Pathology of uveitis

2021-02-02 12:00 AM

Uveitis is a fairly common eye disease with a complex aetiology, often severe clinical damage, many complications, or relapses that can lead to blindness.

Concepts and classifications

Define

The uveal consists of three components: the iris anterior, the ciliary body in the middle, and the black desert in the back. Inflammatory pathology of at least one of the three components is called uveitis.

Classification of uveitis

There are many different classifications of uveitis such as:

Sort by cause

Bacterial, viral, fungal, and parasitic uveitis. There may be unexplained uveitis, which is thought to be related to an allergic mechanism or to an immune factor ...

Classification according to the progression of the disease

Acute uveitis: when uveitis persists for less than three months, then it stabilizes.

Chronic uveitis: when inflammation persists for more than three months.

According to the trauma of the disease

Uveitis with or without granulomatous lesions.

Classification by anatomic location

Is the most basic and simplest classification that many people recognize:

Anterior uveitis: iritis-ciliary inflammation.

Medial uveitis: inflammation of the pars plana region.

Posterior uveitis: adenitis.

Whole uveitis: simultaneous inflammation of both the iris of the eyelids and the macula.

Pathophysiology

The symptoms of uveitis are due to the inflammatory response of the uveitis to infectious or traumatic processes, or an immune, autoimmune, or immune-mediated inflammatory response to either invading antigens or membranes itself peach. The polymorphonuclear leukocytes, eosinophils, and cytoplasm can all contribute to uveitis, but lymphocytes are the predominant inflammatory cells in the intraocular area of ​​uveitis. Chemical mediators of acute infection include serotonin, complement and plasmin. The leukotriene, kinin, prostaglandin alter the second phase of the acute inflammatory response, the activated complement is the agent to attract leukocytes ...

Symptom

Iritis-eyelid inflammation

Subjective symptoms

Blurred vision: is a symptom that appears at the beginning, sometimes there is a feeling of looking through the fog, sometimes blurred vision affects the patient's life.

Eye pain: is the most prominent subjective symptom, usually dull aches and pains, sometimes with severe pain accompanied by vomiting or nausea.

Fear of light, watery eyes, red eyes.

Sometimes patients do not have any subjective symptoms, uveitis is discovered by accident on an eye exam.

Objective symptoms

Edge convergence: convergence around the edge of the cornea, the farther from the edge, the lower the convergence.

Corneal precipitation: inflammatory deposits in the corneal endothelium. The corneal precipitate may be scattered throughout the posterior corneal surface or centrally, but is typically a fan-shaped deposition or an upward facing triangle (Arlt triangle).

The corneal precipitate is sometimes tiny dots like dust, sometimes precipitate into spots like drops of sheep fat.

Signum convergence labrum and Precipitable behind the cornea

Tyndall signs: are suspended bodies in the aqueous humour or inflammatory secretions. The severity of the anterior chamber response was assessed by the number of inflammatory cells seen in the anterior chamber with a 2 mm slit lamp:

O: there are no inflammatory cells.   

1+: less than 10 inflammatory cells.                  

2+: 10-20 inflammatory cells.

3+: 20-30 inflammatory cells.

4+: dense inflammatory cells.

Excretion:

The pupil secretion may form a membrane that seals the pupil area.

Iris secretion: can stick the iris to the front of the vitreous, when the pupil dilator is applied, the sticky spots behind the iris are separated, leaving a ring of pigment on the front of the lens (Vossius ring). .

Excretion in the anterior corner: When the inflammatory process is severe, many secretions settle in the anterior corner to form pus.

Changes in the pupil:

The pupil shrinks, responds slowly.

The pupil can be attached to the front of the vitreous, and if the pupil relaxant is used, it can completely or incomplete cleavage (at that time the pupil is distorted or the pupil looks like star fruit).

Vossius ring and Pupil sticking.

Lesions in the iris:

Inflammation of the iris, when the pupil is attached to the front of the vitreous, aqueous stagnation in the backroom pushes the iris to make the iris show signs of tomato nipple.

Inflammatory nodules in the iris:

Koeppel nodules: Gray-white nodules, on the edge of the pupil, appear early in the inflammatory episode and often go away.

Busacca nodules: nodules located anteriorly or deep in iris parenchyma, grey-white, can last for many months, sometimes organized, with neovascular or degenerative glasses, Busacca nodule is less common than Koeppel nodules.

Degeneration or atrophy of the iris, loss of pigmentation of the iris.

Signs of lash reaction:

Pain reaction when the physician presses two index fingers into the area of ​​the lashes through the upper lids.

Glass form:

Common pigment deposition on the anterior vitreous or cataract may be encountered due to inflammatory disease iris - eyelid.

Eye pressure:

The eye pressure is usually transient in the early stages, there are cases where the eye pressure is permanently low due to the damage of the eyelids causing atrophy of the eyeball; In some cases, an increased intraocular pressure due to iris sticking to the iris or a precaution block secreting inflammation obstructs the circulation of aqueous humour.

Intermediate uveitis (pars-plana inflammation)

Subjective symptoms

Poor subjective symptoms, often discovered by accident on an eye exam.

Blurred vision: usually the phenomenon of seeing objects hovering in front of the eyes like the feeling of flying flies,

Sometimes there are signs of distortion, vision enlarging or shrinking, or central cloudiness due to macular oedema.

Objective symptoms

Discovered by fundoscopy:

The lower vitreous discharge has '' snow clump '' lesions or "snow cloud" lesions in the lower Pars-plana region.

