Cogan Syndrome - All About the Autoimmune Disease

Introduction

Cogan syndrome is a rare disorder particularly affecting young adults. This disease can severely affect optical vision and hearing severely. The syndrome was first described by Dr. David G Cogan in 1945 as a syndrome exhibiting non-syphilitic interstitial keratitis and vestibulo-auditory symptoms, hence the given name. However, since 1945, not more than a hundred cases have been reported in the medical literature. The syndrome is characterized by repetitive chronic ocular inflammation affecting the vision along with hearing loss that can cause deafness if not treated properly. Most patients may also have systemic involvement. Cardiac complications such as aortitis (inflammation of the aorta), as well as digestive and neural manifestations, can also be seen in the patients. The etiology is not known but there are certain triggering factors that can exacerbate the condition.

What Is the Pathogenesis of Cogan Syndrome?

Cogan's syndrome is suggested to be an autoimmune disease that mediates itself as a hypersensitivity response to the various infectious agents related to vasculitis (inflammation of blood vessels). An upper respiratory tract infection usually precedes the ongoing pathogenesis of this syndrome. Therefore, the scientists believed that a viral infection might trigger an antibody response which in turn develops an autoimmune reaction with similar proteins present in the other tissues of the ear, eye, and sometimes in other organs also.

The pathology of the temporal bone includes degeneration of the organ of Corti, infiltration of the spiral ligament with plasma cells and lymphocytes, new bone synthesis of the round window, spiral ganglion cell atrophy, atrophy of the stria vascularis, excessive collection of fluid in the middle ear, demyelination of the vestibulocochlear nerve and inflammation of the internal auditory artery.

It is therefore postulated to be an autoimmune disorder wherein the cornea, inner ear, and vascular antigens are targeted by autoantibodies. Infectious agents like pneumococcal infection, loose watery stools, oral infection, or recent vaccination have been found to trigger the pathogenesis of Cogan’s syndrome.

What Are the Clinical Features of Cogan Syndrome?

The typical symptoms of the disorder involve loss of hearing, headache, bone and joint pain, fever, inflammation of joints, muscle pain and some of the patients even develop vasculitis.

The disease is characterized by two forms:

• Classic form.

• Atypical form.

Classic form

The hallmark features include:

• Interstitial keratitis (blood vessels grow into the cornea).

• Vestibulo-auditory signs and symptoms include nausea, vomiting, tinnitus (ringing in one or both ears), and vertigo (spinning head).

• The subsequent loss of hearing might progress to deafness in a few months if left untreated.

• The symptoms in the auditory system appear within one to two years of the eye symptoms.

The manifestations in the eye include:

• Iritis (inflammation of the iris).

• Conjunctival hemorrhage (bleeding in the conjunctiva).

• The flow of tears (lacrimation).

• Redness in the eyes.

• Photophobia.

Atypical Form

• Inflammation of the vascular layer of the eye choroid with or without blood vessels growing into the cornea (interstitial keratitis).

• The symptoms of the audiovestibular system are also seen in this form.

• There is a gap of more than two years between the appearance of eye and ear symptoms.

The ocular manifestations include:

• Conjunctivitis (inflammation of the conjunctiva).

• Inflammation of sclera.

• Uveitis (inflammation of the middle ear).

• Swelling of the optical disc.

• Glaucoma.

• Degeneration of a portion of the optic nerve.

• Occlusion of the central vein.

• Vasculitis within the optic nerve blood supply.

• Vasculitis of the retina of the eye.

How Is Cogan Syndrome Diagnosed?

There is no specific test recommended by doctors to diagnose Cogan's syndrome. Instead, the healthcare professional will investigate the symptoms and will do a thorough physical examination. A thorough eye check-up is also required to evaluate the signs and symptoms of ocular inflammation and examine the hearing ability. Magnetic resonance imaging and computed tomography are sometimes used by the physician to have an overlook of the eyes and ears.

It is important to keep the following things in mind:

• When the ocular symptoms and signs first appeared in the eyes.

• The time duration between the appearance of symptoms in the eyes and ears.

• The change of symptoms in the ears from one ear to another ear and in how much time.

The following information might help the healthcare professional to rule out any other possible diseases that have the same symptoms.

How Is Cogan Syndrome Treated?

Multiple treatment options are available for Cogan syndrome. Treatment depends on the signs and symptoms of an individual and the severity of those symptoms. However, there might be periodic flare-ups over the years. This pattern should be kept in mind. The healthcare professional might prescribe antibiotics or diuretics to rule out the possibility of any other infection or extra fluid accumulation in the ears that might be causing the symptoms. Certain anti-inflammatory drugs or medications are also suggested by the doctor which may include nonsteroidal anti-inflammatory drugs (NSAIDs), topical or oral glucocorticoids, and drops causing dilation of the eyes.

The following medicines are usually given soon after the appearance of the symptoms and start showing results within a period of ten days. If the symptoms do not improve, contact the doctor to increase the dosage of the medicines.

Immunosuppressant drugs are considered if those medicines do not work to prevent further damage to the eyes, ears, and other body organs by the host’s immune system.

If the symptoms are in the advanced stage, and the affected patient is facing vision and hearing issues, the doctor might suggest:

• Corneal transplantation to improve vision.

• Cochlear implantation to improve hearing problems.

• A surgical procedure to repair injured blood vessels.

What Are the Complications Associated With Cogan Syndrome?

Many patients suffering from Cogan syndrome might lose their vision or hearing if the disorder is left untreated. However, if the treatment is initiated early, significant vision loss or hearing loss can be avoided.

Conclusion

The Cogan syndrome is a rare autoimmune disorder characterized by chronic systemic inflammation of the eyes and ears causing difficulty in vision, hearing problems, dizziness, and tinnitus. If the disease is left untreated, it may lead to permanent blindness and deafness. Therefore, it is very important to consult your healthcare physician immediately once the symptoms have appeared.