Lithium Toxicity Treatment & Management

Emergency medical services (EMS) personnel should do the following:

• Stabilize life-threatening conditions and initiate supportive therapy according to local EMS protocols.
• Obtain intravenous access with isotonic sodium chloride solution.
• Monitor cardiac function to assess rhythm disturbances.
• Obtain all pill bottles available to the patient.

Supportive therapy is the mainstay of treatment of lithium toxicity. Airway protection is crucial due to emesis and risk of aspiration. Seizures can be controlled with benzodiazepines, phenobarbital, or propofol.

GI decontamination

Gastric lavage may be attempted if the patient presents within one hour of ingestion.

Lithium is a monovalent cation that does not bind to charcoal; therefore, activated charcoal has no role. However, activated charcoal might be considered in the case of exposure to co-ingestants. The clinician also has to be aware that acute lithium toxicity can produce vomiting and precipitate aspiration of activated charcoal.

Whole-bowel irrigation with polyethylene glycol lavage can be effective in preventing absorption from extended-release lithium.

Because of its similarity to potassium, the use of sodium polystyrene sulfonate (SPS) has been proposed as a method of eliminating lithium. ^[13] However, hypokalemia has been reported and studies have still not shown definite evidence of benefit. One retrospective review showed a possible decrease in lithium half-life with administration of SPS in patients presenting with chronic lithium toxicity. ^[14] However, it is unknown whether this was clinically relevant or if patient outcome was improved. A newer cation exchange resin, sodium zirconium cyclosilicate (SZC), may provide a safer alternative to SPS for enhancing lithium clearance. ^[15]

The benefit of early decontamination of the digestive tract with sodium polystyrene sulfonate, whole bowel irrigation, or both was demonstrated in a retrospective study of 59 cases of acute lithium poisoning in patients on long-term therapy. Compared with the 44 patients in whom decontamination was delayed more than 12 hours or not performed, the 15 patients who underwent early decontamination had a significantly lower risk of severe poisoning (odds ratio, 0.21; P = 0.049), regardless of the lithium dose ingested or the serum lithium level. ^[16]

Enhanced elimination

The mainstay of treatment is fluid therapy. The goal of saline administration is to restore glomerular filtration rate (GFR), normalize urine output, and enhance lithium clearance.

Lithium is readily dialyzed because of water solubility, low volume of distribution, and lack of protein binding.

Hemodialysis is indicated for patients who have renal failure and are unable to eliminate lithium. It is also indicated in patients who cannot tolerate hydration, such as those with congestive heart failure (CHF) or liver disease, and should be considered in patients who develop severe signs of neurotoxicity, such as profound altered mental status and seizures. An absolute level of 4 mEq/L in acute toxicity and a level of 2.5 mEq/L in chronic toxicity in patients with symptoms should also be considered for hemodialysis, although guidelines for hemodialysis based on levels alone are controversial.

The Extracorporeal Treatments in Poisoning Workgroup recommends extracorporeal treatment in severe lithium poisoning. The group recommends performing extracorporeal treatment in patients with the following ^[17] :

• Impaired kidney function and lithium levels > 4.0 mEq/L
• Decreased consciousness, seizures, or life-threatening dysrhythmias, regardless of lithium levels
• Levels are > 5.0 mEq/L, significant confusion is noted, or the expected time to reduce levels to < 1.0 mEq/L is more than 36 hours

Extracorporeal treatment should be continued until clinical improvement is seen or levels fall to < 1.0 mEq/L. If levels are not readily measurable, extracorporeal treatments should be continued for a minimum of 6 hours.

Because postdialysis rebound elevations in lithium levels have been documented, continuous venovenous hemofiltration (CVVH) has been advocated. ^{[18, 19]}

Patients who are already on peritoneal dialysis should continue with it while awaiting hemodialysis or CVVH.

Hospitalization and discharge

Indications for hospital admission are as follows:

• Admit patients with significant signs or symptoms of toxicity, regardless of serum lithium levels
• Admit patients on long-term lithium therapy who have serum lithium levels higher than 2 mEq/L
• Admit patients with signs of severe neurotoxicity pending hemodialysis to an intensive care unit (ICU)

Transfer may be indicated if hemodialysis facilities are not available locally.

Discharge planning varies, depending on whether the overdose was unintentional or intentional. In unintentional overdose, asymptomatic patients and patients with serum lithium concentrations in the therapeutic range and minor toxicity may be discharged with scheduled follow-up in 1-2 days. In intentional overdose, coordinate care with mental health care providers before discharging the patient from the hospital.

Consider the following consults:

• Poison control center and a medical toxicologist regarding appropriate treatment
• Renal service, for hemodialysis in severe intoxications
• Psychiatric service, for patients with intentional overdose