What is Cogan syndrome?
Cogan syndrome or Cogan’s syndrome is a rare type of a rheumatic disorder. It is characterized by frequent inflammation of the ears and the front portion of the eye i.e., the cornea. These symptoms are also accompanied by frequent episodes of fever, loss of energy and fatigue, episodes of dizziness, weight loss and loss of hearing. If left untreated, the disorder can lead to permanent blindness or deafness. Cogan’s syndrome is also often associated with vasculitis or blood-vessel inflammation in other parts of the body which can ultimately lead to damaging of organs or in some rare cases even death. In most cases, the patients are young adults around 20s or 30s.
Cogan syndrome History
The disease is named after American ophthalmologist David Glendenning Cogan who in 1945 first described these “nonsyphilitic interstitial keratitis and vestibuloauditory symptoms”. A different form of Cogan syndrome known as the “Logan Syndrome” was described for the first time in 1963.
Symptoms of Cogan syndrome
The symptoms that are most commonly seen in a patient suffering from Cogan syndrome include
- Red, sore, painful eyes and blurred vision
- Partial or complete hearing loss; over time this can become permanent
- Vertigo or dizziness
- Lack of balance
- A tendency of nausea and vomiting
- Weight loss
- Fatigue
- Fever
Cogan syndrome can also adversely affect the functioning of various bodily organs and may even cause permanent damage to them. The symptoms related to the various organs and systems of the body are mentioned below:
- Nervous system – Headache, psychosis, encephalitis, meningismus, cavernous sinus thrombosis, cerebral infarction, psychosis, peripheral nerve involvement, shortness of breath
- Cardiac – Ventricular hypertrophy, arrhythmias, aortic insufficiency, valvular defects
- Pulmonary – Pulmonary nodules, Pleuritis
- Lymphoreticular – Lymphoadenopathy or enlarged lymph nodes, hepatomegaly, splenomegaly
- Gastrointestinal – Gastric hemorrhage, abdominal pain
- Skin – Nodules, palpable purpura, non-specific rash
- Musculoskeletal – Arm pain, myalgia or muscle pain, arthritis and arthralgia
- Genitourinary – Testicular pain, proteinuria, hematuria, abnormal urinalysis
Causes of Cogan syndrome
The exact cause for the development of Cogan syndrome is unclear. It is currently believed that the syndrome is caused by the disease of the autoimmune system. However, it is still unknown whether this autoimmune disease is arbitrated by humoral or cellular immunity.
Certain immunological and pathological factors, such as plasma cell infiltration in the cornea and cochlea, presence of antibodies i.e., Immunoglobulin G against the cornea and the inner ear, the beneficial influence of immunosupressants and corticosteroids as well as the presence of lymphocytes indicate towards an autoimmune pathogenesis. Also, the majority of the patients display involvement of multiple organs much like polyarteritis nodosa and collagen diseases that are caused by autoimmune problems.
Laboratory studies indicate that autoantibodies in the patients’ blood tend to attack inner ear tissue. Some patients have been found to be infected with the Chlamydia pneumoniae bacteria before they developed Cogan’s syndrome. This has led some researchers to hypothesize that the autoimmune disorder may have been caused by the bacterial infection. The Chlamydia pneumoniae bacteria generally cause mild pneumonia. However most of the patients infected by the Chlamydia pneumoniae bacteria are not found to develop Cogan’s syndrome.
Pathogenesis of deafness
Temporal bone pathology demonstrates different factors responsible for deafness. These include
- Endolymphatic hydrops
- Lymphocytic infiltration of spiral ligament and plasma cell
- Atrophication of the organ of Corti
- Osteogenesis of the round window
- Demyelinization of eight cranial nerve
- Stria vascularis degeneration
- Degeneration of the spiral ganglion cell
- Internal auditory artery vasculitis
Diagnosis of Cogan syndrome
Diagnosis of Cogan’s syndrome starts with assessment of problems relating to the diseases of the inner ear and the eyes. As long as both the inner ear and eye are not affected, the diagnosis remains a bit uncertain. The auditory and visual problems may develop simultaneously or either of the two areas may get affected first.
