RETINA - INFECTIOUS RETINOPATHIES Flashcards
what is histoplasmosis? what is the name of the species involved?
fungal infection caused by histoplasma capsulatum.
how does someone become infected w/ histoplasmosis?
typically infected by inhaling the fungus from bat or bird poop.
where is histoplasmosis most common?
Ohio & mississippi river valleys
symptoms of histoplasmosis?
- asymptomatic
- metamorphopsia if CNVM
signs of histoplasmosis (triad)?
- histo spots - multiple, small, yellow-white, punched out lesions.
- peripapillary atrophy (PPA)
- maculopathy (CNVM) - appears green/gray.
*** no vitritis or anterior uveitis!
w/u for histoplasmosis?
- Amsler grid to evaluate central vision.
- look for signs of CNV - IVFA confirms CNVM.
- DO FA/OCT.
tx for histoplasmosis?
- Anti-fungal tx is not helpful!
Tx aimed to control CNVM:
* Anti-VEGF – for subfoveal CNVM
* Focal laser photocoagulation – for extrafoveal CNVM
- F/U in pts w/out CNVM but macular changes – every 6 months.
- F/U in pts w/ no macular Dz – every 1 year
what is toxoplasmosis? what species causes it?
it a (protozoan) prasitic infetion caused by toxoplasma gondii.
how does someone become infected with toxoplasmosis?
caused by eating raw meat, exposure to cat feces or can be acquired or passed along in utero.
what are the 2 ways that toxoplasmosis can be acquired?
- congenital - exposure to cat feces by pregnant woman leads to fetal infection.
- acquired - most common in immunocompromised pt and most likely due to eating raw meat or unwashed produced.
Toxoplasma gondii can only complete its reproductive cyle in what organism?
cats
toxoplasmosis is the most common cause of what eye condition?
posterior uveitis
(it is necrotizing)!
symptoms of toxoplasmosis?
- active infection - unilateral: blurry vision + red eye + floaters + uveitis + vitritis
- inactive infection - asymptomatic
signs of toxoplasmosis?
Active/acquired case:
* present with fluffy yellow-white lesions with an overlying vitritis (headlights in the fog) - with no underlying chorioretinal scar b/c there hasn’t been enough time to scar.
Inactive/congenital:
* Sharply delineated singular macular chorioretinal scar.
* strabismic amblyopia
* nystagmus
Other ocular signs:
* cataracts
* anterior uveitis
* RD
* CNVM
* CME
can toxoplasmosis reacvtivate? how does it appear?
yes, appears as an active case: with fluffy white lesion next to past chorioretinal scar.
tx/managment for toxoplasmosis?
- active case - pyrimethamine, sulfadiazine, folinic acid, abx; azithromycin, clindamycin, bactrim, steroids; prednisone.
- refer to neurology to r/o encephalitis.
- no sub-conj or sub-tenon’s injections.
what is toxocariasis? what species is involved?
it is a parasitic infection causes by the roundworm Toxocara canis.
how can someone get toxocariasis?
Children typically infected by transfer of worm eggs via contact w/ dog feces or unwashed produce or undercooked meat.
symptoms of toxocariasis?
blurry vision
signs of toxocariasis?
white signs:
* endophthalmitis
* leukocoria - 2/2 macular dragging due to posterior pole granuloma.
other signs:
* chorioretinal scar
* RD
* vitritis or papilitis
w/u for toxocariasis?
Most helpful to confirm diagnosis:Toxocara (Enzyme-Linked Immunosorbent Assay) ELISA testing
tx for toxocariasis?
- inflammation - topical/oral/ sub-tenon steroid.
- RD - repaired with surgery
what is lyme dz? what species is involved?
bacterial infection caused by borrelia burgdorferi
how does someone get lyme dz?
organism is transmitted to humans through the bite of a tick that has fed on an infected animal, particularly a deer or rodent.
