uveitis Flashcards
waht is the uvea
iris, ciliary body and choroid.
what are the two structures of the iris
stroma and posterior pigmented layer
what are the zones of the stroma of the iris
pupillary zone extends from the pupillary edge to the collarette (thickest part of the iris that separates the two zones).
sphincter pupillae is located here.
what is the collarette
thickest part of the iris that separates pupillary and ciliary zone
role of sphincter pupilae made of what and supplied by
smooth muscle responsible for pupillary constriction with parasympathetic innervation (CNIII) via short ciliary nerves.
origin of ciliary zone and role
extends from the collarette to the origin of the iris at the ciliary body
with dilator pupillar
dilator pupilae made of and innervation
smooth muscle sympathetic innervation via long ciliar nerves
what is the posterior pigmented layer
A pigmented epithelial layer found at the posterior iris surface that is continuous with the neurosensory retina posteriorly.
what are the layers of the ciliary bpdy
stroma - CT where the vascular supply is found
muscle - PNS via CNIII
epithelium
blood supply to the ciliary body
anterior and long posterior ciliary arteries
parts of the ciliary body and its role
2) pars plana
- avascular
- lies between the ora serrata and ciliary processes of the pars plicata.
- Functionless,
- site for intravitreal injections
- vitreous removal (pars plana vitrectomy).
1) pars plicata
- highly vascularised
- forms attachments for the lens zonules
functions
- aqeous humour formation
lens accomodation
aqueous drainage via uveoscleral outflow
what is the choroid and location
posterior component of the uveal tract
between the sclera externally and RPE
consists of bruchs membrane and a vascular layer
role of the choroid
provide nutrients to the outer third of the retina
what is the bruchs membrane and its function
innermost layer before the RPE
has five layer and measures less than 4 micrometres
function - fluid transport from the choroid to the retina and is permeable to small moleules
what is the vascular layer of the choroid
has three layers
- choriocapillaries which are external to the Bruch membrane
- a medium-sized vessel layer
- a large vessel layer.
blood supply of the choroid
two long posterior ciliary arteries, the short posterior ciliary artery and anterior ciliary artery.
what is anterior uveitis
inflammation of the iris +/- pars plicata (anterior ciliary body)
what are keratic precipitates
WBCs on the posterior endothelial layer of the cornea
granulomatous v non-granulomatous precipitataes how do u differentiate in anterior uveitis
Granulomatous is defined by mutton fat KPs whereas nongranulomatous is defined with stellate KPs.
aetiology of anterior uveitis
● Idiopathic (50%).
● HLA-B27-associated conditions (psoriasis, reactive arthritis, inflammatory
bowel disease and ankylosing spondylitis).
● Inflammatory: Sarcoidosis, Behçet syndrome, systemic lupus erythematosus,
juvenile idiopathic arthritis, multiple sclerosis (MS), Fuchs’ heterochromic
cyclitis, tubulointerstitial nephritis, Posner-Schlossman syndrome.
● Infectious: Tuberculosis (TB), Lyme disease, syphilis, varicella zoster virus
(VZV).
Features of anterior uveitis
Painful red eye
blurred vision
photophobia
examination of anterior uveitis
complications
● Irregular miosed pupil: Due to inflammation of the sphincter pupillae of the iris. May predispose to posterior synechiae (adhesion between the iris and lens capsule).
● Anterior chamber cells: Due to inflammation of the ciliary body which produces aqueous humour.
● KP: Stellate or mutton fat depending on aetiology.
● Hypopyon: White cells in the anterior chamber.
● Iris atrophy and nodules: More common in chronic cases.
● Complications: Cystoid macular oedema (CMO) and cataracts.
Mx of anterior uveitis
● Investigate as appropriate based on clinical findings. For example, measuring calcium and serum ACE if sarcoidosis is suspected.
● Potent topical steroid and cyclopentolate to dilate the pupil.
what is intermediate uveitis
Inflammation of the posterior ciliary body (pars plana) and vitreous. Synonym: pars planitis.