Sedation failure in a patient with Fahr syndrome in the intensive care unit

Abstract

Fahr Syndrome, which is a rare neurologic syndrome, is characterized by sporadic or genetically inherited basal ganglion calcification. There are some hypotheses about the pathophysiology of Fahr Syndrome related to a defect in calcium metabolism, metastatic calcium deposits and increased free radical production. Although patients are usually diagnosed with extrapyramidal symptoms, they may also present with cerebellar dysfunction, speech disorders, dementia and neuropsychiatric symptoms. We aimed to discuss sedation failure with dexmedetomidine and midazolam in a 49-year-old female patient with Fahr Syndrome who was admitted to our intensive care unit after suicidal carbamazepine overdose in this case report. Adequate sedation levels could not be reached although infusion of 1.5 µg kg-1 h-1 dexmedetomidine and bolus injections of 1.5 mg midazolam were administered. This may be due to the tolerance to sedatives developed by long-term use of antidepressant and antiepileptic agents. On the other hand; the unique sedative agent dexmedetomidine is a specific and selective α2 agonist and the widespread intracerebral calcification in our patient may have impaired α2 receptor activity. Besides, calcium metabolism disorder, one of the probable causes of Fahr Syndrome, may affect calcium-mediated inhibition of neurotransmitter release through α2 adrenoreceptors and reduced the effectiveness of dexmedetomidine.