Current concepts in the pathogenesis of leprosy. Clinical, pathological, immunological and chemotherapeutic aspects

Peripheral autonomic nerve dysfunction in asymptomatic leprosy contacts

In endemic areas, subclinical autonomic nerve dysfunction may be a manifestation of infection with M. leprae and possibly allow detection before progression to clinical disease. Vasomotor reflex (VMR) testing was performed in 36 asymptomatic leprosy contacts (24 household contacts, 12 hospital contacts) and 47 age- and sex-matched controls in Pokhara, Nepal. Mean age was 30 years, two thirds were male. A Moor instruments DRT4 laser doppler monitor was used for velocimetry of microvascular blood flow. The flow reduction following an inspiratory gasp was recorded from finger and toe tips. Mean percent reduction was 57.8 (standard deviation 14.6) among household contacts, 61.9 (17.5) among hospital contacts and 66.8 (7.8) among controls (p=0.001 by analysis of variance). The prevalence of abnormal test results was 54% among household contacts, 42% among hospital contacts and 15% among controls (p=0.0005 by chi-square test for trend). Subclinical autonomic neuropathy is common among healthy contacts of leprosy patients. Prospective studies are now needed to clarify to what extent abnormal VMR tests predict the risk of progression to clinical disease.

An unusual cause of hand trauma in the emergency department

Leprosy was once a severely mutilating and incapacitating disease with little hope for the afflicted. Today, patients with leprosy do not suffer from the obvious deformities seen in earlier days, so recognition of this disease has become more difficult. We report the case of a man with no previous disabilities who presented to the emergency department with acute unintentional hand trauma secondary to peripheral neuropathy caused by leprosy.

Cutaneous-malignancy and leprosy. Report of a patient with Mycobacterium leprae and basal cell carcinoma concurrently present in the same lesion

BACKGROUND

Leprosy is a chronic systemic infection caused by the bacillus Mycobacterium leprae. Cutaneous neoplasms have been observed in patients with leprosy. Also, albeit less commonly, M. leprae have been documented in the lesions of skin cancer.

OBJECTIVE

To describe a 62-year-old man with chronic sun exposure and exposure to armadillos who subsequently developed lepromatous leprosy, to discuss the cutaneous malignancies that have occurred in patients with leprosy, and to review the literature concerning the concurrent presence of an infectious pathogen and a cutaneous neoplasm in the same lesion.

METHODS

Our patient's basal cell carcinomas were excised, his abdominal plaques were biopsied, and his leprosy infection was treated with dapsone and rifampin. The types of cutaneous malignancies in leprosy patients and infectious pathogens concurrently found in lesions of skin tumors were summarized after evaluating previously published reports.

RESULTS

Skin biopsies from our patient demonstrated M. leprae bacilli not only in his abdominal plaques, but also in all of his basal cell carcinoma lesions. Fungal, mycobacterial, and viral pathogens have concurrently been observed in skin lesions of basal cell carcinomas, Kaposi's sarcoma, melanoma, mycosis fungoides, and squamous cell carcinoma.

CONCLUSION

Patients with leprosy can develop skin cancers and the histologic interpretation of those skin cancers can show evidence of leprosy. It is uncertain to what degree the decreased cell-mediated immunity in patients with lepromatous leprosy either enhances their susceptibility to and/or influences the course of their cutaneous neoplasms; also, in these patients, the coexistence of M. leprae organisms and cutaneous malignancy in the same lesion is likely to be secondary to the high bacillary load that is present.