Rett syndrome: anaesthesia management

SIR—we would like to report the anaesthetic management of a 7-year-old-girl with Rett syndrome who was scheduled for outpatient dental restoration. She had a history of seizures, chronic diarrhoea and episodes of irregular breathing. One month earlier, she had been admitted for dental work-up, and oral midazolam 0.5 mgÆkg was administered by a resident physician; however, surgery was cancelled by a staff anaesthesiologist because the child had diarrhoea. The child became very sleepy and could not be discharged from the hospital before 8 h. On examination, the child weighed 14 kg, was frail, continuously grinding her protruding teeth, and had a limited ability to open her mouth and extend her neck. She was unable to stand or walk, had constant bilateral hand wringing and could not speak, although she heard and, at times, followed her mother’s instructions. There was hypertonia of skeletal muscles with evident wasting in all limbs. Preoperative oxygen saturation on room air was 100%, and EKG demonstrated short P-R and normal Q-T intervals. No premedication was administered and, in the operating room, routine monitors and a bispectral (BIS) index monitor were placed. Anaesthesia was induced via mask using 65% nitrous oxide and oxygen. After taking a few breaths, the patient stopped breathing. The BIS monitor reading was 97. Halothane was then administered. An intravenous catheter was placed, and fentanyl 8 lg, glycopyrrolate 80 lg, and rocuronium 15 mg were administered. She was intubated with an uncuffed RAE nasotracheal tube size 6. Endtidal halothane concentration ranged from 0.6% to 0.3% and the BIS reading from 28 to 50. Surgery lasted for 3 h and, apart from fentanyl, no other analgesics were administered. At the end of the procedure, the child’s neuromuscular block was readily reversible; she was awake and the tracheal tube was removed shortly afterwards. Rett syndrome occurs almost exclusively in girls, and developmental regression becomes evident in late infancy (1). Between 1 and 4 years of age, these girls may show impairment in several areas, such as language, cognitive and motor skills and social interaction. They become irritable, lose the ability to walk, have constant stereotypical hand wringing and may suffer seizures, sleep disorders and attacks of hyperventilation and apnoea (1,2) After Down’s syndrome, Rett syndrome is believed to be the second most common cause of profound mental retardation in girls and women (3). In addition, sudden death, which is possibly due to significantly longer corrected Q-T intervals and more Twave abnormalities than seen in age-matched healthy girls, may occur (4). Our patient seemed to react excessively to midazolam, to 65% nitrous oxide and to halothane. She developed apnoea (possibly from a breathing abnormality) after administration of nitrous oxide. Patients with Rett syndrome may be unduly sensitive to sedative drugs and are often slow in recovering from anaesthesia (2,5). Using an insoluble inhalation agent, such as desflurane or sevoflurane, may be a better choice. An increased dose of nondepolarizing muscle relaxant may be needed; our patient required rocuronium 15 mg to achieve partial paralysis. Although Rett syndrome usually occurs in scattered cases, it has been diagnosed in more than one member in some families, which indicates a genetic basis for the syndrome. Bienvenu et al. (6). reported that mutations in the MECP2 gene accounted for most cases of typical forms of Rett syndrome. The BIS monitor has been validated in children (7), and allowed us to follow anaesthetic depth and to titrate the effect of anaesthetic agents. Our patient was awake and comfortable shortly after the end of the procedure. We conclude that the BIS monitor could be of help in inducing and maintaining an adequate level of anaesthesia in children who are extremely sensitive to anaesthetic drugs and agents.