Click here to view next page of this article Muscle CrampsMuscle cramps are prolonged involuntary muscle contractions that can be painful. Muscle cramping represents motor unit hyperactivity leading to prolonged involuntary muscle contraction. Precipitants include unopposed contraction, electrolyte and volume shifts, and lower motor neuron disease. Ordinary cramps most commonly occur in the gastrocnemius muscle and the intrinsic muscles of the sole of the foot. Their nocturnal predilection appears to be related to unopposed foot plantar flexion while in bed, placing the muscles of the calves and feet in their most shortened and therefore most vulnerable position. Without modulation by opposing muscles, the sustained contraction produces the painful cramp, which is experienced as sudden severe calf pain, often with a palpable or visibly hardened muscle. Clinical EvaluationA detailed description of the cramping is essential and should include the setting in which the episodes occur. Those that develop at night or in the context of hemodialysis, hypoglycemia, or heavy sweating from prolonged exertion are likely to be true cramps, as are those coincident with use of calcium channel blockers or beta-agonists. Cramps.To relieve an established cramp, one must passively stretch the contracting muscle and gradually contract the apposing one. In some cases, this can be accomplished by simply walking around, which produces a relative dorsiflexion of the foot. Massage of the involved muscle sometimes helps. Consciously dorsiflexing at the first sign of a leg or foot cramp might abort it. Prophylactic stretching can also prevent attacks, as might positions in bed that prevent foot dorsiflexion. Swimming-induced cramps can be avoided by sacrificing the ideal plantar-flexed kicking position and maintaining a more neutral foot position. Patients who suffer from repeated attacks of nocturnal leg cramps seek a reduction in the frequency and severity of episodes. Quinine sulfate has been prescribed for decades for this purpose, but only recently have randomized, double-blind, controlled clinical trials been performed to assess its efficacy, and the number of patients studied remains small. Studies using low-to-moderate dose regimens (200-300 mg qhs) show less benefit than do those using higher doses (200 mg at supper, 300 qhs). This pattern suggests that response rates are related to serum level attained, which can vary greatly with age. Other drugs shown to be of some benefit include methocarbamol and chloroquine. Vitamin E is promoted in health food stores for treatment of nocturnal cramps, but it has been found to be no better than placebo when tested in double-blind, placebo-controlled fashion. It may be found in combination with quinine. The calcium channel blocker verapamil has shown promise in preliminary study. Patients with ordinary cramps related to dehydration and sodium depletion respond well to replacement therapy. Those with cramps as a consequence of hemodialysis are best treated with rapid volume expansion (hypertonic dextrose or saline infusion). If hypoglycemia is responsible, then adjustment of insulin regimen is needed . Altering the medication program may be necessary in cases in which beta-agonists or calcium channel blockers. |