Infantile-Onset Spinocerebellar Ataxia (IOSCA)

Overview

☞Spinocerebellar Syndrome, also known as spinocerebellar atrophy or spinocerebellar degeneration, is a progressive, degenerative with multiple types, with an estimated 150,000 people in the United States. Spinocerebellar ataxia (SCA) is hereditary, progressive, and often fatal. There is no known effective treatment or cure. SCA can affect anyone of any age.

At a glance

Infantile-onset spinocerebellar ataxia belongs to a larger group of ☞Spinocerebellar Ataxia. In this case, it is Type 8. It manifests at the age of 9 to 18 months in previously healthy infants. It is characterized by ataxia, athetosis, muscle hypotonia, polyneuropathy, and loss of deep tendon reflexes, and at the later stage, as hypacusis, ophthalmoplegia, optic atrophy, and female primary hypogonadism of the hypergonadotropic type. The cause of premature death is status epilepticus.

Synonyms

OHAHA Syndrome (Ophthalmoplegia, Hypacusis, Ataxia, Hypotonia, and Athetosis Syndrome); Infantile Spinocerebellar Ataxia with Sensory Neuropathy. Some researchers also use the term Spinocerebellar Ataxia (SCA) Type 8 for this disease; however, this term has not been uniformly accepted.

Incidence

The incidence is unknown. Only 19 patients have been reported in the literature, all of them from Finland.

Genetic inheritance

Extremely rare, but more frequent in the Finnish population. The Finnish form of IOSCA presents with slower progressive symptoms with clumsiness and loss of ability to walk as first manifestation. It does not share the same gene locus as OHAHA. It is an autosomal recessive inherited form of spinocerebellar ataxia with the mutation linked to 10q24.

Clinical aspects

Slowly progressive clinical symptoms appear usually between the ages of 10 and 24 months in previously healthy infants. The first symptoms are usually clumsiness and loss of the ability to walk. Ataxia, athetosis, and muscle hypotonia with loss of deep tendon reflexes, ophthalmoplegia with only convergence persisting, and hearing loss can be discovered on clinical examination. A polyneuropathy with profound decrease in sensory nerve conduction velocities and progressive loss of myelinated fibers in sural nerve biopsies may develop by adolescence. Involvement of the vestibular organ can markedly disturb the balance and may be present at the onset of symptoms. Some patients show abnormal background activity on the EEG with advancing age, and seizures (status epilepticus) have been described. Neuroradiologic investigation reveals cerebellar atrophy as the main cause of ataxia.

Precautions before anesthesia

Proper evaluation of the extent of muscle hypotonia must be obtained. Seizure medication must be maintained. An anesthesia consultation is recommended before elective surgery.

Anesthetic considerations

As the disease progresses, nerve stimulation becomes technically more difficult, on the one hand making nerve location and regional anesthesia more unreliable and on the other hand requiring ...