Download A case walks in the door… Decision Time… Pollakiuria Pollakiuria

2013 Tech CE for the Upstate
2/10/2013
A case walks in the door…
APPROACH TO POLYURIA /
POLYDIPSIA
Rob Presley, DVM, MS, DACIM (Int. Med)
Upstate Veterinary Specialists
TCTC Veterinary Technician Program
February 10, 2013
Decision Time…
• Causes of urinary
accidents
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Polyuria
Pollakiuria
Behavioral
Incontinence
• Lower urinary disease
• Neoplasia
• strictures
• “Doc, she’s peeing all over the trailer. I’m
gone need you to
FIXER!!!!”
Pollakiuria
• Increased frequency of urination
– Small amounts of urine produced at a time
– Often seen with stranguria
• Straining to urinate
Pollakiuria
– Uroliths
– Infection
– Obstruction
• 5 yr old FS Weimeraner
Behavioral
• You made someone angry!!!
– More common in cats
• Accidents typically occur 1-2 x day.
• Often accidents occur in the same area
– After going outside (dogs)
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2013 Tech CE for the Upstate
2/10/2013
Behavioral
Incontience
•
Accidental urination
– Intermittent or continuous dribbling of urine
• Very difficult to treat
• Normal urine streams
– Pets are unaware
– Behavior drugs
– Adults
• Alprazolam
• Amytriptylline
• Fluoxetine
• Spayed females
• Often at rest
– USMI
– Puppies
• Congenital defect
– Ectopic ureters
– Environmental enrichment
• Litter box changes
• Separation of pets
Polyuria
•
Medical care
– PPA
– Estrogens
•
Surgical
– Ectopic ureter
– Collagen injections
– Hydraulic occluders
Polyuria
• True increase in VOLUME of urine
production
• Normal urine output
• So how do we determine this?
• Urinary catheterization
• Metabolic cage
• Manual collection
Polydipsia
• Polyuria typically results in polydipsia
– What goes in goes out…
– 1-2mL / kg/ hour
– 24-48 ml/kg/day
Polydipsia
• Is water intake easier to measure than
urine output?
• Unless 3rd spacing fluid
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Pleural effusion
Ascites
Peripheral edema
Short term
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2013 Tech CE for the Upstate
2/10/2013
Polydipsia
• So how much water should a dog drink per
day?
Polydipsia
• Maintenance
– 40-60 ml/kg/day
Polydipsia
• Maintenance fluid rate?
Now we have the basics…
• Let’s go back to our dog
• 4 yr old FS Weim
– 50 kg
• Polydipsic
– > 100ml/kg/day
• We’re suspicious this dog is truly
PU/PD…
• Normal urine production
– 1-2 ml/kg/hr
– 24-40 ml/kg/day
Send dog home…
• Have owners measure water intake
– “A pint’s a pound the world around”
•
•
•
•
1 pint = 16 oz
1 pint = 2 cups
1 cup = 8 oz
1 oz = 30 mL
• 1 cup = 240 mL
Other option
• Free catch urinalysis
– Have owners bring sample from home
• Specific gravity
• Dipstick
• Sediment exam
– Infection
– Casts
– Crystals
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2013 Tech CE for the Upstate
2/10/2013
Urinalysis
• What is the normal specific gravity for
a
– dog?
Urinalysis
• Might be useful to determine if patient is
PU/PD
– If urine is concentrated..
• NOT PU/PD
– Cat?
• Evaluate:
– Sediment
» Lower urinary disease
– Glucose
» Diabetes mellitus
» Renal glucosuria
Urinalysis
Urinalysis
• Specific gravity
• Pre-renal vs renal azotemia
– Must use refractometer
• Dipsticks worthless
• Hypersthenuria
– Specific gravity
• >1.030 dog
– >1.012
• Isosthenuria
• >1.035 cat
– 1.008-1.012
• Hyposthenuria
– <1.008
How do the kidneys concentrate urine?
Basics…
• What are the main functions of the kidneys?
