Muscle cramps

A cramp is an abrupt, sustained, involuntary contraction of a muscle. The everyday kind — nocturnal leg cramps, exercise-associated cramps — is common and usually harmless, driven by muscle fatigue, dehydration, ageing and prolonged positions. But cramps are also a classic signal of disturbed electrolytes and a handful of medical conditions. Low or high potassium, low sodium, low calcium and low magnesium all provoke cramps and spasms. Thyroid disease (especially hypothyroidism) and chronic kidney disease disturb the mineral balance. Medications matter — diuretics (which waste potassium and magnesium), statins (muscle aches and, rarely, damage), and some others. Widespread cramps with weakness, dark urine, or persistent symptoms deserve a blood panel rather than reassurance alone.

• Benign nocturnal leg cramps — common with age; usually no cause found.
• Exercise / dehydration / heat — fluid and electrolyte loss.
• Electrolyte disturbance — low or high potassium, low sodium, low calcium, low magnesium.
• Diuretics — waste potassium and magnesium; a very common drug cause.
• Hypothyroidism — muscle stiffness, cramps, aches.
• Chronic kidney disease — mineral and electrolyte imbalance.
• Statins — muscle aches and cramps; rarely significant muscle breakdown (raised CK).
• Pregnancy — leg cramps are common.
• Nerve or circulation problems — if cramps come with numbness or claudication.

Occasional exercise or night cramps in an otherwise well person rarely need tests. When cramps are frequent, widespread, or come with weakness, a basic panel is worthwhile: electrolytes (potassium, sodium), calcium and magnesium, kidney function (creatinine/eGFR), and TSH for thyroid. Add creatine kinase (CK) if there is muscle pain and weakness, or if you take a statin and symptoms are significant — a high CK signals muscle breakdown. Review diuretics and other contributing drugs. Mediora.AI surfaces the electrolyte, thyroid and kidney pattern from your results and highlights a raised CK; the clinical decision is your GP's.