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|LETTER TO EDITOR
|Year : 2015 | Volume
| Issue : 4 | Page : 624-626
Magnetic resonance neurography identifies involvement of plexuses in leprous neuropathy
Atchayaram Nalini1, Ravinder Jeet Singh1, Jitender Saini2, Chandrajit Prasad2, Anita Mahadevan3
1 Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
2 Department of Neuroimaging and Interventional Radiology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
3 Department of Neuropathology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka, India
|Date of Web Publication||4-Aug-2015|
Department of Neurology, National Institute of Mental Health and Neurosciences, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
|How to cite this article:|
Nalini A, Singh RJ, Saini J, Prasad C, Mahadevan A. Magnetic resonance neurography identifies involvement of plexuses in leprous neuropathy. Neurol India 2015;63:624-6
|How to cite this URL:|
Nalini A, Singh RJ, Saini J, Prasad C, Mahadevan A. Magnetic resonance neurography identifies involvement of plexuses in leprous neuropathy. Neurol India [serial online] 2015 [cited 2019 Sep 19];63:624-6. Available from: http://www.neurologyindia.com/text.asp?2015/63/4/624/162102
Hansen's neuritis constitutes an important subset of treatable neuropathies caused by Mycobacterium leprae. It still affects millions of people in the developing countries causing devastating consequences with disabling motor deficits and mutilating sensory loss. Clinically, it usually presents as mononeuritis multiplex with a predilection for distal, peripheral, superficial, and cooler parts of the body. Involvement of more proximal parts of the peripheral nervous system is under-recognized and rarely reported. Various genetic susceptibility genes have been proposed for leprosy. Neurocysticercosis is a parasitic infection and is one among the common causes of symptomatic epilepsy in South-East Asia. For the first time, we report an interesting patient who had severe leprous neuropathy with combined brachial and lumbosacral plexus thickening that was identified by magnetic resonance (MR) neurography. Interestingly, he also had multiple cerebral cysticercal lesions with symptomatic seizures prior to the onset of neuropathic symptoms.
A 28-year-old male presented with right hand grip weakness and pain for 4 months, and right foot drop and patchy sensory loss over both upper and lower extremities for the last 3 months. He also reported hyperpigmentation of skin over lower extremity with areas of skin oozing for the last 2 months. He had two episodes of generalized tonic clonic seizures 9 months back. Brain magnetic resonance imaging (MRI) showed degenerating granulomas suggestive of neurocysticercosis. He is on levetiracetam with no further seizure recurrences. His medical history was otherwise unremarkable. He denied having any close contact with any person suffering from leprosy. On examination, he had multiple, hypopigmented and hypoesthetic patches with elevated nodular borders on the arms [Figure 1]a and b. There were skin lesions with hyperpigmentation and serous oozing over the legs [Figure 1]c and d. There were multiple thickened, nodular nerves. His mental status and cranial nerve examination were normal. Motor and sensory examination showed weakness and sensory impairment suggestive of mononeuritis multiplex pattern involving the right median, ulnar, radial, tibial, left common peroneal, and sural nerves. There were no subcutaneous nodules.
|Figure 1: (a and b) Hypopigmented hypoesthetic patch with elevated nodular border. (c and d) Skin hyperpigmentation with oozing skin lesions|
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His routine blood tests, serum angiotensin converting enzyme levels and computed tomography of thorax were unremarkable. Electrophysiology was consistent with mononeuritis multiplex pattern confirming the involvement of the right median, ulnar, radial, tibial, left common peroneal, and sural nerves. In addition, it showed right axillary nerve involvement. The skin and nerve biopsy showed well-formed epithelioid granulomas [[Figure 2], asterisk] with Langhan's giant cells [[Figure 2], black arrow], The Fite-Faraco stain was negative. Contrast MR neurography was performed on the 3.0T machine as the patient had involvement of proximal nerve on electrophysiology, and this revealed the presence of asymmetrical irregularly thickened brachial [Figure 3]a and lumbosacral plexuses [Figure 3]b. There were microabscesses in the right median nerve [Figure 3]e. Brain MRI revealed cysticercal cysts on T1-weighted contrast images [Figure 3]c and d. Spine MRI was normal.
