Differentials
Viral gastroenteritis
SIGNS / SYMPTOMS
Can be associated with symptoms such as myalgia and arthralgia, although this is not an absolute rule.
Usually of shorter duration (24-48 hours).
INVESTIGATIONS
No specific differentiating tests.
Stool cultures may identify pathogen, but high rate of false-negative results.
Norovirus is commonly included in stool pathogen panels.
Alternative foodborne bacterial gastroenteritis/traveler's diarrhea
SIGNS / SYMPTOMS
Identical signs, symptoms, and contact risks to foodborne Escherichia coli infection.
INVESTIGATIONS
Stool cultures will identify pathogen (e.g., Salmonella, Shigella), but high rate of false-negative results.
Amebiasis
SIGNS / SYMPTOMS
Subacute onset with diarrhea lasting days to weeks in association with abdominal pain and weight loss.
INVESTIGATIONS
Stool microscopy reveals Entamoeba.
Serum antibody testing positive for antiamebic antibodies.
Noninfectious food poisoning
SIGNS / SYMPTOMS
Examples include mushrooms or toxins.
Often has an acute history and is associated with consumption, with symptoms developing 1-12 hours later.
Symptoms are dependent on the exact mushroom or toxin ingested and can be associated with nausea, vomiting, renal or hepatic failure.
INVESTIGATIONS
Identification of the ingested substance.
Noninfectious drug-induced colitis
SIGNS / SYMPTOMS
Pharmaceutical agents that produce colitis as an adverse drug reaction include nonsteroidal anti-inflammatory drugs (NSAIDs), gold, and cyclooxygenase-2 inhibitors. Cytotoxic agents include vinorelbine, capecitabine, interferon, bevacizumab, rituximab, dasatinib, and topotecan.[38]
INVESTIGATIONS
Colonoscopic evaluation with biopsy.
Ulcerative colitis
SIGNS / SYMPTOMS
Symptoms vary from intermittent rectal bleeding associated with the passage of mucus to frequent loose, bloody stools. Chronic in nature.
INVESTIGATIONS
Colonic mucosal biopsy shows characteristic histologic changes. Vascular markings are lost, owing to engorgement of the mucosa, giving it an erythematous appearance. Petechiae, exudates, touch friability, ulcerations and frank hemorrhage may be present on colonoscopy. Denuded mucosa and deep "bear claw" ulcerations may be seen in severe ulcerative colitis. Colonic involvement begins at the distal rectum and is continuous to the proximal extent of disease.
Microscopic colitis
SIGNS / SYMPTOMS
Chronic watery, nonbloody diarrhea. Other common symptoms include fecal urgency, fecal incontinence, and nocturnal stools. More common in patients >50 years and female.
INVESTIGATIONS
Ileocolonoscopy with biopsies from the right and left colon: confirms diagnosis.[39] Colonic mucosa has a normal or near-normal gross appearance. Biopsy: demonstrates collagenous colitis (i.e., thickened subepithelial collagenous band of ≥10 micrometer (normal <5 micrometer) or lymphocytic colitis (i.e., increased number of intraepithelial lymphocytes of ≥20 per 100 surface epithelial cells (normal <5 micrometer). Both types show an increased inflammatory infiltrate in the lamina propria.[39]
Crohn disease
SIGNS / SYMPTOMS
Usually has a more chronic history, with slower deterioration, and prolonged diarrhea, which is often accompanied by weight loss.
INVESTIGATIONS
Biopsy shows focal ulcerations adjacent to areas of normal-appearing mucosa, along with polypoid mucosal changes that give a cobblestone appearance. Pseudopolyps can be present. Can involve any location along the entire gastrointestinal tract from mouth to perianal region. Unlike ulcerative colitis, segments of intestinal involvement are discontinuous.
Other noninfectious gastrointestinal pathologies
SIGNS / SYMPTOMS
Examples include diverticular disease, malignancy, or celiac disease.
Usually associated with a more chronic history (>4 weeks), and lack of features of sepsis/bacteremia.
Associated symptoms may aid diagnosis (e.g., weight loss in malignancy).
INVESTIGATIONS
Dependent on underlying cause. The majority of conditions are diagnosed by endoscopy or by radiologic exams (CT, MRI).
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