Muscle involvement in polyarteritis nodosa: report of a patient presenting clinically as polymyositis and review of the literature

Muscle symptoms, especially myalgias, appear to be common in patients with polyarteritis nodosa (PAN). We describe a patient who presented with a generalized myopathy and elevated creatine kinase (CK) suggestive of polymyositis. However, subsequent exploratory surgery for an acute abdomen revealed colonic perforation on the basis of PAN. A review of the literature suggests that generalized myopathy and elevated CK are uncommon features of PAN. A muscle biopsy can be a helpful procedure to secure the diagnosis in patients with PAN especially those with myopathies. Strategies for optimizing the choice of biopsy site are discussed.

Lower motor neuron disease in a patient with autoantibodies against Gal(beta 1-3)GalNAc in gangliosides GM1 and GD1b: improvement following immunotherapy

We followed a patient with a lower motor neuron form of motor neuron disease whose neurologic disorder improved following immunotherapy. The patient did not have an M protein but did have IgM antibodies to ganglioside GM1 detectable at serum titers of 1:2,000 by ELISA. These antibodies were found only in the IgM fraction with lambda light chains and immunoreacted with GD1b and Gal (beta 1-3) GalNAc.

Malignant hyperthermia in myotonia congenita

We report a family in which two sisters with myotonia congenita (MyC) were referred for malignant hyperthermia (MH) evaluation after each developed muscle rigidity with anesthesia. Halothane contracture testing of skeletal muscle in both was consistent with MH susceptibility. A third sister without clinical evidence of MyC was negative on contracture testing. These results suggest an association between MyC and MH susceptibility.

Neuropathy and anti-MAG antibodies without detectable serum M-protein

Anti-MAG IgM antibodies were detected by ELISA in a patient with slowly progressive peripheral neuropathy. Serum IgM content was normal, and no M-protein was detected by serum protein electrophoresis, immunoelectrophoresis, or immunostaining. By immunoblot analysis, the anti-MAG antibodies were IgMk; they reacted with human and bovine MAG but not with mouse MAG. The data suggest that there was an anti-MAG IgM M-protein in concentration too low to be detected by conventional techniques. Tests for anti-MAG antibodies should be done in patients with slowly progressive neuropathy of unknown etiology, even in the absence of detectable serum M-protein.