– Excrete nitrogenous waste
– Acid base management
– Endocrine function
• RAAS
• Vitamin D activation
– Blood pressure
– Control fluid balance
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2013 Tech CE for the Upstate
2/10/2013
Kidney structure
Nephron
• Functional unit of the kidney
• Cortex
– Glomerulus
– Renal tubule
– Outer layer
• Medulla
– Inner Layer
• Pelvis
Glomerulus
• Kidneys receive 25% of cardiac output
• Specially designed network of capillaries
– Allows movement of fluid
– Blocks movement of medium to high molecular
weight products
– Prevents protein loss
Renal tubules
• Segments
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Proximal tubule
Descending loop of Henle
Ascending loop of Henle
Distal tubule
Collecting ducts
Renal tubule
• Function is to manipulate glomerular
ultrafiltrate
– Aka: dilute when you need it or concentrate when
you need it
Proximal convoluted tubule
• Reabsorbs most particles
– 100% of glucose
– 80-85% of Na / Cl
– Water soluble vitamins
• Reabsorbs based on what’s available
– i.e. not used for fine tuning
– Overall reabsorbs approximately 75% of the
glomerular filtrate
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2013 Tech CE for the Upstate
Loop of Henle
• Functions as the “Wife” of the nephron
• Most important component for urine
concentration
– Allows for high salt concentration in the inner
medulla
• Sets up concentrating ability of the kidney
Collecting Duct
• Under specific instruction…
– Collecting duct becomes permeable to water
• Pure water is drawn into the inner medulla
• Leaves the salt and wastes in the lumen of the collecting duct
2/10/2013
Collecting Duct
• “Husband” of the system
– Loop of Henle set up high salt medulla
– Without “being told” the tubule doesn’t do any work
• Impermeable to water
• i.e. what comes in, goes out
– Urine is dilute
Summary…
• Loop of Henle
– Does all the work
– Allows for the urine to be concentrated
• Collecting duct
– Urine is concentrated
– Becomes permeable to water
• Concentrates the urine
– Takes all the credit for the work
– Like any husband…
• HAS TO BE TOLD WHAT TO DO!!!!
Antidiuretic hormone
• Anatomy/physiology:
– formed in hypothalamic nuclei
– released from posterior pituitary
• Released in response to:
ADH effects
• VS2 receptors
– Cause insertion of aquaporins into principle cells of
renal collecting ducts
– CNS osmoreceptors
• 2% increase in ECF osmolality
– Maxed out by 5% dehydration
– Baroreceptors
• 10% decrease in circulating volume)
– Angiotensin II
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2013 Tech CE for the Upstate
2/10/2013
ADH effects
ADH effects
Back to our case…
Back to our case…
• We believe she truly is PU/PD
– To be polyuric
• Urine must be dilute
• i.e. effects of ADH are blocked
Primary polydipsia
• Drinks excessively
– Leads to increased urine output
• Psychogenic
– Typically young, active dogs
– Competitive
• Liver disease?
• What are the potential causes of PU/PD??
– In other words, what can keep the kidneys from
concentrating urine?
Primary polyuria
• Diabetes Insipidus
– Central
– Nephrogenic
• Renal Failure
• Hyperadrenocorticis
m
• Hypoadrenocorticis
m
• Hyperthyroidism
• Diabetes Mellitus
• Hepatic
Insufficiency
• Hypercalcemia
• Hypokalemia
• Post obstructive
diuresis
• Normoglycemic
glucosuria
• Pyometra
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2013 Tech CE for the Upstate
2/10/2013
Primary Polyuria
• Hypothyroidism?
Primary Polyuria
• Urinary tract infection
– Once again NO!!!!!
– Causes pollakiuria
– Only exception is renal failure secondary to
pyelonephritis
How do we get a diagnosis?
• Diabetes Insipidus
• Establish PU/PD exists
– Measure water intake
– Measure urine specific gravity
• Get a good history
– Medications
• Including topicals
– Other medical issues
• Polyuria / dysuria / incontinence
• Physical examination
Diagnosis
• Is urine hitting the
ground?
Diagnosis
• Diabetes Insipidus
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
Diagnosis
• Is urine hitting the
ground?
• Diabetes Insipidus
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
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2013 Tech CE for the Upstate
2/10/2013
Diagnosis
• Is urine hitting the
ground?
