Myasthenia gravis and steroid-induced myopathy of the respiratory muscles

Acute rhabdomyolysis complicating status asthmaticus in children: case series and review

OBJECTIVES

To describe a case series of 4 children who developed acute rhabdomyolysis as a complication of acute respiratory failure secondary to status asthmaticus.

METHODS

A retrospective review of all children who were admitted to our pediatric intensive care unit (PICU) with status asthmaticus from November 1998 through July 2004 was performed and all children who developed acute rhabdomyolysis, defined as a 5-fold increase above the upper limit of normal in the serum creatine phosphokinase (CPK) concentration (CPK > or = 1250 IU/L), were identified. Demographic and clinical data were abstracted from the medical record.

RESULTS

During the study period, 108 children with status asthmaticus were admitted to our PICU (3.6% of all admissions). Four children (age 12-19 years) developed acute respiratory failure requiring mechanical ventilation, and all 4 of these children (3.7% of all children with status asthmaticus admitted to the PICU) developed acute rhabdomyolysis. The 4 children who developed acute rhabdomyolysis were older than the children with status asthmaticus, without rhabdomyolysis (median age 15 years vs. 5 years).

CONCLUSIONS

Acute rhabdomyolysis complicating status asthmaticus may be more common than previously ascertained. We therefore suggest that CPK levels should be followed closely in all children with status asthmaticus and acute respiratory failure. The early presentation of rhabdomyolysis in the current series suggests that factors other than corticosteroids and neuromuscular blockers are potentially involved. Mechanical ventilation and older age seem to be significant risk factors for rhabdomyolysis, perhaps implicating a mechanism similar to the pathogenesis of severe exercise-related rhabdomyolysis. Further clinical study of the incidence and causative factors of rhabdomyolysis in this population is warranted.

Predictable recovery from myasthenia gravis crisis with plasma exchange: thirty-six cases and review of current management

Adult, acquired, idiopathic, autoimmune myasthenia gravis has a well-characterized IgG anti-acetylcholine striated-muscle receptor antibody. Removal by plasma exchange is effective, established therapy to augment anti-cholinesterase and immunosuppressive therapy and is the treatment of choice for myasthenia gravis crisis. We report 36 consecutive patients referred and accepted for plasma exchange, 32 of whom were in or entering myasthenia crisis, over a 10 year period. An average of 7.8 (range 1 to 16) plasma exchange procedures were done, with uniform, significant improvement, including extubation of 13 in myasthenic crisis and discharge from hospital in all. We conclude that this is the best treatment for myasthenia gravis crisis in hospital. From recent cases, most, if not all, crises can be prevented by IVIgG or plasma exchange as out-patients with use of corticosteroid and or azathioprine.