Case Study 3- Lithium

Question 1

What is lithium used?

Answer 1

Prophylaxis and treatment of mania, hypomania and depression in bipolar disorder

Question 2

What is the therapeutic/ideal range for lithium?

Answer 2

0.6-0.8 mmol/L
narrow therapeutic window

Question 3

What is the mechanism of action of lithium?

Answer 3

• Reduces excitatory (dopamine and glutamate) neurotransmission

BUT

• Increases inhibitory GABA neurotransmission
• Inhibits dopamine neurotransmission

Question 4

What tests should be carried out before a patient is on lithium?

Answer 4

Before treatment:

Lithium levels

Renal (lithium renally excreted)

Cardiac ECG

BMI

Bloods – thyroid stuff, Ca and lithium

Question 5

When should patients on lithium be reviewed and what needs to be reviewed?

Answer 5

Every 6 months:

Lithium levels

Weight or BMI

Serum electrolytes esp Ca+

eGFR

thyroid function

Question 6

What are the signs and symptoms of lithium toxicity greater than 0.1 mmole/L?

Answer 6

Severe diarrhoea

vomiting anorexia

tremor in hand

Muscle twitching

dehydration

drowsiness

confusion

muscle weakness

slurred speech ataxia

vertigo

restlessness

blurred vision

not able to walk in a straight line (ataxia)

Question 7

What are the signs and symptoms of lithium toxicity greater than 0.2 mmole/L?

Answer 7

Convulsions/ seizures

Renal failure

electrolyte imbalance

hypotension

clouding of consciousness

coma and death

Question 8

What counselling points would you give to patients on lithium ?

Answer 8

• Carry lithium booklet or alert card