Define Malabsorption Syndrome. Describe its causes, clinical features, investigations and management.

Definition

Malabsorption is the impaired absorption of one or more nutrients (fat, carbohydrate, protein, vitamins, minerals) from the small intestine, leading to chronic diarrhoea, steatorrhoea and failure to thrive.

Causes

• Mucosal disease — coeliac disease, tropical sprue, cow-milk protein enteropathy, post-enteritis.
• Pancreatic insufficiency — cystic fibrosis, Shwachman-Diamond syndrome.
• Infective — giardiasis, intestinal tuberculosis, bacterial overgrowth.
• Anatomical — short-bowel syndrome; cholestasis (fat malabsorption from lack of bile).

Clinical Features

• Chronic diarrhoea/steatorrhoea (bulky, pale, greasy, foul stools) and abdominal distension.
• Failure to thrive and weight loss; and features of specific deficiencies — anaemia (iron/folate/B12), rickets, bleeding (vitamin K), oedema (protein).

Investigations

• Stool examination (fat globules, parasites, reducing substances, elastase).
• Screening — CBC, iron studies, calcium, albumin; coeliac serology; sweat chloride (CF).
• Small-bowel biopsy and imaging as guided by the suspected cause.

Management

Treat the underlying cause (gluten-free diet, pancreatic enzymes, antimicrobials for infection) and provide nutritional rehabilitation with correction of specific deficiencies.

Approach to Diagnosis

• Confirm malabsorption (stool fat/steatorrhoea, growth faltering) and identify the affected nutrient(s).
• Use targeted tests to find the cause — coeliac serology, sweat chloride, stool for Giardia, imaging.
• Assess and correct specific micronutrient deficiencies.

Specific Deficiency Signs to Look for

Steatorrhoea with failure to thrive is the common presentation.