Heat Stroke

Aka: Heat Stroke

1. See Also
   1. Heat Illness
   2. Heat Edema
   3. Heat Cramps
   4. Heat Exhaustion
   5. Heat Stroke
   6. Temperature Regulation
   7. Heat Index
   8. Heat Illness Risk Factors
   9. Medications Predisposing to Heat Illness
   10. Heat Illness Prevention
2. Risk Factors
   1. See Temperature Regulation
   2. See Heat Illness Risk Factors
   3. See Medications Predisposing to Heat Illness
3. Types
   1. Classic Heatstroke
      1. Gradual environmental exposure
      2. Usually seen in elderly and debilitated patients
   2. Exertional Heatstroke
      1. Rapid onset over hours
      2. Usually seen in young patients and in athletes
4. Signs
   1. Heat Exhaustion symptoms and signs
   2. Hyperpyrexia (Use rectal probe)
      1. Core Temperature exceeds 40 C (104 F) for Heat Stroke diagnosis
      2. Core temps may range as high as 44 C (111 F)
      3. Reports of temperatures up to 47 C (116.6 F)
   3. Altered Level of Consciousness (Delirium or coma)
   4. Anhidrosis
   5. Tachycardia
   6. Hypotension
   7. Tachypnea
5. Labs
   1. Complete Blood Count (CBC)
   2. Basic Metabolic Panel (Chem8)
   3. ProTime (PT)
   4. Partial Thromboplastin Time (PTT)
   5. Arterial Blood Gas (ABG)
   6. Creatine Phosphokinase (CPK)
   7. Urinalysis
6. Differential Diagnosis (hyperthermia with ALOC)
   1. Sepsis
   2. Meningitis
   3. Cerebrovascular Accident
   4. Brain Tumor
   5. Head Injury
   6. Withdrawal from abused substances
   7. Neuroleptic Malignant Syndrome
   8. Hyperthyroidism (Hyperthyroid storm)
   9. Pheochromocytoma
   10. Anticholinergic Poisoning
7. Management
   1. Rapid cooling to temperature under 101 F (38.3 C)
      1. Evaporative cooling with fans and misting
      2. Cool saline bags applied to groin and axilla
      3. Ice water rectal enemas
      4. Ice water immersion (most effective measure)
         1. Associated with nearly 100% survival rate when used immediately in exertional Heat Stroke
         2. Casa (2007) Exerc Sport Sci Rev 35(3): 141-9
      5. Nasogastric lavage
      6. Peritoneal lavage
   2. Same IV hydration as for Heat Exhaustion
      1. Observe closely for pulmonary edema
   3. ABC Management
      1. Intubation may be needed to protect airway
   4. Altered Level of Consciousness
      1. Treat as Delirium
      2. Check bedside Glucose
      3. Consider banana bag containing Thiamine
      4. Consider Naloxone
   5. Myoglobinuria
      1. Maintain urine output at 50 to 100 ml per hour
      2. Alkalinize urine and force diuresis with mannitol
   6. Disseminated Intravascular Coagulation (DIC)
      1. Fresh Frozen Plasma and platelets as needed
   7. Shivering with rapid cooling
      1. Consider Neuroleptics (e.g. Chlorpromazine)
      2. Dantrolene is not effective in lowering core temp
         1. Bouchama (2002) N Engl J Med 346:1978-88
8. Complications
   1. Disseminated Intravascular Coagulation (DIC)
   2. Rhabdomyolysis
   3. Acute Renal Failure
   4. Adult Respiratory Distress Syndrome (ARDS)
   5. Hepatocellular necrosis
9. Prognosis: Short-Term
   1. Mortality: <10% (if treated appropriately)
      1. Mortality higher in some groups (e.g. firefighters)
   2. Indicators of Poor Prognosis
      1. Core Temperature exceeds 42 degrees Celsius
      2. Aspartate Aminotransferase (AST) >1000 in first day
      3. Prolonged coma exceeds 2 hours
10. Prognosis: Long-Term outcomes for survivors
    1. Increased risk of Heat Stroke under same conditions
       1. Test heat tolerance 8-12 weeks post-episode
       2. Assess for residual injury in Thermoregulation
    2. Long-term neurologic or behavioral deficits
       1. Neurologic injury is permanent in 20% of cases
       2. Dematte (1998) Ann Intern Med 129:173-81
11. Prevention
    1. See Heat Illness Prevention
12. References
    1. Czerkawski (1996) Your Patient Fitness 10(4): 13-20
    2. Sandor (1997) Physician SportsMed, 25(6):35-40
    3. Barrow (1998) Am Fam Physician 58(3):749-56
    4. Becker (2011) Am Fam Physician 83(11): 1325-30
    5. Hett (1998) J Postgrad Med 103(6): 107-20
    6. Howe (2007) Am J Sports Med 35(8): 1384-95
    7. Epstein (1990) Med Sci Sports Exerc 22(1): 29-35
    8. Grafe (1997) Clin Sports Med 16(4):569-91
    9. Jardine (2007) Pediatr Rev 28(7): 249-58
    10. Wexler (2002) Am Fam Physician 65(11):2307-20
    11. Yaqub (1998) J Neurol Sci 156(2):144-51