QuestionSBA
QuestionChoice
This patient is showing signs of lithium toxicity, for which intravenous fluids is the mainstay of treatment. Common causes of lithium toxicity include dehydration, alcohol intake and angiotensin-converting enzyme inhibitors (ACE-i) such as ramipril as they reduce glomerular filtration rate (GFR) and enhance the tubular reabsorption of lithium (thus increasing plasma concentrations of lithium). In addition, the patient has recently been through a time zone change and therefore may have taken his medications at different times to his usual; therefore, one should be alert to the possibility of lithium toxicity
32668
a
Intravenous fluids
QuestionChoice
This patient's presentation could be due to traveller's diarrhoea; however, it would not explain the tremor. If traveller's diarrhoea was the diagnosis, then management is mainly supportive (for example, with intravenous fluids). Antibiotics are generally not indicated in traveller's diarrhoea, however in some cases, they have been shown to improve symptoms, and a fluoroquinolone such as azithromycin may be a reasonable choice. Still, it would not be the basis of treatment
32670
c
Oral azithromycin
QuestionChoice
Benzodiazepines such as lorazepam are used in the treatment of serotonin syndrome, which occurs as a result of high levels of serotonin in the body. It is an uncommon but serious side effect of certain medications used to treat psychiatric conditions such as depression (for example, citalopram, fluoxetine, sertraline). This patient's symptoms could be explained by serotonin syndrome; however, he is not taking any medications that might induce this
32672
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Intravenous lorazepam
QuestionChoice
Chelation is a treatment for heavy metal poisoning, for example, with lead or mercury. It is not used in the treatment of lithium toxicity, and there is no evidence that this patient has come into contact with any heavy metals
32671
d
Chelation therapy
QuestionChoice
Oral antibiotics from the tetracycline, fluoroquinolone or macrolide class would be a reasonable treatment if suspecting an atypical pneumonia such as legionnaires disease. Legionnaires disease is associated with water from ventilation systems. Most people become infected when they inhale microscopic water droplets containing legionella bacteria, e.g., the spray from a shower, faucet or whirlpool, or water from the ventilation systems. Whilst atypical pneumonia such as legionella may present with gastrointestinal symptoms, it would be uncommon to have no respiratory symptoms, and there is no history of a fever. It would also not account for the tremor that the patient has reported
32669
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Oral doxycycline
Concept
Chapter
# Summary

Lithium, commonly used in psychiatric disorders, may produce a range of side effects, which can be categorised into those seen at a therapeutic dose and those indicating toxicity. Therapeutic dose side effects may include fine tremor, dry mouth, GI disturbances, increased thirst and urination, drowsiness, and thyroid dysfunction. Signs of toxicity encompass coarse tremor, CNS disturbance (including seizures, impaired coordination, dysarthria), arrhythmias, and visual disturbance. Diagnosis relies on identifying these clinical features and serum lithium levels. Management involves supportive measures, electrolyte balance maintenance, renal function monitoring, seizure control, IV fluid therapy, and, in severe cases, haemodialysis.

# Indications

Lithium is used primarily to treat bipolar disorder and mania, but can also be used in depression (especially if recurrent) and as mood stabiliser for aggressive/self-harming behaviour.

It is contraindicated in: Addison’s disease, cardiac disease associated with rhythm disorder, personal/family history of Brugada syndrome, low sodium diets and untreated hypothyroidism.

It should be avoided in severe renal impairment due to the risk of toxicity, as it has a very narrow therapeutic index.

# Side Effects

Can be remembered with the mneumonic LITHIuM:

* **L**eucocytosis
* **I**nsipidus
* **T**remor (fine)
* **H**ypothyroid
* **I**ncreased weight
* **U**
* **M**etallic taste 

Women of child bearing age should take contraception if commenced on lithium, which is generally avoided in pregnancy due to the high risk of development of cardiac malformations in the first trimester.

# Monitoring

- Before starting: renal (U+Es), cardiac (ECG), and thyroid function (TFTs). BMI and FBC should also be done beforehand.
- Monitor body-weight or BMI, serum electrolytes, eGFR, and thyroid function every 6 months during treatment, and more often if there is evidence of impaired renal or thyroid function, or raised calcium levels


# Lithium Toxicity

## Signs and Symptoms

### Clinical features at therapeutic dose 

- Fine tremor
- Dry mouth
- Gastrointestinal disturbance
- Increased thirst
- Increased urination
- Drowsiness
- Thyroid dysfunction

### Clinical features in lithium toxicity

- Coarse tremor
- Central nervous system disturbance, which may include seizures, impaired coordination, and dysarthria
- Cardiac arrhythmias
- Visual disturbance




## Differential Diagnosis

Lithium side effects and toxicity may be mistaken for several other conditions:

- **Neurological conditions**: Given the tremors, dysarthria, and impaired coordination, conditions like Parkinson's disease or cerebellar disorders may be considered.
- **Endocrine disorders**: Increased thirst and urination could point towards diabetes insipidus or diabetes mellitus.
- **Cardiac conditions**: Arrhythmias might suggest primary cardiac disease.
- **Substance intoxication or withdrawal**: Some symptoms overlap with those of alcohol or benzodiazepine withdrawal, or other substance intoxications.

## Investigations

- Serum lithium levels: This is the gold standard for diagnosing lithium toxicity.
- Electrolyte levels: To assess for any electrolyte imbalance.
- Thyroid function tests: Given the potential for thyroid dysfunction.
- Renal function tests: Given lithium's potential to cause renal impairment.
- ECG: To assess for arrhythmias.

## Management

Management of lithium toxicity is largely supportive and often requires specialist input. Key strategies include:

- Maintaining electrolyte balance
- Monitoring renal function
- Seizure control
- IV fluid therapy and urine alkalisation, which enhance the excretion of the drug
- Benzodiazepines may be used to treat agitation and seizures
- Haemodialysis might be required if renal function is poor

# References

[Click here to see the BNF guidance on Lithium](https://bnf.nice.org.uk/drug/lithium-carbonate.html)
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Intravenous fluids are the mainstay of treatment for lithium toxicity, as they help to increase hydration, enhance renal clearance, and facilitate the elimination of excess lithium from the body.
A 46-year-old man presents to the Emergency Department with abdominal pain, diarrhoea and vomiting. He feels weak and reports a new-onset tremor. He has just come back from a cruise in the Caribbean. His only past medical history is bipolar disorder, for which he takes lithium and newly diagnosed hypertension, for which his GP has recently started him on ramipril.

What intervention should form the basis of your treatment?
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