The aetiology of abducens nerve palsy depends on whether the sufferer is an adult or a child:
In adults the common causes are:
- tumour - e.g. nerve is compressed on the sharp edge of the petrous temporal bone with raised intracranial pressure, but it may also be directly compressed by a tumour in the cerebellopontine angle. Raised intracranial pressure may result in bilateral palsy.
- trauma - commonly affected in fractured base of skull
- cerebrovascular accidents - e.g. Millard Guber syndrome
- diabetes may cause mononeuritis complex - bilateral or unilateral palsy
- Wernicke's encephalopathy - bilateral
- idiopathic
Frequent causes in children:
- following mastoid and middle ear infections
- brain stem tumour
- infective, e.g. suppurative middle ear disease causing unilateral trigeminal pain and VI nerve palsy
- birth injury or trauma