Internal Medicine

0521779407-09 CUNY1086/Karliner 0 521 77940 7 June 13, 2007 7:54

Hypothermia 799

HYPOTHERMIA

DAVID C. McGEE, MD and STEPHEN J. RUOSS, MD

history & physical

History

■Exposure to cold; wind chill magnifies thermal losses

■Debilitated, elderly, young, alcoholism, psychiatric illness

■Trauma, overdose, and CVAs may mask or amplify hypothermia

Signs & Symptoms

■Hypothermia=core temperature 35◦C; need low-reading rectal

probe or esophageal thermometer

■Mild hypothermia (34–35◦C): apathy, uncooperative, flat affect, shiv-

ers, chills, stiff joints, dizziness, nausea, hunger, pruritus; tachycardia

secondary to catecholamine release

■Moderate hypothermia (30–33◦C): slurred speech, loss of coordina-

tion, ataxia, progressively depressed level of consciousness, coma;

no shivering <32◦C; high urine output secondary to cold diuresis

■Severe hypothermia (<30◦C): bradycardia, dilated, sluggish pupils,

stiffness and rigor mortis; high urine output secondary to cold

diuresis; loss of plantar responses (<25◦C)

tests

Diagnostic Tests

■CBC with differential, electrolytes, renal panel, glucose, calcium,

magnesium, amylase, lipase, coagulation profile, arterial blood gas,

ECG, toxicology screen, CXR

■Acidosis, hypokalemia, and hyperkalemia common; hypoglycemia

(depletion of glycogen stores) and hyperglycemia (inactivation of

insulin) occur. Do NOT treat hyperglycemia because rebound hypo-

glycemia common during rewarming

■ECG shows sinus bradycardia and QT prolongation; Osborn waves

( J-point elevation) seen best in leads II and V6; arrhythmia risk

increases at <32◦C; asystole or silent ECG can occur at temperature

<30◦C

■EEG flat at temperature <18◦C

Other Tests as Appropriate

■Cultures, esp in older patients with preexisting medical conditions

■Cervical spine series when trauma suspected