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In this episode, I’ll discuss ICU complications that could increase the risk of lithium toxicity.
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I discussed lithium toxicity and it’s treatment in episode 130.
One of my physician colleagues advocates as a general rule temporarily holding lithium upon admission to the ICU (Shoutout to “Pulmonology Lou”). He follows this general rule under the presumption that lithium has the potential to do more harm than good in ICU patients.
Fluid balance
Fluid balance is an issue of concern in critically ill patients. Loop diuretics are commonly used to address fluid balance issues. Unfortunately, loop diuretics are known to increase lithium concentration and have the potential to cause severe toxicity. A 2015 study of over 7000 ICU patients found a 51% incidence of loop diuretic use.
Hyponatremia
Sodium depletion can facilitate the development of lithium toxicity. A 2016 study found that although the incidence of hyponatremia in critically ill patients is decreasing, it is still 25%.
Cardiovascular disease
Significant cardiovascular disease also increases the risk of lithium toxicity. Heart failure is the primary cardiovascular concern with lithium toxicity. Many ICU patients have transient demand ischemia and a subsequent elevation of troponin. The effects of this on lithium toxicity have not been studied.
Kidney disease
In general, lithium is avoided in patients with significant renal disease due to the increased risk of toxicity. A 2015 multi-center study found the incidence of acute renal failure in ICU patients to be 57%.
Recognizing lithium toxicity in critically ill patients is difficult
Recognizing signs of lithium toxicity in ICU patients is difficult. This is especially true if multiple comorbidities are present. The symptoms of ataxia, tremor, dystonia and hyperreflexia are difficult to assess in many ICU patients. Non-convulsive status epilepticus is similarly difficult to identify. If seizure does occur, it may be attributed to numerous other causes.
Risk of temporarily holding lithium during critical illness
The risk of temporarily holding lithium during critical illness is a recurrence of bipolar symptoms. Should acute mania recur, it can be treated with antipsychotics, benzodiazepines, and lithium (if there are no contraindications).
Decision time
Ultimately the decision to routinely temporarily hold lithium upon ICU admission comes down to your assessment of the risk vs benefit. I recently asked this question on Twitter:
Should lithium therapy be automatically (but temporarily) held upon ICU admission due to the risk of toxicity developing during ICU stay?
— Pharmacy Joe ?? (@PharmacyJoe) February 26, 2017
I’d love to know your thoughts in the comment section below. Do you routinely hold lithium in the ICU?
If you like this post, check out my book – A Pharmacist’s Guide to Inpatient Medical Emergencies: How to respond to code blue, rapid response calls, and other medical emergencies.
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