Pathological, ultrasonographic, and electrophysiological characterization of clinically diagnosed cases of pure neuritic leprosy

Abstract

A subset of neuritic form of leprosy, called pure neuritic leprosy (PNL), seen in a minority of leprosy patients, is characterized by peripheral neuropathy without skin lesions and an absence of acid‐fast bacilli on skin smears. Patients with PNL are often started on drug therapy without confirmation of diagnosis. We, therefore, did a prospective study of clinically diagnosed PNL patients with correlation of ultrasonographic and biopsy findings. A total of 100 consecutive patients with PNL, diagnosed according to the consensus case definition, were included in the study. All patients underwent nerve conduction study, peripheral nerve ultrasonography, and sural nerve biopsy. Multiple mononeuropathies were present in 75% of cases, mononeuropathy in 18%, and polyneuropathy in the remaining 7%. Compared to clinical examination, ultrasonographic assessment of the peripheral nerves was not only better at the detection of thickening but also helped in characterization of their fascicular architecture, echogenicity, and vascularity. A total of 32 cases were confirmed on nerve biopsy, out of which 75% had demonstrable lepra bacilli. Cranial nerve involvement, presence of trophic ulcers, and bilateral thickening of the great auricular nerve were significantly associated with the positivity of lepra bacilli. A significant improvement in the disability score happened after multidrug therapy. A comprehensive electrophysiologic, ultrasonographic, and histological evaluation may be helpful in establishing a diagnosis of PNL with greater confidence, while ruling out other non‐leprosy diagnoses.

Follow-up assessment of patients with Pure Neural Leprosy in a reference center in Rio de Janeiro—Brazil

“…The WHO currently classifies leprosy into PB and MB based on the number of skin lesion for treatment purposes, but this classification does not specify a separate guideline for PNL [ 14 ]. Shukha et al already proposed that the therapeutic decisions in PNL should be guided by the findings of the nerve biopsy, thus avoiding potential overtreatment with MB-MDT or undertreatment with PB-MDT [ 14 ]. The majority of our patients were treated with a PB-MDT, based on the slit-skin smear negativity.…”

A Hand‐Held Ultrasound Device for the Assessment of Peripheral Nerves in Leprosy

“…It is, therefore, critical to assess for nerve involvement in individuals with suspected leprosy. Several studies of nerve ultrasound have been conducted, showing that nerve enlargement is common, as is increased vascularity (detected by Doppler imaging) 9,10 . It is postulated that superficial nerves are more commonly affected, perhaps because they have a lower temperature environment.…”

“…The following nerves were scanned bilaterally: median at the wrist, forearm, elbow, and mid‐humerus; ulnar at the wrist, forearm, elbow, 4 cm proximal to the elbow, and the mid humerus; C5 cervical root; and greater auricular nerves 13 . These scanning locations were chosen because of previous ultrasound studies for leprosy and chronic inflammatory demyelinating polyneuropathy 7,9,10‐12 . Cross‐sectional areas were measured using the trace function on both devices, with the ultrasound positioned perpendicular to the nerve of interest and tracing just inside the hyperechoic epineurium.…”

Treatment and Evaluation Advances in Leprosy Neuropathy

“…Since intraneural inflammatory lesions in leprosy are multifocal and patchy, the peripheral neuropathy of leprosy is classified as "mononeuritis multiplex." Mononeuritis affecting a single nerve without skin lesions are classified as "pure neuritic leprosy" [32][33][34][35][36]. Neuritis triggered by intraneural inflammatory response, edema, and granuloma formation clinically produces chronic low grade nerve pain.…”