High-Resolution Ultrasonography Uncovers Hidden Nerve Damage in Hansen's Disease, Suggests Study

Subjective clinical exams often delay the detection of nerve involvement in Hansen's disease (HD). To address this diagnostic gap and India's high leprosy burden, Dr. Athira Mohan and colleagues evaluated the sonological features of peripheral nerves to provide a more objective, imaging-based method for early detection.

Therefore, the 18-month descriptive study evaluated 37 patients with suspected leprosy at a tertiary dermatology clinic. Using high-resolution ultrasonography (HRUS), researchers assessed the cross-sectional area, echogenicity, and vascularity of peripheral nerves, excluding patients with neuropathy from other causes.

Key Clinical Findings of the Study Includes:

• Nerve Enlargement Detection: Investigators found that out of 296 extensively imaged nerves, ultrasonography definitively identified 29 thickened nerves that were entirely missed during standard clinical evaluation, confirming actual neural involvement in half of the patients presenting without overt clinical enlargement.

• CSA Variations: Experts highlighted that the highest mean CSA was objectively recorded in the left ulnar nerve at 9±3.5 square millimeters, whereas statistically significant differences between patients with and without lepra reactions were isolated solely to the right median nerve.

• Echogenicity Abnormalities: Researchers noted that 65.25% of the sonologically thickened nerves displayed hypoechogenicity, with poor echogenicity outcomes being significantly more prevalent in multibacillary (MB) leprosy cases (28.5%) compared directly to paucibacillary (PB) manifestations (10%).

• Active Neuritis Markers: Sonologists demonstrated that increased intraneural vascularity on Doppler imaging, a reliable indicator of active neuritis, was exclusively observed in exactly 7 nerves belonging to patients who were actively experiencing acute type 1 or type 2 lepra reactions.

The results suggest that HRUS significantly improves diagnostic accuracy by precisely identifying subclinical peripheral nerve thickening in dozens of nerves that appeared perfectly normal upon physical examination. Consequently, routine ultrasound integration, particularly for patients initially suspected of having PB cases, can efficiently prompt an accurate reclassification to MB disease, thereby preventing unintended under-treatment and subsequent severe relapses.

Thus, the study concludes clinicians may find it highly beneficial to gently incorporate peripheral nerve ultrasonography into their routine diagnostic framework, as this objective imaging modality appears to seamlessly enhance early detection capabilities and carefully help prevent long-term, debilitating complications and permanent deformities associated with delayed leprosy treatment.

While somewhat limited by a relatively small sample size, a single-center structural design, and potential operator-dependent variability during imaging, these initial observations cautiously suggest that further exploration through larger, multicentric clinical cohorts and highly standardized imaging protocols could eventually refine and definitively validate the clinical utility of nerve ultrasonography in managing HD.

Reference

Mohan, A., Sabarinadh, M. G., & Sobhanakumari, K. (2026). Clinico-sonological study of peripheral nerve involvement in leprosy in a tertiary care medical center, India. Journal of Rare Diseases, 5(69).