Factitious Hyperlithemia: Why Lithium Heparin Blood Tubes may get you in Trouble

Introduction

Lithium carbonate administration in patients suffering from bipolar disorders was first introduced in the mid-19^th century and later, in 1970, approved by the U.S. Food and Drug Administration (category D). There is still lack of data regarding the prevalence of lithium treatment during pregnancy. An epidemiologic study conducted in the United Kingdom in 2012 showed low prevalence (0.015%), which remained steady between 1995 and 2012. The majority of patients discontinued medication by the 6^th week of pregnancy (McCrea RL et al., PloS One 2015; 10). Lithium blood levels (LBL) at birth are equal in newborn and maternal blood due to unrestricted placental barrier diffusion. Lithium has a narrow therapeutic window and levels are routinely monitored with a range from 0.6 to 1.2 mmol/l. Toxicity occurs at blood levels>1.5 mmol/l or lower in patients who have received chronic treatment. Lithium intoxication causes severe neurological and renal symptoms (Arslan Z et al., Paediatr Int Child Health 2016; 36: 240–242). Volume restoration in case of depletion and hemodialysis is the treatment of choice. There is no antidote for lithium.

Teratogenic properties, reported in previous studies, have recently been questioned. It remains unclear if lithium treatment causes congenital heart disease (esp. Ebsteinʼs anomaly) or non-cardiac (neuromuscular, thyroid and renal) disorders. No long-term lithium-related side effects have been described in newborns without malformations (Patorno E et al., N Engl J Med 2017; 376: 2245–2254). Transient symptoms including neurosensory deficit (lethargy, floppiness, oral feeding difficulties, weak suckling reflex), respiratory distress or apnea, bradycardia, arrhythmias were reported (Kozma C et al., Am J Med Genet A 2005; 132: 441–444).

In neonatal care there is still a lack of experience monitoring LBL, which can lead to diagnostic and therapeutic errors. We present a case report of factitious hyperlithemia in a newborn whose mother received lithium treatment during pregnancy.