Muscle cramps

Last reviewed: April 2018

Last updated: November 2017

Summary

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.

Definition

A muscle cramp is a sudden, involuntary, painful muscle contraction or spasm, associated with an increase in frequency of motor action potentials. [1] 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

Key diagnostic factors

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)

Full details

Other diagnostic factors

signs of a chronic medical condition (organic cause)

Full details

Risk factors

pregnancy
strenuous exercise
hemodialysis
cirrhosis
imatinib
beta-blockers with intrinsic sympathomimetic activity
statins
age >60 years
female gender
FHx of cramp
other prescribed drugs
creatine supplementation
hypoglycemia in diabetes mellitus
chronic diseases
home parenteral nutrition

Full details

Diagnostic investigations

1st investigations to order

clinical diagnosis

Full details

Investigations to consider

serum hCG
fasting serum metabolic panel
TSH
HbA1c
serum LFTs
PT and INR
serum myoglobin and urinalysis
serum 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 VIEW ALL 

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 declares 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 monograph. JM declares that he has no competing interests. DRPG is an author of a reference cited in this monograph.

Peer reviewers VIEW ALL 

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 monograph.

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.

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Muscle cramps

Summary

Definition

History and exam

Key diagnostic factors

Other diagnostic factors

Risk factors

Diagnostic investigations

1st investigations to order

Investigations 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 VIEW ALL 

Michael Rubin, MD, FRCP(C)

Disclosures

Acknowledgements

Peer reviewers VIEW ALL 

Timothy M. Miller, MD, PhD

Disclosures

Sami Khella, MD

Disclosures

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

Disclosures

Differentials

Guidelines

Patient leaflets

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