Lithium 101

Question 1

What is lithium used in for mainly .. ?

Answer 1

Main therapy for bipolar disorder

Question 2

18 years old who you suspect to have lithium toxicity. Level was 1.6 mEQ/liter … How do you interpret the level ?

Answer 2

It have a narrow therapeutic index (0.6-1.2 mEq/L)

Question 3

What does it mean to have a narrow therapeutic index ?

Answer 3

In chronic use It can have a high saturation burden on the body. So even a low level does not means that brain is not highly saturated.

Question 4

How much does it take lithium to completely absorbed and reach peak effect ?

Answer 4

Peak levels are reached within 2 - 4 hours.

Question 5

When do you think absorption of lithium will be slowed down .. ?

Answer 5

• In massive overdose - sustained release preparations - chronic therapy - elderly

Question 6

How long do you think it will take for distribution to the brain ?

Answer 6

Can take up to 24 hours

Question 7

How do you think lithium is eliminated from the body ?

Answer 7

95 % by the kidney

Question 8

How do you think lithium is similar to sodium ?

Answer 8

Any condition that causes sodium to be reabsorbed will increase the reabsorption of lithium from the proximal tubules as well.

Question 9

What are the conditions that will increase the lithium reabsorption and causes toxicity ?

Answer 9

• advanced age - decreased GFR - decreased sodium intake - thiazide diuretics - NSAID

Question 10

17 years old who took a high dose of lithium of his brother medications. What is the main clinical signs you expect to see ?

Answer 10

• Delayed toxicity due to delayed distribution - High serum levels initially do not correlate with toxicity - GI symptoms is the most common initial presentation. - neurological toxicity might be seen delayed.

Question 11

50 years old who is maintained on lithium who presented with AMS and ataxia .. His level was 1.9 mEQ/liter How can you interpret this level in his case .. ?

Answer 11

• Decreased excretion - Serum levels lower since intracellular levels high - Subacute/nonspecific neurologic symptoms - GI symptoms less severe - Encephalopathy, myoclonus, ataxia severe rigidity, seizures can be seen

Question 12

What EKG findings can be seen .. ?

Answer 12

• Bradycardia - T-wave flattening/inversion - QT prolongation

Question 13

18 years old M. Presnted with overdose and you suspect lithium to be involved .. What diagnostic tests would you do .. ?

Answer 13

• serum lithium level. - Electrolytes - renal function - EKG

Question 14

Main points to consider when interpreting lithium levels?

Answer 14

• serum levels does not correlate with symptoms - serum levels does not correlate with brain levels of saturation - you need to send level in a lithium free tube.

Question 15

In the above patient . Levels turned to be 2 mEQ/liter .. What initial management approach you will take .. ?

Answer 15

• stop any lithium or offending drugs. - improve the GFR and kidney perfusion . Will give you 20 % reduction in lithium level in 6 hours - hydrate patient IVF as tolerated. - avoid forced diuresis. - consider hemodialysis

Question 16

When to consider hemodialysis .. ?

Answer 16

• severe neurotoxicity - can not tolerate volume overload - acute lithium concentration 4 mEQ/liter - chronic level > 2.5 mEQ/liter

Question 17

What do we mean by the rebound phenomenon in lithium .. ?

Answer 17

where clearance of plasma compartment is followed by redistribution from tissue compartment

Question 18

When to consider Activated charcoal for GI decon .. ?

Answer 18

• activated charcoal does not bind lithium. - is quickly absorbed so role is limited - sometimes Whole bowel irrigation might be considered in large sustained release overdose.

Question 19

What do we mean by SILENT syndrome ?

Answer 19

• syndrome of irreversible lithium-effectuated neurotoxicity - it is a neurologic dysfunction caused by lithium in the absence of prior neurologic illness, which persists for a period of at least 2 months following cessation of the drug. ( rare ) ..

Question 20

What do you think the most bad prognostic sign in chronic lithium toxicity .. ?

Answer 20

Hyperthermia