Role of Dialysis in Severe Lithium Toxicity
Hemodialysis is the treatment of choice for severe lithium intoxication, particularly when serum lithium levels are ≥3.5 mEq/L with significant symptoms, or at any level with severe neurological or cardiovascular compromise. 1
Indications for Hemodialysis
The American Heart Association recommends hemodialysis urgently in the following situations 1:
- Serum lithium ≥3.5 mEq/L with significant symptoms (neurological or cardiovascular) 1
- Any lithium level with severe cardiovascular compromise, including symptomatic bradycardia, advanced AV block, or refractory hypotension 1
- Refractory toxicity despite conservative management 1
The FDA drug label confirms hemodialysis as "an effective and rapid means of removing the ion from the severely toxic patient." 2
Acute vs. Chronic Toxicity: Critical Distinction
Patients with chronic or acute-on-chronic toxicity require more aggressive dialysis intervention than those with acute overdose alone. 3, 4
Acute intoxication (overdose in lithium-naive patients): Often presents with milder symptoms despite potentially lethal levels (>3.5 mEq/L), as lithium has not yet distributed into tissues 3
- In one series, 10 patients with acute toxicity and levels ≥3.5 mEq/L had mild symptoms; 5 received hemodialysis and 5 did not—none died or had permanent sequelae 3
Chronic toxicity (during maintenance therapy): Associated with prolonged tissue exposure, greater intracellular accumulation, and more severe neurological/cardiovascular symptoms at lower serum levels 3, 4
- These patients should receive hemodialysis if serum lithium >2.5 mmol/L with clinical features 4
Hemodialysis Protocol
Duration and monitoring are critical to prevent rebound toxicity: 1
- Continue hemodialysis until lithium level <1.0 mEq/L is achieved after redistribution 1
- Typical duration: 6-8 hours 1
- Measure lithium level 4-6 hours post-dialysis to evaluate for rebound, as lithium redistributes from intracellular compartments 1
- Mean lithium clearance with hemodialysis: 173 ml/min 5
Rebound Phenomenon and Extended Dialysis Strategies
Serum lithium frequently rebounds after standard hemodialysis due to redistribution from tissues, often requiring repeated treatments. 6, 4
To address this limitation:
Hemodialysis followed by continuous venovenous hemodiafiltration (CVVHDF) effectively prevents rebound by continuing lithium removal during the redistribution phase 5
Prolonged hemodialysis (>16 hours) or continuous arteriovenous/venovenous hemodiafiltration allows effective total body lithium removal and avoids rebound 4
Alternative Dialysis Modalities
Peritoneal dialysis is less effective than hemodialysis but can be used when hemodialysis is unavailable: 7, 6
- Peritoneal dialysis lowers lithium levels more slowly than hemodialysis 7, 6
- Should only be considered if hemodialysis facilities are not accessible 6
Conservative Management for Mild-Moderate Toxicity
For patients who do not meet criteria for dialysis 2, 7:
- Cessation or reduction of lithium dosage 2, 7
- Gastric lavage if recent ingestion 2, 7
- Correction of fluid and electrolyte imbalance 2
- Maintenance of high-normal sodium levels to promote lithium excretion 7
- Regulation of kidney function 2
Critical Pitfalls to Avoid
Do not rely solely on serum lithium levels to guide dialysis decisions in chronic toxicity—clinical symptoms (especially neurological) are more important, as tissue levels may be significantly elevated despite moderate serum concentrations 3, 4
Permanent neurological sequelae can occur despite effective hemodialysis if treatment is delayed—prolonged exposure to toxic tissue levels causes irreversible basal ganglia and cerebellar damage 6
Single hemodialysis sessions may be insufficient—always check post-dialysis levels after redistribution period to identify rebound requiring additional treatment 1, 4