How is Susacs syndrome diagnosed?

Susac syndrome is diagnosed through a combination of clinical evaluation and the identification of its classic triad: encephalopathy, branch retinal artery occlusions (BRAO), and sensorineural hearing loss. Because Susac syndrome is a rare microangiopathy, diagnosis often requires specialized neuro-ophthalmological and radiological imaging, such as brain MRI showing characteristic "snowball" lesions in the corpus callosum.

How is Susac syndrome diagnosed?

The diagnostic process for Susac syndrome is notoriously challenging because patients rarely present with all three classic symptoms simultaneously at the onset. Physicians typically begin with a comprehensive neurological examination, followed by a series of specialized tests to visualize the microvascular damage characteristic of the condition. Because Susac syndrome affects the small blood vessels of the brain, retina, and inner ear, a multidisciplinary approach is required to confirm the diagnosis.

What tests and examinations are required?

To confirm a diagnosis of Susac syndrome, clinicians rely on a specific set of diagnostic investigations:

• Brain MRI: Specifically looking for "snowball" lesions in the central fibers of the corpus callosum, which are highly specific to this condition.


• Fluorescein Angiography: An essential test to identify branch retinal artery occlusions (BRAO) that might not be visible during a standard eye exam.


• Audiometry: To document sensorineural hearing loss, which often manifests as low-frequency hearing impairment.


• Lumbar Puncture: Often performed to check for elevated protein levels in the cerebrospinal fluid (CSF) in the absence of inflammatory cells.


• Differential Diagnosis: Specialists must rule out conditions such as Multiple Sclerosis (MS), acute disseminated encephalomyelitis (ADEM), lupus, and other systemic vasculitides that mimic Susac syndrome.

Why is the "diagnostic odyssey" so difficult for patients?

The path to a diagnosis of Susac syndrome is frequently long and isolating. Because it is a rare autoimmune endotheliopathy, many general practitioners and even some neurologists may never see a case in their entire career. It is common for patients to spend months—or even years—seeing various specialists before the correct constellation of symptoms is recognized. At DiseaseMaps.org, we have seen 20 community members navigate this exact frustration; please know that your experience of being misdiagnosed or dismissed is unfortunately common, but it does not mean your symptoms are not real.

Which medical specialists should be involved?

If you suspect you have Susac syndrome, it is vital to consult with specialists who have experience with rare neuro-inflammatory diseases. You should seek out a neurologist (preferably with a sub-specialty in neuro-immunology), a neuro-ophthalmologist, and an otolaryngologist (ENT). Because Susac syndrome is a systemic disease, having a coordinated team is the best way to ensure that subtle findings in the eyes or ears are not overlooked.

Next steps

• Request a referral to an academic medical center or a neuro-immunology clinic with experience in rare vasculitis.


• Bring a copy of your brain MRI results to your specialist and specifically ask about "corpus callosum lesions."


• Join the Susac syndrome community at DiseaseMaps.org to connect with others who have navigated the diagnostic process.


• Keep a detailed symptom diary, noting any sudden changes in vision or hearing, to share with your medical team.

Medical disclaimer: This content is for educational purposes only and does not constitute professional medical advice, diagnosis, or treatment; always consult with your physician regarding your specific health needs.

References

• NIH Genetic and Rare Diseases Information Center (GARD): Susac Syndrome.


• Orphanet: Susac Syndrome (ORPHA:3264).


• American Academy of Ophthalmology: Clinical findings in Susac Syndrome.


• Susac Syndrome Foundation: Patient resource and diagnostic guidance.