The clinical features resulting from an Arnold-Chiari malformation depend upon the patient's age and type of malformation.
Infant presentations are with respiratory difficulties and lower cranial nerve palsies due to severe type II or III deformities. Death may occur from aspiration pneumonia or from complications of associated malformations, e.g. spina bifida. Mild forms may present with horizontal nystagmus, retrocollis - neck extension - and spasticity.
In childhood, gait ataxia may develop. It is often accompanied by features of an associated syringomyelia, for example, dissociated sensory loss and spastic quadriparesis.
Adults may present with occipital headaches - induced by coughing and straining; downbeat nystagmus - on looking down - or rotatory nystagmus - on lateral gaze; gait ataxia; and spastic quadraparesis. Bulbar symptoms may develop - lower cranial nerve palsies, respiratory difficulties.
Oscillopsia is common; the patient is aware of 'wobbly' vision due to nystagmus.
Last reviewed 04/2022