GASTROENTERITIS is the most common bacterial cause of
– Inflammation of the lining of the
stomach and intestines, predominantly manifested by upper GI tract symptoms
(anorexia, nausea, vomiting), diarrhea, and abdominal discomfort.
Etiology and Epidemiology
Gastroenteritis may be of nonspecific, uncertain, or unknown etiology or of bacterial,
viral, parasitic, or toxic etiology
Campylobacter infection is the most common bacterial
cause of diarrheal illness in the USA
transmission is especially common with gastroenteritis
caused by Shigella, Escherichia coli, Giardia, Norwalk virus, and rotavirus.
Certain bacterial species elaborate enterotoxins, which impair intestinal
absorption and can provoke secretion of electrolytes and water e.g. the enterotoxin
of Vibrio cholerae and E. coli enterotoxin
Shigella, Salmonella, and E. coli species penetrate the mucosa of
the small intestine or colon and produce microscopic ulceration, bleeding,
exudation of protein-rich fluid, and secretion of electrolytes and water.
– Gastroenteritis may
follow ingestion of chemical toxins
contained in plants (e.g. mushrooms, potatoes, garden flora), seafood (fish,
clams, mussels), or contaminated food.
Symptoms and Signs
is often sudden and sometimes dramatic, with anorexia, nausea, vomiting,
borborygmi, abdominal cramps, and diarrhea (with or without blood and mucus).
malaise, muscular aches, and prostration may occur
vomiting causes excessive fluid loss, metabolic alkalosis with hypochloremia
occurs; if diarrhea is more prominent, acidosis is more likely
vomiting or diarrhea may cause hypokalemia
– Severe dehydration and acid-base imbalance can produce
headache and muscular and nervous irritability.
– Persistent vomiting and diarrhea may result in severe
dehydration and shock, with vascular collapse and oliguric renal failure.
A history of ingestion of potentially
contaminated food, untreated surface water, or a known GI irritant; recent
travel; and contact with similarly ill persons may be important.
examination for fecal WBCs and culture are indicated
may also require culture of vomitus, food, and blood.
may indicate parasitic infection
General Principles of Treatment
Supportive treatment is most important.
Bed rest with convenient access to a toilet or
bedpan is desirable
nausea or vomiting is mild or has ended, oral glucose-electrolyte solutions,
strained broth, or salted bouillon may prevent dehydration or treat mild
if vomiting, the patient should take frequent but small sips of such fluids
because the vomiting may resolve with volume replacement
vomiting is protracted or if severe dehydration is prominent, IV replacement of
appropriate electrolytes is necessary
vomiting is severe and a surgical condition has been excluded, an antiemetic
(e.g. dimenhydrinate 50 mg IM q 4 h, chlorpromazine >=
25 to 100 mg/day IM) or prochlorperazine 10 mg po tid (suppository 25 mg bid)
may be beneficial.
50 mg IM q 3 or 4 h may be given for severe abdominal cramps.
the patient can tolerate fluids without vomiting, bland food (cereal, gelatin,
bananas, and toast) may be added to the diet gradually.
after 12 to 24 h, moderate diarrhea persists without severe systemic symptoms
or blood in the stool, diphenoxylate 2.5 to 5 mg tid or qid in tablet or
liquid form, loperamide 2 mg po qid, or bismuth subsalicylate 524 mg (two
tablets or 30 mL) po six to eight times/day may be given.
appropriate to sensitivity testing should be given when systemic infection is
antibiotics do not help patients with simple gastroenteritis, nor do they help asymptomatic carriers to