Practical Diagnostic Approach to Uveitis

Anthony Grillo; Ralph D Levinson; Lynn K Gordon

Disclosures

Expert Rev Ophthalmol. 2011;6(4):449-459. 

In This Article

Clinical Examination

A comprehensive ophthalmic and targeted systemic examination will help guide diagnosis, classification and treatment. Specific findings on external exam may suggest a defined syndrome or systemic disease. For example, vitiligo and poliosis may be a late finding in Vogt–Koyanagi–Harada (VKH) syndrome, oral ulcers may raise suspicion in patients with a presentation suggestive of Adamantiades Behçet's disease, vesicular rashes in a dermatomal distribution is consistent with varicella zoster, and enlargement or abnormalities of the lacrimal gland may be observed in granulomatous inflammatory diseases.[8,16,21,22]

Evaluation of best-corrected Snellen visual acuity is important. If central visual acuity is decreased then it is important to delineate the underlying cause, whether from the anterior segment, posterior segment or optic nerve involvement. Pupillary examination may be challenging in the setting of atrophy or synechia, but it is important to determine the presence of a relative afferent pupillary defect, which would provide evidence for optic nerve or retinal involvement. Extraocular muscle findings or abnormalities in motility are uncommon in ocular inflammatory disease, but may be present if the underlying disease involves the CNS, as in the case of lymphoma or multiple sclerosis.

The conjunctiva is often inflamed in cases of AAU, but is less commonly involved in chronic and posterior uveitis. In cases of juvenile idiopathic arthritis (JIA) there are often no symptoms and no conjunctival involvement, yet there are often profound and devastating uveitis complications.[17,23–27] These children must be thoroughly examined on a regular schedule in order to screen for intraocular inflammation.[28]

Initial assessment of the anterior segment for evidence of inflammation should occur prior to installation of fluorescein to allow for evaluation of flare and corneal sensation. Keratic precipitates (KPs), collections of inflammatory cells on the endothelial surface, are an important corneal finding in uveitis. The typical distribution of KPs occurs in the inferior half of the cornea as a triangle with an inferior base (Arlt's triangle). By contrast, a hallmark finding in Fuch's heterochromatic iridocyclitis (FHI) is fine KPs distributed throughout the cornea.[26] Features of KPs generally do not differentiate most cases of infectious from noninfectious uveitis, although diffuse fine KPs or localized KP, not in Arlt's triangle distribution, may suggest infectious, particularly viral, etiologies. KPs associated with granulomatous disease are often larger and can have a more greasy appearance to them, giving rise to the classic 'mutton-fat' precipitates found in sarcoidosis and tubercular disease. These characteristic findings are not reliable, however, as a spectrum of precipitate size and form may be found depending on the timing of presentation in relation to the onset of disease. The inflammatory composition of KPs may change over the course of active uveitis.

Evaluation of cell and flare in the anterior chamber is a critical part of slit-lamp biomicroscopy. Several systems of cell grading on a 0–4+ scale have been reported, but the preferred method uses a narrow slit beam allowing for greater resolution of inflammatory cells. The presence of hypopyon does not differentiate the underlying etiology as this finding may be observed in patients with AAU associated with HLA-B27, Behçet's disease and patients with infectious endophthalmitis.[29] One should be aware of pseudohypopyons, which may be collections of neoplastic cells or fungal elements. These are often irregular and may change in shape with change of head position. They may also be associated with a 'quiet' eye, without redness, pain or fibrin; however, in the case of infections they may be associated with an inflamed eye. Flare is also clinically graded on a 0–4+ scale and grading of both cell and flare may be helpful in clinical assessment of the patient over time and in determining response to therapy. Formal measurements of flare have been used in clinical studies and investigations, but are typically not used in general practice. Careful evaluation of the iris must be performed prior to dilation in order to identify iris nodules such as the Koeppe nodule at the pupillary border or Busacca's nodules on the iris surface.[8,30] The presence of iris nodules may indicate granulomatous inflammatory disease and are more specific than granulomatous-appearing KPs. These must be distinguished from neoplastic lesions, which are very rare, such as metastatic carcinoma or primary iris neoplasia, including melanomas or the lesions of juvenile xanthogranuloma.[10] Gonioscopy should be performed to evaluate the patient for possible peripheral anterior synechiae prior to dilation, and evaluation for posterior synechiae should be performed following dilation. Intraocular pressure measurement is critical as patients with uveitis may have low, normal or high pressure. Increased intraocular pressure may be secondary to the disease process or to the therapeutic use of corticosteroids.

All patients with uveitis must undergo a dilated evaluation of the posterior segment. Evaluation of the lens following dilation is important to document the presence of cataract, which may obscure a complete posterior segment examination. Inflammation in the vitreous, both haze and cells, must be carefully documented. Importantly, patients with intermediate uveitis (IU) may have anterior segment inflammation but a dilated evaluation with indirect ophthalmoscopy reveals clumps of inflammatory cells, such as 'snowballs', in the periphery, which are critical to making the diagnosis. Retinal evaluation must be thorough and include binocular direct ophthalmoscopy as well as indirect ophthalmoscopy with scleral depression. Identification of retinal or choroidal lesions, presence of cystoid macular edema, macular star and retinal vascular abnormalities are often key to making the diagnosis of specific syndromes. Abnormalities of the optic disc including hyperemia, disc edema, atrophy and neovascularization may also be helpful in creating a differential diagnosis in patients with uveitis.

Ancillary testing is important in the initial evaluation of patients with uveitis and for longitudinal evaluation. Fundus photography and fluorescein angiography may be helpful in defining abnormalities in the retina and choroid and in particular are often used in the various white dot syndromes.[12,31] Ocular coherence tomography is helpful in evaluating macular edema and is also used for investigations of the nerve fiber layer.[32] Fundus autofluorescence measurements have gained recent interest, in particular as an aid in evaluating foveal disease and as a correlation to decreased visual acuity in white dot syndromes.[33] Formal visual field testing may define abnormalities of the peripheral visual function.[34] Visual physiology studies including color vision and electroretinograms may be helpful in following patients over time.[35,36]

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