An Extended Lithium Saga: Case Report

Case Report

Austin J Clin Case Rep. 2019; 6(5): 1158.

An Extended Lithium Saga: Case Report

Matchett C* and Laura Maursetter DO

Division of Nephrology, Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA

*Corresponding author: Caroline Matchett, Division of Nephrology, Department of Medicine, University of Wisconsin School of Medicine and Public Health, 1685 Highland Avenue Madison, Madison, WI, 53792, USA

Received: November 25, 2019; Accepted: December 26, 2019; Published: December 31, 2019

Abstract

Lithium remains a drug of choice in the treatment of bipolar disorder, despite its extremely narrow therapeutic window. The toxic effects of lithium are well described, as is the use of intermittent hemodialysis (IHD) to remove lithium in patients with established toxicity. What remains elusive is the duration of therapy required to reduce lithium levels to therapeutic range (‹1.0mEq/L) following intoxication, especially when sustained-release preparations are ingested. We describe a case of acute on chronic lithium toxicity with an extended-release preparation that necessitated a total of 45 hours of IHD to normalize serum lithium levels (‹1mEq/L).

Keywords: Lithium; Toxicity; Extended-Release; Hemodialysis

Introduction

Lithium continues to be a preferred treatment for bipolar affective disorder [1]. Unfortunately, the therapeutic level of lithium (0.6–1.2 mEq/L) is extremely close to the toxic range. Lithium toxicity (levels ›1.5mEq/L) may manifest as gastrointestinal disturbances, cardiac arrhythmias, altered mentation, seizures or death [2,3].

Lithium is highly dialyzable due to its low molecular weight (6.94Da), negligible protein binding, and small volume of distribution (0.8-1.2 L/kg) [4]. The rapid reduction in serum lithium by intermittent hemodialysis (IHD) places it as the treatment of choice for cases of severe intoxication [4,5]. However, the appropriate duration of IHD for the treatment of lithium poisoning remains controversial. The literature is especially scarce in describing the time course of treatment when extended-release preparations are ingested. We report a case of acute on chronic intoxication with extendedrelease lithium that required prolonged IHD to achieve safe serum lithium levels.

Case Presentation

A 29-year old man with bipolar disorder who was chronically taking extended-release lithium carbonate presented to the emergency department 5 hours after an intentional overdose of 141g. On arrival, his temperature was 36.1°C, heart rate 115bpm, and blood pressure 170/94mmHg. Physical examination was limited due to significantly altered mentation, agitation, and emesis. Toxicology screening was negative for alcohol and illicit drugs. Initial laboratory values showed: sodium 146mmol/L, potassium 4mmol/L, BUN 13mg/dL, creatinine 0.87mg/dL, glucose 127mmol/L, white cell count 9.9×103/uL, hemoglobin 13.7g/dL platelets 338×103/uL and normal liver enzymes. Serum lithium level was 3.32mEq/L (therapeutic range 0.6–1.2 mEq/L). EKG demonstrated sinus tachycardia. Patient was intubated for airway protection and central venous access was obtained. An orogastric tube was placed and whole bowel irrigation with 3L polyethylene glycol was performed in an attempt to decrease gastrointestinal lithium absorption. The patient received a 2L normal saline bolus and then continued on 150mL/h with adequate urine output throughout. Nephrology consultation was obtained. Given that a repeat lithium level had decreased to 2.72mEq/L (8 hours after ingestion), the decision was made to hold the initiation of dialysis and continue to trend lithium levels. Hemodialysis was subsequently started (14 hours after ingestion) when serum lithium increased to 4.12mEq/L and repeat EKG revealed QTc prolongation.

The hemodialysis prescription included a high flux dialyzer with blood flows of 400mL/min and dialysate flows of 800mL/min through a 16 French right internal jugular catheter. There were no episodes of clotting reported and lithium levels were periodically checked (Figure 1). Plans were made to continue hemodialysis until a goal lithium of ‹1mEq/L was achieved.

Citation: Matchett C and Laura Maursetter DO. An Extended Lithium Saga: Case Report. Austin J Clin Case Rep. 2019; 6(5): 1158.