A 55-year-old man is admitted to the hospital due to fever and altered mental status. He was seen in an urgent care clinic 2 days ago for cellulitis of the left leg, for which he received a prescription for oral doxycycline. The patient has no other medical conditions and takes no medications. Temperature is 39 C (102.2 F), blood pressure is 80/60 mm Hg, and pulse is 112/min. Oxygen saturation is 94% on 2 L/min of oxygen via nasal cannula. The patient is drowsy but moves all the extremities on verbal command. Examination of the left leg reveals significant tenderness with erythema, swelling, and warmth. Laboratory results are as follows: Finger-stick blood glucose is 46 mg/dL. Blood pressure improves to 100/70 mm Hg with a fluid bolus. Which of the following is the most likely cause of the low glucose levels in this patient?

Question

A 55-year-old man is admitted to the hospital due to fever and altered mental status.  He was seen in an urgent care clinic 2 days ago for cellulitis of the left leg, for which he received a prescription for oral doxycycline.  The patient has no other medical conditions and takes no medications.  Temperature is 39 C (102.2 F), blood pressure is 80/60 mm Hg, and pulse is 112/min.  Oxygen saturation is 94% on 2 L/min of oxygen via nasal cannula.  The patient is drowsy but moves all the extremities on verbal command.  Examination of the left leg reveals significant tenderness with erythema, swelling, and warmth.  Laboratory results are as follows:  Finger-stick blood glucose is 46 mg/dL.  Blood pressure improves to 100/70 mm Hg with a fluid bolus.  Which of the following is the most likely cause of the low glucose levels in this patient?

Quizplus · Accepted Answer

11ec25c8_d3c2_abad_bc81_ab8ff9e1d4aa_MD0003_00 This patient has worsening cellulitis associated with hypotension, fever, and severe leukocytosis, findings consistent with sepsis. He also has significant hypoglycemia despite no history of diabetes and no treatment with antidiabetic medications (eg, insulin, sulfonylureas). Hypoglycemia is uncommon in patients who are not treated with insulin or sulfonylureas for diabetes mellitus. However, it can occur in those with sepsis or other critical illnesses due to increased use of glucose in the tissues, which is promoted by inflammatory cytokines. Sepsis may also lead to suppression of gluconeogenesis in the liver. The risk is also higher in patients with renal insufficiency, likely due to decreased renal gluconeogenesis and reduced clearance of endogenous insulin. Severe physiologic stress (eg, sepsis) can lead to a catecholamine (eg, epinephrine) surge, which stimulates hepatic glycogenolysis and gluconeogenesis; however, this effect would manifest as hyperglycemia rather than hypoglycemia (Choice D). (Choice A) Infection in patients with chronic adrenal insufficiency can precipitate adrenal crisis, presenting with hypoglycemia, shock, and abnormal mental status. However, this patient has no prior symptoms of adrenal insufficiency (eg, anorexia, weight loss) or hyponatremia. Also, the hypotension in adrenal crisis does not usually respond to fluids alone and typically requires cortisol replacement. The mild increase in this patient's serum potassium is likely due to lactic acidosis from sepsis. (Choice B) Depletion of glycogen stores is not a primary contributor to hypoglycemia in the early stages. It is typically seen after a prolonged fast (ie, >24-48 hr), such as in binge alcohol drinkers. (Choice C) As circulating glucose levels fall in patients with sepsis, insulin secretion is suppressed, not increased. (Choice F) Severe pancreatic injury can cause loss of insulin-producing beta cells, leading to pancreatogenic diabetes. Although concurrent loss of glucagon-secreting alpha cells can increase the risk for insulin-induced hypoglycemia, hyperglycemia is the primary effect. (Choice G) Besides antidiabetic agents, drugs that can cause hypoglycemia include quinolones, ACE inhibitors, and likely beta blockers. Doxycycline does not significantly affect blood glucose. Educational objective: Hypoglycemia can occur in patients with critical illness due to increased use of glucose in the tissues and suppression of gluconeogenesis in the liver. The risk is higher in patients with renal insufficiency, likely due to decreased renal gluconeogenesis and reduced clearance of endogenous insulin. References: Hospitalization With Hypoglycemia in Patients Without Diabetes Mellitus: A Retrospective Study Using a National Inpatient Database in Japan, 2008-2012. (http://www.ncbi.nlm.nih.gov/pubmed/28640135)

A 55-Year-Old Man Is Admitted to the Hospital Due to Fever