High-Resolution Sonography: A New Technique to Detect Nerve Damage in Leprosy

Abstract

BackgroundLeprosy is the most common treatable peripheral nerve disorder worldwide with periods of acute neuritis leading to functional impairment of limbs, ulcer formation and stigmatizing deformities. Since the hallmarks of leprosy are nerve enlargement and inflammation, we used high-resolution sonography (US) and color Doppler (CD) imaging to demonstrate nerve enlargement and inflammation.Methology/Principal FindingsWe performed bilateral US of the ulnar (UN), median (MN), lateral popliteal (LP) and posterior tibial (PT) nerves in 20 leprosy patients and compared this with the clinical findings in these patients and with the sonographic findings in 30 healthy Indian controls.The nerves were significantly thicker in the leprosy patients as compared to healthy controls (p<0.0001 for each nerve). The two patients without nerve enlargements did not have a type 1 or type 2 reaction or signs of neuritis. The kappa for clinical palpation and nerve enlargement by sonography was 0.30 for all examined nerves (0.32 for UN, 0.41 for PN and 0.13 for LP). Increased neural vascularity by CD imaging was present in 39 of 152 examined nerves (26%). Increased vascularity was observed in multiple nerves in 6 of 12 patients with type 1 reaction and in 3 of 4 patients with type 2 reaction. Significant correlation was observed between clinical parameters of grade of thickening, sensory loss and muscle weakness and US abnormalities of nerve echotexture, endoneural flow and cross-sectional area (p<0.001).Conclusions/SignificanceWe conclude that clinical examination of enlarged nerves in leprosy patients is subjective and inaccurate, whereas sonography provides an objective measure of nerve damage by showing increased vascularity, distorted echotexture and enlargement. This damage is sonographically more extensive and includes more nerves than clinically expected.

New sonographic measures of peripheral nerves: a tool for the diagnosis of peripheral nerve involvement in leprosy

“…The primary finding was that nerves that showed a reversal reaction toward a more intense immune response had a hypervascular pattern, as demonstrated by Doppler studies (or by a marked T2 intensity and increased gadolinium enhancement on MRI). Jain et al (2009), using high-resolution sonography, clearly showed that the kappa value between clinical palpation and the assessment of nerve size by sonography is low. They concluded that clinical examination of enlarged nerves is subjective and inaccurate, whereas sonography provides an objective measure of the nerve dimensions and reveals structural changes over a longer length of the nerve.…”

“…Current technological developments leading to improved image quality, reduced US device sizes and reductions in price will make it possible for US to become a tool that can be used in countries in which leprosy is endemic (Jain et al 2009). …”

“…US and MRI are effective in diagnosing nerve dam-MRI are effective in diagnosing nerve damare effective in diagnosing nerve damage in leprosy, primarily during leprosy reactions (Martinoli et al 2000, Jain et al 2009). In our study, US was performed at the time of leprosy diagnosis and 17 patients (22%) presented with neuritis and/or clinical signs of reversal reactions, which were not always associated with US abnormalities.…”

Ultrasound in the diagnosis of peripheral neuropathy: structure meets function in the neuromuscular clinic

“…In normal nerves there is no detectable blood flow 26. Increased blood flow may be detected in compressive mononeuropathy and inflammatory PN,16 27 possibly reflecting vascular proliferation precipitated by chronic trauma or inflammation (figure 3). …”

“…Nerve enlargement and loss of fascicular pattern are seen on US 27 64. These abnormalities are most frequent at common sites of nerve entrapment, in particular the cubital tunnel.…”