II. Epidemiology

  1. Acclimatized athletes and laborers at end of work

III. Pathophysiology

  1. Hyponatremia and volume depletion from profuse sweating and replacement with hypotonic fluids
  2. Provoked by muscle overload or Fatigue, dehydration or electrolyte disturbance

IV. Risk Factors

  1. See Heat Illness Risk Factors
  2. See Medications Predisposing to Heat Illness
  3. Athletes
  4. Field workers
  5. Roofers
  6. Steel Workers
  7. Coal Miners

V. Symptoms

  1. Symptom onset during or after exertion
  2. Brief, intermittent painful muscle contractions or cramps (esp. larger muscle groups)
    1. Abdominal Muscles
    2. Gastrocnemius (Calves)
    3. Quadriceps
    4. Hamstrings
  3. Associated symptoms
    1. Increased thirst
    2. Excessive sweating
    3. Sinus Tachycardia

VI. Signs

  1. Distinguish from Heat Exhaustion
  2. Findings of Heat Stroke are absent
    1. Normal mentation and
    2. Core Temperature <104 F

VII. Labs

  1. Labs are not indicated in most cases of isolated Heat Cramps
    1. Consider lab testing if systemic symptoms suggest associated Heat Exhaustion
  2. Basic chemistry panel (chem8)
    1. Hyponatremia
    2. Hypochloremia
  3. Creatinine phosphokinase (CPK)

VIII. Management

  1. Rest
  2. Oral hydration with electrolyte replacement (salt containing solution)
  3. Stretching and massage of cramping muscles

IX. Prevention

  1. See Heat Illness Prevention
  2. Prior to work or Exercise:
    1. Adequate Stretching
    2. Adequate water intake
  3. With Exercise (especially longer than 1 hour)
    1. Ingest a drink containing Glucose and Sodium

X. References

  1. Czerkawski (1996) Your Patient Fitness 10(4): 13-20
  2. Salinas and Ruttan (2017) Crit Dec Emerg Med 31(9): 3-10
  3. Sandor (1997) Physician SportsMed, 25(6):35-40
  4. Zink (2020) Crit Dec Emerg Med 34(3): 19-27
  5. Barrow (1998) Am Fam Physician 58(3):749-56 [PubMed]
  6. Gauer (2019) Am Fam Physician 99(8):482-9 [PubMed]
  7. Hett (1998) Postgrad Med 103(6):107-20 [PubMed]
  8. Wexler (2002) Am Fam Physician 65(11):2307-20 [PubMed]

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Related Studies

Ontology: Heat Cramps (C0085592)

Concepts Injury or Poisoning (T037)
MSH D018882
ICD9 992.2
ICD10 T67.2
SnomedCT 87108006, 157725005
English Cramp, Heat, Cramps, Heat, Heat Cramp, Effects of heat cramp, heat cramps, heat cramps (diagnosis), Heat cramp, Heat cramps, Heat cramps (disorder), Heat cramp (finding), heat cramp, Heat cramp (disorder), Stokers' cramp, cramp(s); heat, cramp(s); stoker's, heat; cramp(s), stoker's; cramp(s), Heat Cramps
Japanese 熱痙攣, ネツケイレン
Czech křeče z horka, Křeče z horka
French Crampes de chaleur, Crampes dues à la chaleur
German Hitzekrämpfe, Hitzekrampf, Hitzekraempfe
Spanish calambres por calor (trastorno), calambre por calor (hallazgo), calambre por calor, calambre de los fogoneros, Calambres por Calor, calambres por calor, Calambres por calor
Korean 열경련
Portuguese Cãibras devidas ao Calor, Cãibras pelo calor
Hungarian Hőgörcs
Italian Crampi da calore
Norwegian Hetekramper
Dutch hitte; kramp, kramp; hitte, kramp; stoker, stoker; kramp, Hittekramp, hittekrampen, Kramp ten gevolge van oververhitting