Reference no: EM133676003

Question

An 18-year-old woman is brought to the emergency department by her mother because the daughter seems confused and is behaving strangely. The mother reports the patient has always been healthy and has no significant medical his- tory, but she has lost 20 lb recently without trying and has been complaining of fatigue for 2 or 3 weeks. The patient had attributed the fatigue to sleep distur- bance, as recently she has been getting up several times at night to urinate. This morning, the mother found the patient in her room, complaining of abdominal pain, and she had vomited. She appeared confused and did not know that today was a school day. On examination, the patient is slender, lying on a stretcher with eyes closed, but she is responsive to questions. She is afebrile, and has a heart rate of 118 bpm, blood pressure of 125/84 mm Hg, with deep and rapid respirations at the rate of 24 bpm. Upon standing, her heart rate rises to 145 bpm, and her blood pressure falls to 110/80 mm Hg. Her funduscopic examination is normal, her oral mucosa is dry, and her neck veins are flat. Her chest is clear to auscultation, and her heart is tachycardic with a regular rhythm and no murmur. Her abdomen is soft with active bowel sounds and mild diffuse tenderness, but no guarding or rebound. Her neurologic examination reveals no focal deficits. Laboratory studies include serum Na 131 mEq/L, K 5.3 mEq/L, Cl 95 mEq/L, CO2 9 mEq/L, blood urea nitrogen (BUN) 35 mg/dL, creatinine 1.3 mg/dL, and glucose 475 mg/dL Arterial blood gas reveals pH 7.12 with PCO2 24 mm Hg and PO2 95 mm Hg. Urine drug screen and urine pregnancy test are negative, and urinalysis shows no hematuria or pyuria, but 3+ glucose and 3+ ketones. Chest radiograph is read as normal and plain film of the abdomen has nonspecific gas pattern but no signs of obstruction. What is the most likely diagnosis? What is your next step?