Differentials
Infectious colitis
SIGNS / SYMPTOMS
May have similar clinical features.
INVESTIGATIONS
Colonoscopy will demonstrate if ischaemia or pseudomembranes are present.
Stool cultures may reveal causative organism.
CT may show marked thickening of the colon with bacterial infection.
Ulcerative colitis
SIGNS / SYMPTOMS
Form of inflammatory bowel disease that affects the rectum and extends proximally. Characterised by diffuse inflammation of the colonic mucosa and a relapsing, remitting course.
Patients commonly experience bloody diarrhoea, chronic diarrhoea (or both), lower abdominal pain, faecal urgency, and extraintestinal manifestations, particularly those related to activity of the colitis.
INVESTIGATIONS
Diagnosis requires endoscopy with biopsy and negative stool culture.
Crohn's disease
SIGNS / SYMPTOMS
Inflammatory bowel disease that may involve the entire gastrointestinal tract.
Common presenting symptoms include chronic diarrhoea, 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 ischaemia. Fever common in diverticulitis; diarrhoea common, usually no haematochezia.
INVESTIGATIONS
CT may demonstrate focal colonic thickening and evidence of diverticulosis and diverticulitis.
Large bowel obstruction
SIGNS / SYMPTOMS
Obstipation may be a symptom.
Closed loop obstruction, in particular, can lead to ischaemia.
INVESTIGATIONS
In most instances, CT will demonstrate cause of obstruction, such as tumour, internal hernia, or volvulus.
Peptic ulcer disease
SIGNS / SYMPTOMS
Pain is generally epigastric and less severe, but may be generalised abdominal discomfort. Nausea and vomiting are common. Usually symptoms are less acute.
INVESTIGATIONS
Oesophagogastroduodenoscopy 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
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 diarrhoea or haematochezia.
INVESTIGATIONS
Elevated serum amylase and lipase (usually much higher than in bowel ischaemia). 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 ill contacts. May have a significant component of nausea and vomiting. Pain is often less profound than in patients with ischaemia.
INVESTIGATIONS
CT may demonstrate thickened loops of small bowel or mesenteric lymphadenopathy without evidence of ischaemia or infarction.
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