A 41-year-old man with a history of bipolar disorder is brought to the emergency department by his mother for confusion and agitation that she noticed while visiting today. The patient denies suicidal ideation and intentional overdose of his medication or illicit drugs. His only known medication is lithium.
His temperature is 37.2° C (99° F), blood pressure is 94/52 mm Hg, pulse is 89/min, and respirations are 18/min. The patient's pulse oximetry is 96% on room air. Examination shows dry mucous membranes, clear lung fields, and normal first and second heart sounds. The patient has a flat affect and does not answer most questions. He has a significant tremor in both hands.

Electrocardiogram shows normal sinus rhythm. Intravenous fluids are initiated.
Which of the following is the most appropriate next step in management?

Question

A 41-year-old man with a history of bipolar disorder is brought to the emergency department by his mother for confusion and agitation that she noticed while visiting today.  The patient denies suicidal ideation and intentional overdose of his medication or illicit drugs.  His only known medication is lithium.
His temperature is 37.2° C (99° F), blood pressure is 94/52 mm Hg, pulse is 89/min, and respirations are 18/min.  The patient's pulse oximetry is 96% on room air.  Examination shows dry mucous membranes, clear lung fields, and normal first and second heart sounds.  The patient has a flat affect and does not answer most questions.  He has a significant tremor in both hands.

Electrocardiogram shows normal sinus rhythm.  Intravenous fluids are initiated.
Which of the following is the most appropriate next step in management?

Quizplus · Accepted Answer

This patient's presentation (sluggishness, confusion, agitation, and neuromuscular excitability with irregular, coarse tremors) is consistent with acute-on-chronic lithium poisoning. Acute intoxication often presents with nausea, vomiting, diarrhea, and late development of neurologic symptoms. Chronic lithium toxicity can exhibit neurologic symptoms, but it usually occurs gradually over months or years. Patients taking chronic lithium may also have signs of nephrogenic diabetes insipidus or thyroid dysfunction. Serum lithium levels do not always correlate with signs of toxicity, especially in the acute setting. Initial management includes evaluating and stabilizing the airway and circulation. Saline infusion is the first-line therapy to ensure significant lithium clearance. Hemodialysis is indicated for serum lithium levels > 4 mEq/L (4 mmol/L) OR levels > 2.5 mEq/L PLUS either signs of significant lithium toxicity (eg, seizures, depressed mental status) or inability to excrete lithium (eg, renal disease, decompensated heart failure). (Choice A) Activated charcoal is not indicated for lithium toxicity as it does not prevent lithium absorption in the gastrointestinal tract. (Choice B) Forced diuresis has little clinical effect and may predispose the patient to further volume depletion. (Choice D) Ipecac is not recommended as it can be effective in inducing vomiting but does not necessarily ensure lithium removal. (Choice E) Whole-bowel irrigation with polyethylene glycol may be given to awake and asymptomatic patients within 2-3 hours of lithium consumption. Polyethylene glycol may be an alternate therapy to hemodialysis in these patients as it can empty the bowel and decrease toxin absorption. However, it is not beneficial for chronic toxicity. Educational objective: Lithium toxicity should be managed initially by stabilizing the airway and circulation and aggressive saline infusion to ensure significant lithium clearance. Hemodialysis is indicated for serum lithium levels > 4 mEq/L (4 mmol/L) OR levels > 2.5 mEq/L PLUS either signs of significant lithium toxicity or inability to excrete lithium. __________ References: Preventing lithium intoxication. Guide for physicians. (http://www.ncbi.nlm.nih.gov/pubmed/11561336) Toxicology in the ICU: part 1: general overview and approach to treatment. (http://www.ncbi.nlm.nih.gov/pubmed/21896525)

A 41-Year-Old Man with a History of Bipolar Disorder Is