Cogan’s syndrome
Overview
Cogan’s syndrome is a rare autoimmune-mediated rheumatic disorder of interstitial keratitis (inflammation of the cornea) that develops in children and young adults shortly after their recovery from an otherwise unremarkable respiratory infection. First reported in 1945, Cogan’s syndrome causes symptoms that are similar to those of syphilic keratitis although there is no evidence of syphilis infection in Cogan’s syndrome.
Symptoms
Cogan’s syndrome causes eye inflammation, including conditions such as keratitis, iritis, scleritis, or conjunctivitis, associated with balance problems, dizziness and ear ringing (tinnitus) and other symptoms that resemble Meniere’s disease. These vestibuloauditory symptoms can progress to rapid bilateral deafness due to inflammation affecting the 8th cranial nerve. Other symptoms include vasculitis, nausea, vertigo, poor balance, fever, fatigue, weight loss, vomiting, light sensitivity, and a bilateral blurring of vision. Rarely, patients may exhibit enlarged lymph nodes, rash, chest pain, night sweats, arm pain, cardiac involvement and shortness of breath. Systemic cardiac manifestations of Cogan’s syndrome include aortitis, aortic valve insufficiency, pleuritis, pericardial effusion, coronary arteritis, and possibly myocardial infarction. Vasculitis in Cogan’s syndrome can cause major organ damage, and in rare instances it can be fatal. Hearing loss is often progressive and can lead to permanent deafness within two years without early diagnosis and treatment intervention.
Causes
It is currently thought that Cogan's syndrome is an autoimmune disease. The inflammation in the eye and ear are due to the patient's own immune system producing antibodies that attack the inner ear and eye tissue. Autoantibodies can be demonstrated in the blood of some patients, and these antibodies have been shown to attack inner ear tissue in laboratory studies. Infection with the bacteria Chlamydia pneumoniae has been demonstrated in some patients prior to the development of Cogan's syndrome, leading some researchers to hypothesis that the autoimmune disease may be initiated by the infection. Chlamydia pneumoniae is a common cause of mild pneumonia, and the vast majority of patients who are infected with the bacteria do not develop Cogan's syndrome
Diagnosis
The erythrocyte sedimentation rate and the C-reactive protein tests show mild to marked elevations. Vasculitis, if present, can be detected with imaging tests and confirmed with tissue studies. While there are no formal diagnostic criteria for Cogan’s syndrome, it is diagnosed in patients recovering from respiratory infection with rapid-onset sensorineural hearing loss, eye inflammation, and symptoms of vasculitis. In a few cases, Cogan’s syndrome has been associated with Chlamydia infection, with patients showing high titers of antibodies to Chlamydia.
Treatment
Anti-inflammatory eye drops are used in cases of mild eye symptoms. If signs of infection occur, antibiotic eye drops can be used. In severe eye disease, oral corticosteroids or immunosuppressive medications such as cyclosporine or cyclophosphamide may be used. In cases where the eye’s blood vessels are damaged, surgical intervention and corneal transplant may be required. If excess fluid in the inner ear affects balance, diuretics may be used to reduce fluid. Antihistamines such as diphenhydramine (Benadryl) are also used for problems with imbalance. Cochlear implants are used in cases of hearing loss.