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Behçet Disease

URGENT — Uveitis

Symptoms

Presentation

  • Sudden onset of bilateral decreased vision.
  • Floaters and photophobia.
  • Mild to moderate ocular pain.

Clinical Findings

Disease overview

  • Relapsing-remitting multisystem vasculitis affecting arteries and veins of all sizes.
  • Classic demographic: "Silk Road" ancestry (Middle Eastern, Mediterranean, Central Asian, Japanese).
  • Typically affects young adults (ages 20–40); more severe in men.
  • Strong association with HLA-B51.

Diagnostic criteria (international study group)

  • Mandatory requirement: Recurrent oral aphthous ulcers (≥3 episodes in 12 months).
  • Plus at least two of the following:
  • Recurrent genital ulcers (heal with scarring).
  • Ocular lesions (uveitis or retinal vasculitis).
  • Skin lesions (erythema nodosum, pseudofolliculitis, or acneiform papules).
  • Positive pathergy test (papule formation 24–48 hours after sterile needle stick).

Ocular features

  • Bilateral, simultaneous, non-granulomatous panuveitis.
  • Shifting hypopyon: Anterior chamber pus that moves with head position (hallmark sign).
  • Occlusive retinal vasculitis: Affects both arteries and veins simultaneously.
  • Ischemic signs: Retinal hemorrhages, branch vessel occlusions, and capillary nonperfusion.
  • Complications: Cystoid macular edema (CME), vitreous hemorrhage, neovascular glaucoma, and optic atrophy.
  • Prognosis: High risk of blindness within 5 years if not aggressively treated.

Systemic features

  • Vascular: Deep vein thrombosis (DVT) and pulmonary artery aneurysms (major cause of death).
  • Neurologic (Neuro-Behçet): Meningoencephalitis and cerebral venous sinus thrombosis.
  • GI: Ulcerations throughout the tract mimicking inflammatory bowel disease (IBD).
  • Articular: Seronegative non-erosive arthritis of the knees and ankles.

Etiology

Pathophysiology

  • Idiopathic systemic vasculitis with a genetic predisposition (HLA-B51).
  • Characterized by neutrophil hyperreactivity and widespread vascular inflammation.

Ancestry

  • High prevalence in populations along the historic Silk Road trading route.

Red Flags

  • Shifting hypopyon in a young patient of Mediterranean or Middle Eastern descent.
  • Occlusive retinal vasculitis: Requires immediate systemic immunosuppression (steroids alone are insufficient).
  • Hemoptysis: May indicate a life-threatening pulmonary artery aneurysm.
  • Neuro-Behçet symptoms: Any new neuropsychiatric changes or focal neurologic deficits.

Investigations

Infectious rule-out

  • Syphilis serology (RPR/FTA-ABS) and TB screening (PPD or IGRA).
  • Chest X-ray or CT (to rule out sarcoidosis and TB).
  • Serum ACE and lysozyme.

Immunologic & genetic

  • HLA-B51: Supportive evidence, especially in endemic populations.
  • Pathergy test: Skin hypersensitivity reaction to minor trauma.

Clinical monitoring

  • ESR and CRP: Often elevated during systemic flares.

Treatment

Pharmacotherapy

  • Systemic corticosteroids: Used as bridging therapy for acute flares.
  • Anti-TNF agents (First-line for posterior uveitis): Infliximab or adalimumab.
  • Steroid-sparing agents: Azathioprine, cyclosporine, or interferon-alpha.

Complication management

  • Manage neovascularization with panretinal photocoagulation (PRP).
  • Aggressive control of intraocular pressure if secondary glaucoma develops.

Long-term care

  • Multidisciplinary coordination between ophthalmology and rheumatology.
  • Lifelong surveillance is mandatory due to the relapsing-remitting nature.

Clinical Pearl

A shifting hypopyon with occlusive retinal vasculitis in a young patient of Silk Road descent is Behçet until proven otherwise. HLA-B51 supports the diagnosis, and early use of anti-TNF biologics has transformed the prognosis.

Differential Diagnosis

  • Sarcoidosis (typically granulomatous)
  • Acute retinal necrosis (ARN)
  • Syphilis (the great masquerader)
  • Granulomatosis with polyangiitis (GPA)
  • Systemic lupus erythematosus (SLE)

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