A 66-year-old woman is brought to the emergency department due to agitation, slurred speech, and muscle jerks after her daughter found her confused at home. Medical history includes gastroesophageal reflux, osteoarthritis, hypertension, and bipolar disorder controlled with lithium therapy. The patient cannot recall her other medications, but her daughter reports that a new antihypertensive medication was prescribed 2 weeks ago.
Temperature is 36.7 C (98.1 F), blood pressure is 136/84 mm Hg, pulse is 90/min and regular, and respirations are 16/min. On physical examination, the patient is restless and confused. Neurologic examination shows coarse tremors, sporadic myoclonic jerks, and ataxia. She has no nuchal rigidity and can move all extremities. Deep tendon reflexes are symmetric. The remainder of the physical examination is unremarkable.
Laboratory results are as follows:
Which of the following medications most likely contributed to this patient's current presentation?

Question

A 66-year-old woman is brought to the emergency department due to agitation, slurred speech, and muscle jerks after her daughter found her confused at home.  Medical history includes gastroesophageal reflux, osteoarthritis, hypertension, and bipolar disorder controlled with lithium therapy.  The patient cannot recall her other medications, but her daughter reports that a new antihypertensive medication was prescribed 2 weeks ago.
Temperature is 36.7 C (98.1 F), blood pressure is 136/84 mm Hg, pulse is 90/min and regular, and respirations are 16/min.  On physical examination, the patient is restless and confused.  Neurologic examination shows coarse tremors, sporadic myoclonic jerks, and ataxia.  She has no nuchal rigidity and can move all extremities.  Deep tendon reflexes are symmetric.  The remainder of the physical examination is unremarkable.
Laboratory results are as follows:
 Which of the following medications most likely contributed to this patient's current presentation?

Quizplus · Accepted Answer

11ec193a_9692_c022_853d_4b5b0dda64da_MD0002_00 This patient has confusion, agitation, ataxia, and neuromuscular excitability (eg, myoclonic jerks), findings consistent with acute lithium toxicity. Lithium is cleared primarily by the kidneys; medications or medical conditions that reduce glomerular filtration can precipitate a rise in blood lithium levels, resulting in clinical toxicity. Commonly used medications that reduce renal lithium clearance include ACE inhibitors (eg, lisinopril), angiotensin II receptor blockers, nonsteroidal anti-inflammatory drugs, and diuretics. Serum lithium levels in acute lithium toxicity may not directly correlate with symptom severity, so management is determined primarily by clinical features. Treatment includes supportive care (eg, intravenous hydration), gastrointestinal decontamination (eg, bowel irrigation with polyethylene glycol), and hemodialysis for severe toxicity. (Choices A, B, C, and D) Amlodipine, carvedilol, clonidine, and hydralazine have a lesser effect on glomerular filtration than ACE inhibitors and are less likely to cause acute lithium toxicity. Educational objective: Lithium is cleared primarily by the kidneys; medications (eg, ACE inhibitors, nonsteroidal anti-inflammatory drugs, diuretics) that reduce glomerular filtration can precipitate a rise in blood lithium levels, resulting in clinical toxicity. Treatment measures include intravenous hydration, gastrointestinal decontamination, and hemodialysis. __________ References: Preventing lithium intoxication. Guide for physicians. (http://www.ncbi.nlm.nih.gov/pubmed/11561336) Lithium therapy and its interactions. (http://www.ncbi.nlm.nih.gov/pubmed/32675910)

A 66-Year-Old Woman Is Brought to the Emergency Department Due