The pathophysiology of penicillamine‐induced myasthenia gravis

Abstract

The temporal course and pathophysiology of penicillamine-induced myasthenia gravis were studied in detail in a typical case. Our results suggest that this disorder and idiopathic autoimmune myasthenia gravis share the same essential pathophysiological features, including the presence of anti-acetylcholine receptor (AChR) antibody, serum-induced blockade of AChRs, antibody-mediated accelerated degradation of AChRs, and a resultant quantitative reduction in available junctional AChRs. An initial severe reduction in junctional AChRs was reversed and the patient recovered, both within 8 months of stopping penicillamine. Our data suggest that penicillamine probably produced myasthenia gravis by initiating a new autoimmune response rather than by enhancing ongoing autoimmunity.

Myasthenia gravis and primary biliary cirrhosis. Common immunological features and rare coincidence

“…After secession of D-penicillamine treatment clinical complaints resolved within a six to eight month period which was paralleled by a decrease in anti-AChR antibody titers and reversal of previously abnormal electromyography. This clinical course implies independent reversible effects of the drug on the immune system, rather than preexisting subclinical myasthenia gravis which was unmasked by D-penicillamine (6,9). Further support to this view derives from the distinct HLA association of D-penicillamine-induced myasthenic syndrome and classic myasthenia.…”

Connective Tissue Diseases, Vasculitis, and the Nervous System

“…[236][237][238] The prevalence of SLE is also increased in patients with myasthenia. 240,241 POLYNEUROPATHY Distal symmetric axonal polyneuropathy can accompany many of the illnesses discussed in this chapter. 239 Myasthenia can be a toxic effect of penicillamine or chloroquine.…”

Neuromuscular complications of connective tissue diseases

“…Myasthenia gravis may occur as a complication of drug therapy. Less than 1% of patients treated with penicillamine for RA or systemic sclerosis develop myasthenia, which typically resolves months after the penicillamine is stopped 2, 97, 166. Chloroquine rarely causes myasthenia 148…”