Muscle cramps

Overview 
Theory 
Diagnosis 
Management 
Follow up 
Resources 

Last reviewed: 1 Apr 2025

Last updated: 31 Jan 2025

Muscle cramps are mostly benign and self-limited, but 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. Quinine is used in some countries for the prevention of idiopathic cramps, but is associated with serious side effects (e.g., cardiac arrhythmias, thrombocytopenia, hepatotoxicity, blindness). Therapeutic trialing of various medications used for symptomatic benefit is a reasonable approach.

Definition

A muscle cramp is a sudden, involuntary, painful muscle contraction or spasm, associated with an increase in frequency of motor action potentials.[1][2][3] 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 (motor unit hyperactivity). These are most commonly idiopathic cramps, but can be associated with other conditions.

History and exam

Key diagnostic factors

concurrent hemodialysis (organic cause)
cirrhosis (organic cause)
pregnancy (idiopathic cramp)
strenuous exercise (idiopathic cramp)
medication use (idiopathic cramp)
nocturnal onset (idiopathic cramp)
gastrocnemius muscle involvement, with or without foot involvement (idiopathic cramp)
duration <10 minutes (idiopathic cramp)
unilateral (idiopathic cramp)
precipitation by both trivial movements and 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)

Full details

Other diagnostic factors

signs of a chronic medical condition (organic cause)

Full details

Risk factors

pregnancy
strenuous exercise
hemodialysis
cirrhosis
use of imatinib
use of beta-blockers with intrinsic sympathomimetic activity
age >60 years
female sex
family history of cramp
use of statins
use of other agents that may cause muscle cramps
hypoglycemia in patients with diabetes mellitus
chronic diseases
home parenteral nutrition

Full details

Diagnostic tests

1st tests to order

clinical diagnosis

Full details

Tests to consider

serum or urine hCG
fasting serum metabolic panel
thyroid-stimulating hormone (TSH)
HbA1c
serum liver function tests
prothrombin time (PT) and INR
serum myoglobin and urinalysis
serum creatine kinase (CK)-MM
serum alpha-tocopherol (vitamin E)
serum zinc
EMG
nerve conduction studies
serum aldolase
muscle biopsy
genetic studies

Full details

Treatment algorithm

ONGOING

idiopathic cramps

exercise-associated

hypoglycemia-associated in diabetes mellitus

pregnancy-associated

dialysis-associated

cirrhosis-associated

multiple sclerosis- or lower motor neuron disease-associated

familial syndrome-associated

medication-associated

Contributors

Authors

Michael Rubin, MD, FRCP(C)

Professor of Clinical Neurology

Weill Cornell Medical College

Attending Neurologist

Director, Neuromuscular Service and EMG Laboratory

New York Presbyterian Hospital

New York

Disclosures

MR states that he has no competing interests.

Acknowledgements

Dr Michael Rubin would like to gratefully acknowledge Dr Justin Mhoon and Dr David R.P. Guay, previous contributors to this topic. JM declares that he has no competing interests. DRPG is an author of a reference cited in this topic.

Peer reviewers

Timothy M. Miller, MD, PhD

Assistant Professor of Neurology

Department of Neurology

Washington University School of Medicine

St. Louis

Disclosures

TMM is an author of a reference cited in this topic.

Sami Khella, MD

Physician

Department of Neurology

Penn Presbyterian Medical Center

University of Pennsylvania Health System

Philadelphia

Disclosures

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

Auckland

New Zealand

Disclosures

FG-S declares that she has no competing interests.

References

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Key articles

Katzberg HD. Case studies in management of muscle cramps. Neurol Clin. 2020 Aug;38(3):679-96. Abstract

Leung AK, Wong BE, Chan PY, et al. Nocturnal leg cramps in children: incidence and clinical characteristics. J Natl Med Assoc. 1999;91:329-32.Full text Abstract

Maughan RJ, Shirreffs SM. Muscle cramping during exercise: causes, solutions, and questions remaining. Sports Med. 2019 Dec;49(suppl 2):115-24. Abstract

Zhou K, West HM, Zhang J, et al. Interventions for leg cramps in pregnancy. Cochrane Database Syst Rev. 2015;(8):CD010655.Full text Abstract

Maquirriain J, Merello M. The athlete with muscular cramps: clinical approach. J Am Acad Orthop Surg. 2007;15:425-431. Abstract

Garrison SR, Korownyk CS, Kolber MR, et al. Magnesium for skeletal muscle cramps. Cochrane Database Syst Rev. 2020 Sep 21;(9):CD009402.Full text Abstract

El-Tawil S, Al Musa T, Valli H, et al. Quinine for muscle cramps. Cochrane Database Syst Rev. 2015;(4):CD005044.Full text Abstract

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials
- Tetany
- Tetanus
- Occupational cramps
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Guidelines
- International classification of sleep disorders 3rd edition, text revision
- Assessment: symptomatic treatment for muscle cramps (an evidence-based review)
More Guidelines
Patient information
Leg cramps: what are they?
Leg cramps: what treatments work?
More Patient information
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Muscle cramps

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic tests

1st tests to order

Tests to consider

Treatment algorithm

idiopathic cramps

exercise-associated

hypoglycemia-associated in diabetes mellitus

pregnancy-associated

dialysis-associated

cirrhosis-associated

multiple sclerosis- or lower motor neuron disease-associated

familial syndrome-associated

medication-associated

Contributors

Authors

Michael Rubin, MD, FRCP(C)

Disclosures

Acknowledgements

Peer reviewers

Timothy M. Miller, MD, PhD

Disclosures

Sami Khella, MD

Disclosures

Felicity Goodyear-Smith, MB CHB, DipObs, MGP, FRNZCGP, MFFLM, RCP

Disclosures

References

Key articles

Reference articles

A full list of sources referenced in this topic is available to users with access to all of BMJ Best Practice.

Differentials

Guidelines

Patient information

Log in or subscribe to access all of BMJ Best Practice

Log in or subscribe to access all of BMJ Best Practice

Log in to access all of BMJ Best Practice