Criteria for diagnosis of pure neural leprosy

J Neurol. 2003 Jul;250(7):806-9. doi: 10.1007/s00415-003-1081-5.


The clinical diagnosis of pure neural leprosy (PNL) remains a public health care problem mainly because skin lesions-the cardinal features of leprosy-are always absent.Moreover, the identification of the leprosy bacillus is not easily achieved even when a nerve biopsy can be performed. In an attempt to reach a reliable PNL diagnosis in patients referred to our Leprosy Outpatient Clinic, this study employed a variety of criteria. The nerve biopsies performed on the 67 individuals whose clinical, neurological, and electrophysiological examination findings strongly suggested peripheral neuropathy were submitted to M. leprae identification via a polymerase chain reaction (PCR). Mononeuropathy multiplex was the most frequent clinical and electrophysiological pattern of nerve dysfunction, while sensory impairment occurred in 89% of all cases and motor dysfunction in 81%. Axonal neuropathy was the predominant electrophysiological finding, while the histopathological nerve study showed epithelioid granuloma in 14% of the patients, acid fast bacilli in 16%, and nonspecific inflammatory infiltrate and/or fibrosis in 39%. PCR for M. leprae was positive in 47% of the nerve biopsy samples (n=23). PCR, in conjunction with clinical and neurological examination results, can be a powerful tool in attempting to identify and confirm a PNL diagnosis.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Female
  • Follow-Up Studies
  • Humans
  • Leprosy, Tuberculoid / diagnosis*
  • Leprosy, Tuberculoid / microbiology*
  • Male
  • Middle Aged
  • Mycobacterium leprae*
  • Peripheral Nerves / microbiology
  • Peripheral Nerves / pathology