inflammation subsides. Less frequently, systemic or periocular corticosteroids are necessary to control inflammation. The long-term prognosis is very good, with rare development of vision-threatening posterior segment complications including, CME and epiretinal membranes [38].

19.4.3  Tub ulointerstitial Nephritis and Uveitis (TINU)

19.4.3.1  Historical Context

First described in 1975 by Dobrin et al. [39], TINU is a distinct clinical syndrome involving acute renal inflammation coupled with uveitis. It is usually seen in children and young adults (11–20 years old), with a predominance of females (3:1) [40]. TINU is rare, but may be underdiagnosed if the associated interstitial nephritis was subclinical or is resolved by the time the intraocular inflammation developed.

19.4.3.2  Clinical Findings/Natural History

Acute interstitial nephritis usually precedes uveitis, although ocular involvement can precede or be simultaneous to kidney involvement. Patients commonly present with systemic/renal signs and symptoms including fatigue, malaise, anorexia, abdominal pain, fever, and anemia. However, patients may present with ocular symptoms including redness, pain, blurred vision, and photophobia.

The uveitis is usually a bilateral and nongranulomatous reaction limited to the anterior segment. However, posterior segment findings occur 1/5th of the time and include diffuse vitreous opacities, optic nerve swelling, and retinal exudates [40, 41]. Recurrent uveitis is common, in contrast to the nephritis, which typically resolves completely either spontaneously or in response to systemic corticosteroid therapy.

Pathophysiology/Genetics

The etiology remains unclear. Histologic studies noting a predominance of activated helper T lymphocytes in the kidney interstitium suggest a role for cellular immunity. Renal biopsies demonstrate severe fibrosis [40, 41].

TINU has been associated with HLA-A2, -A24, -DR6, and -B27 [42–44]. In addition, the syndrome has been associated with HLA-DQ in Caucasians from North America and with HLA-DR14 in Spanish patients [45].

Diagnosis/Treatment/Complications

The diagnosis of TINU is made clinically by the presence of the typical uveitis associated with acute interstitial nephritis. The nephritis is characterized by an abnormal serum creatinine or decreased creatinine clearance, an abnormal urinalysis with increased B2-microglobulin, proteinuria, and the presence of eosinophils, pyuria or hematuria, urinary white cell casts, and normoglycemic glycosuria. An associated systemic illness consisting of fever, weight loss, anorexia, fatigue, arthralgias, and myalgias is characteristic. Patients may also have abnormal liver function tests, eosinophilia, and an elevated ESR.

High-dose oral corticosteroids are very effective in controlling the renal disease [46]. Topical corticosteroid treatment plus a cycloplegic agent are usually adequate in controlling anterior uveitis [47]. Patients with persistent uveitis may require systemic immunosuppressive therapy as a steroid sparing agent.

Cases of chronic renal failure, despite the use of systemic corticosteroids and other immunosuppressants, have been reported [48]. Intraocular complications include posterior synechiae, optic disc swelling, CME, macular pucker, chorioretinal scar formation, cataract formation, and glaucoma.

19.4.4  Sarcoidosis

19.4.4.1  Historical Context

Sarcoidosis is a chronic multisystem disease of unknown etiology characterized by noncaseating granulomas. Cutaneous lesions that represented sarcoidosis were independently described in the late 1860s by Jonathan Hutchinson and Carl William Boeck. Approximately 20 years later the histologpathology of cutaneous lesions was described as consisting of epithelioid and giant cells and the term “sarkoid” was introduced to depict the sar- coma-like histologic appearance. Around 1910 multisystem involvement, including iritis, was recognized [49].