Lithium Toxicity

Has narrow therapeutic window, so toxicity is quite common.
Three major organ systems involved:

1. GI - nausea,vomiting, diarrhea - can perpetuate cycle, as this leads to dehydration and worsening renal function --> impaired lithium excretion
2. Cardiac - arrhythmias, especially bradycardia
3. Neuro - tends to be a later finding, can get ataxia, confusion, agitation, tremors, fasciculations, hyperreflexia, and even seizures and flat out encephalopathy.  Interestingly, neuro findings can persist despite clearance of the drug, for up to months and even years!

Chronic Lithium toxicity has some overlap, but additionally, can get thyroid dysfunction, renal toxicity, and nephrogenic diabetes insipidus.

• Management - ensure stability of ABCs first, stop lithium, and give IVFs
• If severe toxicity, can consider hemodialysis for lithium removal.  However, may require prolonged and multiple sessions.

(Chanu Rhee MD, 8/26/10)