From the Guidelines
The workup for generalized muscle cramps should begin with a thorough history and physical examination to identify potential causes, followed by initial laboratory tests including a complete blood count, comprehensive metabolic panel, thyroid function tests, and creatine kinase levels, as recommended by the most recent guidelines 1. The initial step in evaluating generalized muscle cramps is to take a comprehensive history and perform a physical examination to identify potential underlying causes. This should be followed by laboratory tests to rule out common causes of muscle cramps. Key laboratory tests include:
- Complete blood count
- Comprehensive metabolic panel (including electrolytes, calcium, magnesium, and renal function)
- Thyroid function tests
- Creatine kinase levels If these initial tests are unrevealing, further testing may be considered, such as:
- Vitamin D levels
- Parathyroid hormone levels
- Autoimmune panel in selected cases
- Electromyography and nerve conduction studies if neurological causes are suspected It is also important to review the patient's medication list, as certain medications like statins, diuretics, beta-agonists, and steroids can cause muscle cramping, as noted in the guidelines for statin-associated side effects 1. Management of muscle cramps typically involves addressing any identified underlying causes, such as electrolyte abnormalities, and ensuring adequate hydration. For symptomatic relief, options may include:
- Quinine sulfate 200-300mg at bedtime, although this carries FDA warnings for serious side effects
- Magnesium supplements (300-400mg daily)
- Vitamin B complex
- Calcium channel blockers like diltiazem Physical measures such as stretching exercises before bedtime, proper warm-up before exercise, and maintaining hydration are also important preventive strategies, as hyperexcitability of motor neurons, altered neuromuscular junction transmission, or direct muscle fiber abnormalities can contribute to muscle cramps 1.
From the Research
Generalized Muscle Cramps (Myalgias) Workup
The workup for generalized muscle cramps (myalgias) involves a combination of history, physical examination, and laboratory tests.
- The approach to the patient with cramps should emphasize the history, physical examination, and, if the diagnosis is unclear, minimal routine laboratory data 2.
- A workup in a patient suspected of having muscle cramps is proposed, which includes differentiating true muscle cramps from muscle stiffness and muscle twitching 3.
Laboratory Tests and Physical Examination
- Laboratory tests may include a complete blood count, hepatic, renal, and thyroid function testing, although these are more commonly associated with itch than muscle cramps 4.
- The physical examination should detect signs of under-virilization or systemic disease, although this is more relevant to gynecomastia evaluation 5.
Treatment and Management
- Stretching exercises and quinine have been proposed as therapies for ordinary cramps, with quinine showing effectiveness in treating nocturnal muscle cramps 2, 6.
- The use of selective estrogen receptor modulators (SERMs), aromatase inhibitors (AIs), and non-aromatizable androgens is not justified in general for conditions like gynecomastia, and by extension, possibly for muscle cramps 5.