A 45-year-old man is brought to the hospital due to confusion. His family had last seen him at lunch a few hours ago, and he was normal at that time. The patient has a history of schizoaffective disorder, Tourette syndrome, and polysubstance use disorder. Temperature is 38.5 C (101.3 F), blood pressure is 110/70 mm Hg, pulse is 120/min and regular, and respirations are 30/min. Oxygen saturation is 96% on room air. Pupils are 3 mm and reactive to light. Lungs are clear to auscultation. Epigastric tenderness is present, but there is no rebound or rigidity. The patient is not oriented to place or person. Neurologic examination shows no focal deficits. Deep tendon reflexes are normal. Laboratory results are as follows: Which of the following is the next best step in the management of this patient?

Question

A 45-year-old man is brought to the hospital due to confusion.  His family had last seen him at lunch a few hours ago, and he was normal at that time.  The patient has a history of schizoaffective disorder, Tourette syndrome, and polysubstance use disorder.  Temperature is 38.5 C (101.3 F), blood pressure is 110/70 mm Hg, pulse is 120/min and regular, and respirations are 30/min.  Oxygen saturation is 96% on room air.  Pupils are 3 mm and reactive to light.  Lungs are clear to auscultation.  Epigastric tenderness is present, but there is no rebound or rigidity.  The patient is not oriented to place or person.  Neurologic examination shows no focal deficits.  Deep tendon reflexes are normal.  Laboratory results are as follows:  Which of the following is the next best step in the management of this patient?

Quizplus · Accepted Answer

Explanation: 11ec25c8_d1db_9c68_bc81_c5a5a11fde30_MD0003_00 This patient's confusion, hyperthermia, tachypnea, elevated lactate, and anion gap metabolic acidosis raise suspicion for acute salicylate toxicity. Most cases are caused by excessive ingestion of aspirin, although it can also be seen due to overuse of other salicylate products (eg, oil of wintergreen [methylsalicylate]). Toxic quantities of salicylates quickly overwhelm the ability of the liver to metabolize the compound, which prompts prolonged serum elevation of the drug due to slower renal excretion. Patients usually have the following manifestations: Nausea, vomiting, and epigastric pain due to stimulation of the chemoreceptor trigger zone in the medulla, irritation of the gastric mucosa, and reduced gastric epithelial prostaglandin production Hyperventilation due to stimulation of the respiratory center in the medulla Anion gap metabolic acidosis due to interference with the Krebs cycle and oxidative phosphorylation, which leads to lactic acidosis (because gluconeogenesis is impaired) and hyperthermia (because byproducts of energy production are dissipated as heat) Confusion due to neuroglycopenia and cerebral edema Tinnitus also commonly occurs. The diagnosis is made with serum salicylate level. Treatment includes supportive therapy and activated charcoal if aspirin was ingested. (Choice A) Carboxyhemoglobin level is elevated in carbon monoxide poisoning, which often presents with confusion, lactic acidosis, and anion gap metabolic acidosis. However, patients do not typically have hyperthermia. (Choice B) CT mesenteric angiogram can diagnose acute mesenteric ischemia, which often causes severe abdominal pain, nausea/vomiting, and lactic acidosis. However, tachypnea, hyperthermia, and confusion are less common. In addition, most patients have a risk factor for acute embolism, such as atrial fibrillation (eg, irregular rhythm). (Choice C) CT scan of the abdomen could diagnose an abdominal abscess, which may cause abdominal pain, nausea/vomiting, and lactic acidosis from sepsis. However, it is unlikely that symptoms would progress over a few hours; several days would be more common. Peptic ulcer disease (sometimes noted as mucosal discontinuity on CT) can cause epigastric pain but would not cause lactic acidosis in the absence of hypotension (eg, hypoperfusion, perforation with rebound/guarding). (Choice D) Dantrolene treats neuroleptic malignant syndrome (NMS), a hypermetabolic syndrome associated with some antipsychotic agents. Although NMS can cause hyperthermia and altered mental status, severe muscle rigidity would be expected. (Choice E) This patient's metabolic abnormalities suggest a condition outside the CNS. Although this patient may undergo noncontrast head CT scan due to confusion, a brain MRI is expensive, time consuming, and generally reserved for identifying cerebrovascular events, tumors, and other conditions with focal neurologic deficits. (Choice F) Naloxone reverses acute opioid overdose, which can cause decreased level of consciousness but is not typically associated with hyperthermia and is generally marked by miotic pupils (eg, <2 mm) and decreased respiratory rate (not tachypnea). Educational objective: Salicylate toxicity is generally marked by nausea/vomiting, anion gap metabolic acidosis, elevated lactate level, hyperthermia, and tachypnea. Diagnosis is made with serum salicylate level.

A 45-Year-Old Man Is Brought to the Hospital Due to Confusion