There may be manifestations of inflammation of the peripheral retinal vein wall: the "sheath" phenomenon.

Lesions of the macula: Cystic macular oedema, which is the cause of much loss of vision in medial uveitis.

Adenitis

Central Serous Chorioretinopathy

Subjective symptoms

Very few subjective symptoms without inflammation of the central melanoma. Patients are often unnoticed and accidentally discovered during routine eye exams when the inflammation has stabilized into scarring.

The flash phenomenon is caused by the stimulation of rods and cones.

The feeling of seeing a `` flying fly '' or a `` spider web '' when there is a cataract infection.

See whether the deformed object grows or becomes smaller when there is damage to the macula.

Physical symptoms

Adenitis is often accompanied by inflammation of the retina and vitreous.

Vitreous displacement: Tyndall signs in vitreous, partially or completely posterior vitreous detachment.

Fundoscopy may reveal focal or multiple foci, or diffuse ganglions, which are grey-white or pale-yellow areas that are often unknown, sometimes accompanied by sub-retinal haemorrhage. The corresponding retina is usually opaque white, thickened or may have retinal detachment due to secretion - retinal detachment internal medicine.

Old dark retinitis can leave proliferating scar areas and pigmented metastases or thin atrophy of the dark retina.

Subclinical symptoms

Biochemical test

Testing blood, aqueous humour or vitreous for specific pathogens or antibodies (immunofluorescence, Elisa, PCR ...), determine leukaemia antigens HLA-B27, HLA-B5 ...

Supersonic

Evaluate the status of vitreous and retinal fluid in case of vitreous, posterior vitreous detachment, medical retinal detachment ...

Measuring the eyeball

Helps evaluate pigment epithelial function, the outer layers of the retina.

Fundus fluorescence

Helps to identify dark lesions, active or scarring, cystic macular oedema...

Differential diagnosis

Acute angle glaucoma closed attacks

In uveitis corneal precipitate is inflammatory precipitate, grey-white colour and corneal precipitate in Glorucoma as a pigment; in uveitis, pupil shrinkage, while in glaucoma dilated pupil distortion, loss of reflexes.

Black retinopathy centre fluid

Central darker it is (posterior uveitis) can cause central retinal discharge but always accompanied by symptoms of inflammation, secretion deep in the wall or diffuse, clear fluorescence angiography these inflammatory foci or regions.

In central retinal serious disease, there is only central retinal serosa, no exudation into spots, plaques, no changes in pigmentation, fluorescein detection images in ink or water jet, Central serous dark retinopathy can go away on its own without treatment.

Symptoms

Glaucoma

Glaucoma is a fairly common complication of anterior uveitis, glaucoma during acute inflammation is due to obstruction of the pupil, obstruction of the anterior chamber due to secretions. Glaucoma in old uveitis is caused by anterior angular attachment or pupil occlusion or by neovascularization of the iris (neovascular glaucoma). Also to include glaucoma due to prolonged use of corticosteroids in the treatment of uveitis.

Glass chisels

Cataracts are common in chronic or recurrent eyelid iritis, a complication of the inflammatory process itself or from prolonged corticosteroid therapy.

Cystic macular oedema

Intermediate uveitis or adenitis can cause cystic macular oedema with impaired vision.

Eyeball atrophy

In severe eyelid iritis, the ciliary body permanently reduces fluid secretion, leading to atrophy of the eyeball.

Organize glass translation

Glass fluid is cloudy, organized to reduce eyesight; posterior vitreous detachment can cause degeneration, retinal detachment.

Retinal detachment

Posterior uveitis can cause retinal detachment due to secretion or detachment of the retina due to contractile vitreous fibres.

Other complications

Membrane front retina.

New vessels under the retina.

Treatment

Internally medical treatment

Treatment of uveitis is often difficult because treatment is based on a diagnosis of the cause and in many cases, the cause cannot be found.

Treat the cause with specific drugs

Antibacterial antibiotics, antivirals, antifungal drugs, antiparasitic drugs ...

The drug dilates the pupils and paralysis of the eyelids

Atropin 1-4% apply eye drops 1-2 times / day. the drug works to dilate the pupils, separate the iris from the front of the vitreous body; Reducing secretion and resting the eyelid body has the effect of reducing inflammation and pain.

Anti-inflammatory drugs

Corticoids are the main anti-inflammatory drugs in the treatment of uveitis. The drug has many forms and many routes of use: eye, eye injection or systemic route (oral, intramuscular, intravenous). Dosage 1 mg/kg body weight/day, reduce the dose gradually. It is possible to use high doses intravenously together with the monitoring of internal medicine ... The drug has many side effects, so it is necessary to closely monitor when using the drug.

Non-corticosteroid anti-inflammatory drugs: can be used as an alternative in case of contraindications to corticosteroids: Indomethacin, Diclofenac ...

Immunosuppressants

Used in cases of severe uveitis, anti-corticosteroid. Including drugs such as Cyclophosphamide, Clorambuxil, Azathioprine, Methotrexate, Cyclosporin .... When using these drugs must monitor liver and kidney function, stop the drug when seeing signs of toxicity or no drug use. results in therapeutic doses.

Surgery

Surgery mainly to treat uveitis complications:

Cataract surgery.

Surgical treatment of glaucoma.

Cut vitreous, peel off the membrane before the retina.

Retinal detachment surgery.