Foster–Kennedy syndrome

Overview

Foster–Kennedy Syndrome is a rare neurological condition characterized by a specific combination of optic nerve findings. It involves optic atrophy in one eye and papilledema (optic disc swelling due to increased intracranial pressure) in the other. This syndrome is typically associated with a mass lesion, such as a tumor, in the frontal lobe that compresses the optic nerve on one side while simultaneously raising intracranial pressure. It is named after neurologist Robert Foster Kennedy, who first described it in the early 20th century.

Causes

Foster–Kennedy Syndrome results from the presence of a space-occupying lesion in the anterior cranial fossa that affects both the optic nerve and intracranial pressure. Common causes include:

• Frontal lobe tumors: Especially meningiomas of the olfactory groove or sphenoid wing.

• Other intracranial masses: Such as gliomas, metastases, or large aneurysms.

• Trauma or surgical complications: That result in asymmetric optic nerve damage and raised intracranial pressure.

Symptoms

The hallmark features of Foster–Kennedy Syndrome result from optic nerve dysfunction and elevated intracranial pressure. Common symptoms include:

• Unilateral optic atrophy: Pale optic disc and vision loss in one eye.

• Contralateral papilledema: Swelling of the optic disc in the other eye.

• Progressive visual loss: Including blurred vision, decreased acuity, and visual field defects.

• Headache: Due to increased intracranial pressure.

• Nausea and vomiting: Common symptoms of intracranial hypertension.

• Anosmia (loss of smell): May occur if the olfactory nerve is compressed.

• Behavioral or personality changes: If the frontal lobe is involved.

Diagnosis

Diagnosis of Foster–Kennedy Syndrome is based on clinical evaluation and neuroimaging studies. Key diagnostic steps include:

• Ophthalmic examination: Fundoscopy to assess for optic atrophy and papilledema.

• Visual field testing: To identify deficits associated with optic nerve damage.

• Neuroimaging: MRI or CT scan to detect the presence and location of a mass lesion in the frontal lobe.

• Intracranial pressure assessment: May be inferred from symptoms or confirmed via lumbar puncture (if safe).

Treatment

Treatment of Foster–Kennedy Syndrome focuses on addressing the underlying cause of the mass lesion and reducing intracranial pressure. Management strategies include:

• Surgical removal of the tumor: The primary treatment if the mass is operable.

• Radiotherapy or chemotherapy: In cases where the tumor is malignant or not suitable for surgery.

• Corticosteroids: May help reduce inflammation and intracranial pressure temporarily.

• Management of intracranial hypertension: Includes diuretics like acetazolamide or therapeutic lumbar punctures if indicated.

• Ophthalmic follow-up: Regular vision monitoring and supportive therapies.

Prognosis

The prognosis of Foster–Kennedy Syndrome depends on the nature and progression of the underlying lesion. Benign tumors, such as meningiomas, may be successfully treated with surgery, leading to stabilization or improvement of symptoms. However, if the lesion is malignant or if diagnosis and treatment are delayed, permanent vision loss or neurological deficits may occur. Early detection and appropriate management are essential to improve outcomes and preserve neurological function.