The correct answer is:

Begin intravenous fluids, consider whole bowel irrigation, and emergently consult nephrology for immediate hemodialysis.

Educational Objective:

Discuss recognition and management of severe acute lithium toxicity.

Key Point:

An acute serum level > 4 mEq/L is considered a severe ingestion for which immediate dialysis and possibly whole bowel irrigation are warranted.

Explanation:

Whole bowel irrigation is no longer recommended for acute or chronic lithium overdose; the exception is a severe, acute overdose, especially with sustained released tablets, in which case whole bowel irrigation may be considered in conjunction with dialysis because several pills might not yet have been absorbed. A session of hemodialysis may rapidly clear the extracellular compartment of lithium; however, if a large gastrointestinal depot remains, the lithium level can be expected to increase again, possibly dramatically after hemodialysis.

The goal of hemodialysis following an acute overdose is to remove lithium from the extracellular compartment before a sufficient amount has moved intracellularly to cause neurotoxicity.

Following an acute overdose, hemodialysis is meant to prevent neurotoxicity; by contrast, the goal of dialysis in a chronic overdose is to hasten the movement of lithium already causing toxicity out of the nervous system back into the extracellular compartment and ultimately towards elimination.

There is no defined role for sodium polystyrene sulfonate in the management of lithium overdose. Lithium, like other metal salts, does not appreciably adsorb to activated charcoal.

Pearl: Neurologic manifestations occur several hours after ingestion in acute toxicity because the lithium redistributes slowly into the CNS from the serum.

Figure: Hemodialysis for Acute Lithium Toxicity

References:

Theobald JL. Lithium. (Chapter 154) In: Walls R, et al. Rosen’s Emergency Medicine: Concepts and Clinical Practice. 9th ed., 2018: 1934-1936.e1

Greller HA. Lithium (Chapter 70). In: Nelson L, et al. Goldfrank's Toxicologic Emergencies. 11th ed., 2019.