Differentials
Colorectal cancer
SIGNS / SYMPTOMS
Bleeding, altered bowel habit, tenesmus, sudden onset of symptoms, family history of bowel cancer, previous polyps.
INVESTIGATIONS
Colonoscopy: reveals mass within the colon.
Barium enema: typical apple core stricture appearance as passage of barium is restricted by the mass.
Cauda equina syndrome
SIGNS / SYMPTOMS
Lower back pain, weakness and numbness in lower limbs, sciatic pain radiating down one or both legs, perianal anesthesia.
INVESTIGATIONS
MRI spine: may show degenerative arthritic changes, disc herniation, infection, or tumors causing spinal cord compression.
Crohn disease
SIGNS / SYMPTOMS
Inflammatory bowel disease may alter bowel habit due to inflammation and altered bowel compliance. The resulting rapid transit may overcome the continent mechanisms. Often blood is present in the stools. There may be abdominal pain and constitutional symptoms.
INVESTIGATIONS
Barium enema or barium meal: may show strictures, ulceration, and sometimes fistulae.
Colonoscopy: good visualization of small ulcers, allows biopsies to be taken.
Capsule endoscopy: lesions in the small bowel.
Ulcerative colitis
SIGNS / SYMPTOMS
Inflammatory bowel disease may alter bowel habit due to inflammation and altered bowel compliance. The resulting rapid transit may overcome the continent mechanisms. Often blood is present in the stools. There may be abdominal pain and constitutional symptoms.
INVESTIGATIONS
Flexible sigmoidoscopy or colonoscopy: erythematous mucosa, ulceration, friable mucosa.
Rectal biopsy: cryptitis, crypt branching, plasma cells in the lamina propria, crypt abscesses.
Small bowel follow-through: strictures, absence of lesions in small bowel.
Traveler's diarrhea
SIGNS / SYMPTOMS
Usually occurs within 2 weeks of arrival in a developing world country, often accompanied by nausea and vomiting, tenesmus, and abdominal cramping.
INVESTIGATIONS
Fecal leukocytes: presence of large numbers of white blood cells.
Stool culture: growth and identification of bacterial etiology.
Stool ova and parasite exam: identifies common parasites.
Giardia stool antigen test: positive ifGiardia present.
Acute diarrhea
SIGNS / SYMPTOMS
Unusual food intake in last 2 to 3 days, other family members may be affected, recent travel, accompanied by vomiting and often abdominal cramps. Recent hospitalization or use of broad-spectrum antibiotics may suggest Clostridium difficile infection.
INVESTIGATIONS
Stool culture: positive for growth if infection is the cause.
Stool test forClostridium difficile toxin.
Chronic diarrhea
SIGNS / SYMPTOMS
Greater than three loose stools/day for >4 weeks; may be associated with weight loss, blood in stool, abdominal pain, or bloating. Can be caused by a variety of etiologies including celiac disease, diverticular disease, and lactose intolerance.
INVESTIGATIONS
Duodenal biopsy: increased intraepithelial lymphocytes, villous atrophy, and crypt hyperplasia (celiac disease).
Colonoscopy: diverticular present (diverticular disease).
Lactose tolerance test: blood sugar does not increase after drinking a liquid containing lactose (lactose intolerance).
Fistulae
SIGNS / SYMPTOMS
History of anorectal abscess or inflammatory bowel disease; fistulae opening may be seen around anus or on proctoscopy.
INVESTIGATIONS
Examination under anesthetic: visualization and examination of fistula tract.
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