A 20-year-old previously healthy woman is brought to the emergency department due to lethargy. According to her mother, the patient had a "stomach bug" 2 days ago, with nausea, vomiting, and abdominal pain that began after eating in a restaurant. Her vomiting has resolved since that time, but she continues to have nausea and abdominal pain. Review of systems is positive for excessive thirst and a 4-kg (9-lb) weight loss over the past 2 weeks. She is not sexually active, and her last menstrual period was 10 days ago. The patient occasionally drinks beer but does not smoke or use illicit drugs. Temperature is 37.2 C (99 F), blood pressure is 100/56 mm Hg, pulse is 120/min, and respirations are 28/min. Pulse oximetry is 97% on room air. On examination, the patient is lethargic but easily arousable; she responds to questions in short sentences and moves all extremities spontaneously. Mucous membranes are dry, and the neck is supple. Other than tachycardia, cardiopulmonary examination is normal. There is diffuse abdominal tenderness without rebound tenderness, guarding, or rigidity. Which of the following is the best immediate next step in management of this patient's illness?

Question

A 20-year-old previously healthy woman is brought to the emergency department due to lethargy.  According to her mother, the patient had a "stomach bug" 2 days ago, with nausea, vomiting, and abdominal pain that began after eating in a restaurant.  Her vomiting has resolved since that time, but she continues to have nausea and abdominal pain.  Review of systems is positive for excessive thirst and a 4-kg (9-lb) weight loss over the past 2 weeks.  She is not sexually active, and her last menstrual period was 10 days ago.  The patient occasionally drinks beer but does not smoke or use illicit drugs.  Temperature is 37.2 C (99 F), blood pressure is 100/56 mm Hg, pulse is 120/min, and respirations are 28/min.  Pulse oximetry is 97% on room air.  On examination, the patient is lethargic but easily arousable; she responds to questions in short sentences and moves all extremities spontaneously.  Mucous membranes are dry, and the neck is supple.  Other than tachycardia, cardiopulmonary examination is normal.  There is diffuse abdominal tenderness without rebound tenderness, guarding, or rigidity.  Which of the following is the best immediate next step in management of this patient's illness?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d198_c6a9_bc81_d3b30d18a4a0_MD0003_00 This patient's presentation suggests diabetic ketoacidosis (DKA) from new-onset type 1 diabetes mellitus (T1DM). DKA was likely triggered by her recent gastrointestinal illness (ie, nausea and vomiting), which exacerbated dehydration and precipitated ketosis. Features of this patient's illness consistent with DKA include: Young age: Although T1DM is classically associated with childhood onset, one-fourth of new cases are diagnosed in young adults. DKA is the second most common initial presentation of T1DM. Symptoms: Rapid onset of weight loss, polydipsia (increased thirst), and diffuse abdominal pain occurs, possibly from acidosis and electrolyte abnormalities impairing gastrointestinal function (eg, delayed gastric emptying, ileus). Clinical signs: Dehydration (evidenced by tachycardia and hypotension) and hyperventilation (ie, compensation for metabolic acidosis) are prominent. Therefore, checking fingerstick glucose is the appropriate next step in management. This test is rapid and minimally invasive; it can narrow the differential diagnosis and initial treatment for this patient's gastrointestinal symptoms and lethargy. Glucose levels of 300-800 mg/dL should prompt empiric treatment for DKA (eg, insulin, intravenous fluids) and confirmatory testing (eg, serum ketones, arterial blood gas). (Choice A) Although infection is a common trigger of DKA, blood glucose measurement should be performed first because it can rapidly confirm a presumptive diagnosis and guide management. (Choice B) Abdominal pain, hypotension, and vomiting can be seen in primary adrenal insufficiency, diagnosed via cosyntropin stimulation testing. However, adrenal insufficiency is unlikely to explain polydypsia and hyperventilation; moreover, it is associated with hypoglycemia. Assessing fingerstick glucose is a more optimal approach to narrowing the diagnosis. (Choices C and E) Severe upper gastrointestinal bleed and mesenteric ischemia can cause acute abdominal pain and hypotension, and may be detected on CT scan of the abdomen and endoscopy. However, neither condition explains this patient's polydypsia or hyperventilation, and her young age and absence of associated risk factors (eg, excessive alcohol intake, atrial fibrillation) make either diagnosis unlikely. (Choice F) Although salicylate poisoning (detectable on urine toxicology screen) may lead to abdominal pain, lethargy, and nausea, associated symptoms of tinnitus and vertigo are absent in this patient. Moreover, her 2-week prodrome of polydipsia and weight loss point to diabetes mellitus. Educational objective: Diabetic ketoacidosis can be the initial manifestation of type 1 diabetes mellitus. Typical symptoms include acute onset of weight loss, polydipsia, abdominal pain, hyperventilation, and altered mentation. Fingerstick blood glucose can rapidly provide a presumptive diagnosis, and treatment should begin immediately with intravenous fluids and insulin. References: The evolution of diabetic ketoacidosis: an update of its etiology, pathogenesis and management. (http://www.ncbi.nlm.nih.gov/pubmed/26975543) Evidence-based management of hyperglycemic emergencies in diabetes mellitus. (http://www.ncbi.nlm.nih.gov/pubmed/21978840)

A 20-Year-Old Previously Healthy Woman Is Brought to the Emergency