Four days after admission to the hospital for anorexia nervosa, a 20-year-old woman has new-onset palpitations and paresthesias in all four limbs. Prior to admission, she was found unconscious by her parents on the floor of a residential treatment center. The patient was started on a trial of nutritional rehabilitation upon arrival to the hospital. Her temperature is 36°C (96.8°F), pulse is 47/min, and blood pressure is 90/60 mmHg. She is 160 cm tall and weighs 35 kg; BMI is 14 kg/m2. The patient appears emaciated. Examination shows lower leg edema. A 2/6 holosystolic murmur is heard over the 5th intercostal space at the midclavicular line. An ECG shows intermittent supraventricular tachycardia and QTc prolongation. Serum studies show: Day 2 Day 4 Potassium (mEq/L) 3.5 2.7 Calcium (mg/dL) 8.5 7.8 Magnesium (mEq/L) 1.2 0.5 Phosphorus (mg/dL) 3.6 1.5 Which of the following is the most likely underlying cause of this patient's condition?
AUncompensated metabolic alkalosis
BThiamine deficiency
CEuthyroid sick syndrome
DRapid gastric emptying
EIncreased insulin release
An ECG from an 8-year-old male with neurosensory deafness and a family history of sudden cardiac arrest demonstrates QT-interval prolongation. Which of the following is this patient most at risk of developing?
AHypertrophic cardiac myopathy
BCardiac tamponade
CEssential hypertension
DTorsades de pointes
EFirst degree atrioventricular block
A 53-year-old man with obesity and heart disease presents to your outpatient clinic with complaints of orthopnea, significant dyspnea on minimal exertion, nausea, vomiting, and diarrhea. He says that his old doctor gave him "some pills" that he takes in varying amounts every morning. Physical exam is significant for a severely displaced point of maximal impulse, bilateral rales in the lower lung fields, an S3 gallop, and hepatomegaly. You decide to perform an EKG (shown in figure A). Suddenly, his rhythm changes to ventricular tachycardia followed by ventricular fibrillation, and he syncopizes and expires despite resuscitative efforts. High levels of which medication are most likely responsible?
APropranolol
BAmiodarone
CLidocaine
DVerapamil
EDigoxin
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