High Resolution Nerve Ultrasound in the Diagnosis of Pure Neuritic Leprosy

We aimed to compare the clinical, electrophysiologic, and sonographic characteristics of commonly affected peripheral nerves in suspected cases of pure neuritic leprosy (PNL) and to describe an ultrasound-guided fine needle aspiration cytology (FNAC) procedure to improve diagnostic capabilities in PNL.

This retrospective study was carried out at Roy Neuro Care Centre, Ranchi, Jharkhand, India through revisiting charts of suspected cases of PNL from October 2022 to June 2024. The charts of individuals with a history, examination, and nerve ultrasound consistent with PNL were reviewed. We retrospectively analyzed the diagnostic steps, including the skin biopsy (which had been guided by electrophysiology and/or nerve ultrasound) and the ultrasound-guided FNAC of nerves that had been sent for histopathological examination, acid-fast bacilli (AFB) staining, and polymerase chain reaction (PCR).

Charts of 52 patients derived from the records of those with mononeuropathy or mononeuritis multiplex suspected to have PNL during October 2022-June 2024 were evaluated. The skin biopsy was diagnostic of PNL in 23 patients, while 29 patients had an inconclusive result. Those with an inconclusive result had an ultrasound-guided FNAC followed by cytology and AFB staining. The review of the records of these cases revealed that in 24 (82.8%) cases there were features suggestive of PNL, while 5 patients had negative cytology and AFB staining. Three of these individuals had PCR, with a positive result in 1 (33.3%). A positive correlation was noted between the duration of illness and markers of progressive involvement of nerves, as determined by electrodiagnosis and ultrasound.

Nerve ultrasound and ultrasound-guided nerve FNAC can assist in the early diagnosis of PNL.