Behcet's Syndrome

🧩 Behçet's syndrome is a chronic, relapsing, multisystem vasculitis of unknown aetiology, affecting both small and large vessels (arterial and venous). It classically presents with the triad of recurrent oral ulcers, genital ulcers, and uveitis.

🌍 Introduction

• Multisystem, chronic-relapsing inflammatory disorder
• Predominantly targets the venous system (thrombophlebitis, cerebral venous sinus thrombosis)
• Classic triad: recurrent oral ulcers + genital ulcers + uveitis

🧬 Aetiology

• Unknown cause; strong association with HLA-B51
• Most common in populations from the Middle East, Far East, and Mediterranean (“Silk Road distribution”)
• Neurological involvement in up to one-third (stroke, brainstem disease, venous sinus thrombosis)

🩺 Clinical Features

• 💋 Painful recurrent oral aphthous ulcers
• 🍑 Genital ulcers (scarring typical)
• 👁️ Ocular disease: anterior/posterior uveitis, retinal vasculitis → risk of blindness
• 🦵 Musculoskeletal: arthritis, myalgia
• 🩸 Vascular: venous thrombosis, aneurysms
• 🩹 Skin lesions: erythema nodosum, pseudofolliculitis; positive pathergy test
• Diagnosis is clinical – no single confirmatory test

🧠 CNS Manifestations (Neuro-Behçet’s)

• Parenchymal (5–20%): Brainstem lesions → diplopia, ataxia, dysphagia, pseudobulbar speech, hemiparesis
• Meningoencephalitis: Headache, confusion, drowsiness progressing over days
• Cerebral venous thrombosis: Headache, raised ICP, haemorrhagic infarcts
• Psychiatric: Depression, paranoia, hallucinations (rare)

🔍 Differential Diagnosis

• Multiple sclerosis (relapsing neuro course)
• Neurosarcoidosis
• Stroke / vasculitis

🧪 Investigations

• Bloods: FBC, U&E, LFTs; CRP/ESR may be ↑
• 🧷 Pathergy test: skin hyperreactivity at needle prick within 24–48h (not specific)
• IL-6 levels may correlate with disease activity
• MRI: Brainstem/basal ganglia T2 lesions, meningoencephalitis, venous thrombosis
• CTV/MRV if CVST suspected
• CSF: ↑ WCC (neutrophils often predominate) in parenchymal neuro-Behçet’s

📋 Diagnostic Criteria

Mouth sores ≥3 times in 12 months plus two of the following:

• Recurrent genital ulceration (± epididymitis/orchitis)
• Ocular inflammation (uveitis, retinal vasculitis)
• Skin lesions (erythema nodosum, pseudofolliculitis, papulopustules)
• Positive pathergy test

💊 Management

• Topical corticosteroids for ulcers; colchicine for mucocutaneous disease
• 👁️ Ophthalmology referral: steroid drops, azathioprine, biologics (infliximab, interferon)
• 🧠 Neurology: IV methylprednisolone for acute CNS disease ± long-term azathioprine, mycophenolate, or methotrexate
• 💉 Severe disease: cyclophosphamide, interferon-α, or biologics (anti-TNF, e.g. infliximab, etanercept)
• Anticoagulation for cerebral venous thrombosis (with caution if arterial aneurysms)

📚 References

• Diagnosis and management of Neuro-Behçet’s disease: international consensus recommendations
• Diagnosis and treatment of cerebral vasculitis – Peter Berlit, Ther Adv Neurol Disord (2010)

Cases — Behçet’s Syndrome

• Case 1 — Classic triad 👄👀: A 27-year-old Turkish man presents with recurrent painful oral ulcers, genital ulcers, and episodes of red, painful eyes. Ophthalmology exam: anterior uveitis. Diagnosis: Behçet’s syndrome. Managed with topical steroids for ulcers and systemic immunosuppression (colchicine, azathioprine).
• Case 2 — Vascular involvement 🫀: A 35-year-old woman presents with sudden leg pain and swelling. Doppler: femoral vein thrombosis. History reveals recurrent oral aphthous ulcers and erythema nodosum–like lesions on the shins. Screening: positive pathergy test. Diagnosis: Behçet’s with vascular involvement. Treated with anticoagulation and immunosuppressants.
• Case 3 — Neurological features 🧠: A 40-year-old man of Middle Eastern background presents with headache, unsteadiness, and double vision. MRI: brainstem lesions suggestive of neuro-Behçet’s. History of recurrent genital ulcers and past uveitis. Managed with high-dose steroids and cyclophosphamide under neurology and rheumatology teams.

Teaching Point 🩺: Behçet’s is a multi-system vasculitis most common along the Silk Road (Turkey, Middle East, East Asia). Key features: recurrent oral/genital ulcers, uveitis, skin lesions, vascular and neurological disease. Always consider in unexplained venous/arterial thrombosis in a young patient.