ISCHEMIC STROKE / ETIOLOGY
Cogan syndrome
Updated on 09/07/2024, published on 27/06/2024
Introduction
- Cogan syndrome (CS) is a rare, chronic, inflammatory disorder characterized by ocular and audiovestibular manifestations, often associated with systemic vasculitis
- first described by David Cogan in 1945, the syndrome primarily affects young adults with no gender predilection
- the etiology remains unknown, but an autoimmune mechanism is suspected due to the presence of autoantibodies and their association with other autoimmune conditions
- systemic involvement can predispose patients to a variety of complications, including rare cerebrovascular events such as stroke
Clinical presentation
- CS is clinically classified into two forms:
- typical form – includes interstitial keratitis and audiovestibular symptoms resembling Ménière’s disease
- atypical form – involves other ocular inflammatory diseases and systemic symptoms
Ocular symptoms
- interstitial keratitis – the hallmark of typical CS, presenting as photophobia, pain, and decreased vision. Slit-lamp examination reveals stromal inflammation and corneal opacity.
- other ocular involvements
- scleritis and episcleritis
- uveitis
- conjunctivitis
Audiovestibular symptoms
- sensorineural hearing loss – sudden onset, fluctuating, and progressive; bilateral involvement is typical
- vestibular dysfunction – vertigo, tinnitus, and balance disturbances, often mimicking Ménière’s disease
Neurologic manifestations
- cerebrovascular involvement is very rare and involves:
- vasculitis (Albayram, 2001) (Rolon, 2022)
- large-artery infarcts from cardiac emboli secondary to valvular disease
- other neurological symptoms
- headaches
- cognitive dysfunction (encephalopathy)
- myelopathy
Systemic manifestations
- fever, weight loss, fatigue
- medium and large vessel vasculitis may lead to complications such as aortitis, aortic aneurysms, and aortic insufficiency
- musculoskeletal symptoms – arthralgia and myalgia
Diagnostic evaluation
- no test is diagnostic of Cogan’s syndrome; the diagnosis is primarily clinical, based on the characteristic combination of ocular and audiovestibular symptoms
- laboratory tests are non-specific:
- elevated inflammatory markers (ESR, CRP), leukocytosis, anemia, and thrombocytosis
- autoantibodies such as rheumatoid factor and nuclear antibodies are usually negative
- audiometry confirms sensorineural hearing loss
- imaging studies
- CT – possible intralabyrinthine calcifications, CTA may demonstratě vasculitic changes
- MRI – soft tissue obliteration of the membranous labyrinth, rarely multiple white matter lesions (WML) consistent with cerebral vasculitis
- a biopsy of affected tissues can confirm vasculitis
Differential diagnosis
- autoimmune Inner Ear Disease (AIED)
- rapidly progressive, bilateral sensorineural hearing loss, often fluctuating with tinnitus
- episodic or continuous dizziness and balance disturbances
- response to corticosteroid therapy can be diagnostic
- Meniere’s disease – results from abnormal endolymphatic fluid dynamics, which leads to hydrops
- spontaneous, recurrent episodes lasting 20 minutes to several hours
- sensorineural, often fluctuating, usually unilateral initially
- tinnitus
- aural fullness (feeling of pressure or fullness in the ear)
- syphilis
- sarcoidosis
- granulomatosis with Polyangiitis (GPA)
Management
Immunosuppressive therapy
- the treatment is empiric and not based on any formal therapeutic trial because of the rarity of the disease
- corticosteroids – high-dose prednisone is the first-line treatment
- typically starting at 1 mg/kg/day
- gradually tapered over 2–6 months
- immunosuppressive agents – methotrexate, azathioprine, and cyclophosphamide are commonly used for steroid-sparing and refractory cases
- biologic agents – anti-TNF agents (infliximab, etanercept) and rituximab have shown efficacy in severe and refractory cases
- ocular and audiovestibular management
- topical corticosteroids for keratitis
- hearing aids or cochlear implants for hearing loss
- patients with severe aortic or cardiac disease may benefit from aortic valve replacement or vascular bypass surgery
Acute stroke therapy and stroke prevention
- the standard protocols should be followed
Prognosis
- early diagnosis and aggressive treatment can prevent complications and preserve organ function
- untreated or refractory cases may lead to permanent vision and hearing loss, systemic complications, and reduced quality of life
- the prognosis of stroke in patients with Cogan syndrome depends on the extent of cerebral involvement and the promptness of treatment
- recurrent strokes and progressive vasculitis can lead to significant morbidity and impact the quality of life