A 64-year-old woman was found poorly responsive in her apartment and brought to the hospital via ambulance. She has recently become more withdrawn and no longer participates in events at her local senior center during the past few weeks. Her medical history includes severe degenerative arthritis of her hips and knees, type 2 diabetes mellitus, hyperlipidemia, and hypertension. Her medications include aspirin, atenolol, lovastatin, metformin, and NSAIDs in unknown doses. She has no known drug allergies. She has no history of tobacco or alcohol use.
Examination shows that she is lethargic and complains of poor hearing. She is only oriented to person. Her temperature is 37.3°C (99.1°F), blood pressure is 130/76 mm Hg, pulse is 110/min, and respirations are 24/min. Her pulse oximetry shows 94% on room air. Her neck is supple. Examinations of the heart and lungs show no abnormalities. Abdominal examination reveals no tenderness. She has 2+ pulses, with warm extremities. There are no focal neurologic findings.
The patient's laboratory studies reveal:

Chest x-ray shows no abnormalities.
Which of the following interventions would be most beneficial for this patient?

Question

A 64-year-old woman was found poorly responsive in her apartment and brought to the hospital via ambulance.  She has recently become more withdrawn and no longer participates in events at her local senior center during the past few weeks.  Her medical history includes severe degenerative arthritis of her hips and knees, type 2 diabetes mellitus, hyperlipidemia, and hypertension.  Her medications include aspirin, atenolol, lovastatin, metformin, and NSAIDs in unknown doses.  She has no known drug allergies.  She has no history of tobacco or alcohol use.
Examination shows that she is lethargic and complains of poor hearing.  She is only oriented to person.  Her temperature is 37.3°C (99.1°F), blood pressure is 130/76 mm Hg, pulse is 110/min, and respirations are 24/min.  Her pulse oximetry shows 94% on room air.  Her neck is supple.  Examinations of the heart and lungs show no abnormalities.  Abdominal examination reveals no tenderness.  She has 2+ pulses, with warm extremities.  There are no focal neurologic findings.
The patient's laboratory studies reveal:

Chest x-ray shows no abnormalities.
Which of the following interventions would be most beneficial for this patient?

Quizplus · Accepted Answer

This patient's clinical presentation is strongly suggestive of salicylate toxicity, with the classic clinical features summarized in the table below. Salicylate directly stimulates the central respiratory center to cause a respiratory alkalosis and also uncouples oxidative phosphorylation to cause an increased anion gap metabolic acidosis (due to increased lactate). 11ec193a_971f_e4b4_853d_554109d20c01_MD0002_00 Salicylate intoxication often results in decreased hearing, tinnitus, and a lower serum uric acid level (decreased tubular reabsorption of uric acid). Salicylate can also directly suppress synthesis of some vitamin K-dependent coagulation factors, resulting in mild elevation of the prothrombin time. Diagnosis is confirmed by an elevated plasma salicylate level. Treatment involves supportive care (i.e., oxygen). Patients should not be intubated, if possible, because aspirin acts on the respiratory center in the medulla and can cause a marked increase in minute ventilation. Alkalinization of the urine with intravenous bicarbonate traps the ionic form of salicylic acid in tubular fluid and enhances renal elimination. Note that alkalinization is NOT contraindicated, despite the presence of alkalemia from respiratory alkalosis. Hemodialysis is reserved for patients with altered mental status, pulmonary or cerebral edema, renal insufficiency, and salicylate level >100 mg/dL. (Choice A) N-acetylcysteine is a treatment for acetaminophen toxicity, which may present with abnormal mental status, elevated liver function tests, and increased prothrombin time. However, this patient's liver function tests are only mildly elevated and do not explain the remainder of the clinical scenario (i.e., poor hearing, low uric acid, and acid-base disturbance). N (Choice B) Pulmonary embolism typically presents with hypoxia, pleuritic chest pain, and respiratory alkalosis. This patient has respiratory alkalosis, but the elevated prothrombin time and altered mentation without hypoxia are less consistent with pulmonary embolism. (Choice C) While an acute neurologic event may cause altered mentation, a stroke is not consistent with this patient's laboratory values and clinical presentation. (Choice E) Sepsis can result in combined respiratory alkalosis and anion gap metabolic acidosis due to increased lactate. This patient has normal urinalysis and a negative chest x-ray; early sepsis could still be possible but is less likely. Educational objective: Combined respiratory alkalosis and increased anion gap metabolic acidosis suggest the presence of salicylate intoxication. Other clinical and laboratory features include decreased hearing, tinnitus, and very low serum uric acid. Treatment is supportive and involves alkalization of the urine with intravenous bicarbonate to promote renal excretion. Dialysis is reserved for more serious cases. __________ References: Unrecognized adult salicylate intoxication (http://www.ncbi.nlm.nih.gov/pubmed/999110)

A 64-Year-Old Woman Was Found Poorly Responsive in Her Apartment