Differentials
Active Crohn's disease
SIGNS / SYMPTOMS
Can be distinguished from SBS by the presence of signs such as abdominal pain, worsened diarrhoea, or joint pains.
The distinction is important, as active Crohn's disease is treated very differently from SBS.
INVESTIGATIONS
Endoscopy or other imaging modalities (e.g., CT/MR enterography) show mucosal inflammation and ulceration, typical findings of active Crohn's disease.
C-reactive protein and erythrocyte sedimentation rate may be elevated but are not specific.
Coeliac disease
SIGNS / SYMPTOMS
Dermatitis herpetiformis is a characteristic rash that, when present, is almost always associated with coeliac disease.
Symptoms of coeliac disease recede when patients are placed on a gluten-free diet.
INVESTIGATIONS
Immunoglobulin A-tissue transglutaminase shows elevated titres in coeliac disease.
Small bowel biopsy is diagnostic and shows characteristic intra-epithelial lymphocytes, villous atrophy, and crypt hyperplasia.
Small bowel malignancy
SIGNS / SYMPTOMS
No differentiating signs or symptoms. Patients with Crohn's disease are at risk for gastrointestinal malignancy, which can present with similar symptoms of diarrhoea, weight loss, and fatigue.
INVESTIGATIONS
CT enterography or endoscopy is likely to reveal a small bowel tumour.
Bacterial over-growth
SIGNS / SYMPTOMS
No clear differentiating signs or symptoms. Patients with bacterial over-growth often have symptoms of diarrhoea, weight loss, and malabsorption similar to SBS. More common in patients without an ileocaecal valve. Bacterial over-growth in the context of SBS has been poorly studied. It is more common in patients who have dilated segments of bowel.[16]
Anorexia nervosa
SIGNS / SYMPTOMS
Weight loss and malnutrition can be a consequence of a lack of appropriate food intake. A careful dietary history is required to eliminate this possibility.
Anorexia nervosa can be distinguished by a history of psychiatric illness, a predominance of nausea, loss of appetite, or night-time diarrhoea.
INVESTIGATIONS
Stool laxative testing to identify laxative abuse.
Direct observation of oral intake.
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