[Rhabdomyolysis associated with pseudohypoparathyroidism type Ib--a case report].

An 18-year-old Japanese female with pseudohypoparathyroidism (PHP) type Ib presented with rhabdomyolysis. The patient, who had been tired after long-distance hiking, experienced paresthesiae and subsequent muscle cramps of the four extremities after drinking a small quantity of alcohol. An occurrence of rhabdomyolysis was confirmed by marked elevation of serum CK activities and muscle necrosis revealed by both CT scanning and biopsy. The exertion and alcohol intake probably induced the initial muscle injury. Subsequently, the muscle necrosis might have worsened the asymptomatic hypocalcemia and decreased 1,25-(OH)2 vitamin D synthesis in PHP type Ib, which resulted in severe muscle cramps and further muscle destruction.