Critical Alerts

• Chronic toxicity is more dangerous than acute overdose at same serum level
• Neurological symptoms are the hallmark of severe toxicity
• Hemodialysis is the definitive treatment for severe toxicity
• Rebound phenomenon occurs - repeat dialysis often needed
• Watch for nephrogenic diabetes insipidus - common complication

Key Diagnostics

• Serum lithium level (therapeutic 0.6-1.2 mEq/L)
• BMP (sodium, creatinine - critical for context)
• Serial lithium levels (every 2-4 hours until declining)
• ECG (conduction abnormalities)
• TSH (chronic effects)

Emergency Treatments

• IV fluids: Normal saline for volume depletion
• Avoid NSAIDs, ACE inhibitors, thiazides: Increase lithium levels
• Whole bowel irrigation: For sustained-release formulations
• Hemodialysis: Severe neurological symptoms, level >4 mEq/L
• Supportive care: Airway protection if needed

Lithium toxicity is a potentially life-threatening condition resulting from elevated lithium levels, either from acute ingestion or chronic accumulation. Lithium has a narrow therapeutic index, making toxicity relatively common among patients on chronic therapy.

Types of Lithium Toxicity

Therapeutic vs Toxic Levels

Important: Clinical status matters more than level alone, especially in chronic toxicity

Epidemiology

• Prevalence of toxicity: 25% of lithium-treated patients experience toxicity
• Common triggers: Dehydration, drug interactions, renal impairment
• Mortality: <1% with appropriate treatment

Critical Findings

SILENT Syndrome

Syndrome of Irreversible Lithium-Effectuated Neurotoxicity

• Persistent cerebellar dysfunction
• Cognitive impairment
• Basal ganglia dysfunction
• May occur despite appropriate treatment
• More common with delayed treatment or chronic toxicity

Conditions Mimicking Lithium Toxicity

Causes of Tremor in Psychiatric Patients

• Lithium therapeutic effect (fine tremor)
• Lithium toxicity (coarse tremor)
• Antipsychotic-induced parkinsonism
• Valproate tremor
• Essential tremor
• Caffeine/stimulant use

Initial Assessment

Key History

• Lithium dose and formulation (immediate vs sustained-release)
• Time since last dose or overdose
• Acute vs chronic ingestion
• Recent changes in medications
• Dehydration, illness, sodium intake
• Symptoms and timeline

Laboratory Studies

Serial Lithium Levels

Essential for Management

• Draw every 2-4 hours
• Continue until clearly declining
• Sustained-release: Peak may be delayed 12+ hours
• Post-dialysis: Recheck at 6 hours (rebound)

Level Interpretation

ICU Admission Criteria

• Altered mental status
• Seizures
• Severe toxicity requiring hemodialysis
• Hemodynamic instability
• Need for airway protection

Monitored Bed Admission

• Moderate toxicity with neurological symptoms
• Elevated level requiring serial monitoring
• Unclear whether acute or chronic

Observation

• Acute ingestion, asymptomatic, mildly elevated level
• Normal renal function
• Access to serial levels

Discharge Criteria

• Asymptomatic
• Lithium level declining and <1.5 mEq/L
• Stable renal function
• Cause of toxicity identified and addressed
• Psychiatric assessment if intentional
• Follow-up arranged for lithium level and clinical status

Understanding Lithium

• Lithium is an effective medication for bipolar disorder
• It has a very narrow safety margin
• Many factors can affect lithium levels
• Regular blood monitoring is essential

Preventing Future Toxicity

Medication Safety

• Take lithium exactly as prescribed
• Do not change dose without physician guidance
• Maintain consistent salt and fluid intake
• Avoid dehydration (illness, exercise, hot weather)

Drug Interactions to Avoid

• NSAIDs (ibuprofen, naproxen)
• Do not start new medications without checking with physician/pharmacist

Warning Signs

• Increased thirst or urination
• Tremor worsening
• Nausea, vomiting, diarrhea
• Confusion, slurred speech
• Muscle weakness

Regular Monitoring

• Lithium levels as directed
• Kidney function tests
• Thyroid function tests

Elderly Patients

• More susceptible to toxicity
• Reduced renal function with age
• More sensitive to neurological effects
• Start at lower doses
• More likely to have drug interactions

Pregnancy

• Lithium associated with cardiac malformations (Ebstein's anomaly)
• Continue only if benefits outweigh risks
• Switch to alternative if possible in first trimester
• Levels decrease during pregnancy; increase postpartum
• Hemodialysis safe in pregnancy if indicated

Renal Impairment

• Reduced lithium clearance
• Requires dose adjustment
• More frequent monitoring
• Lower threshold for toxicity
• May need chronic renal replacement if caused by lithium

Intentional Overdose

• Psychiatric evaluation required
• May have additional ingestions
• Thorough toxicological workup
• Suicide risk assessment

Performance Indicators

Documentation Requirements

• Type of exposure (acute, chronic, acute-on-chronic)
• Formulation (immediate vs sustained-release)
• Time of ingestion
• Serial lithium levels with times
• Clinical status at each level
• Treatment provided
• Dialysis details if performed
• Disposition rationale

Diagnostic Pearls

1. Chronic toxicity is more dangerous at same serum level
2. Neurological exam is critical - level alone doesn't predict severity
3. Sustained-release peaks late - repeat levels beyond 12 hours
4. Look for the precipitant - dehydration, drugs, renal impairment
5. Expect rebound after hemodialysis - recheck at 6 hours

Treatment Pearls

1. Charcoal does not bind lithium - don't use it
2. WBI for sustained-release - may have ongoing absorption
3. Normal saline first - restore volume and sodium
4. Hemodialysis is definitive for severe toxicity
5. Multiple dialysis sessions often needed

Disposition Pearls

1. ICU for any significant neurological symptoms
2. Serial levels until declining - don't d/c on single level
3. Address the cause - change meds, patient education
4. Psychiatric consult if intentional overdose
5. Close follow-up - reinitiate lithium carefully if needed