Relapse of Mycobacterium leprae infection with ocular manifestations

Initial diagnosis of leprosy in patients treated by an ophthalmologist and confirmation by conventional analysis and polymerase chain reaction

PURPOSE

To report the initial diagnosis of leprosy in patients seeking treatment from an ophthalmologist in a tertiary eye care center, its confirmation by histopathologic and polymerase chain reaction analysis, and review of literature.

DESIGN

Noncomparative retrospective case series.

PARTICIPANTS

Patients with no known history of leprosy who were selected based on either a clinical suspicion or a histopathologic diagnosis and were found to have ocular or periocular lesions suggestive of leprosy.

METHODS

Review of clinical records of patients with no known history of leprosy seen by an ophthalmologist at a tertiary eye care referral center.

MAIN OUTCOME MEASURES

Patient demographics, presenting symptoms and signs, diagnostic studies, complications, and treatment.

RESULTS

Among the 6 patients (5 women and 1 man; average age, 55 years), only 2 were found to have leprosy from clinical examination alone. Histopathologic characteristics or demonstration of acid-fast bacilli, suggestive of leprosy, were found in 5 patients. Definite confirmation of leprosy was made by polymerase chain reaction performed on formalin-fixed, paraffin-embedded tissues of 4 patients having suspected leprosy based on clinicohistopathologic examination results.

CONCLUSIONS

The diagnosis of leprosy relies on the clinical symptom complex, epidemiologic factors, and demonstration of acid-fast bacilli in the tissue sample. Considering that the global leprosy population is 12 million, a patient with leprosy may be found anywhere. The ophthalmologist may be the first one to encounter such patient, in which case suspicion and detection of ocular findings may lead to early treatment of the infection. Polymerase chain reaction may be a new tool in the definite diagnosis of leprosy when suspicion of the diseases is raised by clinicohistopathologic studies.

The continuing challenges of leprosy

Leprosy is best understood as two conjoined diseases. The first is a chronic mycobacterial infection that elicits an extraordinary range of cellular immune responses in humans. The second is a peripheral neuropathy that is initiated by the infection and the accompanying immunological events. The infection is curable but not preventable, and leprosy remains a major global health problem, especially in the developing world, publicity to the contrary notwithstanding. Mycobacterium leprae remains noncultivable, and for over a century leprosy has presented major challenges in the fields of microbiology, pathology, immunology, and genetics; it continues to do so today. This review focuses on recent advances in our understanding of M. leprae and the host response to it, especially concerning molecular identification of M. leprae, knowledge of its genome, transcriptome, and proteome, its mechanisms of microbial resistance, and recognition of strains by variable-number tandem repeat analysis. Advances in experimental models include studies in gene knockout mice and the development of molecular techniques to explore the armadillo model. In clinical studies, notable progress has been made concerning the immunology and immunopathology of leprosy, the genetics of human resistance, mechanisms of nerve injury, and chemotherapy. In nearly all of these areas, however, leprosy remains poorly understood compared to other major bacterial diseases.