Undifferentiated Arthritis Revealing Cogan’s Disease

Abstract

Background: Cogan’s syndrome is a rare autoimmune vasculitis (less than 300 cases described in the literature) characterized in its typical form by cochleovestibular involvement, interstitial keratitis, and an inflammatory involvement of large vessels. It is frequently accompanied by general signs and cardio-vascular, rheumatologic, and digestive complications. Its management is essentially based on the use of corticosteroids and immunosuppressants. The outcome of the treatment, even if rapid, does not always avoid functional complications. This disease is probably under-diagnosed in Africa. Objective: The objective of this study was to report a case of Cogan syndrome in sub-Saharan Africa. Case report: A 78 year old black African female patient presented with arthritis of the left knee without fever. The examination also revealed a bilateral deafness of rapidly progressive onset. The patient was known to be diabetic and hypertensive, and was regularly monitored. The biology revealed an inflammatory syndrome and an inflammatory joint puncture fluid. Pure tone audiometry confirmed a 77% hearing loss. The ophthalmological examination revealed stromal oedema and hypertensive retinopathy of Kendall stage III. The rheumatological evolution was good under methylprednisolone and methotrexate, but the deafness persisted. The occurrence of a fever on day 12 of treatment required further investigations (blood culture, PCR-Covid 19 test, cytobacteriological examination of sputum, thoracic CT). The evolution was unfavourable with the death of the patient. Conclusion: Cogan’s disease is a rare inflammatory disease. Its diagnosis and management are multidisciplinary. The treatment can be disappointing.