Differentials
Colonic pseudo-obstruction
SIGNS / SYMPTOMS
Typically seen in older adults when hospitalised for a severe illness.
Patients may give a history of chronic constipation.
No systemic manifestations.
INVESTIGATIONS
Absence of an elevated WBC count and metabolic abnormalities.
Contrast enema will confirm the diagnosis and exclude mechanical causes in most cases.
Acute mesenteric ischaemia
SIGNS / SYMPTOMS
Patients may give a history of risk factors for acute mesenteric ischaemia, including coronary artery disease, hypertension, diabetes, smoking, and hypercholesterolaemia.
Diffuse abdominal pain with systemic manifestations, but abdominal distension is often absent.
INVESTIGATIONS
Abdominal film findings are often normal in the presence of acute mesenteric ischaemia.
CT scan will show signs of bowel wall ischaemia including bowel wall thickening, thumb printing, and pneumatosis.
Large bowel obstruction
SIGNS / SYMPTOMS
A history of constipation may be present.
Signs of systemic toxicity are absent in the early stages.
There may be a palpable abdominal mass on clinical examination suggesting an underlying malignancy or diverticular mass.
INVESTIGATIONS
Gaseous distension of the large bowel on plain abdominal film; 'kidney bean' shape seen in volvulus.
Water-soluble contrast enema shows obstruction to contrast at site of lesion; 'bird's beak' appearance seen in volvulus.
Hirschsprung's disease
SIGNS / SYMPTOMS
Diagnosed in infancy or early childhood.
Abdominal distension that is usually not accompanied by abdominal pain.
Increased anal sphincter tone and presence of constipation, which may be relieved with digital rectal examination.
INVESTIGATIONS
Abdominal films characteristically reveal rectal and distal large bowel dilation with collapsed proximal large and small bowel.
Absence of ganglion cells on rectal biopsy.
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