Lithium toxicity: Difference between revisions
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==Diagnosis== | ==Diagnosis== | ||
*Lithium level | *Lithium level | ||
** | **Therapeutic level = 0.6-1.2 meq/L | ||
**''level may be falsely elevated if placed in a green top tube due to the heparin lithium interaction'' | **''level may be falsely elevated if placed in a green top tube due to the heparin lithium interaction'' | ||
* | *Metabolic Panel | ||
** | **↑ Na 2/2 nephrogenic diabetes insipidus | ||
** | **Evaluate renal function | ||
*TSH | *TSH | ||
*ECG | *ECG | ||
**QT prolongation | **QT prolongation | ||
** | **T-wave flattening or inversion | ||
*Acetaminophen and Salicylate Levels (possible coingestants) | |||
==Treatment== | ==Treatment== | ||
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<references/> | <references/> | ||
*Tintinalli | *Tintinalli | ||
*Rosen's Chapter 160 - Lithium | |||
[[Category:Tox]] | [[Category:Tox]] |
Revision as of 03:07, 21 June 2015
Background
- Toxicity most often involves a drug-drug interaction or decreased renal excretion
- Pts most frequently die of respiratory failure or CV collapse
Precipitants
- Overdose
- Renal failure
- Volume depletion
- Diuretic use, vomiting, diarrhea, diaphoresis, decreased oral intake
- Hyperthermia
- Infection
- CHF
- Surgery
- Cirrhosis
Clinical Features
- GI
- Usually first to develop
- N/V
- Diarrhea
- Generalized abd pain
- CNS
- Usually develops as GI symptoms are abating; more common in chronic toxicity
- Tremor
- Muscle weakness
- Ataxia
- Stupor
- Seizure
- Coma
- Cardiac
- Hypotension
- Conduction Abnormalities
- Ventricular dysrhythmias
- Prolonged QT, transient ST depression, TWI
- Endocrine
- Hyper/Hypothyroidism or hyperparathyroidism
- Hypothyroidism most common
- Renal
- Nephrogenic Diabetes Insipidus
- Can be seen mildly at therapeutic levels
- Causes polyuria and polydipsia
- Nephrogenic Diabetes Insipidus
Diagnosis
- Lithium level
- Therapeutic level = 0.6-1.2 meq/L
- level may be falsely elevated if placed in a green top tube due to the heparin lithium interaction
- Metabolic Panel
- ↑ Na 2/2 nephrogenic diabetes insipidus
- Evaluate renal function
- TSH
- ECG
- QT prolongation
- T-wave flattening or inversion
- Acetaminophen and Salicylate Levels (possible coingestants)
Treatment
- GI decontamination
- Consider lavage for massive ingestions (>4gm) if can be performed w/in 1hr
- Activated charcoal is ineffective
- Fluid resuscitation
- Average pt has Na/volume deficit; giving fluid helps reestablish normal Li excretion
- Give 2L NS bolus; then give 200mL/hr
- Average pt has Na/volume deficit; giving fluid helps reestablish normal Li excretion
- Seizure
- Benzos are 1st line
- Phenobarbital is 2nd line
- Phenytoin is ineffective
- Dialysis
- Indications:
- Li level >4 (acute overdose)
- Li level >3.5 (chronic toxicity)
- Little change in Li level after 6hr IVF
- Sustained Li level >1.0 after 36hr
- Baseline renal failure
- Ingestion of sustained-release preparations
- Goal:
- Li level <1
- Must monitor for up to 8hr following dialysis to ensure levels stay <1
- Li level <1
- Indications:
Disposition
- Consider discharge for pts asymptomatic after 4-6hr obs with 2 downtrending levels
- Admit all pts w/ Li level >1.5
- Admit all pts w/ ingestion of sustained-release preparation (regardless of Li level)
See Also
References
- Tintinalli
- Rosen's Chapter 160 - Lithium