• Routine labwork
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Complete Blood Count
Serum Chemistries
Urinalysis
Urine culture
• Diabetes Insipidus
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
Diagnosis
• Is urine hitting the
ground?
• Routine labwork
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Complete Blood Count
Serum Chemistries
Urinalysis
Urine culture
Diagnosis
• Is urine hitting the
ground?
• Routine labwork
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Complete Blood Count
Serum Chemistries
Urinalysis
Urine culture
• ACTH stimulation test
• Diabetes Insipidus
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
• Routine labwork
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Complete Blood Count
Serum Chemistries
Urinalysis
Urine culture
• ACTH stimulation test
• Total T4 (cats)
• Diabetes Insipidus
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
Diagnosis
• Is urine hitting the
ground?
• Routine labwork
–
–
–
–
Complete Blood Count
Serum Chemistries
Urinalysis
Urine culture
• ACTH stimulation test
Diagnosis
• Is urine hitting the
ground?
• Diabetes Insipidus
• Diabetes Insipidus
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
Diagnosis
• Is urine hitting the
ground?
• Routine labwork
–
–
–
–
Complete Blood Count
Serum Chemistries
Urinalysis
Urine culture
• ACTH stimulation test
• Total T4 (cats)
• Diabetes Insipidus
– Central
– Nephrogenic
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Renal Failure
Hyperadrenocorticism
Hypoadrenocorticism
Hyperthyroidism
Diabetes Mellitus
Hepatic Insufficiency
Hypercalcemia
Hypokalemia
Post obstructive diuresis
Normoglycemic glucosuria
Pyometra
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2013 Tech CE for the Upstate
2/10/2013
What’s left???
Available tests
• Diabetes insipidus
• DDAVP response test
• Water deprivation test
– Central DI
– Nephrogenic DI
– DO THESE TESTS LAST!!!
• Psychogenic water drinker
– Distinguish
• Psychogenic polydipsia
• Central DI
• Primary nephrogenic DI
Modified water deprivation test
– Basics
Modified water deprivation test
• Absolute endpoints
• Measure water consumption prior to test
– Slowly begin limiting water over 1-2 weeks
» Trying to correct medullary washout in kidneys
• Make sure an absolute endpoint is reached
• If hasn’t concentrated at endpoint, give dose
of ADH
– Azotemia (ABSOLUTE contraindication)
– Plasma osmolality > 320 mOsm/kg
– Urine specific gravity
• >1.030 (dogs)
• >1.035 (cats)
– Loss of 5% body weight
Modified water deprivation test
Interpretation
Disorder
Initial
5% dehyd
Post-ADH
Complete
CDI
Partial CDI
<1.006
<1.006
>1.018
<1.006
NDI
<1.006
1.0081.020
<1.006
10-50%
increase
<1.006
1°
polydipsia
1.0021.020
>1.030
NA
• Most clinicians strongly recommend
AGAINST performing this test
– Can be very dangerous even if monitored very
closely
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2013 Tech CE for the Upstate
DDAVP Response Test
• Better option to modified water deprivation
test
• Protocol:
– measure water intake 2-3 d
– catch urine at same time each day
– treat with DDAVP for 5-7 d
– monitor water intake and urine on d 5-7
2/10/2013
DDAVP Response Test
• Interpretation:
– Central DI
• dramatic reduction in water intake and/or increase in urine
concentration (>50%)
– Nephrogenic DI
• No response
Diabetes insipidus
DDAVP response test
• Must monitor electrolytes
– If psychogenic
• May become hyponatremic
– Fluid overloaded
– Continued water consumption despite FORCED urine concentration
• Signalment
– Central DI
• dogs
– no sex, age or breed predilection
– most < 2 or > 6 yrs
• cats - too few cases to say.
– Nephrogenic DI
• dogs - too few cases to say; young dogs?
• cats - not reported
Treatment of pu/pd
Questions???
• Treat underlying disease
• Unless psychogenic polydipsia, do NOT
restrict water intake
• Central DI:
– replace ADH (DDAVP, Desmopressin®)
– chlorpropamide (Diabenese®)
• Nephrogenic DI: thiazide diuretics
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