Maarij Mirza
Introduction
Foster Kennedy Syndrome (FKS), named after neurologist Robert Foster Kennedy (1884-1952), is a rarely reported phenomenon resulting in painless progressive loss of vision that is seen within neuro-ophthalmology. It is characterised by visual loss and optic atrophy in one eye and papilledema in the opposite eye due to a space occupying lesion intracranially. It presents sporadically with less than 1% of people with intracranial tumours affected (1).
Aetiology and Pathophysiology
Foster Kennedy syndrome was first described in 1911, where Robert Foster Kennedy noted the triad of optic disc pallor, contralateral optic disc oedema and anosmia in a 37-year old woman presenting with decreased visual acuity, later found to have a large olfactory meningioma (2). Type 1 FKS is characterised by the presence of an intracranial mass that results in the direct compression of the optic nerve and ischaemic damage to axons, ultimately leading to optic atrophy and disc pallor. This can elevate intracranial pressure and results in optic nerve oedema contralaterally. Type 2 FKS is described as unilateral optic atrophy and bilateral papilledema, whereas Type 3 FKS involves bilateral papilledema with atrophy (2). Meningiomas in the anterior cranial fossa and tumours of the pituitary gland are the most common culprits for this clinical finding as cited by various case reports (3). Pseudo-Foster Kennedy Syndrome (PFKS) is characterised by the same clinical findings without the presence of an intracranial mass. The resultant findings are hypothesised to occur due to optic neuritis and ischaemic optic neuropathy (4).
Clinical Manifestation
The onset of visual loss in one eye is insidious in nature, ranging from weeks to months where patients notice reduced visual acuity (5). Associated symptoms may also be present in the context of raised intracranial pressure such as headaches, nausea or vomiting and anosmia. Where lesions are localised to the frontal lobe, changes in emotional lability may also manifest. As the disease progresses, compression of other nerves can also give rise to cranial nerve palsies (6). On examination, a relative afferent pupillary defect (RAPD) can be observed in the eye where optic atrophy is present. On dilated fundoscopy, optic atrophy and pallor will be seen in one eye whereas optic disc swelling will be seen in the other (3).
Management
All suspected cases of FKS or pseudo-FKS should have prompt neuroimaging to investigate the presence of a space occupying lesion. In many cases, visual symptoms occur as a late finding and preceding generalised symptoms of raised intracranial pressure or space occupying lesions may warrant earlier neuroimaging. This may explain why FKS is a rare phenomenon to encounter (2). Prognosis is dependent on the malignant potential of the lesion and extent of disease. Treatment modality for intracranial tumours can range from symptomatic management with systemic steroids, chemotherapy, radiotherapy and surgical resection (3,8).
References
1. Lotfipour S, Chiles K, Kahn JA, Bey T, Rudkin S. An unusual presentation of subfrontal meningioma: a case report and literature review for Foster Kennedy syndrome. Intern Emerg Med. 2011 Jun 1;6(3):267–9.
2. Lai AT, Chiu SL, Lin IC, Sanders M. Foster Kennedy Syndrome: Now and Then. Journal of Neuro-Ophthalmology. 2014 Mar;34(1):92.
3. Musa MJ, Zeppieri M. Foster Kennedy Syndrome. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2025. Available from: http://www.ncbi.nlm.nih.gov/books/NBK582149/
4. David C, Suvac E, Tăbăcaru B, Stanca TH. Pseudo-Foster Kennedy Syndrome – a case report. Rom J Ophthalmol. 2016;60(4):270–4.
5. Singh SR, Mehta A, Dogra M. Foster Kennedy syndrome. QJM: An International Journal of Medicine. 2019 Aug 1;112(8):623–4.
6. 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 21;100(12):587–90.
7. Musa MJ, Zeppieri M. Foster Kennedy Syndrome. In: StatPearls [Internet] [Internet]. StatPearls Publishing; 2023 [cited 2025 Jan 19]. Available from: https://www.ncbi.nlm.nih.gov/sites/books/NBK582149/
8. Armstrong TS, Ying Y, Wu J, Acquaye AA, Vera-Bolanos E, Gilbert MR, et al. The relationship between corticosteroids and symptoms in patients with primary brain tumors: utility of the Dexamethasone Symptom Questionnaire-Chronic. Neuro Oncol. 2015 Aug;17(8):1114–20.