Correct!
5. All of the above.
In a patient with unknown etiology of encephalopathy it is important to maintain a broad differential. Given the elevated blood pressure, tachycardia and fever, all the differentials above including drug intoxication and overdose should be considered.
Drug intoxication or overdose was thought to be less likely given urine drug screen was positive for opioids and benzodiazepines and not for cocaine or methamphetamine. Serotonin syndrome and neuroleptic malignant syndrome were also considered but were unlikely given patient did not have increased muscle tone, had normal reflexes and had not been taking medications prior to admission based on pharmacy review.
Overt hyperthyroidism patients typically present with anxiety, weakness, tremors, palpitation, heat intolerance and increased perspirations. Our patient did have many of these symptoms but our patient’s TSH and free T4 were within normal limits (1).
Heat stroke presents with a core body temperature >40 degrees C with CNS dysfunction in the setting of a large environment heat load and the body having impaired thermoregulation. Typically, this is caused by chronic medical conditions such as cardiovascular disease, neurologic disorders, obesity, and decreased mobility. It can also be caused by medications (beta-blockers, diuretics, anticholinergics) or recreational drugs (alcohol, cocaine, methamphetamine) (2). In Arizona, the summer temperatures can be above 100 degrees F and patients are at higher risk for heat stroke. Although at risk given apparent homelessness, our patient was not on any causative medications and does have any chronic medical conditions making it less likely.
Given our patient’s history of IV drug use and track marks on physical exam, he is at much higher risk for infective endocarditis causing embolic stroke (3). If this were the cause of his encephalopathy, he would have likely presented with murmur on exam, vegetations on echocardiogram, pulmonary infiltrates or other embolic phenomenon. This patient did not have any of these findings.
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