A 57‐year‐old man is brought to the emergency department due to lethargy and altered mental status. His family suspects a suicide attempt. Medical history is significant for dilated cardiomyopathy and major depressive disorder. On arrival, blood pressure is 76/46 mm Hg, pulse is 38/min, and respirations are 16/min. Pupils are 3 mm and reactive. Oropharynx is normal. Examination shows bilateral wheezing. There is no peripheral edema. Capillary refill is 3 seconds. There is no diaphoresis. Which of the following categories of medication did this patient most likely ingest?

Question

A 57‐year‐old man is brought to the emergency department due to lethargy and altered mental status.  His family suspects a suicide attempt.  Medical history is significant for dilated cardiomyopathy and major depressive disorder.  On arrival, blood pressure is 76/46 mm Hg, pulse is 38/min, and respirations are 16/min.  Pupils are 3 mm and reactive.  Oropharynx is normal.  Examination shows bilateral wheezing.  There is no peripheral edema.  Capillary refill is 3 seconds.  There is no diaphoresis.  Which of the following categories of medication did this patient most likely ingest?

Quizplus · Accepted Answer

11ec160b_3c3e_c300_9249_0959754c6dc0_MD0001_00 This patient has altered mental status and difficulty breathing in the setting of hypotension and bradycardia. The body typically compensates for hypotension by becoming tachycardic. It is unusual to see both bradycardia and hypotension simultaneously, and medication overdose should be suspected in these cases. Although several medications can cause hypotension and bradycardia, this patient's wheezing suggests bronchospasm and makes beta blocker toxicity most likely. Beta-1 receptors are located primarily in the heart, whereas beta-2 receptors are located on the smooth muscle of the lung bronchioles and skeletal muscle arterioles, as well as on hepatocytes. When activated by catecholamines, beta-1 receptors cause increased heart rate and cardiac contractility and beta-2 receptors cause smooth muscle relaxation with bronchodilation. Beta-2 receptor activation also stimulates hepatocellular gluconeogenesis and glycogenolysis to increase blood glucose. Beta blockers are commonly used to treat high blood pressure and arrhythmias, and often target both beta-1 and beta-2 receptors. Because beta blockers act as competitive antagonists for endogenous catecholamines, beta blocker toxicity prevents the catecholamine-mediated effects on the heart, lungs, and liver, causing hypotension, bradycardia, bronchospasm, and hypoglycemia. The hypotension (ie, poor organ perfusion) and hypoglycemia contribute to altered mental status. (Choice B) Although cardiac glycoside (eg, digoxin) toxicity causes hypotension and bradycardia, bronchospasm is not seen. Toxicity also presents with nausea, vomiting, tachyarrhythmias, and visual changes. (Choice C) Opioid overdose presents with respiratory depression, depressed mental status, and pinpoint pupils. Bronchospasm is not typically seen. In fact, opioids help suppress cough receptors. (Choice D) Although organophosphate toxicity can cause bronchorrhea/bronchospasm and bradycardia, clinical features are dominated by other findings of cholinergic excess (eg, salivation/drooling, lacrimation, diaphoresis); pupils are also usually constricted. (Choice E) Serotonin syndrome primarily manifests with neuromuscular hyperactivity (ie, tremor, muscle rigidity, myoclonus, hyperreflexia). Bronchospasm is uncommon. Educational objective: Beta blockers act as competitive antagonists for endogenous catecholamines; therefore, toxicity presents with hypotension, bradycardia, bronchospasm, and hypoglycemia. The hypotension and hypoglycemia contribute to altered mental status. __________ References: Beta-Blocker Toxicity (http://www.ncbi.nlm.nih.gov/pubmed/28846217)

A 57‐year‐old Man Is Brought to the Emergency Department Due