Download Gastroenteritis – “stomach flu” but is not related to influenza at all

Gastroenteritis – “stomach flu” but is not related to influenza at all
 Irritation or inflammation of the stomach and intestines
 N/V/D and abdominal pain – metabolic acidosis (bicarb wasting)
 Most cases are acute, benign and self-limited
 Pts do not always seek medical attention
Diarrhea
 Acute diarrhea (<3wks) = INFX
 Chronic diarrhea (>1 month) = disease process
 COMPLICATIONS: dehydration, orthostasis, tachycardia, hypotension, lethargy, electrolytes, AMS
Risk Factors:
1. Contagious – meal preparers and healthcare providers
2. Abx – alter normal bowel flora
3. Mes (antacids, H2 blockers) and surgery – alter normal acidic pH
4. Hypomobility
5. Immunocompromised states
6. Untreated drinking water
PE
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Hydration, nutrition, blood/mucus/impaction, acute abdomen, bowel sounds, tenderness, masses
Pathophysiology:
 Viral, bacterial, protozoa
 Agents invade GI mucosa, produce cytotoxins and enterotoxins (alter the permeability of GI wall leading
to increased fluid secretion, decreased absorption by GI mucosa).
 Causes dehydration, loss of electrolytes and nutrients
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Diarrhea
o Osmotic – excessive intake and diminished absorption
o Inflamed mucosa
o Secretory – increased secretions
o Motile – increased motility
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Enterotoxins – act on secretory mechanisms producing large amounts of watery (rice water) diarrhea
Cytotoxins – result in mucosal cell destruction leading to bloody diarrhea with inflammatory cells
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Why vomiting? Role of serotonin? Neurotoxins produced by S. aureus and Bacillus cereus
HISTORY: travel, camping, Abx, daycare, ingestion of raw seafood, similar illness in contacts (contag)
Viral
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Most common etiology (50-70%)
Prodrome Sx, N/V/D, malaise, HA, fatigue,
Transmission: fecal-oral; contagious via food handlers; fomites
o Norwalk virus is the leading cause of viral gastroenteritis in US
o Rotavirus Oct – April –most common in children <5 (vaccine aval – intussception)
o Adenovirus throughout year
o Calicivirus, Astrovirus, parvovirus, coronavirus
Common in developed and nondeveloped – transmitted thru humans
Low infx dose
Incubation 1-3 days
Fever not common except Rotavirus and Norwalk
No bloody diarrhea
Vomiting common
Dx via exclusion
Tx: supportive and hydration
Bacterial
 Areas of poor hygiene, summer/rainy months – transmitted thru animals and humans
 High infx dose
 Incubation 1-7 days; if bacterial toxins – hrs
 Fever common if cause inflammatory diarrhea (Salmonella, Shingella)
 Frequent bloody diarrhea
 Vomiting not common unless preformed toxins (S. aureus and bacillus cereus)
 Dx: leukocytes, blood/stool cultures to identify pathogens
 Tx: supportive, hydration and ABx
“I think bloody diarrhea is SECSY”
 Salmonella, Enterohemoragic E. coli, Camplyobacter, Shingella, Yersinia
Enterocyte invasion – secretory mechanisms
1. Campylobacter Jejuni
a. G- rod
b. Contaminated food/water, birds and other animals
c. Erythromycin or fluoroquinolones
d. Complications: toxic megacolon; colonic hemorrhage
2. Salmonella
a. G- rod
b. Food does not appear/smell spoiled
c. Poultry, contaminated water, eggs, dairy, reptiles
d. Only Tx Salmonella if immunocompromised: Ciprofloxacin or Bactrim (sulfamethoxazole/TMP)
e. Complication = Reiter’s syndrome (can’t see, can’t see, can’t dance with me)
i. TYPHOID FEVER – salmonella typhi = unremitting fever, rose spots, splenomegaly and
bradycardia. Bacteria spreads to organs and blood = bacteremia (in blood)
1. Tx: Ceftriaxone of Cephalosporins
2. Vaccine available
3. Yersinia Entercolitica
a. G- Bacillus
b. Transmitted thru contaminated pork, milk, water
c. Lymphoid rxn in terminal ilieum = mucosal ulceration spread to mesenteric L.N. = bacteremia
d. May mimic appendicitis
e. Tx: supportive but Bactrim, Ciprofloxacin if immunocompromised
Bacterial Toxins
1. Enterotoxic Escherichia Coli
a. Aerobic bacteria
b. Major cause of traveler’s diarrhea
c. Food, water, contaminated feces, undercooked meat
d. Tx: self-limited; can five fluoroquinolones or Bactrim x3 days
2. Vibrio Cholera
a. G - rod
