Susac's syndrome

Overview

Susac's syndrome is a rare autoimmune disorder characterized by a clinical triad of encephalopathy (brain dysfunction), branch retinal artery occlusions (leading to vision loss), and sensorineural hearing loss. It is also known as Susac’s syndrome or retinocochleocerebral vasculopathy. The syndrome results from inflammation and blockage of small blood vessels (microangiopathy) in the brain, retina, and inner ear.

Susac's syndrome most commonly affects young women aged 20-40 years but can occur in men and children. Early diagnosis and treatment are essential to prevent permanent neurological, visual, and auditory impairments.

Causes

The exact cause of Susac's syndrome is unknown, but it is believed to be an autoimmune process where the body’s immune system attacks the endothelial cells lining small blood vessels. This leads to microvascular occlusions and ischemic damage in the affected organs.

Potential contributing factors include:

• Autoimmune dysregulation

• Genetic predisposition

• Environmental triggers such as infections

Symptoms

Susac's syndrome presents with a triad of symptoms, though all three may not appear simultaneously, complicating diagnosis:

Neurological Symptoms (Encephalopathy)

• Headache

• Confusion and cognitive difficulties

• Memory loss

• Seizures

• Personality changes

• Motor and sensory deficits

Ocular Symptoms

• Visual disturbances such as scotomas (blind spots)

• Sudden vision loss due to branch retinal artery occlusions

• Retinal whitening or ischemic lesions visible on eye examination

Audiological Symptoms

• Sensorineural hearing loss, often sudden and bilateral

• Tinnitus (ringing in the ears)

• Vertigo or balance problems

Diagnosis

Diagnosis of Susac’s syndrome requires a combination of clinical evaluation and specialized investigations:

• Brain MRI: Shows characteristic lesions in the corpus callosum and white matter.

• Fluorescein angiography: Detects branch retinal artery occlusions and vascular leakage.

• Audiometry: Confirms sensorineural hearing loss.

• Lumbar puncture: May show elevated protein or mild lymphocytic pleocytosis.

• Blood tests: To exclude infections and other autoimmune diseases.

• Clinical history and examination: To identify the classic triad or partial manifestations.

Treatment

Susac's syndrome requires aggressive immunosuppressive therapy to control inflammation and prevent permanent damage:

• Corticosteroids: High-dose steroids are used initially to reduce inflammation.

• Immunosuppressive agents: Such as azathioprine, mycophenolate mofetil, or cyclophosphamide.

• Intravenous immunoglobulin (IVIG): Used to modulate immune response.

• Biologic therapies: In refractory cases, drugs like rituximab may be considered.

• Symptomatic treatment: Hearing aids, physical therapy, and cognitive rehabilitation as needed.

Prognosis

The prognosis of Susac's syndrome varies. Many patients experience a relapsing-remitting course, with periods of flare and remission. Early diagnosis and prompt immunosuppressive treatment improve outcomes and reduce the risk of permanent neurological, visual, or auditory impairment.

Without treatment, the syndrome can lead to significant disability. Long-term follow-up and multidisciplinary care are essential for managing symptoms and improving quality of life.