A Dual Hit by Lithium: Sinus Node Dysfunction and Pulmonary Artery Hypertension

Rationale: Lithium is used as an anti-manic and mood-stabilising drug in psychiatric clinical setting. It has a narrow therapeutic window with multiple side effects, which can occur even at normal therapeutic range. Among many side effects, pulmonary artery hypertension (PAH) and sinus node dysfunction ( SND) is a very rare condition associated with chronic lithium use . Reversibility of PAH even after permanent drug cessation is not known. Case presentation: We present a case of a 52-year old male on lithium therapy for last 5 years for bipolar disorder (BD) with no past history of cardiac illness, presented with moderate to severe pulmonary artery hypertension (PAH) and symptomatic sinus node dysfunction with frequent episodes of presyncope and syncope. Symptomatic sinus node dysfunction and severe pulmonary artery hypertension necessitated cessation of lithium treatment. Within two weeks, patient reverted back to normal sinus rhythm. Pulmonary artery hypertension took also improved over next six months from RVSP of 70mmHg to 35mmHg. Considering the fact that abrupt cessation of lithium therapy can lead to rebound in symptoms of bipolar disorder, he was switched to alternative antipsychotic agent Divalproex 250 mg BD under the guidance of psychiatrist. Conclusion: Patient on chronic lithium therapy presenting with any symptoms should be properly evaluated and investigated. Even within the normal therapeutic range, patient can present with rarest of the rare side effects like in our case. Sick sinus syndrome in most cases reversible within weeks. Contrary to the only case repot published till now, this case shows that PAH is reversible with time. To the best of our knowledge this is the first case report showing reversibility of pulmonary hypertension after lithium cessation.