Heat stroke: Difference between revisions

Revision as of 04:55, 6 March 2016

Classic (nonexertional) - insidious development over days
- Seen in children and elderly
Exertional - rapid onset during exercise or other exertion
- Seen in otherwise young, healthy individuals

Symptoms^[1]
- Elevated temperature >40°C (104°F) PLUS
- CNS neurologic abnormalities (e.g. Inappropriate behavior, Confusion, Delirium, Ataxia, Coma, Seizures)
Anhidrosis is frequently present; however, its absence does NOT rule out heat stroke

Blood glucose
CBC
Chemistry
Elevated LFTs sensitive for heat stroke
- AST > 1000, poor prognosis
- Especially in exertional heat stroke
Arterial blood gas or Venous blood gas
- PaCO2 is often <20 2/2 hyperventilation
Lactate (often elevated in exertional heat stroke)
Coagulation studies
Creatine phosphokinase and myoglobin
Urine analysis
ECG
Chest x-ray
CT brain and/orLP as needed

Address ABCs
Rapid cooling (see below) - mainstay of treatment
- Reduces morbidity, should be started in prehospital setting if no other life-threats exist^[1]
Remove from environment
IVF (for renal protection and avoiding rhabdomyolysis)
- Bolus if hypotensive
- Infusion titrated to UOP (goal 250mL/hour)

Goal is to reduce temp to 39C (102.2F) and then stop to avoid overshoot hypothermia
Antipyretics (ASA and acetaminophen) and dantrolene have no role
Cooling blankets work too slowly to be employed as sole treatment
Ice packs to neck, axillae, groin are useful as adjunct only
Cold IVF is not effective
Techniques
- Evaporative
  - Method of choice
  - Spray cool water (15C (59F)) on most of pt's body surface; turn on fan
  - Complications
    - Shivering (occurs when skin temp is <30C (86F): treat with short-acting benzodiazepines
    - Electrodes not sticking: place on pt's back instead
- Ice-water immersion
  - Consider especially in young, healthy pts
  - Complications
    - Shivering
    - Inability to perform defibrillation or resuscitative procedures
- Invasive
  - Consider if evaporative cooling or immersion is insufficient
  - Cardiopulmonary bypass
  - Cold water gastric, bladder or rectal lavage

Hypotension
- BP will usually respond to small fluid bolus (500cc) and body cooling
  - If ineffective consider vasopressors (dopamine or dobutamine)
  - Avoid peripheral vasoconstriction (norepinephrine)
    - May redirect blood flow away from skin
Electrolyte abnormalities
- Variable: hypokalemia and hyper or hyponatremia may be seen
Hematologic
- DIC or abnormal bleeding
Hepatic injury
- Almost always reversible
Renal failure
ARDS
Seizure
- Treat with Benzodiazepines
Neurologic deficit
- Persistent in 20%, associated with high mortality

↑ ^1.0 ^1.1 Becker JA, Stewart LK. Heat-related illness. Am Fam Physician. 2011 Jun 1;83(11):1325-30.

Authors:

@@ Line 20: / Line 20: @@
 ===Non-Environmental===
 *Infectious
-**[[Sepsis]]
+**[[Sepsis (Main)|Sepsis]]
 **[[Meningitis]]
 **[[Encephalitis]]
@@ Line 27: / Line 27: @@
 **[[Tetanus]]
 *Endocrine
-**[[Thyroid Storm]]
+**[[Thyroid storm]]
 **[[Pheochromocytoma]]
-**[[DKA]]
+**[[Diabetic ketoacidosis|DKA]]
 *Neurologic
 **Hypothalamic bleeding or infarct
-**[[CVA]]
+**[[Stroke (main)|CVA]]
 **[[Status epilepticus]]
 *Toxicologic
-**Anticholinergic toxidrome
+**[[Anticholinergic toxicity|Anticholinergic toxidrome]]
-**[[Sympathomimetic overdose]]
+**[[Sympathomimetic toxicity]]
-**[[Salicylate overdose]]
+**[[Aspirin (Salicylate) toxicity]]
 **[[Serotonin syndrome]]
 **[[Malignant hyperthermia]]
-**[[Neuroleptic Malignant Syndrome]]
+**[[Neuroleptic malignant syndrome]]
-**Withdrawal (ETOH, benzo)
+**Withdrawal (e.g. ETOH, Benzodiazepines)
 {{AMS and fever DDX}}