Muscle Cramps (ตะคริว): Causes, Management, and When to Worry
- Mayta
- 4 days ago
- 3 min read
1. Definition
A muscle cramp is a sudden, painful, involuntary contraction of a muscle or muscle group, most commonly affecting the calves, feet, hamstrings, and sometimes hands or abdomen.
Most cases are benign and arise from neuromuscular irritability due to electrolyte imbalance, dehydration, or muscle fatigue.
2. Epidemiology
Very common: affects up to 60% of adults.
More frequent at night and in elderly.
Certain populations (pregnant women, athletes, diuretic users) are at higher risk.
3. Etiology (Causes)
Use mnemonic “F-E-M-O-D-E-L”
F – Fatigue
Prolonged standing
Intense exercise
Overuse of muscles
E – Electrolyte imbalance
↓ Magnesium
↓ Potassium
↓ CalciumThese increase neuromuscular excitability → cramps.
M – Medications
Diuretics (furosemide, HCTZ)
Statins
Beta-agonists
Steroids (rare)
O – Overexertion or dehydration
Hot environment
Sweating
Inadequate water intake
D – Disease-related
Peripheral artery disease
Neuropathy (diabetes)
Varicose veins
Cirrhosis
Thyroid disorders
E – Electrolyte loss from GI issues
Vomiting
Diarrhea
L – Lifestyle factors
Low intake of Mg/Ca
Alcohol consumption
Caffeine excess
4. Pathophysiology
Muscle cramps occur when:
Motor neuron hyperexcitability increases.
Neuromuscular junction triggers sustained contraction.
Electrolyte abnormalities alter ion channels → unstable membrane potentials.
Muscle fatigues → impaired relaxation process.
5. Clinical Presentation
Typical symptoms
Sudden painful contraction
Hard palpable muscle knot
Lasts seconds to minutes
May leave soreness for hours afterward
Red flags
(Require evaluation)
Persistent unilateral swelling
Weakness or numbness
Skin discoloration
Severe cramps unrelated to exertion
Cramps + dark urine (risk rhabdomyolysis)
6. Differential Diagnosis
Electrolyte disorders (Mg, Ca, K)
Peripheral artery disease
Peripheral neuropathy
Hypothyroidism
Varicose veins
Medication-induced cramps
Restless legs syndrome
Motor neuron disease (rare)
7. Evaluation
A. History
Ask:
Frequency & timing (night vs daytime)
Exercise / dehydration
Medications
Diet
Pregnancy?
Red-flag symptoms
B. Physical Examination
Calf muscle tenderness
Pulses (PAD)
Varicose veins
Neurological exam
Peripheral edema
C. Laboratory Investigation (if persistent or severe)
Electrolytes: Na, K, Mg, Ca, Phos
Renal function: BUN/Cr
Fasting glucose / HbA1c
TSH / Free T4 (thyroid)
Vitamin D level (optional)
D. Imaging
Only if vascular or neurological cause suspected:
Doppler US
Nerve conduction study
🩺 8. MANAGEMENT REGIMEN (OPD)
Evidence-based + Practical + Student-FriendlyAll doses USMLE-safe and guideline-based.
A. Definitive Treatment (Fix the cause)
1. Magnesium Supplementation — FIRST LINE
Most effective in reducing nocturnal leg cramps.
Magnesium oxide (MgO) 400 mg
1×1 PO at bedtime (HS)Duration: 2–4 weeks
If GI upset → switch to:
Magnesium glycinate 200–400 mg HS
Better tolerated, less diarrhea
2. Hydration Therapy
Drink 1.5–2.5 L/day water
If sweating/exercise: add ORS 1–2 sachets/day
3. Electrolyte Replacement
If confirmed deficiency or patient at risk:
Potassium chloride
600 mg PO 1×2–3 after meals(individually adjusted)
Calcium carbonate
500 mg 1×1–2 with meals
4. Medication Review
STOP or ADJUST drugs causing cramps:
Diuretics
Beta-agonists
Statins
Antipsychotics
Steroids
5. Treat underlying diseases
If diagnosed:
PAD → aspirin + exercise therapy
Diabetic neuropathy → glycemic control
Varicose veins → compression stockings
Hypothyroidism → levothyroxine
B. Supportive Treatment (Symptom relief)
1. Stretching Program
Calf stretch
20–30 sec × 3 repetitions × twice daily
Hamstring stretch
20–30 sec × 3
Quadriceps stretch
20–30 sec × 3
2. Heat Therapy
Warm compress 10–15 min
Warm bath before bed
3. Massage
Roll from calf toward knee
Helps break contracted muscle fibers
4. Proper footwear
Arch support
Avoid high heels
Avoid worn-out shoes
5. Adequate nutrition
Eat:
Bananas (K)
Nuts/seeds (Mg)
Dairy (Ca)
Leafy greens
Hydrating fruits
Avoid:
Excess caffeine
High alcohol intake
❌ Treatments NOT recommended
Quinine → causes arrhythmia, thrombocytopenia
NSAIDs → do NOT relieve cramp but can help soreness
Muscle relaxants → not helpful
Vitamin B complex → only if deficiency
9. When to Refer / Further Workup Needed
Seek doctor if:
Daily cramps for > 2–3 weeks
Significant swelling
Weakness or numbness
Night cramps causing insomnia
Family history of neuromuscular disease
Dark urine + severe cramps → rhabdomyolysis
10. Prognosis
Excellent.Most patients improve with:
Adequate hydration
Stretching
Magnesium therapy
Only a small percentage require further evaluation.
11. Patient Education Points
You should explain:
Most cramps are benign and treatable
Hydration, stretching, electrolytes prevent recurrence
Take magnesium at bedtime
Seek help if red-flag symptoms occur
🧪 12.OPD MANAGEMENT PLAN (Regimen Summary)
Diagnosis: Recurrent muscle cramps (likely benign)Setting: OPD
✔ Medication
Magnesium oxide 400 mg 1×1 PO HS for 4 weeks
ORS 1–2 sachets/day if dehydrated
Calcium carbonate 500 mg 1×1 with meals (if dietary deficiency)
✔ Lifestyle & Supportive
Stretching routine twice daily
2 L water/day
Warm compress before sleep
Massage after cramps
Proper footwear
Reduce caffeine & alcohol
Increase electrolyte-rich foods
✔ Monitor / Follow-up
Re-evaluate in 4 weeks
Check electrolytes if no improvement
Consider vascular/neurologic workup if symptoms persistent
✔ Education
Avoid prolonged standing
Do gentle stretching before sleep
Maintain hydration
Recognize red flags
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