A rare case of Lithium/SSRI-induced neuroleptic malignant syndrome

ABSTRACT Selective serotonin reuptake inhibitors (SSRIs), including escitalopram, are primarily associated with serotonin syndrome; however, rare cases of neuroleptic malignant syndrome (NMS) have also been reported. The proposed mechanism involves serotonergic modulation of dopaminergic pathways, resulting in a functional hypodopaminergic state that may contribute to NMS-like manifestations. In addition, SSRIs may produce extrapyramidal symptoms such as rigidity, tremors, and dystonia through serotonin-mediated inhibition of dopaminergic neurotransmission. In this case, we present a 73-year-old male patient who has been brought to the outpatient department with the chief complaints of fever, difficulty in swallowing, and rigidity of all four limbs. According to the family members, the patient was on escitalopram 20 mg and lithium 450 mg twice daily; he is not on any other medication for last 4 years. The patient has a history suggestive of bipolar depression for 14 years. Both lithium and escitalopram were stopped 4 days before consulting at our hospital, as he went into an altered sensorium. The patient was admitted as he was in an altered sensorium with high fever, having difficulty in swallowing, and also having mild shortness of breath. After admission, investigations revealed high serum creatine phosphokinase levels of 2892 mg/dl, white blood cell count: 19,000, serum creatinine: 1.4 mg/dl, and serum lithium: 0.4 meq/l. Other investigations, such as an electrocardiogram, 2D echo, computed tomography brain plain, urine, blood culture, and sensitivity, were normal. A diagnosis of lithium-/SSRI-induced NMS was made, and appropriate treatment was given; the patient stayed in the hospital for 3 weeks and was discharged in a stable condition.