Extensive sonographic ulnar nerve enlargement above the medial epicondyle is a characteristic sign in Hansen’s neuropathy

Abstract

ObjectiveEarlier studies have shown sonographic enlargement of the ulnar nerve in patients with Hansen’s neuropathy. The present study was performed to determine whether sonography or electrophysiological studies can detect the specific site of ulnar nerve pathology in leprosy.MethodsEighteen patients (thirty arms) with Hansen’s disease and an ulnar neuropathy of whom 66% had borderline tuberculoid (BT), 27% lepromatous leprosy (LL) and 7% mid-borderline (BB) leprosy were included in the study. Cross-sectional area (CSA) of ulnar nerve was measured every two centimeters from wrist to medial epicondyle and from there to axilla. All patients underwent standard motor and sensory nerve conduction studies of the ulnar nerve. Thirty age and sex matched controls underwent similar ulnar nerve CSA measurements and conduction studies.ResultsUlnar nerve was clinically palpable in 19 of the 30 arms of patients. Motor and sensory nerve conduction studies of the ulnar nerve showed a reduced compound motor action potential and sensory nerve action potential amplitude in all patients. Motor Conduction Velocity (MCV) in patients were slower in comparison to controls, especially at the elbow and upper arm, but unable to exactly locate the site of the lesion. In comparison to controls the ulnar nerveCSA was larger in the whole arm in patients and quite specific the maximum enlargement was seen between nulnar sulcus and axilla, peaking at four centimeters above the sulcus.ConclusionsA unique sonographic pattern of nerve enlargement is noted in patients with ulnar neuropathy due to Hansen’s disease, while this was not the case for the technique used until now, the electrodiagnostic testing. The enlargement starts at ulnar sulcus and is maximum four centimeters above the medial epicondyle and starts reducing further along the tract. This characteristic finding can help especially in diagnosing pure neuritic type of Hansen’s disease, in which skin lesions are absent, and alsoto differentiate leprosy from other neuropathies in which nerve enlargement can occur.

Ultrasound Measurements and Assessments of the Ulnar Nerve at the Elbow and Cubital Tunnel: A Scoping Review

“…The other four studies used CSA measurements at set points proximal and distal to the cubital tunnel to calculate a ratio to assess for differences between symptomatic and asymptomatic participants. 7,21,22,29 The CSA was consistently reported as significantly larger in participants with UNE compared to healthy controls, 3,4,6,12,[16][17][18][19][20]22,23 with the typical appearance of a nerve with increased size dimensions demonstrated in Figure 4. It was also correlated with electrodiagnostic test results, endorsing it as a complementary test in the diagnosis of UNE.…”

Coexistence of Nerve Enlargement and Neuratrophy Detected by Ultrasonography in Leprosy Patients

“…The same trend was also noted in other groups, such as the MB/PB, R/NR, D/ND and longer/shorter duration groups. Nerve enlargement is generally reported 10 , 13 – 15 , whereas neuratrophy is rarely mentioned in leprosy patients. Our study observed that peripheral nerves in the lower limbs (CF) were thinner in almost all subgroups of the leprosy patients than those in the controls, and significantly thinner bilateral CF nerves were noted in the longer duration group than those in the shorter duration group.…”

“…The median (M), ulnar (U) (at the cubital tunnel (Ut) and proximal to the tunnel (Upt)) and common fibular (CF) nerves represent the most critical peripheral nerves of leprosy patients assessed by US. Comparisons of cross-sectional areas (CSAs) between leprosy patients and controls have revealed extensive enlargement of the U, M and CF nerves 10 , 13 – 15 . Of these nerves, extensive enlargement of the U nerve, as assessed by US, is the characteristic sign of neuropathy in leprosy patients 10 , 13 .…”

“…Comparisons of cross-sectional areas (CSAs) between leprosy patients and controls have revealed extensive enlargement of the U, M and CF nerves 10 , 13 – 15 . Of these nerves, extensive enlargement of the U nerve, as assessed by US, is the characteristic sign of neuropathy in leprosy patients 10 , 13 . One study reported that the CSAs of nerves were thicker in multibacillary (MB) patients than those in paucibacillary (PB) patients, regardless of whether the readings were obtained before or after multi-drug therapy (MDT).…”

Neurological Complications of Leprosy

“…70 Recently, a specific pattern of enlargement was described for ulnar neuropathy, found to start at the ulnar sulcus with a maximum of 4 cm above the medial epicondyle with reduction along the tract toward the axilla. 71 Overall, ultrasound shows promise for clinical use, especially for the purpose of evaluating for structural changes at nerve sites that cannot be biopsied. 72 Although not always readily available, magnetic resonance imaging may also be used to demonstrate perineural inflammation in addition to ultrasound 73 and to exclude structural abnormalities such as abscesses, which have been reported as a rare complication of leprosy.…”