BACKGROUND
A 38-year-old man is brought by ambulance to the emergency department (ED). The patient was found lying near the stoop of an apartment building. The paramedics were unable to obtain any history from the patient en route because the patient has an altered mental status.
On arrival, the patient’s vital signs are an oral temperature of 95.72°F (35.4°C), a blood pressure of 88/40 mm Hg, a heart rate of 38 bpm, and a respiratory rate of 24 breaths/min. His oxygen saturation could not be obtained. The patient appears to be a homeless, disheveled man and looks older than his chronologic age, with a faint smell of alcohol on his breath. He can be aroused but does not follow simple commands. He has intact gag and corneal reflexes. His pupils are equal and reactive to light. No obvious signs of head trauma are noted, and the examination of his oropharynx is unremarkable. The results of his cardiac examination are significant for marked bradycardia. A lung examination reveals rhonchi in the right lower lung field. The patient’s skin is cold, and his blood glucose level is 104 mg/dL.
An electrocardiogram (ECG) was performed before the physical examination (see Image).
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What is the diagnosis and treatment?
HINT
The patient’s rectal temperature is 87.7°F (31°C).
Authors:
Malkeet Gupta, MS, MD,
Department of Emergency Medicine,
UCLA/Olive View – UCLA Emergency Medicine Residency Program,
Los Angeles, Calif
Joshua M. Kosowsky, MD,
Attending Physician,
Department of Emergency Medicine,
Brigham and Women’s Hospital,
Boston, Mass
eMedicine Editors:
Rick G. Kulkarni, MD,
Assistant Professor,
Yale School of Medicine,
Section of Emergency Medicine,
Department of Surgery,
Attending Physician,
Medical Director,
Department of Emergency Services,
Yale-New Haven Hospital, CT
ANSWER
Hypothermia secondary to alcohol use and environmental exposure: The patient’s ECG demonstrates the classic abnormalities associated with hypothermia, the most evident being profound sinus bradycardia. In addition, all leads show classic Osborn waves (J waves seen at the junction of the QRS complex and the ST segment). As always, the ECG must be interpreted within the clinical context; in this case, the apparent elevations of the ST segment should not be misinterpreted as evidence of myocardial injury. Other common ECG findings associated with hypothermia that are not seen on this tracing include atrial and ventricular dysrhythmias, as well as prolongation of the PR, QRS, and QT intervals.
This case features the most common etiology of hypothermia (ie, environmental exposure or accidental hypothermia). Other conditions often coexist, such as infection, metabolic abnormalities (eg, hypoglycemia), drug or alcohol overdose, and endocrine problems (eg, hypothyroidism); on occasion, any one or a combination of these conditions may also be the etiology.
In general, the life-threatening cardiovascular complications of hypothermia are cardiogenic shock and malignant dysrhythmias. Typically, rewarming the patient is sufficient to restore normal myocardial contractility and cardiac rhythm. For patients in shock who do not respond to resuscitation with warmed intravenous fluid and other passive and active rewarming techniques, low-dose dopamine is the recommended agent because of its inotropic and peripheral vasoconstrictive effects. Atrial dysrhythmias are generally associated with a slow ventricular response; therefore, treatment with digoxin or calcium channel blockers is not warranted. Bretylium has long been recommended for the treatment and prevention of ventricular dysrhythmias, though little evidence supports this practice. The use of amiodarone has increased in recent years as a result of shortages in the world supply of bretylium. For refractory bradydysrhythmia, external noninvasive pacing is recommended in favor of transvenous pacing because insertion of pacing wires into a hypothermic ventricle can potentially cause a fatal dysrhythmia.
Hypothermia is often diagnosed before an ECG is performed; however, the ECG can provide important clues to the diagnosis and yields critical information regarding the overall severity of the patient’s condition, from an electrophysiologic standpoint.
References:
Solomon A, Barish RA, Browne B, Tso E: The electrocardiographic features of hypothermia. J Emerg Med 1989 Mar-Apr;7(2):169-73. [Medline: 2738372]
McCullough L, Arora S: Diagnosis and treatment of hypothermia. Am Fam Phys 2004 Dec 15;70(12):2325-32. [Medline: 15617296]
Marx JA, Hockberger RS, Walls RM. Rosen’s Emergency Medicine: Concepts and Clinical Practice. St Louis, Mo: Mosby-Year Book; 2002.