b. Ingestion of food or water contaminated by feces
c. Rice water diarrhea
d. Can be fatal (QUICK) – dehydration and electrolyte imbalances
e. Tx: Tetracycline, IV fluids
Cytotoxins – mucosal destruction and bloody diarrhea
1. Enterohemorrhagic E. coli [o157:H7]
a. Fecal-oral route
b. Progression watery diarrhea  bloody diarrhea
c. Hemolytic uremic syndrome (HUS) triad:
i. Anemia (hemolytic)
ii. Renal failure
iii. Thrombocytopenia
1. Can lead to thrombo thrombocytopenic purpura (TTP)
a. Fever and neurologic Sx
d. Tx: RBCs destroyed and kidney fails = transfusions and kidney dialysis
e. INFX DZ CONSULT FOR ABX
2. Clostridium difficile aka “psuedomembrane colitis”
a. Fecal-oral; common nosocomial
b. Onset with ABx: ampicillin and clindamycin – disrupted normal flora
c. Dx: C. diff toxin assays, acute abdomen, pseudomembranous adherent yellowish-whitish plaques
3. Shingella dysenteriae
a. Swimming in pools with out chlorine, raw veg, dairy, poutry
b. Fecal-oral
c. Tenesmus and dysentery
d. Tx: ampicillin, Bactrim or fluoroquinolones AVOID ANTIDIARRHEAL TX
4. Vibrio parahaemolyticus
a. Undercooked seafood
b. Tx: tetracycline or doxycycline
Food-Borne
1. Staphylococcus aureus
a. MC toxin induced gastroenteritis
b. Custard, processed meats, mayonnaise
c. Tx: supportive; hospitalization
2. Bacillus cereus
a. Enterotoxin- cell wall – secretions
b. Fried rice or bean sprouts left on steam tables
c. Supportive
3. Clostridium perfringes
a. Enterotoxin – cell wall secretions
b. High protein foods (meat, poultry, potato salads)
c. Watery diarrhea
d. supprotive
4. Clostridium Botulinum
a. Neurotoxin – from gut to peripheral nervous synapses where it blocks the release of ACH.
i. Dysphagia, diplopia, dysarthria, weakness, dyspnea
ii. Symmetric descending extremity paralysis (w/in 12-36 hrs)
iii. Dx: serum Botulinum toxin assay
iv. Tx: trivalent botulism anti-toxin
1. No effect on neurotoxin already bound to neuromuscular junction
b. Spores in meats and vegetables; canned foods and honey
Parasitic Gastroenteritis (10-15%)
1. Giardia lamblia
a. Protozoa + ova
b. Most common parasitic gastroenteritis in US
c. Explosive watery foul-smelling diarrhea w bloating and flatulence
d. Contaminated food/water
e. Travelers drank untreated Mt. water, daycare, homosexual men
f. Tx Metronidazole of Furazolidone for 10 days
2. Entamoeba histolytica aka “amebiasis” aka “traveler’s dysentery”
a. Fecal contamination of food/water
b. Develop liver abscess – sepsis, seizures and kidney failure
c. Tx: Metronidazole
3. Cryptosporidium parvum
a. Commonly in AIDs pts
b. Contaminated water or rodents
c. Acid-fast stain of stool
d. Tx: no effective Tx (HIV) spiramycin = temporary relief
Non-bacterial food poisoning: FISH POISONING
1. Cinguatera poisoning
a. Bottom dwelling fish of tropics
b. Paresthesia lips, tongue, limbs
c. supportive
2. Scombroid poisoning
a. Tuna, mackerel, bluefish, herring
b. Heat stable toxin from proteus morganii
c. Sx ~ histamine rxn
i. Flushing, HA, dizziness, cramping, V/D
d. Tx: antihistamines
3. Tetraoden poisoning
a. Consumption of puffer fish
b. Neurotoxin paresthesia of face and extremities
c. May need ventilator support
Dx:
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In general, stool culture is not necessary or cost-effective
Electrolytes and renal function (if dehydrated)
Determine etiology:
o CBC: eosinophilia (parasities)
o Leukocytes = bacterial infx
o Fecal leukocytes = salmonella, shingella
Stool cultures may require different media
Ova and parasites x3 if pt recent travel
ELISA – enzyme linked immunosorbent assay
Tx:
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Supportive – rest, hydration, electrolyte correction
BRAT diet
Pepto-Bismol – bismuth subsalicylate and Kaolin-pectin (Kaopectate)
o Anti-secretory agent decreases fluid in lumen
Anti-motility drugs – Lomotil, Imodium, codeine
o Contraindicated in infx diarrhea
Avoid aspirin and NSAIDS – could irritate GI tract
Other causes of N/V
 Drugs, ABx, NSAIDs, chemotherapy
 Psychiatric
 Pregnancy
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Acute MI
Neuro – motion sickness, vertigo
GI – obstructions, PUD, GERD, paralytic ileus, peritonitis, IBS, IBD, gastritis, appendicitis
Visceral acute conditions
Metabolic
Celiac sprue
Milk/food allergies
Complications:
 Hypotension/dehydration
 Sepsis
 Electrolyte disturbance
 Metabolic acidosis