What is the workup for muscle cramping (muscle cramp)?

From the Guidelines

Muscle cramping workup should prioritize identifying and addressing underlying causes, with a focus on correcting electrolyte imbalances, particularly hypokalemia and hypomagnesemia, and considering medications like baclofen or albumin infusion for management, as recommended by the most recent guidelines 1. When evaluating a patient with muscle cramping, it is essential to start with a detailed history and physical examination to identify potential causes. This should include assessing the patient's hydration status, electrolyte levels (particularly sodium, potassium, calcium, and magnesium), medication use, and exercise patterns. Laboratory tests should include a complete blood count, comprehensive metabolic panel, thyroid function tests, and creatine kinase levels. For persistent or severe cramping, consider checking vitamin D levels, parathyroid hormone, and performing nerve conduction studies or electromyography.

Key considerations in the management of muscle cramping include:

• Correcting electrolyte imbalances, such as hypokalemia and hypomagnesemia, which are common in patients with liver disease and can be exacerbated by diuretic therapy 1.
• Using medications like baclofen, which has been shown to be effective in managing muscle cramps in patients with liver disease, with a recommended dose of 10 mg/day, increasing by 10 mg/day weekly up to 30 mg/day 1.
• Considering albumin infusion, which may also be beneficial in managing muscle cramps, particularly in patients with cirrhosis and ascites 1.
• Addressing underlying conditions, such as hypothyroidism, peripheral vascular disease, or neuropathy, which can contribute to muscle cramping.

It is crucial to prioritize the most recent and highest quality evidence when making recommendations for muscle cramping workup and management. The 2021 practice guidance by the American Association for the Study of Liver Diseases 1 provides the most up-to-date recommendations for managing ascites, spontaneous bacterial peritonitis, and hepatorenal syndrome, including guidance on muscle cramp management. Baclofen and albumin infusion are recommended as first-line treatments for muscle cramps in patients with liver disease, particularly those with cirrhosis and ascites 1.

From the Research

Diagnosis of Muscle Cramps

• Muscle cramps are characterized by involuntary, painful, visible contraction of a muscle (or a part of muscle) and are always associated with irregular repetitive firing of motor unit action potentials (200 à 300 Hz) which is caused by hyperexcitability of intramuscular terminal motor axons 2.
• A careful history and examination should allow the physician to determine the significance of cramp 2.
• ENMG and biological tests are needed in cases of severe symptoms (severity and frequency of cramps) and/or abnormal examination 2.

Classification of Muscle Cramps

• Idiopathic and secondary (drug or metabolic disorders) cramps are the most common groups 2.
• It's very important to search the motor unit diseases (neuropathy, radiculopathy, plexopathy, neuromyotonia, and a cramp fasciculation syndrome which can preceded ALS) 2.
• Muscle cramps can be exercise induced, idiopathic or symptomatic 3.

Treatment of Muscle Cramps

• The first goal in management of cramp is to determine if there is an underlying cause and the second to use physical measures (stretching) 2.
• Pharmacologic treatments have a moderate interest because of the potential of toxicity (quinine sulfate) or a little effectiveness (vitamin B complex, naftidrofuryl, and calcium channel blockers such as diltiazem, gabapentin) 2, 4.
• Quinine has been used to treat cramps of all causes, and there is moderate quality evidence that quinine significantly reduces cramp frequency, intensity and cramp days in dosages between 200 and 500 mg/day 5.
• Magnesium supplements are marketed for the prophylaxis of cramps, but the efficacy of magnesium for this indication has never been evaluated by systematic review, and it is unlikely that magnesium supplementation provides clinically meaningful cramp prophylaxis to older adults experiencing skeletal muscle cramps 6.

Diagnostic Approach

• The main questions for clinicians are: (1) Is this a muscle cramp, a contracture or a mimic? (2) Are the cramps exercise induced, idiopathic or symptomatic? (3) What is/are the presumed cause(s) of symptomatic muscle cramps or contractures? (4) What should be the diagnostic approach? and (5) How should we advise and treat patients with muscle cramps or contractures? 3.