How can I differentiate between nocturnal leg cramps and other causes of leg pain in my patients?

To differentiate nocturnal leg cramps from other causes of leg pain in patients, consider the following clinical features:

• Timing and nature of pain: Nocturnal leg cramps typically occur at night and present as sudden, painful, involuntary contractions of the calf or other leg muscles that last a few minutes and resolve spontaneously. The pain is often severe and localized to the muscle belly.
• Muscle tenderness and relief: After a cramp, the muscle may be tender. Stretching and massaging the affected muscle (e.g., dorsiflexing the ankle for calf cramps) can alleviate the cramp, which is characteristic of idiopathic leg cramps.
• Absence of neurological symptoms: Unlike neurological causes of leg pain, nocturnal leg cramps do not present with persistent numbness, tingling, weakness, bladder or bowel dysfunction, or progressive neurological deficits. Presence of such symptoms warrants neurological assessment and referral.
• Idiopathic nature and reassurance: Most nocturnal leg cramps are idiopathic with no underlying serious cause and can resolve spontaneously. If cramps are frequent, severe, or impact quality of life, further assessment or referral may be needed.
• Exclusion of systemic or neurological causes: Consider referral if the diagnosis is uncertain, if cramps are associated with systemic signs (e.g., altered consciousness, anuria, electrolyte imbalance), or if neurological signs are present, to exclude conditions such as motor neuron disease or peripheral neuropathy.

In summary, nocturnal leg cramps are characterized by sudden, brief, painful muscle contractions at night without neurological deficits, relieved by stretching, and usually idiopathic. Other causes of leg pain often have additional neurological or systemic features requiring further investigation or referral ¹,².