Letters to the Editor

West Nile Virus and MADSAM Neuropathy To the Editor: We report a 61-year-old man who presented to the hospital with chief complaints of acute onset ascending weakness and bilateral leg pain. He was at work as a night-time security officer when over the course of hours he began experiencing bilateral foot and calf pain. Within 12 hours, he developed ascending paresis to the point where he could not ambulate. He also reported that his arms were beginning to feel week at the same time. He denied fever, chills, nausea, vomiting, rash, headache, muscle aches, confusion, recent upper respiratory and gastrointestinal illness, or travel. He was subsequently admitted to the intensive care unit for close monitoring and workup. The patient’s weakness progressed rapidly to the point where he was electively intubated within 24 hours of admission for poor inspiratory force. Serological tests, lumbar puncture, neurophysiological tests, and imaging studies were performed, the results of which are discussed below. The patient’s religious beliefs forbade the use of blood products, so he could receive neither plasmapheresis nor intravenous immunoglobulins. Supportive therapy along with aggressive physical therapy and occupational therapy were instituted. The patient’s pulmonary function parameters improved to the point that he could be extubated 3 days after intubation. His appendicular strength improved more slowly, and he was able to be transferred to the floor; he was eventually discharged to an acute rehabilitative facility with mild bilateral upper extremity and moderate bilateral lower extremity weakness. There was no evidence of albumin-cytological dissociation with cerebrospinal fluid (CSF) protein of 100 mg/dL and cell count of 125. Magnetic resonance imaging of the lumbar spine revealed subtle linear enhancement along the margins of the cord terminus/conus and along the proximal aspect of cauda equina. Rapid plasma reagin,

Venereal Disease Research Laboratory, Campylobacter, HIV, herpes simplex, Varicella Zoster, hepatitis panel, Lyme titers (serum and CSF), antineutrophil antibodies, creatine kinase, aldolase, porphyrins, and porphyrobilnogens were all unremarkable. West Nile virus (WNV) antibodies were positive in the serum (IgG, 2.18; IgM, 5.29) as well as in the CSF (IgG, 1.77; IgM, 2.80). Electromyography and nerve conduction studies on admission demonstrated a motor predominant polyneuropathy in the upper and lower extremities, with features of predominantly axonal neuropathy. Compound muscle action potentials (CMAPs) had moderate to severe reduction in amplitude, mildly prolonged distal latency, with relatively normal conduction velocity. Sensory nerve action potentials (SNAPs) showed moderately prolonged peak latencies and moderately reduction amplitudes and conduction velocities. Normal insertional activity was seen on needle study with mildly reduced recruitment. A repeat study was performed approximately 3 weeks after presentation. In comparison with the initial study, a much more pronounced sensory involvement was evident along with demyelinating features. CMAPs remained with reduced amplitudes and prolonged distal latency, whereas SNAPs were almost entirely absent. Conduction blocks were noted in the ulnar and peroneal nerves and F wave latencies were nonrecordable; this spectrum of findings was consistent with multifocal acquired demyelinating sensory and motor neuropathy (MADSAM) syndrome. WNV, a mosquito-borne RNA flavivirus and human neuropathogen, was first isolated from a febrile woman in the West Nile region of Uganda, Africa in 1937.1 In the original New York City outbreak in 1999, several case series attributed neuromuscular complications, particularly acute flaccid paralysis to peripheral neuronal processes, namely Guillain–Barré syndrome, motor axonopathy, or severe axonal polyneuropathy.2 Lymphocytic infiltration of nerves and occasional degenerating axons also has been described,

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Letters to the Editor

suggesting that WNV may reach the central nervous system (CNS) through peripheral nerves. Recent evidence suggests that axonal transport mediates WNV entry into the CNS and induces acute flaccid paralysis.2 This patient presented as an acute aggressive paraparesis severe enough to impede pulmonary function. Extensive workup was notable for high WNV antibody titers in the CSF and serum while remaining negative for other infectious and autoimmune causes. Magnetic resonance imaging showed subtle enhancement only of the nerve roots, whereas electrodiagnostic studies were consistent with a MADSAM syndrome. WNV infection can cause protean manifestations in the CNS; a polio-like direct infection of the anterior horn cells is most common but other manifestations can include acute meningoencephalitis.2 A prior case series of electrodiagnostic studies done during the acute infective stage of WNV patients showed normal SNAPs and normal or only mildly reduced CMAPs without slowed conduction velocity,3 similar to our patient’s initial presentation; however, a repeat study done after the acute infective stage in these patients was not reported. Our patient displayed pronounced asymmetric sensory involvement as can be seen in MADSAM later in the course. The evolution of electrodiagnostic profiles in WNV infections has not been published, and given the varied manifestations of acute infection, may be widely varied as well. This case is particularly illustrative in that it involves a patient who initially presented with symptoms of MADSAM syndrome and was later found to have WNV antibodies. Thus, it gives us an insight into the natural history of a WNV CNS infection, beginning as an inflammatory demyelinating polyneuropathy and continuing as prolonged motor and sensory neuropathy. Bhavesh Trikamji, MBBS* Edward Chang, MD, PhD† Shri K. Mishra, MD, MS, FAAN, FANA‡ *Department of Neurology, Olive View UCLA Medical Center, Sylmar, CA †Department of Neurology, UCLA David Geffen School of Medicine, Los Angeles, CA

‡Department of Neurology, USC Keck School of Medicine, Los Angeles, CA Poster presented at American Neurological Association (ANA) conference, October 15, 2013, New Orleans, LA. The authors report no conflicts of interest.

REFERENCES 1. Smithburn KC, Hughes TP, Burke AW, et al. A neurotropic virus isolated from the blood of a native of Uganda. Am J Trop Med. 1940;20:471–492. 2. Leis AA, Stokic DS. Neuromuscular manifestations of human West Nile virus infection. Curr Treat Options Neurol. 2005;7:15–22. 3. Al-Shekhlee A, Katirji B. Electrodiagnostic features of acute paralytic poliomyelitis associated with West Nile virus infection. Muscle Nerve. 2004;29:376–380.

An Asymmetric Sensory Polyneuropathy Related to Thiamine Deficiency From a Gluten-Free Diet To the Editor: A 34-year-old woman who presents to neurology clinic for the evaluation of sensory changes in her legs. About 1 year before presentation, she had started to notice numbness in the right lateral shin. This soon progressed to involve the right foot. Over months, the symptoms spread to the left foot. She also noticed that her balance was off as she was tripping while playing tennis. Her other medical history was notable for hypothyroidism. Her only medication was levothyroxine. She did not abuse alcohol or use recreational drugs. When prompted, she mentioned that she was on a gluten-free diet, although she did not have celiac disease. In fact, she had had negative duodenal biopsy, tissue transglutaminase antibody, and genetic haplotype testing for celiac disease (HLADQ2 and HLA-DQ8). She also had negative allergy testing for wheat. She chose this diet because she felt gluten contributed to her chronic urticaria. Her neurologic examination showed normal mental status and cranial nerves. Her muscle strength was normal, and there was

Copyright © 2015 Wolters Kluwer Health, Inc. All rights reserved.

Copyright © 2015 Wolters Kluwer Health, Inc. Unauthorized reproduction of this article is prohibited.

West Nile Virus and MADSAM Neuropathy.

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