Cardiology I – A Review of Cardiovascular Anatomy and Physiology
by Cwanza A. Pinckney, M.D.
Figure 3: Assessment Figure 2: Management

Case 2: Cocaine Overdose

-Presentation:

A concerned 16 year old female calls the EMS and states that her boyfriend has overdosed on cocaine. She reports that they went to a party, and her boyfriend, who has never done drugs, snorted 6 lines of cocaine. The girl is concerned because her boyfriend is complaining of palpitations and is extremely agitated.

diagram

Upon arrival to the house you find a 17 year old male pacing around the house wearing dark sunglasses. As you question the young man, he informs you that he has never had any health problems in the past and that his friends pressured him into trying the cocaine. The young man tells you that he feels like his heart is going to jump out of his chest and that he feels like he cannot sit still.

On examination, the young man has dilated, blood-shot eyes, and he is tachycardic (with a heart rate of 135). He is also hypertensive (with a blood pressure of 200/120). He has clear respirations. The rest of his physical exam is normal, except for his inability to remain still.

-Keys to the History and Physical Exam:

-The Patient History:

1) This patient reports no significant past medical history, so a chronic medical disease most likely does not apply here.

2) This patient admits to cocaine use, which can stimulate the sympathetic nervous system (see the “cocaine toxicity” section below for more details).

3) The patient states that he is having palpitations and is agitated, which is consistent with cocaine use.

-The Physical Exam:

1) The patient is tachycardic, with a heart rate of 130, secondary to sympathetic (Beta-adrenergic) stimulation.

2) The patient is hypertensive, with a blood pressure of 200/120, secondary to sympathetic (alpha-adrenergic) stimulation.

3) The patient is wearing sunglasses because sympathetic stimulation has caused his eyes to dilate.

4) The patient is extremely agitated, which often results from an overwhelming sympathetic response in some patients.

-Cocaine Toxicity:

-Description:

Cocaine is a naturally occurring extract of the coca bush, Erythroxylon coca, a plant which is indigenous to South America.

-Pharmacology:

Cocaine is absorbed across all mucosal surfaces, including: the oral, nasal, gastrointestinal, and vaginal epithelium. Consequently, cocaine can be applied topically, swallowed, injected intravenously, or smoked in the form of crack or free base cocaine. When cocaine is used nasally, the peak effect occurs within 15 to 25 minutes, and its duration of action lasts around 1 to 3 hours. The intravenous and inhalational methods have rapid onsets and have durations of effect lasting around 15 to 30 minutes.4

-Effects:

Cocaine is both a local anesthetic and a central nervous system stimulant.

-Local Anesthetic: Like other local anesthetics, cocaine inhibits conduction of nerve impulses by blocking fast sodium channels in the cell membrane.

-Cardiovascular Effects: Cocaine has very dynamic effects on the heart. For example, in large doses, cocaine can be toxic to the myocardium of the heart, resulting in wide complex dysrhythmias and tachycardia. In addition, cocaine can activate the sympathetic nervous system through the excess release of neurotransmitters, which can lead to hypertension and tachycardia.

-Other Effects: Sympathetic activation can also lead to other characteristic physical exam findings, such as mydriasis (or eye dilation) and diaphoresis (or sweating). In addition, excess sympathetic stimulation predisposes a person to dysrhythmias, seizures, hyperthermia, and agitation.

-Initial Assessment and Management:

-See figures that follow.

Figure 3: Assessment Figure 2: Management