Multifocal motor neuropathy secondary to gluten intolerance: a case report

Peripheral nervous system manifestations of gluten sensitivity usually present as distal symmetric axonal polyneuropathy, small fiber neuropathy, or sensory neuropathy, often accompanied by ataxia or painful symptoms. By contrast, motor neuropathies are extremely rare, with only a few cases of multifocal motor neuropathy reported. Notably, the most recent guidelines of the European Society for the Study of Coeliac Disease do not recognize multifocal motor neuropathy as a classical neurological manifestation of gluten-related disorders. The main differential diagnoses include amyotrophic lateral sclerosis and chronic inflammatory demyelinating polyneuropathy. Currently, strict adherence to a gluten-free diet remains the only therapeutic option. Although clinical improvement is not universal, when observed, it strongly supports the causal role of gluten-related neurotoxicity.

We report the case of a 50-year-old North African man with a history of dermatitis herpetiformis and persistent chronic diarrhea. Over the past 5 years, he developed progressive asymmetric motor weakness. Clinical examination revealed an asymmetric, pure motor, peripheral neurogenic syndrome, confirmed by nerve conduction studies, without evidence of proximal conduction block. Cerebrospinal fluid analysis showed elevated protein levels (0.75 g/L), and serum anti-GD3 IgM antibodies were positive. Brachial plexus magnetic resonance imaging revealed bilateral hypertrophy on T1-weighted sequences, with hyperintensity on short tau inversion recovery sequences but no contrast enhancement. The motor deficit gradually improved after the introduction of a gluten-free diet. The patient also received intravenous immunoglobulin without significant clinical benefit. On the basis of clinical, paraclinical, and follow-up findings, a diagnosis of multifocal motor neuropathy secondary to gluten intolerance was established.

This case highlights the importance of considering gluten intolerance as a potential etiology, particularly given the reversible nature of this neuropathy, which can otherwise be misdiagnosed as a more severe condition such as amyotrophic lateral sclerosis. Further studies are needed to better elucidate the pathophysiology of this rare gluten-related neurological phenotype.