Cramps

💡 What Are Cramps?

• ⚡ Involuntary, painful contractions of a muscle or part of a muscle.
• 🧠 Thought to originate distally in the motor neuron; often with palpable, knot-like hardening of the muscle.
• 🤸 Relieved by passive stretching of the affected muscle.
• 🌙 Common at night, during or after exercise, or following physical activity.

🔎 Common Causes of Cramps

• ✅ Benign: Night-time or exercise-related cramps without underlying disease.
• 🧠 Neurological: Motor neuron disease, polyneuropathy.
• ⚖️ Metabolic: Pregnancy, uremia, hypothyroidism, adrenal insufficiency.
• 💧 Fluid/Electrolyte: Dehydration, hemodialysis, or disturbances in potassium, magnesium, calcium.

🩺 Management & Treatment

• 🤸 Stretching: Passive stretching often provides immediate relief.
• 🔍 Address Reversible Causes: Correct dehydration, electrolyte imbalance, or metabolic disorders.
• 💊 Pharmacological Options:
  • Daytime cramps:
    • Phenytoin: 300–400 mg PO daily.
    • Carbamazepine: 200–400 mg PO TDS.
    • Baclofen or oxcarbazepine – occasionally used (limited evidence).
  • Nocturnal cramps:
    • Quinine sulfate: 325 mg PO at bedtime (⚠️ use cautiously).
    • Phenytoin: 100–300 mg at bedtime.
    • Carbamazepine: 200–400 mg at bedtime.
    • Diazepam: 5–10 mg at bedtime.
  • Other agents (occasional benefit in small studies): Levetiracetam, gabapentin.

⚠️ Risks & Cautions

• Quinine sulfate: Effective but may cause serious complications:
  • Haemolytic uremic syndrome–thrombotic thrombocytopenia purpura (HUS-TTP).
  • Disseminated intravascular coagulation (DIC).
  • Bleeding diathesis.
  👉 Should only be used if cramps are disabling and resistant to other measures.
• Always consult a clinician before starting medication for cramps.

📌 Conclusion

• Most cramps are benign, best managed with stretching and correction of underlying causes.
• Drug therapy should be reserved for severe, refractory cases and used with caution—particularly quinine.

Note: Evidence for drug therapy (e.g., phenytoin, carbamazepine, quinine) is limited. Prescribe only under medical supervision.

3 Clinical Cases — Muscle Cramps ⚡

• Case 1 — Nocturnal leg cramps in an older adult 🌙: A 72-year-old woman reports painful calf cramps waking her at night, occurring 2–3 times weekly. No weakness or numbness. PMH: osteoarthritis, mild hypertension; meds: bendroflumethiazide. Exam: normal pulses, normal neuro exam. Teaching: Common in older adults, often idiopathic but can be drug-related (diuretics). Management is reassurance, stretching exercises before bed, reviewing medications, and maintaining hydration. Quinine is rarely used due to adverse effects.
• Case 2 — Exercise-induced cramps in a young man 🏃: A 24-year-old runner develops severe calf cramps after long runs, sometimes with dark urine. Exam between episodes is normal. CK mildly raised. Teaching: Think metabolic myopathy (e.g. McArdle’s disease/glycogen storage disorder) or electrolyte loss with exertion. Investigations include CK, renal function, and urine for myoglobin. Advice: hydration, graded training, avoid triggers; refer neurology/metabolic clinic if recurrent with rhabdomyolysis.
• Case 3 — Painful cramps with neuropathy 🧠: A 58-year-old man with type 2 diabetes presents with recurrent painful cramps in his feet, worse at night, with tingling and numbness. Exam shows reduced vibration sense and absent ankle jerks. Teaching: Likely due to diabetic peripheral neuropathy. Management includes optimising diabetes control, gabapentin/pregabalin or duloxetine for neuropathic pain, and lifestyle advice (foot care, stretching). Always consider electrolyte imbalance (Na, Ca, Mg, K) if sudden or severe.