Chronic arsenic poisoning masquerading as Landry-Guillain-Barré syndrome.

Acute arsenic intoxication may present as Landry-Guillain-Barré syndrome because of similarities in clinical symptoms involving the gastrointestinal tract, weakness, and sensory symptoms. Electrodiagnostic findings may be similar with demyelinating changes predominating early in both diseases. A case is presented of repeated arsenic poisoning over two years misdiagnosed as Landry-Guillain-Barré syndrome. Proximal F-loop latency (M-wave latency at wrist + F-wave latency at wrist - 2 M-wave latency at axilla) helped to establish the correct diagnosis. Serial electrodiagnostic studies were done documenting the evolution of chronic repeated arsenic poisoning from a picture showing demyelination to one with severe axonal loss.

Eosinophilia-myalgia syndrome: myopathic electrodiagnostic characteristics.

Eosinophilia-myalgia syndrome (EMS) is a disorder characterized by generalized muscle pain and eosinophilia. The etiology of this syndrome appears to be related to the ingestion of L-tryptophan. Most studies to date describe an associated peripheral neuropathy or combined myopathy and peripheral neuropathy. This report presents 2 EMS patients with myopathy, confirmed by muscle biopsy in 1 case and electrophysiology in both cases. No clinical evidence of neuropathy was found. Both routine and single fiber electromyography failed to demonstrate abnormalities, suggesting neuropathy. Electrodiagnostic abnormalities paralleled the clinical course. After 10 months, both patients continued to have symptoms of muscle cramping and reduced endurance, with mild electromyographic abnormalities, perhaps reflecting changes in their motor unit.