The diagnostic value of electron microscopy in human immunodeficiency virus-positive patients with gastrointestinal disease.

BACKGROUND

Our aim was to determine the diagnostic value of electron microscopy in evaluating the etiology of gastrointestinal disease in patients infected with the human immunodeficiency virus (HIV).

METHODS

A retrospective review of electron microscopic and light microscopic results of all HIV-positive patients with gastrointestinal and liver diseases was made during a 3-year period from June 1995 to June 1998.

RESULTS

A total of 145 HIV-positive patients had their electron microscopy specimens reviewed. Of these, 136 were investigated for diarrhea, and the other 9 for increased liver enzymes. Twenty-seven of the 145 (18.6%) HIV-positive patients had a pathogen identified by electron microscopy, compared with only 13 of 145 (9%) identified by light microscopy (P < 0.005). The sensitivity of light microscopy for detecting opportunistic pathogens was 68%. Twenty-one of the 27 (77.8%) patients diagnosed by electron microscopy had microsporidiosis, and the most commonly diagnosed species was Enterocytozoon bieneusi. Light microscopy failed to identify 12 cases of microsporidiosis and 2 cases of leishmaniasis.

CONCLUSIONS

Electron microscopy contributes substantially to the identification of pathogens in HIV-positive patients. Light microscopy failed to identify one of every two pathogens diagnosed by electron microscopy.