Foster Kennedy's syndrome

Synonyms: Kennedy's phenomenon; Gowers-Paton-Kennedy syndrome

What is Foster Kennedy's syndrome?

Foster Kennedy's syndrome (FKS) is a rare neurological sign first described in 1911 by Robert Foster Kennedy. ¹ He was a British neurologist, who spent the majority of his working life in America (1884-1952). It consists of:²

• Unilateral, ipsilateral optic atrophy, produced by direct pressure on the optic nerve.

• Contralateral papilloedema secondary to raised intracranial pressure (ICP).

• Central scotoma.

• Anosmia.

Pseudo-FKS has also been described, in which there is unilateral optic disc swelling with contralateral optic atrophy in the absence of an intracranial mass.³ This occurs typically due to bilateral sequential optic neuritis or ischaemic optic neuropathy. Cases secondary to other pathologies have also been reported.

Pathogenesis

It is most commonly caused by a tumour on the inferior surface of the frontal lobe. This is usually an olfactory groove meningioma or a medial third sphenoidal wing meningioma.

It has also been reported as a consequence of:

• A metastatic cerebral tumour.⁴

• Arteriovenous malformation, in which chronic venous hypertension was the likely aetiology.⁵

• Juvenile nasopharyngeal angiofibroma (a rare benign tumour of the nasopharynx that occurs in adolescent boys with epistaxis and nasal obstruction).⁶

• Trigeminal cystic schwannoma.⁷

A review of the 36 previously reported cases of FKS revealed that only eight (22%) of the cases satisfied Foster Kennedy's original hypothesis for the pathogenesis of his syndrome. 12 cases (33%) were probably caused by bilateral optic nerve compression.⁸ The authors conclude that as more sophisticated imaging permits earlier and more precise diagnosis, future cases of FKS caused by a mass will probably be found to result from bilateral direct optic nerve compression.

Associated symptoms

These include:

• Nausea.

• Vomiting.

• Memory loss.

• Emotional lability, ie other frontal lobe signs.

Management and prognosis

Both depend on the underlying cause.