Category: Drug-Induced Movement Disorders
Objective: To share an exciting case of effective treatment of Syndrome of Irreversible Lithium Effectuated Neurotoxicity (SILENT) after an inadvertent lithium overdose using Deep Brain Stimulation (DBS).
Background: SILENT syndrome is a rare consequence of lithium toxicity, characterized by persistent neurological symptoms for at least 2 months post-lithium cessation with the absence of pre-existing neurological disorders[1]. Typical clinical presentation consists of cerebellar dysfunction, brainstem dysfunction, and extrapyramidal symptoms [2].This condition is more commonly seen among chronic lithium users [3]. SILENT poses a management challenge [4]. The efficacy of DBS in managing drug-induced tremors was prescribed, however literature on DBS application in SILENT syndrome is limited [5]. We present a case of effective treatment of SILENT syndrome using DBS [4].
Method: A 64-year-old Lady with a history of bipolar disorder presented with debilitating involuntary movements affecting all extremities and trunk of 2-years duration. Movements started after 10-day coma following accidental lithium overdose and have persisted despite attempts with various medications(Carbidopa-Levodopa, propranolol,and primidone).Patient felt symptoms were worsening, with more difficulty with daily activities and increased falls. Clinical examination revealed kinetic tremors in all limbs(< 4.5 Hz)and torso, bradykinesia and rigidity predominantly on the right side, positive cerebellar signs and shuffling gait.
Results: The patient was diagnosed with SILENT syndrome due to acute Lithium toxicity. After inadequate response to medical therapy, the patient opted for Left Ventral Intermediate (Vim) DBS. After two months, a partial improvement in the right arm noticed, progressing to complete resolution of rest tremor at 5-month follow-up and sustained at 4-year follow-up. Patient declined right Vim DBS due to anxiety associated with awake surgery.
Conclusion: DBS has been utilized in a variety of movement disorders including those induced by medications, however there are few reports of the application of DBS in patients with ataxia and medications-induced tremor. This case highlights the application of DBS to achieve a favorable outcome observed in managing SILENT syndrome. This suggests that further consideration should be given to DBS in cases of SILENT symptom refractory to medical management.
References: [1] Señga MM, Sarapuddin G, Saniel E. A Case Report on an Atypical Presentation of the Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT) in a War Veteran with Bipolar Disorder and PTSD. Case Rep Psychiatry. 2020 Jun 4;2020:5369297.
[2] Lithium toxicity: The SILENT threat – PubMed [Internet]. [cited 2024 Feb 6]. Available from: https://pubmed-ncbi-nlm-nih-gov.ezp.slu.edu/34802989/
[3] Lithium intoxication: Incidence, clinical course and renal function – a population-based retrospective cohort study – PubMed [Internet]. [cited 2024 Feb 3]. Available from: https://pubmed-ncbi-nlm-nih-gov.ezp.slu.edu/27307388/
[4] Santos CF, Gomes R. Syndrome of Irreversible Lithium-Effectuated Neurotoxicity (SILENT): A Review. European Psychiatry. 2022 Jun;65(S1):S717–S717.
[5] Amerika WE, van der Gaag S, Mosch A, van der Gaag NA, Hoffmann CFE, Zutt R, et al. Medical and Surgical Treatment for Medication‐Induced Tremor: Case Report and Systematic Review. Mov Disord Clin Pract. 2022 May 24;9(5):676–87.
To cite this abstract in AMA style:
L. Okar, P. Murin, A. Prabhune, C. Pratap. Reversing the irreversible: The application of Deep Brain Stimulation in The Syndrome of Irreversible Lithium Effectuated Neurotoxicity. [abstract]. Mov Disord. 2024; 39 (suppl 1). https://www.mdsabstracts.org/abstract/reversing-the-irreversible-the-application-of-deep-brain-stimulation-in-the-syndrome-of-irreversible-lithium-effectuated-neurotoxicity/. Accessed October 9, 2024.« Back to 2024 International Congress
MDS Abstracts - https://www.mdsabstracts.org/abstract/reversing-the-irreversible-the-application-of-deep-brain-stimulation-in-the-syndrome-of-irreversible-lithium-effectuated-neurotoxicity/