A 19-year-old woman is brought to the emergency department by her mother due to suspected drug poisoning. The patient has severe depression treated with fluoxetine and lives with her mother and grandparents. The patient suddenly became ill at home earlier today and developed nausea and vomiting. Her mother suspects the patient may have intentionally ingested a substance to harm herself as her grandparents' medicine cabinet door was found open. On further questioning, the patient states that she swallowed a handful of one of the medications in the cabinet but does not specify further. Her grandparents' medical conditions include anxiety, seasonal allergies, coronary artery disease, and chronic back pain. The patient's mother does not know the specific names and dosages of the medications. Currently, the patient reports nausea and dizziness and has vomited 3 times since arriving at the emergency department. She has smoked a pack of cigarettes daily for the past 5 years and drinks 1 or 2 beers occasionally. She has a history of prior ecstasy use but has no recent use of illicit drugs. Temperature is 38.1 C (100.6 F) , blood pressure is 100/55 mm Hg, pulse is 110/min, and respirations are 28/min. Pulse oximetry shows 99% saturation on ambient air. Examination reveals an awake, agitated young woman with dry mucous membranes. The pupils are 4 mm bilaterally and reactive to light. Heart sounds are normal and the lungs are clear to auscultation. The abdomen is soft, nontender, and nondistended; bowel sounds are normoactive. Motor and sensory deficits are absent, and the patient is fully oriented. A 12-lead ECG shows sinus tachycardia. Chest x-ray reveals clear lung fields and no cardiomegaly. The patient is given intravenous fluids and is placed on continuous ECG monitoring. Laboratory tests are ordered. Item 1 of 2
Which of the following is the most likely cause of this patient's condition?

Question

Quizplus · Accepted Answer

Explanation: 11ec2b69_c019_a86a_8f63_77f0d9f1496b_MD0005_00 This patient with marked tachypnea, tachycardia, hyperthermia, dizziness, and gastrointestinal symptoms after ingestion of an unknown substance likely has acute salicylate toxicity from aspirin ingestion. Salicylate crosses the blood-brain barrier and directly stimulates the medullary respiratory center (increasing respiratory rate and causing respiratory alkalosis) and the chemoreceptor trigger zone (causing nausea and vomiting). Cochlear neurotoxicity may result in tinnitus (early symptom). Cerebral tissue injury and neuroglycopenia lead to cerebral edema and mental status changes. Inhibition of cellular metabolism causes lactic acidosis and hyperthermia. In severe cases, pulmonary edema, arrhythmia, and death may result. Serum salicylate levels do not correspond to symptoms, but patients frequently develop toxicity with levels >40 mg/dL. (Choice A) Anticholinergic toxicity (often due to tricyclic antidepressant intake) can cause fevers, dry mucous membranes, and tachycardia; however, the toxidrome typically includes nonreactive mydriasis, skin erythema, anhidrosis, altered mental status, and urinary retention. It would not be expected to cause nausea and vomiting or tachypnea. (Choice B) Benzodiazepine poisoning causes central nervous system depression, which typically causes slurred speech and sedation and in severe cases (typically with intravenous use) may lead to respiratory depression. It would not be expected to cause hyperthermia, tachypnea, tachycardia, or gastrointestinal distress. (Choice C) Opiate intoxication would cause central nervous system depression. Associated symptoms include sedation, respiratory depression, slurred speech, constricted pupils, and hypoactive bowel sounds. (Choice E) Serotonin syndrome, classically due to ingestion of selective serotonin reuptake inhibitors, causes autonomic dysfunction including tachycardia, hyperthermia, and nausea and vomiting. However, patients are expected to have clonus, hyperreflexia, slow horizontal eye movements (ocular clonus), tremor, and rigidity. Educational objective: Salicylate toxicity causes nausea and vomiting, tachypnea with respiratory alkalosis, lactic acidosis, hyperthermia, and altered mental status, due to its stimulation of the medullary respiratory center and chemoreceptor trigger zone and the inhibition of cellular metabolism.

A 19-Year-Old Woman Is Brought to the Emergency Department by Her