Vogt-Koyanagi-Harada Disease

Description

Vogt-Koyanagi-Harada (VKH) disease is a rare autoimmune condition with significant ocular and systemic manifestations. It was originally regarded as two separate conditions – Vogt-Koyanagi syndrome and Harada’s disease. The former was characterized by anterior uveitis and changes in the skin and the latter by posterior segment inflammation and neurological conditions. As there are many features in common, the two conditions are now regarded as being part of the same disease process. The etiology is unknown although a preceding viral infection or immune reactions to melanocytes have both been postulated. There is evidence of a genetic susceptibility as indicated by the presence of HLA antigens DR4 and DW15 in some cases.

Symptoms

The symptoms of VKH disease are typically bilateral with patients complaining of vision loss, redness, pain and photophobia. A careful case history may elicit prior viral flu-like symptoms of feeling unwell, fever, headache and nausea. An increased sensitivity of the skin and hair to touch has been reported in the early stages of the illness. The patient may have noted a hearing loss and tinnitus.

Signs

(a) Anterior: signs of bilateral granulatomatous uveitis including anterior chamber cells and flare, and keratic precipitates (KP) that may have a “mutton-fat” appearance. Iris nodules and posterior synechiae can occur.

(b) Posterior: may manifest bilateral chorioretinitis, hyperemia and edema of the optic disc, together with the development of multifocal exudative sensory retinal detachments. The latter usually resolve following treatment to leave atrophic scars.

(c) Skin: Some weeks or months after the onset of the disease, a patchy alopecia, poliosis (whitening of the eyelashes) and vitiligo (skin depigmentation) may occur.

(d) Other systemic: may include a hearing loss, encephalopathy (see symptoms above) and pleocytosis of cerebrospinal fluid.

Prevalence

Overall, the condition is rare. A study in the United States of VKH patients showed that 74% of the cases were women and only 3% were white. The disease is more common in young to middle-aged people of darker skin, particularly the Japanese.

Significance

The uveitis may become chronic and recurrent leading to potentially sight-threatening sequelae such as cataract, glaucoma, sub-retinal neovascularization and bullous retinal detachment.

Differential Diagnosis

Posterior segment: Consider central serous retinopathy, acute multifocal placoid pigment epitheliopathy and posterior scleritis. Anterior segment: Other forms of granulomatous uveitis e.g, sympathetic ophthalmitis, or related to tuberculosis or sarcoidosis.

Management

Additional investigations

Fluorescein angiography typically shows many small areas of hyperfluorescence indicating leakage through the retinal pigment epithelium. Indocyanine green angiography may aid in the identification of changes in the choroidal circulation.

Systemic and Topical Medications

Steroids are the mainstay of treatment in VKH disease, and may need to be administered intravenously in high doses in the acute stages. Topical steroids and a cycloplegic agent are also required. Both systemic and topical steroids may be necessary for several months with a slow taper. If the patient is unresponsive to or intolerant of steroids, immunosuppressive medications can be used.

Prognosis and Review

If treatment is effective, the prognosis for vision is good in most cases. Regular follow-up is essential given the potentially recurrent nature of the disease.