Lithium (Li) is an element from the group of light metals. It occurs in the human body as a trace element.
Pharmacologically, it finds application in psychiatry for bipolar disorders (manias). Since it has only a small therapeutic range, poisoning can occur in case of overdose.
Excretion is renal (i.e., via the kidneys) and is enhanced by high intake of sodium and water.
In lithium poisoning, the following symptoms (signs of intoxication) may occur:
- Arrhythmias (cardiac arrhythmias).
- Ataxia (disturbances in the coordination of movement).
- Abdominal pain
- Disturbance of consciousness
- Dehydration (lack of fluids)
- Diarrhea (diarrhea)
- Dysarthria (speech disorders): e.g., slurred speech.
- Thirst
- Epileptic seizures (convulsions)
- Vomiting
- Fasciculations – irregular and involuntary contractions of muscle fiber bundles that are visible macroscopically.
- Confusion (confusion)
- Fatigue
- Muscle pain
- Muscle weakness
- Muscle twitching
- Nausea (nausea)
- Tremor (shaking)
- Nausea / vomiting
The first symptoms usually occur at a concentration of > 1.5 mmol/l blood. Concentrations > 4 mmol/l can be potentially lethal (fatal).
The procedure
Material needed
- Blood serum
Preparation of the patient
- Blood sampling should be performed 12 hours after ingestion of the last dose of lithium
Confounding factors
- Not known
Normal values – blood serum (values in mmol/l)
| Normal value (prophylactic effect) | 0,6-0,8 |
| Normal value (antimanic effect) | 1,0-1,2 |
Intoxication* (poisoning)
|
> 1,5 |
|
> 3,0 |
|
> 4,0 |
* In individual cases, initial symptoms of lithium poisoning may occur even at lower serum lithium concentrations!
Indications
Interpretation
Interpretation of lowered values
- Not relevant to disease
Interpretation of elevated values
- Therapeutic overdose
- Renal insufficiency (kidney weakness) and concomitant lithium therapy.
- Lithium therapy and concomitant administration of
- NSAIDs (non-steroidal anti-inflammatory drugs) such as ibuprofen.
- Methyldopa (high blood pressure medication)
- Diuretics (diuretic drugs) such as furosemide.
Other notes
- In pregnancy, lithium is contraindicated because this is embryotoxic!
- According to a Japanese epidemiological studies, there is an inverse correlation between the lithium concentration of drinking water and the standardized mortality rate (death rate) for suicides (suicide; SMRS).