The doctor will first try to rule out the chances of any infections, especially the ones like tuberculosis, syphilis, Chlamydia, viral infections, leprosy and Lyme disease or any other rheumatic diseases, such as sarcoidosis, rheumatoid arthritis and Wegener’s granulomatosis as these may trigger the symptoms of the disease. The doctor will recommend the patient for an eye checkup by an ophthalmologist. A slit-lamp examination is necessary to observe any inflammations of the cornea, a condition generally known as interstitial keratitis. The doctor will also evaluate the nervous system and check on sensation, strength and reflexes as well as thoroughly check up the ears by evaluating inner ear function, balance and hearing. Other tests carried on the patient will include Doppler test, caloric test, echocardiography and angiography.
The results of erythrocyte sedimentation rate (ESR) test, white blood cells test and C-reactive protein test may produce abnormal results and there may be signs of anemia or thrombocytosis. However, none of these evaluations are conclusive enough to suggest the patient is suffering from Cogan’s syndrome. This syndrome is particularly difficult to diagnose in case of children.
Expected Duration of Cogan syndrome
Cogan’s syndrome is a chronic disorder. The symptoms of this disease often come and go in phases. A patient might respond well to proper medical care and attention, but normally the patients suffering from Cogan syndrome experience the health problems for a prolonged period of time, sometimes even for their entire lives.
Cogan syndrome Prevention
There are no known ways to prevent or protect an individual from getting infected by Cogan’s syndrome.
Treatment of Cogan syndrome
While treating ear problems that are a part of the Cogan syndrome, high doses of systemic oral corticosteroids (around 1-2 mg/Kg/day) are needed to be applied. The dosage needs to be lowered gradually based on the results of the audiogram tests.
If hearing becomes difficult and the drugs prescribed fail to ease the problem, using cochlear implants can act as a useful aid.
In cases where large quantities of steroids are needed or if the syndrome has reached a severe level and the response to steroid therapy is not meeting the expected results, certain other immunosuppressive medications are to be recommended. These immunosuppressive medications include cyclophosphamide (Neosar, Cytoxan), methotrexate (Rheumatrex),azathioprine (Imuran) or cyclosporine (Sandimmune, Neoral). A combination of medications mentioned above may also be used in some cases. If Cogan syndrome results in the damage of blood vessels, then surgery needs to be done to rectify the problem.
Diuretic medications are prescribed in cases where excess amount of fluid in the inner ear causes dizziness and balance problems. These drugs trigger urination, thus removing excess amount of fluid from the patient’s body. Drugs like benzodiazepines or antihistamines can be used along with bed rest to cure problems created by imbalance.
When to call a Professional
If you feel that you are experiencing significant auditory or visual problems or you are losing your balance and feeling dizzy, you should immediately consult your doctor or health care professional and get yourself evaluated, especially if the symptoms seem to be lingering.
Cogan syndrome Prognosis
The ophthalmic prognosis in patients having interstitial keratitis is generally considered to be quite positive and visual acuity impairment has been found in very few instances. Severe visual complications are found to occur mostly in patients having chronic inflammation of the posterior pole and victims of atypical disease.
Auditory prognosis, on the other hand, seems to be quite poor. In most cases of Cogan’s syndrome, complete and bilateral deafness seems to be the predominant outcome. Nearly 25% to 50% of all patients suffer from deafness even with prompt administration of corticosteroids, with around 95% of patients having moderate to complete auditory impairment after 5 years of medical attention. Vestibular signs and symptoms tend to improvise with time. However, persistent and lingering cases of oscilloscopia and ataxia have been recorded in around 15% of the total number of cases.
In less than 10% of cases the syndrome has led to fatal results. The majority of the patients are able to effectively manage the symptoms of the disease with regular treatment and limit all the associated complications.
Cogan syndrome is a disease that in most cases leads to complete loss of hearing and in some rare cases lead to damage of bodily organs. However, with regular medical attention and treatment the symptoms of this disorder can be kept well under control and the patient may lead a healthy and normal life.
References:
http://www.uveitis.org/medical/articles/case/cogan%27s.html
http://en.wikipedia.org/wiki/Cogan_syndrome
http://www.intelihealth.com/IH/ihtIH/WSIHW000/9339/35151.html
http://www.dizziness-and-balance.com/disorders/autoimmune/cogans_syndrome.htm