Cogan syndrome: causes, symptoms, diagnosis, treatment, and prognosis

Cogan syndrome, also known as interstitial keratitis-vertigo-sensorineural deafness syndrome, is a systemic disease characterized by non-syphilitic interstitial keratitis, vestibular neurological symptoms such as vertigo, severe bilateral sensorineural deafness, and systemic vasculitis manifestations such as gastrointestinal hemorrhage and congestive heart failure.


Causes

The causes are unknown. The disease may be caused by an autoimmune response to the unknown common autoantigen of the cornea and inner ear. 10% - 30% of patients are also accompanied by severe systemic vasculitis, including life-threatening aortitis.


Signs and Symptoms

Acute onset is often present. Some patients have acute respiratory infections as prodromal symptoms, some have polyarthritis or polyarthralgia as the main symptoms, some have unexplained fever with rash as the first symptom, and some present with sudden deafness with ocular abnormalities as an early manifestation. Systemic symptoms include fatigue, general malaise, apositia, and insomnia.

The incidence of ocular symptoms is 38%, the incidence of vestibular auditory system symptoms is 46%, and the incidence of concurrent ocular and vestibular auditory system symptoms is 15%. After 5 months of progression, 75% of patients are accompanied by the ocular and vestibular auditory system symptoms. Non-specific systemic manifestations include fever, headache, arthralgia, and myalgia.

Ocular symptoms

Ocular involvement includes bilateral stromal keratitis or other stromal keratitis, episcleritis or scleritis, uveitis, optic papillitis, and other ocular inflammatory reactions such as hyalitis and choroiditis.

Ocular symptoms include irritation, pain, photophobia, and impaired vision. Ophthalmologic examination reveals typical patchy stromal keratitis, ocular congestion, papilledema, or proptosis.

Figure 1 Cogan syndrome

Figure 2 Cogan syndrome

8th cranial nerve symptoms

8th cranial nerve symptoms, also known as vestibulocochlear nerve symptoms, can appear several weeks to several months after ocular symptoms occur, often bilateral, including nausea, vomiting, tinnitus, vertigo, nystagmus, ataxia, and sensorineural deafness.

Circulatory system manifestations

Approximately 1/10 of patients may have aortic regurgitation. There may be no obvious symptoms in the early stage, and only significant diastolic murmurs can be heard in the aortic valve area during physical examinations. As the disease progresses, symptoms of heart failure may be manifested by palpitation, dyspnea, and edema of the lower extremities.

Digestive system presentations

Some patients may have abdominal discomfort. Stomach and colon ulcers may occur in severe patients. Gastrointestinal ulcers are caused by mucosal vasculitis, sometimes causing upper or lower gastrointestinal hemorrhage. Some patients develop agnogenic diarrhea.

Skin manifestations

Large and small arterial necrotizing vasculitis can occur and is characterized by non-specific rash, purpura, nodules, and oral ulcers.

Systemic symptoms

10% of patients have polychondritis, pustules, and vesicles in the ears and nose, 63% of patients have one organ involvement, and 34% of patients have multiple organ involvements. Regional enteritis, juvenile rheumatoid arthritis, and pyoderma gangrenosum may occur.

Increased white blood cell count (79%), anemia (39%), elevated platelets, increased erythrocyte sedimentation rate (78%), elevated C-reactive protein, liver dysfunction (16%), can abnormal serum protein electrophoresis ( 52%) can be present at onset. Dysaudia can be found in continuous hearing test.

Complications

About 1/4 of patients have joint and muscle involvement, characterized by myalgia, arthritis, or arthralgia. About 1/10 of patients have hypertension, which may be caused by renal artery involvement. Some patients may have enlarged lymph nodes and splenomegaly. Few patients may have cerebral artery occlusion, manifested by varying degrees of hemiplegia, headache, motor speech disorder, and cranial nerve palsy. Peripheral nerve injury is manifested by asymmetric peripheral neuritis.


Diagnosis

According to the occurrence of specific ocular abnormalities followed by 8th cranial nerve symptoms, the diagnosis is not difficult.


Treatment

Corneal scars can occur in untreated patients, causing impaired vision, and 60% - 80% of patients eventually develop permanent deafness. Keratitis, episcleritis, and anterior uveitis can usually be treated with topical 1% prednisolone acetate eye drops once an hour to 4 times a day. Oral prednisone 1mg/kg once a day for 2 - 6 months can treat deep inflammation of the eyeballs and vestibular auditory symptoms to avoid progression into permanent damage. Cyclophosphamide, methotrexate, and cyclosporine can be selected in the treatment of refractory patients.


Prognosis

The duration of the disease varies depending on the clinical symptoms. Some patients die within few months after onset, and some patients can survive for more than 10 years, with an average survival time of 5 - 7 years.