Differentials
Infectious colitis
SIGNS / SYMPTOMS
May have similar clinical features.
INVESTIGATIONS
Colonoscopy will demonstrate if ischemia or pseudomembranes are present.
Stool cultures may reveal causative organism.
CT may show marked thickening of the colon with Clostridioides difficile.
Ulcerative colitis
SIGNS / SYMPTOMS
Form of inflammatory bowel disease that affects the rectum and extends proximally. Characterized by diffuse inflammation of the colonic mucosa and a relapsing, remitting course.
Patients commonly experience bloody diarrhea, chronic diarrhea (or both), lower abdominal pain, fecal urgency, and extraintestinal manifestations, particularly those related to activity of the colitis.
INVESTIGATIONS
Diagnosis requires endoscopy with biopsy and negative stool culture.
Crohn disease
SIGNS / SYMPTOMS
Inflammatory bowel disease that may involve the entire gastrointestinal tract.
Common presenting symptoms include chronic diarrhea, weight loss, and right lower quadrant abdominal pain mimicking acute appendicitis.
INVESTIGATIONS
Diagnosis confirmed by colonoscopy with ileoscopy and tissue biopsy.
Diverticular disease
SIGNS / SYMPTOMS
Symptomatic disease may have similar clinical features to bowel ischemia. Fever common in diverticulitis; diarrhea common, usually no hematochezia.
INVESTIGATIONS
CT may demonstrate focal colonic thickening and evidence of diverticulosis and diverticulitis.
Large bowel obstruction
SIGNS / SYMPTOMS
Obstipation may be a symptom.
INVESTIGATIONS
In most instances, CT will demonstrate cause of obstruction, such as tumor, internal hernia or volvulus.
Peptic ulcer disease
SIGNS / SYMPTOMS
Pain is generally epigastric and less severe, but may be generalized abdominal discomfort. Nausea and vomiting are common. Usually symptoms are less acute.
INVESTIGATIONS
Esophagogastroduodenoscopy will demonstrate gastritis and ulcers.
Erect chest x-ray will demonstrate pneumoperitoneum in patients with perforated peptic ulcer disease.
Small bowel obstruction
SIGNS / SYMPTOMS
Often have a history of previous abdominal surgery. Nausea, vomiting, and abdominal distension are the predominant features.
INVESTIGATIONS
X-ray studies will show air-fluid levels and dilated small bowel. CT will show dilated proximal small bowel with distal decompression, with a possible transition point.
Acute pancreatitis
SIGNS / SYMPTOMS
May provide a history of gallstones or recent alcohol use. Pain usually focal at epigastrium and radiates to back. Usually no diarrhea or hematochezia.
INVESTIGATIONS
Elevated serum amylase and lipase (usually much higher than in bowel ischemia). Abdominal ultrasound and CT demonstrate pancreatic inflammation and may show related gall bladder pathology.
Gastroenteritis
SIGNS / SYMPTOMS
May have similar clinical features. Possible history of sick contacts. May have a significant component of nausea and vomiting. Pain is often less profound than in patients with ischemia.
INVESTIGATIONS
CT may demonstrate thickened loops of small bowel or mesenteric lymphadenopathy without evidence of ischemia or infarction.
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