Pseudo-Foster Kennedy Syndrome is defined as unilateral optic atrophy with optic disc swelling in the contralateral eye in the absence of an intracranial mass. We reported an uncommon manifestation of nonarteritic ischemic optic neuropathy presenting as Pseudo-Foster Kennedy Syndrome in a fifty years old male.
Pseudo-Foster Kennedy syndrome is defined as ipsilateral optic atrophy with disc edema in the contralateral eye with absence of intracranial mass . It has been usually reported in cases of Benign Intracranial hypertension . Ischemic optic neuropathies and Optic nerve hypoplasia in literature. Here, we describe a case of Pseudo-Foster Kennedy Syndrome in a patient presenting with visual impairment of both eyes and high blood glucose level on first medical consultation.
Anterior Ischemic Optic Neuropathy (AION) is categorized into Arteritic (AAION) and Non-arteritic (NAION) types. NAION typically occurs among middle age males with systemic vascular risk factors such as smoking and diabetes, causing hyperemic edema with disc hemorrhage, segmental pallor and attenuated blood vessels . ESR, C-reactive Protein (CRP) and platelet levels are normal. AAION cause the swollen nerve-the one affected more recently-often displays pallid edema. It affects older people more common among female and has worse visual outcomes than NAAION patients with rare late improvement. They usually have elevated ESR, CRP and platelet levels. A 2- to 3-cm temporal artery biopsy with pathologic examination of consecutive slices spaced at 0.25 cm is the gold standard for diagnosis.
The first case of Foster Kennedy Syndrome was described by British neurologist Robert Foster Kennedy in 1911 . Pseudo-Foster Kennedy syndrome has been reported in Nonarteritic ischemic optic neuropathy, optic neuritis and optic disc hypoplasia in literature . Pseudo-Foster Kennedy is usually a diagnosis of exclusion. There was no other cause for the disc edema except the high blood sugar leading to non-arteritic anterior ischemic optic neuropathy in our patient. The disc edema in left eye and pallor optic disc in right eye have been set in due to untreated diabetic non-arteritic anterior ischemic optic neuropathy and poor glycemic control. Few cases of diabetic papillopathy mimicking non-arteritic anterior ischemic optic neuropathy were reported presenting as Pseudo-Foster Kennedy syndrome in literature .
Follow-up is essential during period of four to eight weeks to be sure that the swelling is resolving and is being replaced by pallor . There have been case reports of patients who were initially diagnosed with bilateral sequential NAION and later proved to have a compressive lesion with development of neurologic symptoms . On strict glycemic control, the disc edema was resolved in our patient during follow up at six months.
We concluded that the Pseudo-Foster Kennedy syndrome in our patient was due to diabetic non-arteritic anterior ischemic optic neuropathy.