Cerebellar ataxia with neuropathy and vestibular areflexia syndrome (CANVAS) - a case report and review of literature

Abstract

CANVAS (cerebellar ataxia with neuropathy and vestibular areflexia syndrome) is a rare neurological syndrome of unknown etiology. The main clinical features include bilateral vestibulopathy, cerebellar ataxia and sensory neuropathy. An abnormal visually enhanced vestibulo-ocular reflex is the hallmark of the disease. We present a case of 58-year-old male patient who has demonstrated gait disturbance, imbalance and paresthesia of feet for 2 years. On examination ataxia of gait, diminished knee and ankle reflexes, absence of plantar reflexes, fasciculations of thigh muscles, gaze-evoked downbeat nystagmus and abnormal visually enhanced vestibulo-ocular reflex were found. Brain magnetic resonance imaging revealed cerebellar atrophy. Vestibular function testing showed severely reduced horizontal nystagmus in response to bithermal caloric stimulation. Nerve conduction study revealed loss of upper and lower limb sensory nerve action potentials. The course of illness was progressive with ataxic gait and unsteadiness as the most disabling symptoms. We report 4-year follow-up of the patient since the beginning of the disease.

Keywords: Cerebellar ataxia; Cerebellar ataxia with neuropathy and vestibular areflexia syndrome; Sensory neuropathy; Vestibulopathy; Visually enhanced vestibulo-ocular reflex.