|Figure 2: Nerve biopsy shows well - formed epithelioid granulomas (asterisk) with Langhan's giant cells (black arrows)|
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|Figure 3: Magnetic resonance neurography showing (a) asymmetrical irregularly thickened brachial plexuses; (b) Left lumbosacral plexus; (c and d) Contrast enhancing small cysticercal lesion in right parietal lobe; (e) Microabscesses in the median nerve|
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In view of the clinical phenotype, electrophysiology, and skin and nerve biopsy findings, he was diagnosed to be having leprous neuropathy and was started on multidrug therapy with dapsone 100 mg daily, clofazimine 50 mg daily, and rifampicin 600 mg. A short course of steroid was given in view of the possibility of a reversal reaction. For his symptomatic seizures, he was continued on the anticonvulsant, levetiracetam. Two weeks after starting the treatment, the patient reported a reduction in his hand pain though neurologically he remained status quo.
Hansen's neuritis/leprous neuropathy constitute an important subset of treatable neuropathies caused by M. leprae. It still affects millions of people in most developing countries causing devastating consequences with disabling motor deficits, mutilating sensory loss, and disfiguring skin damage. Clinically, it usually presents as mononeuritis multiplex with a predilection to involve distal, peripheral, superficial, and cooler parts of the body.  Involvement of more proximal parts of the peripheral nervous system is under-recognized and rarely reported. Various genetic susceptibility genes have been proposed for leprosy.  Typically, patients present with mononeuritis multiplex with thickened palpable nerves and skin lesions. The pure neuritic form is a well-recognized entity  in which patients lack the skin lesions leading to a delay in the diagnosis, especially in nonendemic areas. Involvement of proximal parts such as the roots, trunks, and plexuses of the peripheral nervous system is not customarily looked for in Hansen's neuritis as M. leprae is known to have thermotropism for cooler regions, which are more superficial and hence, distal body parts are commonly affected. Thus, proximal, deeper, and warmer regions are assumed to be spared. Only a few reports mentioning the involvement of dorsal root ganglia and having a central nervous system histopathological examination are available. , Neurocysticercosis is a parasitic infection and is among the commonest causes of symptomatic epilepsy in South-East Asia. Our report contributes two new observations to the existing literature. First is the combined involvement of brachial and lumbosacral plexuses in Hansen's disease and the second is the presence of microabscesses in peripheral nerve and both were detected with MR neurography. At this juncture, it is difficult to decide whether the involvement of plexuses reflects a severe form of leprous neuropathy (with the involvement of more proximal areas of the nervous system) or suggests an immune mediated reversal reaction with plexus involvement. There are anecdotal case studies that report nerve abscesses in Hansen's neuritis. These abscesses are included among the differential diagnoses of soft tissue masses in patients with Hansen's disease, but the role of these findings in the patient's outcome is rarely emphasized. , It would be interesting to investigate whether these novel imaging findings have prognostic significance suggesting a poor recovery, as is seen in many patient with more severe/advanced forms of leprous neuropathy; or, that it indicates a robust immune system with the formation of microabscesses and involvement of proximal nerves due to systemic immune activation. This report also contradicts the conventional belief in the pathophysiology of leprous neuropathy regarding the involvement of distal parts of the peripheral nervous system only; it emphasizes the role of MR neurography in investigating clinical/subclinical proximal nerve involvement; and, it demonstrates the presence of nerve microabscesses in the natural history of leprous neuropathy and its correlation with disease outcome. Another interesting observation was the co-existence of bacterial and parasitic infection in the same host suggesting shared genetic susceptibility such as Toll-like receptor 2 of innate immunity. , It invokes new possibilities worth investigating as it may provide an insight into the pathogenesis of these two common infections.
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[Figure 1], [Figure 2], [Figure 3]