Cramps are sudden, involuntary, painful muscle contractions. Their pathophysiology remains poorly understood. One hypothesis is that cramps result from changes in motor neuron excitability (central origin). Another hypothesis is that they result from spontaneous discharges of the motor nerves (peripheral origin). The central origin hypothesis has been supported by recent experimental findings, ...

Gitelman syndrome (GS) is a renal tubular disorder characterized by hypokalemia, hypomagnesemia, metabolic alkalosis and hypocalciuria due to defective tubular reabsorption of magnesium and potassium. This disease is caused by mutations of the thiazide-sensitive Na-Cl cotransporter (NCCT) gene, SLC12A3. Manifestations of GS are heterogeneous, from asymptomatic to mild symptoms of cramps and eas...

A 10-year-old boy was evaluated for a 4-month history of muscle cramps. Initially, the cramps occurred twice weekly, usually in his calves. More recently, he had been having cramps in both arms and hands which lasted for up to 5 minutes. On occasion, his fi ngers would get “stuck” for several minutes before he could straighten them. Although he still participates in gym class, his mother report...

The authors studied a 53 year old woman and her 22 year old son with episodes of paroxysmal muscle cramps and dark urines lasting several hours related to high fat diet and strenuous physical exercise beginning on both at age 14 years. The father, paternal uncle, paternal grandfather and another son of the mother also had paroxysmal muscle cramps. The two studied cases showed normal findings fo...

A case of carnitine palmityl transferase deficiency in skeletal muscle is described. The usual symptoms associated with this disease (recurrent muscle cramps or pain and pigmenturia) were observed but sudden exposure to cold precipitate rhabdomyolysis in this patient.