INTERMEDIATE UVEITIS : UNDERSTANDING SYMPTOMS SIGNS and COMPLICATIONS

In this article we shall discuss in detail about the Intermediate uveitis. If you are an audio visual learner you can visit my video on the Intermediate uveitis here. Also you may refer to the text below as a read along notes for the same.

What is Intermediate Uveitis?

  • Intermediate Uveitis is a chronic, insidious in onset inflammation of the intermediate part of the eye. It has a long and relapsing course. 
  • In 1987, the International uveitic study group (IUSG) adopted the term INTERMEDIATE UVEITIS as a part of its anatomic classification scheme for intraocular inflammation. 
  • The IUSG group referred it to as an inflammatory disorder mainly involving the anterior vitreous, peripheral retina, and ciliary body, with minimal or no anterior segment or chorioretinal inflammatory signs.

  • The Standardization of Uveitis Nomenclature (SUN) Working Group however has defined intermediate uveitis as disease where the VITREOUS is the major site of inflammation

    It also gave the criteria for the term “PARS PLANITIS.

  • For anatomy of ciliary body click here! 

image depicting the site of inflammation in intermediate uveitis

Intermediate Uveitis V/S Parsplanitis

  • IU may be idiopathic (at least half) or associated with a systemic disease. 
  • According to the SUN group (2005), Pars planitis (PP) is the term used for a subset of IU in which there is snow banking and/or snowball formation plus the inflammation is idiopathic.

  • It means that there is no identifiable underlying infection or systemic disease in pars planitis .

  • Video on anterior Uveitis , click here!

Brief History

  • The first description of what probably was IU was reported by Fuchs in 1908. At that time, he used the term chronic cyclitis.
  • The clinical description of intermediate uveitis was further elucidated in 1950 by Schepens
  • Later his group reported other clinical findings like peripheral vascular abnormalities and exudation along the pars plana.(Described Below)
  • In 1960, Welch and associates coined the term pars planitis. 
  • A lot of other terms have been described in literature for intermediate uveitis like Vitritis ,Peripheral Exudative Retinitis, Cyclo-chorioretinitis ,Chronic Posterior Cyclitis and Peripheral Uveoretinitis
history of intermediate uveitis

Intermediate Uveitis In Pediatric Population

  • Although the incidence of uveitis in children is low, intermediate uveitis may account for up to 25% of cases
  • It is the second most common uveitis in children 
  • It is commonly associated with optic disc edema in children 
  • Vitreous Hemorrhage is also more common in Pediatric IU 

What are the Causes Of Intermediate Uveitis ?

There are a lot of pathologies that can lead to intermediate uveitis. These can be infective and non infective in nature. However the most common etiologies include undifferentiated IU, Tuberculosis, sarcoidosis and multiple sclerosis.

INFECTIVE CAUSES 
  • Tuberculosis
  • Syphilis
  • Lyme disease
  • Cat scratch Fever
  • Toxocariasis
  • HTLV-1 infection (Human T-cell lymphoma virus type 1)
NON-INFECTIVE CAUSES (SYSTEMIC CAUSES )
  • Sarcoidosis
  • Multiple sclerosis
  • Inflammatory bowel disease
  • Whipple’s disease

What are the Symptoms Of Intermediate Uveitis ?

  • Insidious onset of Blurred vision
  • Accompanied by Vitreous floaters.
  • There is usually mild to no pain and photophobia
  • Mild redness.
  • Note: pain, photophobia are symptoms of anterior uveitis due to inflammation of the ciliary body.
  • The visual acuity of the patient with intermediate uveitis depends on extent of inflammation and complications , like CYSTOID MACULAR EDEMA
  • The disease may last as long as 15 years and preservation of vision will depend largely on control of macular disease.
  • The disease is usaully bilateral  (70% to 80% of patients at the time of presentation).
  • In unilateral cases, one-third of them will develop the disease in the other eye as well subsequently.

IMPORTANT CLINICAL TIP 

An insidious onset of blurred Vision accompanied by vitreous floaters without pain and redness suggests a possible diagnosis of intermediate uveitis.

What are the Clinical Signs seen in Intermediate Uveitis ?

  • VITRITIS :Vitreous cells predominantly in anterior vitreous  are almost universally found in IU.
  • Vitreous condensation and haze is found in severe cases. Nussenblat 1985/National eye Institute grading of vitreous haze is followed for grading vitritis clinically
image showing vitreous cells in intermediate Uveitis
  • Nussenblatt 1985/National eye Institute grading of vitreous haze is followed for grading vitritis clinically
table depicting grading of vitreous haze given by national eye institute
nussenblat classification of vitreous haze
  • SNOWBALLS: Whitish focal collections of inflammatory cells(epithelioid cells and multinucleated giant cells) and exudate usually most numerous in the inferior vitreous.
  • Active Snowballs have fluffy and fuzzy margins. They are larger in size and are surrounded by vitreous cells.
  • Inactive Snowballs have well defined margins are smaller in size and have a contracted or shrunken appearance.
image showing vitreous snowballs in intermediate uveitis

