Lithium Toxicity


Lithium is a mood stabilizer used to treat bipolar disorder & Mania. Toxicity results from overdose or altered renal clearance. Death is usually from respiratory or cardiac failure.

SYMPTOMS/EXAM

DIAGNOSIS

Grading of Chronic Lithium Toxicity:
Grade Serum Lithium Level* Clinical Features Treatment
Grade 1 1.5–2.5 mEq/L Nausea, vomiting, tremor, hyperreflexia, ataxia, agitation, muscular weakness IV saline diuresis
Oral sodium polystyrene sulfonate
Grade 2 2.5–4.0 mEq/L Stupor, muscle rigidity, hypertonia, hypotension IV saline diuresis
Oral sodium polystyrene sulfonate
Consider renal replacement therapy
Grade 3 >4.0 mEq/L Coma, seizures, myoclonus, cardiovascular collapse Renal replacement therapy


Treatment

Stabilization include securing Airway & Ventilatory & Hemodynamic support.
  1. IV Access, Cardiac monitor, ECG.
  2. LABS: CMP, CBC, Serum lithium levels & other possible ingestions (UDS, TCA, Blood alcohol, Acetaminophen, Salicylate level).
  3. Seizure/Agitation: IV Benzodiazepines.
  4. GI decontamination for acute ingestions (ineffective for chronic ingestions)
  5. IV NS 2L bolus over 30-60 min followed by 200cc/hr continuous infusion.
  6. Kayexelate (15-30 g in sorbitol PO x 1) has been shown to decrease serum lithium levels due to lithium’s similarity to K+, but its effect on outcome is uncertain.
  7. Hemodialysis
  8. AVOID
Approximate Lithium Clearance with Different Treatments in Normal Adults:
Therapy Elimination Half-Life (hours) Clearance (ml/minute)
No treatment 18-24 20
IV saline 18-20 -
Sodium polystyrene sulfonate 12 -
Peritoneal dialysis - 10-15
Hemodialysis 4-6 50-100
Continuous venovenous hemofiltration - 20-30

DISPOSITION:

COMPLICATIONS

 

Acute lithium ingestion → high serum levels, minimal CNS effects.
Chronic lithium toxicity → lower serum levels, significant CNS effects.
Indications for Hemodialysis in Lithium Toxicity:
  • Pt w/ Renal failure & rising lithium level
  • Level >4.0 mEq/L in acute ingestion
  • Level >3.5 mEq/L with moderate CNS symptoms in chronic ingestion.
  • No change in litium levels after 6 hrs of IV NS.