Comparison of patients hemodialyzed for lithium poisoning and those for whom dialysis was recommended by PCC but not done: what lesson can we learn?

AIMS: To compare patients for whom hemodialysis was done for lithium poisoning and those for whom it was recommended by the poison control centre (PCC) but not done and to evaluate the effect of withholding hemodialysis on outcomes.
METHODS: All lithium overdoses brought to the attention of the PCC were prospectively followed from January 1 to December 31, 1996. Patients for whom hemodialysis was done were compared with those for whom it was recommended but not done in terms of clinical presentation, lithium elimination half-life, need for transfer to another centre for hemodialysis, and outcome (death, or sequel or recovery).
RESULTS: A total of 205 cases of lithium overdoses were collected including 110 with levels higher than 1.5 mmol/l. There were 12 acute lithium overdoses; no patients required hemodialysis and there were no sequel or deaths. There were 174 acute on chronic overdoses; hemodialysis was recommended in 9 patients but only 6 underwent hemodialysis; one patient died during hemodialysis but no other had sequel. There were 19 chronic poisonings; hemodialysis was recommended in 9 patients but only 2 had hemodialysis, a third patient underwent hemodialysis despite it not being recommended; one patient died without hemodialysis and one other had sequel after hemodialysis. No difference were observed between the groups for age, sex, type of poisoning (acute on chronic/chronic), levels (initial/peak/6 hours/extrapolated at 30 hours), time of presentation post-ingestion, presence of co-ingestants, symptoms and signs, Hansen and Amdisen grade, initial creatinine, time of recommendation to perform hemodialysis (daytime or nighttime), need to transfer patients to another centre to perform hemodialysis, and outcome. Patients with acute on chronic poisoning that were not hemodialyzed had longer elimination half-life than those for whom hemodialysis was done even before hemodialysis was performed: 50.1 +/- 13.6 h (n = 3) versus 12.9 +/-12.1 (n = 3) (p = 0.007), respectively.
CONCLUSION: No difference was observed between patients for whom hemodialysis was done and those for whom it was recommended by PCC but not done. Despite the death of one patient clearly associated with voluntary withholding hemodialysis, sequel was not seen in that group. The indications for hemodialysis in lithium poisoning should be reconsidered to include only the more severe cases.