What is the Cause of Diarrhoea in HIV/AIDs Patients?

Chronic diarrhoea is one of the most common presenting problems in patients with advanced HIV infection, most commonly in areas with a lack of safe water.

Diarrhoea is a major cause of wasting in these patients.

The differential diagnosis of this diarrhoea depends on whether the presentation is with large bowel symptoms or small bowel symptoms

The presentation and aetiology of acute diarrhoea are similar to those in HIV-uninfected patients

Large-bowel Diarrhoea

Acute diarrhoea caused by the bacterial enteric pathogens Campylobacter, Shigella and Salmonella occur more frequently than in HIV-uninfected people and the illness is more severe in these patients.

As a healthcare provider, you should consider diarrhoea caused by Clostridium difficile if there has been prior exposure to antibiotics.

CMV colitis presents with chronic large-bowel symptoms and fever in patients with CD4 counts below 100 cells/mm3.
On colonoscopy, ulcers are seen, mostly involving the left side of the colon and on biopsy of ulcers shows typical ‘owl’s-eye’ inclusion bodies.

Small-bowel Diarrhoea

Chronic small-bowel diarrhoea may be due to HIV enteropathy, but this is a diagnosis of exclusion.
This kind of diarrhoea typically presents with chronic watery diarrhoea and wasting without fever.
Infection with one of three unicellular organisms is responsible for most cases:

• cryptosporidiosis,
• microsporidiosis and
• isosporiasis

All three are intracellular parasites that invade enterocytes.