changes in household (the addition or loss of another cat or
human; intercat aggression).
A few cases have had a muscle condition called inclusion body myositis. Pathologic changes found on
biopsy of paraspinal muscles have included inflammation and vacuoles within the myofibers. In people,
this is thought to be an immune-mediated disease similar to polymyositis
Haws Syndrome
Haws syndrome is characterized by elevation of the third eyelids. It is likely an autonomic imbalance,
associated most frequently with gastrointestinal (GI) inflammation/ disease. In England, Haws syndrome
has been associated with Toro virus infection of the GI tract in cats. Other GI conditions that have been
associated with Haws: internal parasites, dietary hypersensitivity, inflammatory bowel disease,
pancreatitis.
Most cats with haws seem to have mild GI signs, usually a chronic low-grade diarrhea, and often-mild
dehydration. Most cases resolve in several weeks, but it isn’t known if treatment of the GI disease results
in resolution or if the signs just spontaneously resolve. Some cases will linger for a few months.
Feline Cerebellar Hypoplasia
Feline cerebellar hypoplasia is caused by in utero infection with the panleukopenia virus (parvovirus),
which has a predilection for actively dividing cells. The virus affects the external germinal layer of the
cerebellum, preventing the formation of the granular layer and which results in atrophy. Some affected
cats have a concurrent hydrocephalus and hydranencephaly.
The queen is usually asymptomatic for the infection; only the developing cells of the kitten are affected.
Some kittens may be born dead; others will have signs of cerebellar degeneration that become noticeable
when the kittens first start to ambulate. Not all kittens in a litter from a parvovirus-infected queen will show
signs of cerebellar disease and the severity of signs can vary.
The clinical signs are of a diffuse cerebellar disease. Signs are non-progressive which distinguishes
cerebellar hypoplasia from cerebellar abiotrophy, storage diseases (GM1 and GM2 gangliosidosis,
mannosidosis, sphingomyelinosis) and infections (toxoplasmosis and feline infectious peritonitis).
History and clinical signs support diagnosis. Magnetic resonance imaging may help to define the nature of
the lesion. No treatment is helpful.
Another cause of cerebellar hypoplasia is the administration of a modified live panleukopenia vaccine
during the later stages of pregnancy. Modified live panleukopenia virus vaccine should be avoided in the
pregnant cat.
28