Lithium

Lithium provides an opportunity to examine one aspect of the renal handling of drugs and to understand the importance of drug distribution as a factor in the risk assessment of poisoning. Lithium is a commonly used drug and patients can be seen following acute ingestions or with chronic toxicity. Distinguishing between the two is clinically important

• To be able to do a risk assessment of a lithium poisoning
• Consider variables which may affect the risk assessment
• Understand the distribution kinetics of lithium
• Understand treatment of lithium toxicity
• Calculate lithium clearance during dialysis

1. Hansen HE, Amdisen A . Lithium intoxication. Report of 23 cases and review of 100 cases from the literature. Q J Med 1978;47:123-44
2. Waring WS, Laing WJ, Good AM, Bateman DN. Pattern of lithium exposure predicts poisoning severity: evaluation of referrals to a regional poisons unit. QJM [Internet]. 2007 May [cited 2010 Nov 4];100(5):271-276. Available from: http://www.ncbi.nlm.nih.gov/pubmed/17412747
3. Markowitz GS, Radhakrishnan J, Kambham N, Valeri AM, Hines WH, D'Agati VD. Lithium nephrotoxicity: a progressive combined glomerular and tubulointerstitial nephropathy. J. Am. Soc. Nephrol [Internet]. 2000 Aug [cited 2010 Nov 4];11(8):1439-1448. Available from: http://www.ncbi.nlm.nih.gov/pubmed/10906157
4. WikiTox: Lithium monograph

1. Beckmann U, Oakley PW, Dawson AH, Byth PL. Efficacy of continuous venovenous hemodialysis in the treatment of severe lithium toxicity. Clinical Toxicology 2001;39(4):393-397.
2. Oakley PW, Whyte IM, Carter GL. Lithium toxicity: an iatrogenic problem in susceptible individuals. Australian and New Zealand Journal of Psychiatry 2001;35:833-840 .
3. Oakley PW, Dawson AH, Whyte IM. Lithium: thyroid effects and altered renal handling. Clinical Toxicology 2000;38(3):333-337.
4. Waise A, Fisken RA Unsuspected nephrogenic diabetes insipidus BMJ (fulltext)
5. Eyer F. Pfab R. Felgenhauer N. Lutz J. Heemann U. Steimer W. Zondler S. Fichtl B. Zilker T. Lithium poisoning: pharmacokinetics and clearance during different therapeutic measures. [Journal Article] Journal of Clinical Psychopharmacology. 26(3):325-30, 2006 Jun

A 20-year-old 60 kg man presents 3 hours after taking his mother’s lithium. He appears clinically well.

1. Would you decontaminate him?
2. What do you think his maximal concentration should be if all the 12 g were absorbed?
   Without decontamination his levels peak at 4.0 mmol/L.
3. He remains asymptomatic. Why is this so?
4. His level is lower than you predicted. Assuming he has taken the medication, what are the possible reasons for this disparity?

A 60-year-old woman is admitted for elective repair of an abdominal hernia. She has been on 500 mg of Lithium BD for 20 years. Following surgery she develops an ileus and is given 3 litres of IV fluid a day. Concerned about the possibility of acute relapse of mania her lithium is continued. The resident was confident that she was well hydrated as she had been passing 4 litres of fluid a day. You are asked to see her 4 days after surgery as she is confused, drowsy with occasional jerky movements. She is afebrile and asking for water. Serum lithium is 2.7.

On the day you see her sodium is 130, Urea 30, Creatine 250. Her renal function was normal on admission.

1. What is the significance of her urinary output?
2. Postulate a sequence of events that has led to toxicity.
3. What would your treatment be?
4. You decide to dialyse her but then wonder if it is working. How would you calculate the lithium clearance for the dialysis procedure