Anaesthesia recommendations for Kennedy disease

Kennedy disease (KD) is an adult -onset. X-linked recessive trinucleotide, polyglutamine (poly -G) disorder, caused by expansion of a polymorphic CAG tandem repeat in exon 1 of the androgen -receptor (AR) gene on chromosome Xq11-12 [1]. The exact mechanism resulting in neuronal degeneration and loss is currently unknown: however, the severity of disease does appear to increase with increasing number of trinucleotide repeats. The estimated world-wide incidence of KD is approximately one in 40,000 males. Because of the X -linked transmission, KD almost exclusively affects males but is transmitted by female carriers [2]. Patients usually present between 30 and 50 years of age with amyotrophic weakness and wasting of the facial, bulbar and proximal limb muscles. There are occasionally sensory and/or endocrine disturbances, such as androgen resistance, gynaecomastia, elevated testosterone or progesterone, and reduced fertility [3-5]. Specific initial symptoms may include tremor, muscle cramping, fatigue, and slurred speech. As the disease progresses, patients may develop difficulty chewing and swallowing, tongue wasting, dysarthria, dysphonia, and impaired mobility. Severe cases may develop respiratory compromise and are at risk for aspiration. In addition, patients may suffer from spontaneous, self-limited laryngospasm. Some features of KD resemble the early signs of amyotrophic lateral sclerosis (ALS), which can lead to misdiagnosis. A formal diagnosis of KD is confirmed by genetic testing confirming >35 CAG trinucleotide repeats in the AR gene. A number of studies are under way examining the efficacy of various pharmacologic treatments. Currently, there is no known effective treatment for Kennedy's disease.