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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.  He was a British neurologist, who spent the majority of his working life in America (1884-1952). It consists of:
- Unilateral, ipsilateral optic atrophy, produced by direct pressure on the optic nerve.
- Contralateral papilloedema secondary to raised intracranial pressure (ICP).
- Central scotoma.
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. This occurs typically due to bilateral sequential optic neuritis or ischaemic optic neuropathy. Cases secondary to other pathologies have also been reported.
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.
- Arteriovenous malformation, in which chronic venous hypertension was the likely aetiology.
- Juvenile nasopharyngeal angiofibroma (a rare benign tumour of the nasopharynx that occurs in adolescent boys with epistaxis and nasal obstruction).
- Trigeminal cystic schwannoma.
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. 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.
- Memory loss.
- Emotional lability, ie other frontal lobe signs.
Management and prognosis
Both depend on the underlying cause.
Further reading and references
Yeh WY, Cheng CK, Peng PH, et al; Foster Kennedy Syndrome in a Case with Retinitis Pigmentosa. Ophthalmic Surg Lasers Imaging. 2010 Mar 9:1-3. doi:
Ramdasi R, Thorve S, Vekariya M, et al; Reverse Foster Kennedy Syndrome Caused by an Intra-axial Tumor. Neurol India. 2022 Jul-Aug70(4):1655-1657. doi: 10.4103/0028-3886.355138.
Ayele B, Mengesha A, Wotiye A, et al; Giant Pituitary Adenoma Presenting with Foster-Kennedy Syndrome in a 21-Year Old Ethiopian Patient: A Rarely Reported Phenomenon: A Case Report. Ethiop J Health Sci. 2020 Mar30(2):311-314. doi: 10.4314/ejhs.v30i2.19.
Stone JL, Vilensky J, McCauley TS; Neurosurgery 100 years ago: the Queen Square letters of Foster Kennedy. Neurosurgery. 2005 Oct57(4):797-808
Musa MJ, Zeppieri M; Foster Kennedy Syndrome.
Egbu E, Ihemedu C, Eze UA, et al; Steroid-Induced Hiccups in a Patient Managed for Pseudo Foster-Kennedy Syndrome: A Case Report of Good Outcome With the use of Gabapentin. Cureus. 2021 Jan 2513(1):e12893. doi: 10.7759/cureus.12893.
Yildizhan A; A case of Foster Kennedy syndrome without frontal lobe or anterior cranial fossa involvement. Neurosurg Rev. 199215(2):139-42.
Liang F, Ozanne A, Offret H, et al; An atypical case of Foster Kennedy syndrome. Interv Neuroradiol. 2010 Dec16(4):429-32. Epub 2010 Dec 17.
Aga A; Juvenile nasopharyngeal angiofibroma presenting as Foster Kennedy Syndrome. Ethiop Med J. 2001 Jul39(3):251-60.
Mahjoub Y, Wan M, Subramaniam S; Pearls & Oy-sters: Trigeminal Cystic Schwannoma Presenting With Foster Kennedy Syndrome, Sixth Nerve Palsy, and Focal Seizures. Neurology. 2023 Mar 21100(12):587-590. doi: 10.1212/WNL.0000000000201700. Epub 2022 Dec 19.
Watnick RL, Trobe JD; Bilateral optic nerve compression as a mechanism for the Foster Kennedy syndrome. Ophthalmology. 1989 Dec96(12):1793-8.