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.
Nadir görülen nörolojik bir sendrom olan Fahr Sendromu, sporadik ya da genetik geçişli bazal ganglion kalsifikasyonuyla karakterizedir. Fahr Sendromu’nun patofizyolojisiyle ilgili olarak; kalsiyum metabolizma bozukluğu, metastatik kalsiyum depozitleri ve artmış serbest radikal üretimi gibi bazı hipotezler mevcuttur. Hastalar genellikle ekstrapiramidal semptomlarla tanı alsa da, serebellar disfonksiyon, konuşma bozuklukları, demans ve nöropsikiyatrik semptomlarla da başvurabilirler. Bu olgu sunumunda amacımız, intihar amaçlı karbamazepin alımı sonrası yoğun bakımımıza kabul edilen 49 yaşındaki kadın hastadaki sedasyon yetersizliğinden bahsetmektir. Hastaya 1.5 mcg kg-1 sa-1 deksmedetomidin infuzyonu ve 1.5 mg midazolam bolusları uygulandığı halde yeterli sedasyon düzeyine ulaşılamamıştır. Bu durum uzun süreli antiepileptik ve antidepresan kullanımına bağlı olabilir. Diğer yandan da, benzersiz bir sedatif ajan olan deksmedetomidin spesifik ve selektif bir α2 agonistidir. Hastamızdaki yaygın serebral kalsifikasyon, α2 reseptör aktivitesini bozmuş olabilir. Bunun yanında Fahr Sendromu’nun muhtemel nedenlerinden biri olan kalsiyum metabolizma bozukluğu da α2 adrenoreseptör aracılıklı kalsiyum ilişkili nörotransmitter salınımını etkilemiş ve böylece deksmedetomidinin etkinliğini azaltmış olabilir
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