IMPORTANT CLINICAL TIP 

  • Do not decide treatment based on the snowballs. They take a long time to go away.
  • Use other tests to monitor inflammation and response to treatment.
  • SNOWBANKING: Grey–white fibrovascular and/or exudative plaque that may occur in any or all quadrants, but is most frequently found inferiorly.
  • Snow banking indicate severe inflammation and treatment should also be aggressive .
  • Histologic examination of this snowbank reveals collapsed vitreous; blood vessels; fibroglial cells, including fibrous astrocytes; and scattered inflammatory cells, predominantly lymphocytes.
snowbanking in intermediate uveitis

IMPORTANT CLINICAL TIP 

  • When a snowbank is observed, the area should be carefully examined for the presence of neovascularization because these areas are a source of potential vitreous hemorrhage.

  • PHERIPHERAL VASCULITIS/ PERIPHLEBITIS:
  • Inflammation of the peripheral vessels of retina is common in Intermediate uveitis. 
  • Usually involves the lower quadrant 
  • The vessels show perivascular exudates/cuffing , occlusive vasculitis and sheathing.
  • NOTE : Superior Vasculitis is  particularly common in  multiple sclerosis.

  • A diffuse phlebitis leads to breakdown of the blood–ocular barrier and release of inflammatory cells, cytokines, and other inflammatory mediators that settle inferiorly as a snowbank. therefore a snowbank indicates severe inflammation.

Fundus photograph of peripheral periphlebitis in intermediate uveitis
  • OPTIC DISC EDEMA
  • Optic disc swelling is common, especially in younger patients.
  • Disc edema is seen in 50% of the children with Intermediate Uveitis .
  • OPTIC NEURITIS

  • In peditaric intermediate Uveitis, we find disc edema commonly. But if optic neuritis with drop of vision or pale disc is seen, one must suspect multiple sclerosis.

What are the Complications seen in Intermediate Uveitis ?

  • CYSTOID MACULAR EDEMA
  • CME occurs in up to half of patients and is the major cause of impaired visual acuity. 
  • An epiretinal membrane might also be present along with cystoid macular edema.

CLINICAL NUGGET 

  • Cystoid macular edema is the most common cause of visual loss in intermediate Uveitis.
  • The amount of CME does not correlate with the amount of the inflammation or vitritis.
fundus photograph of cystoid macular edema. The oct showing CME
  • NEOVASCULARISATION AND VITREOUS HEMORRHAGE 
  • Neovascularization is particularly common in the retinal periphery (often associated with snowbanks) and on the optic nerve head
  • The latter usually resolves when inflammatory activity is controlled.
  • As new vessels are associated with fibrous proliferations as well, this can sometimes lead to vitreous hemorrhage, retinal detachment and cyclitic membrane formation.
  • Vitreous haemorrhage is more common in children
image showing neovascularisation as a complication in intermediate uveitis

VASOPROLIFERATIVE TUMOURS (VPTs)

  • Vasoproliferative tumour is a mix of vascular and glial tissue.
  • Continuousnflammatory insult leads to breakdown of the blood retinal barrier.
  • This causes uncontrolled release of the cytokines and angiogenesis occurs.
  • Uncontrolled proliferation of the fibrous tissue and angiogenesis leads to development of  the yellowish orangish masses of Vaso proliferative tumors.
daigramatic represntaion of vasoproliferative tumor in intermediate Uveitis
  • RETINOSCHISIS
  • Uncontrolled intermediate uveitis leads to persistent capillary leakage due to vasculitis.
  • Also there is subclinical peripheral ischemia and constant low grade vitreous inflammation present.
  •  This leads to vitreous shrinkage and condensation. This can lead to traction on the retina.
  • Because of traction the neurosensory retina splits leading to development of the peripheral retinoschisis.
  • RETINAL DETACHMENT
  • Seen in 2.2-5.1 % of cases 
  • All three types of retinal detachment may develop as complications in IU
  • Exudative RD : secondary to inflammation in IU
  • Tractional RD: due to fibrovascular traction
  • Rhegmatogenous RD : Due to development of a retinal break secondary to traction 
Retinal detachment and retinoschisis as a complication of the intermediate uveitis
  • CATARACT
  • Cataract can be caused by steroid treatment or by the inflammation itself.
  • Posterior subcapsular cataract is the most common lenticular opacity
  • RAISED IOP , GLAUCOMA
  • Prolonged inflammation and steroid usage for treatment can causes raised Intraocular pressure.
  • Incidence is 7.6 %
  • HYPOTONY
  • prolonged Inflammation causes atrophy of the ciliary body process 
  • There is also a development of exudative membrane extending from the ciliary body to behind the lens (Cyclitic Membrane)
  • These interfere with the functioning of the ciliary body
  • Aqueous production decreases (Ciliary shutdown)
  • This leads to hypotony.

Conclusion

If you would like to watch the detailed video on intermediate uveitis click below-

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