Makindo Medical Notes

🧠👁️👂 Susac's syndrome is a rare autoimmune microangiopathy affecting the brain, retina, and cochlea. 💡 Always consider in young women with hearing loss + visual disturbance + encephalopathy. Classical triad = 1) Sensorineural hearing loss, 2) Branched Retinal Artery Occlusions (BRAOs), 3) Encephalopathy.

📖 Introduction

• First described by John O. Susac in 1979.
• Autoimmune endotheliopathy causing microinfarctions in the cochlea, retina, and brain.
• Predominantly affects young women.

🔺 Classical Triad

• 🧠 Subacute encephalopathy.
• 👁️ Retinal arteriolar branch occlusions (BRAOs).
• 👂 Sensorineural hearing loss.

🧬 Aetiology / Pathology

• Microangiopathy with microinfarcts in cochlea, retina, corpus callosum.
• Corpus callosum = most frequently affected region.
• Possible role of anti-endothelial cell antibodies.

🔎 Clinical Features

• 🧠 Cognitive changes: headache, memory loss, personality change, confusion, seizures.
• 🚶 Ataxia, migrainous headaches, delirium.
• 👁️ Acute visual loss from BRAOs.
• 👂 Asymmetric, bilateral sensorineural hearing loss (low-frequency loss).
• 📈 Typically monophasic, lasting 2–4 years; may relapse, especially in pregnancy.

🧪 Investigations

• 🧪 Bloods: Often normal (FBC, U&E, CRP).
• 💉 CSF: ↑ protein, mild lymphocytosis.
• 🧲 MRI: Pathognomonic findings:
  • Central corpus callosum lesions ("snowball" lesions).
  • “String of pearls” or “spoke lesions” along the callosal roof.
  • Leptomeningeal enhancement (⅓ cases).
• 🌈 Fluorescein angiography: BRAOs.
• 🎧 Audiogram: Low-frequency sensorineural loss.

🖼️ Imaging Examples

⚖️ Differential Diagnoses

• Atypical MS or ADEM.
• CADASIL, SLE, APL syndrome, vasculitis.
• Neuro-Behçet’s disease.
• Lymphoma, temporal arteritis.
• Cogan’s syndrome (ocular + vestibuloauditory, no encephalopathy).

💊 Management

• 🎯 Immunotherapy (mainstay):
  • IV methylprednisolone, then oral prednisolone taper.
  • IVIG or plasmapheresis for refractory/active disease.
  • Immunosuppressants: azathioprine, mycophenolate, rituximab, cyclophosphamide.
• 👂 Hearing loss: Intratympanic dexamethasone may give temporary relief.
• 🔄 Monitoring: Serial MRI, audiometry, and fluorescein angiography to track disease activity.
• 🧠 Course is usually self-limiting (2–4 yrs), but relapse prevention and close follow-up essential.

📚 References

• Rennebohm et al. Guidelines for treatment of Susac’s syndrome (Int J Stroke, 2018)
• ACNR: New Developments in Susac’s Syndrome
• AJNR Review: Susac’s Syndrome