Post-streptococcal uveitis (PSU) is uveitis that develops via immune-mediated mechanisms after infection with group A beta-hemolytic streptococcus (GAS: Group A Streptococcus). It was first reported as a disease entity in 1991. Since then, literature describing this disease has been limited, and it is considered a rare condition 12.
Group A streptococcal infections themselves are extremely common. Each year, over 600 million cases of group A streptococcal pharyngitis and 100 million cases of group A streptococcal pyoderma are reported worldwide. However, the frequency of developing uveitis after infection is low.
Post-streptococcal uveitis primarily occurs in young people. Most cases occur in patients under 15 years of age, and the timing of medical visits is concentrated from winter to spring. This seasonality coincides with the epidemic period of group A streptococcal infections.
Group A streptococcal infections occur in hundreds of millions of cases annually, but reports of post-infectious uveitis are limited to case reports. It is not a well-known complication compared to rheumatic fever or glomerulonephritis, and is an extremely rare disease.
The typical symptom of post-streptococcal uveitis is blurred vision lasting from several days to several weeks.
There is often a history of upper respiratory tract infection, influenza-like illness, sore throat, or skin infection within a few weeks. However, preceding symptoms may not be noticed in subclinical infections.
The median incubation period from initial infection to onset of ocular symptoms is 2 weeks. Reported range is 3 days to 3 years.
Anterior Segment Findings
Keratic precipitates (KP): Fine KP are observed inferiorly. Some cases present with mutton-fat KP.
Anterior chamber reaction: Mild to fibrinous anterior chamber inflammation is observed. Some cases are accompanied by hypopyon.
Conjunctival injection: Conjunctival hyperemia is observed.
Anterior scleritis: Rarely occurs as a complication.
Posterior Segment Findings
Vitritis: Vitreous cells appear in the anterior, inferior, and posterior lens surface.
Retinal vasculitis: Periphlebitis and retinitis may be observed.
Macular edema: Cystoid macular edema can occur.
Optic disc swelling: Seen in some cases.
The most common form is bilateral non-granulomatous anterior uveitis. Up to 32% of cases remain unilateral. Posterior uveitis is relatively rare, occurring in about 37.5% of patients. Posterior segment findings include iris adhesions, retinal pigment epithelial detachment, secondary glaucoma, and choroiditis 34.
The development of uveitis after streptococcal infection involves an immune-mediated reaction following group A streptococcal infection. It is considered one of the post-streptococcal syndromes, similar to rheumatic fever, glomerulonephritis, and polyarthritis.
The most important risk factor is untreated prior group A streptococcal infection.
Risk factors for group A streptococcal infection in children include the following:
Risk factors in adults are as follows.
The median incubation period from initial infection to the onset of eye symptoms is about 2 weeks. However, the range is wide, from 3 days to 3 years, and if the infection is subclinical, preceding symptoms may not be noticed.
There is no specific definitive diagnostic method for post-streptococcal uveitis; diagnosis is made comprehensively based on a combination of clinical findings and serological tests.
Post-streptococcal uveitis is strongly suspected when the following three elements are present.
| Diagnostic Element | Specific Details |
|---|---|
| Preceding Infection | History of pharyngitis or tonsillitis |
| Microbiological evidence | Positive throat culture |
| Ocular findings | Presence of intraocular inflammation |
Perform additional serological tests to exclude uveitis/vasculitis due to other causes based on risk factors.
ASOT levels vary greatly with age, season, and region, and alone cannot lead to a definitive diagnosis. It is difficult to rule out post-streptococcal uveitis based solely on normal ASOT values. Combined testing with anti-DNase B (sensitivity 95.5%, specificity 88.6%) is considered useful for improving diagnostic accuracy.
A multidisciplinary approach is recommended for the treatment of uveitis following streptococcal infection. It involves both treating the causative infection and controlling ocular inflammation.
Administer penicillin for active or residual streptococcal infection.
For anterior uveitis, the basic treatment is topical steroids (betamethasone or dexamethasone) and mydriatic eye drops. Mydriatics are administered to prevent posterior synechiae.
Treatment is intensified stepwise according to disease severity.
Appropriate treatment of the triggering streptococcal infection is the most important preventive measure. Data on prophylactic administration to close contacts are conflicting, and if performed, it should be limited to individuals exposed for more than 24 hours within one week.
Long-term antibiotic prophylaxis is generally not recommended due to the risk of drug resistance. However, it may be considered in individual patients with recurrent vision-threatening uveitis.
Although tonsillectomy may reduce the recurrence rate of group A streptococcal pharyngitis, its effect on preventing recurrence of post-streptococcal uveitis is unknown.
Continuous monitoring of ASOT and close clinical follow-up are recommended. In addition to steroid eye drops and mydriatics, immunosuppressive drugs such as methotrexate and adalimumab are considered for refractory cases. If vision-threatening recurrences occur repeatedly, prophylactic antibiotic administration or tonsillectomy may be considered on an individual basis.
The pathogenesis of post-streptococcal uveitis has not been fully elucidated, but it is thought to be centered on an immune-mediated reaction following group A streptococcal infection.
Group A Streptococcus is a gram-positive beta-hemolytic bacterium. It has three proteins on its cell wall: M, T, and R. The M protein is a major virulence factor that helps evade phagocytes. Furthermore, the M protein is thought to have a strong stimulatory effect on T cell proliferation and possess superantigen properties.
The following stages are presumed in the development of post-streptococcal uveitis6.
The mechanisms of post-streptococcal syndromes all involve molecular mimicry. In acute rheumatic fever, antibodies against N-acetylglucosamine cross-react with human laminin and myosin. In glomerulonephritis, antibodies to streptococcal antigens react with laminin, collagen, and the glomerular basement membrane. In post-streptococcal uveitis, the S-antigen is the target, and eye tissue-specific inflammation occurs, which is characteristic.
Benjamin A, Tufail A, Holland GN. Uveitis as the only clinical manifestation of poststreptococcal syndrome. Am J Ophthalmol. 1997;123(2):258-260. PMID: 9186136. ↩
Gallagher MJ, Muqit MMK, Jones D, Gavin M. Post-streptococcal uveitis. Acta Ophthalmol Scand. 2006;84(3):424-428. PMID: 16704712. ↩
Tinley C, Van Zyl L, Grötte R. Poststreptococcal syndrome uveitis in South African children. Br J Ophthalmol. 2012;96(1):87-89. PMID: 21427459. ↩
Curragh DS, McAvoy CE, Rooney M, McLoone E. Post-streptococcal uveitis syndrome in a Caucasian population: a case series. Eye (Lond). 2019;33(3):380-384. PMID: 30228367. ↩ ↩2
Blyth CC, Robertson PW. Anti-streptococcal antibodies in the diagnosis of acute and post-streptococcal disease: streptokinase versus streptolysin O and deoxyribonuclease B. Pathology. 2006;38(2):152-156. PMID: 16581656. ↩
Rossi DC, Sadeghi Y, Di Lucca J, Maitre S, Hofer M, Guex-Crosier Y. Post-Streptococcal Uveitis: a Rare Entity. Klin Monbl Augenheilkd. 2017;234(4):561-563. PMID: 28147402. ↩
