Although mostly benign and self-limited, muscle cramps may also be indicative of a wide variety of potentially serious systemic disorders.
Idiopathic (ordinary) muscle cramps are common, short-lived, and usually involve the calf muscle and/or foot.
The diagnostic approach for idiopathic muscle cramps is one of exclusion. Cramps due to known pathologies can be ruled out reasonably quickly and easily by medical history and targeted physical exam.
Nonpharmacologic therapy forms the cornerstone of management of muscle cramps in the acute phase. Passive and/or active stretching of the affected muscle(s) is by far the most effective and safest therapy for most acute idiopathic muscle cramps.
Data are extremely sparse regarding ongoing prevention of muscle cramps. With the exception of drug therapies targeted at underlying/precipitating conditions, there are no proven, specific, effective, and safe drug therapies for muscle cramps. Therapeutic trialing of various medications used for symptomatic benefit is a reasonable approach.
A muscle cramp is a sudden, involuntary, painful muscle contraction or spasm, associated with an increase in frequency of motor action potentials. Idiopathic (ordinary) muscle cramps are common. About 80% of episodes involve the gastrocnemius, with a mean duration per episode of 8 to 9 minutes in adults and 2 minutes in children. The focus of this topic is true cramps, which are most commonly idiopathic cramps, but which can be associated with other conditions.
History and exam
- hx of concurrent hemodialysis (organic cause)
- hx of cirrhosis (organic cause)
- pregnancy (idiopathic cramp)
- hx of strenuous exercise (idiopathic cramp)
- hx of medication use (idiopathic cramp)
- nocturnal onset (idiopathic cramp)
- gastrocnemius muscle involvement, with or without foot involvement (idiopathic cramp)
- duration <10 minutes (idiopathic cramp)
- predominantly unilateral (idiopathic cramp)
- precipitation by both trivial movements and by forceful contractions (idiopathic cramp)
- visible or palpable muscular knotting
- good response to passive/active stretching (idiopathic cramp)
- normal neurologic exam (idiopathic cramp)
- normal general physical exam (idiopathic cramp)
- other local muscle involvement (neuromuscular disease cramp)
- widespread muscle cramps (lower motor neuron disease)
- duration >10 minutes (organic cause)
- abnormal neurologic exam (organic cause)
- abnormal musculoskeletal exam (organic cause)
- strenuous exercise
- beta-blockers with intrinsic sympathomimetic activity
- age >60 years
- female gender
- FHx of cramp
- other prescribed drugs
- creatine supplementation
- hypoglycemia in diabetes mellitus
- chronic diseases
- home parenteral nutrition
Michael Rubin, MD, FRCP(C)
Professor of Clinical Neurology
Weill Cornell Medical College
Director, Neuromuscular Service and EMG Laboratory
New York Presbyterian Hospital
MR is an assistant editor for Neurology Alert and a contributor to Merck Manuals.
Dr Michael Rubin would like to gratefully acknowledge Dr Justin Mhoon and Dr David R.P. Guay, previous contributors to this monograph. JM declares that he has no competing interests. DRPG is an author of a reference cited in this monograph.
Timothy M. Miller, MD, PhD
Assistant Professor of Neurology
Department of Neurology
Washington University School of Medicine
TMM is an author of a reference cited in this monograph.
Sami Khella, MD
Department of Neurology
Penn Presbyterian Medical Center
University of Pennsylvania Health System
SK declares that he has no competing interests.
Felicity Goodyear-Smith, MB CHB, DipObs, MGP, FRNZCGP, MFFLM, RCP
Professor and Goodfellow Postgraduate Chair
Department of General Practice & Primary Health Care
University of Auckland
FG-S declares that she has no competing interests.
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