Background:
Dentatorubral–pallidoluysian atrophy (DRPLA) is an autosomal dominant degenerative disease of the dentatorubral and pallidoluysian systems of the central nervous system, caused by a mutation in the ATN1 gene and characterized by ataxia and dementia. Depending on the age of onset, these symptoms can be associated with choreoathetosis, myoclonus, epilepsy and psychiatric symptoms. There is scarce literature about the anaesthetic approach of spinocerebellar ataxia, including DRPLA.

Case Report:
58-year-old male, ASA III (DRPLA) proposed for percutaneous endoscopic gastrostomy (PEG) placement under monitored anaesthetic care. The onset of DRPLA was at the age of 30 with progressive ataxia, followed by dysphagia. He became wheelchair-dependent after innumerous falls and had recurrent aspiration pneumonias. He was undernourished (BMI=18kg/m2) and was medicated with diazepam, risperidone, clonazepam, sodium valproate, quetiapine and sertraline.

We provided a deep sedation and analgesia with small boluses of midazolam (2 mg total), fentanyl (20 mcg total) and propofol (55 mg total) after placing the patient in dorsal decubitus with left tilt to lower pulmonary aspiration risk. A nasal cannula was placed for oxygen inhalation and the patient was monitored according to ASA standards. The PEG placement lasted 20 minutes, was uneventful, and the patient maintained a deep sedation state with spontaneous breathing and haemodynamic stability throughout the procedure, after which he remained deeply sedated, so we administered flumazenil 0,2 mg, with successful recovery of consciousness. No adverse events occurred, like seizures or aspiration.

Discussion:
To our knowledge, there are no reports of sedation techniques in DRLPA patients. One paper reported the occurrence of a postoperative seizure after the administration of naloxone and another reported an apparent effectiveness of propofol and benzodiazepines in seizure prevention in general anaesthesia. GABA neurotransmission in basal ganglia might be decreased in DRPLA and intravenous anaesthetics can have both pro and anticonvulsant activities. The safety of anaesthetic drugs is unknown in DRPLA. Also, sedation carries the risks of ventilatory depression and pulmonary aspiration.

Learning Points:
In DRPLA patients, PEG can be safely performed under small doses of midazolam, fentanyl and propofol associated with oxygen supplementation. Several factors can lower seizure threshold during and after anaesthesia.

09 / Anaesthetic considerations for monitored anesthetic care in a dentatorubral-pallidoluysian atrophy patient