The etiologic and pathogenic factors in VKH syndrome are still unclear. The clinical course of VKH syndrome with an influenza like episode suggests a viral or post infectious origin. Some studies invoke a possible role of Epstein-Barr virus reactivation in this disease
(9,10). Although a viral cause has been proposed, no virus has been isolated or cultured from patients with VKH syndrome. Morris and Schlaegel found virus like inclusions bodies in the subretinal fluid of a patient with VKH syndrome
(6).
Clinical and experimental data continue to support an immunologic etiology. An autoimmune reaction seems to be directed against an antigenic component shared by uveal, dermal and meningeal melanocytes, possibly tyrosinase or a tyrosinase-related protein(7). The possibility of autoimmune pathogenesis in VKH syndrome is also supported by the statistically significant frequency of HLA-DR4, an antigen which commonly associated with other autoimmune diseases.
It is suspected, but not definitely established, that this is a viral disease. It has been suggested that the disease results from an autoimmune response to uveal pigment. Hague(1) considered the possibility of virus infection on the basis of involvement of the hypothalamus.
VKH syndrome occurs more frequently in individuals with darker pigmentation. It occurs most frequently in the Far East countries and South America and frequently in dark-skinned people. Women appear to be affected more frequently than men. The onset of VKH syndrome has been reported to range from10-52 years, with a maximum frequency in the thirties, although often unrecognized VKH syndrome may affect children(5).
VKH syndrome is not associated with mortality. Acute disturbances in hearing and vision may occur, and the cutaneous changes may be permanent.
The disease can be divided into three phases with a subacute chronic course: Acute ophthalmic, meningoencephalitic, and convalescent phase. The ophthalmic-auditory phase is characterized by common features such as decreased visual acuity, eye pain, eye irritation and loss of vision(7,10). Dysacusis and tinnitus develop in 50% of patients. In the meningoencephalitis phase, the degree of neurological symptoms may vary(4). Most of the neurological symptoms have been directly attributed to inflammatory aracnoiditis or resulting subaracnoidal adhesions. The convalescent phase is characterized by cutaneous signs developing after uveitis begins to subside, usually within 3 months from the onset of the disease. Poliosis, which occurs in %90 of the patients, involves the eyebrows and eyelashes and, occasionally, the scalp and body hair. Vitiligo manifests in 63% of patients and is often symmetric. Halo nevi may be present. Pigmentary changes tend to be permanent. VKH syndrome may initially present as aseptic meningitis, without specific ophthalmological symptoms. In suspected cases a very detailed CSF cell analysis is needed, because the presence of MLMs can confirm the diagnosis(1). Cranial MRI may show multiple focal lesions and T2 hyperintense periventricular lesions(2,3). Although there is no specific therapy at present, corticosteroids given during the early stages are effective. But it must be kept in mind that this stage may persist for months with or without exacerbations so the treatment may be required for longer periods. Surgical therapy for glaucoma is necessary in some patients. The goals of pharmacotherapy are to reduce morbidity and to prevent complications. The most important long-term complications include reversible and irreversible vision loss. Final visual outcome depends on the rapidity and congruity of the treatment(8).
The diagnosis of VKH which can be defined as chronic, bilateral granulomatous ocular and multisystem inflammatory condition, of unknown cause, is usually made on the basis of clinical findings and by excluding the other possible uveomeningoencephalitic syndromes(10,11). For this reason clinical criteria recommended by the American Uveitis Society can be used(7). Our case is also met this criteria. The diagnosis of VKH syndrome was made depending on the history, clinical signs and laboratory findings and by excluding the other degenerative, vasculitic, connective tissue diseases, chronic infectious and granulomatous diseases.
However the most interesting feature of our case was the severity of the neurologic impairment and relapsing status epilepticus attacks. There was also no report of status epilepticus with VKH syndrome in the literature. Therefore in case of bilateral visual loss, skin changes and neurological impairment even as status epilepticus, VKH syndrome should be remembered.
Received by: 12 September 2007
Revised by: 17 December 2007
Accepted: 10 January 2008
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