Infections of Eye Flashcards
1
Q
blepharitis
A
- inflammation of eyelid margins
- redness, swelling, no bump
- caused by Staph aureus
2
Q
stye
A
- inflammation of eyelid glands or follicles
- usually benign; small tender painful bumps on inside or outside of eyelid
- caused by Staph aureus
3
Q
conjunctivitis aka “pink eye”
A
- can be caused by viruses, bacteria, fungi, parasites, chemicals, allergies
- viral most common in late fall and early spring
- redness, watery eyes, irritation, occasional photophobia
- most commonly caused by adenovirus
4
Q
bacterial conjunctivitis
A
- stringy discharge; could cause eyelids to stick together
- swelling, redness, tearing, irritation/gritty feeling
- usually starts in one eye; could spread to the other
- could be caused by staph, strep, haemophilus (not common - vaccine), chlamydia trachomatis (triad of NGU, arthritis & conjunctivitis = Ritter’s syndrome; usually neonates), N. gonorrhoeae
5
Q
viral conjunctivitis
A
- watery discharge; irritation, redness
- starts in one eye, spreads to the other
- adenovirus (most common), HSV (most serious - rarely goes to eyes though), CMV (AIDS pts)
- less common but possible: VZV, Coxsackie, measles, rubella
6
Q
allergic conjunctivitis
A
- itching, tearing, swollen eyelids
- usually affects both eyes simultaneously
7
Q
most common cause of infectious blindness?
A
Chlamydia trachomatis
8
Q
cause of bacterial conjunctivitis in kids/adults v. neonates
A
- children and adults = S. aureus, S. pneumonia, H influenza
- neonates: S. aureus, Pseudomonas, Chlamydia trachomatis, N. gonorrhoeae
9
Q
Chlamydia trachomatis
A
- # 1 cause of infectious blindness worldwide
- serotype A-C; not the STD (sero D-K)
- repeated infection by direct contact = 3Fs = fomites, flies, fingers; formation of scar tissue –> corneal abrasions –> blindness
- neonates can be infected in eye and urogenital tract (serotypes D-K)
10
Q
C. trachomatis: dx, tx, prevention
A
- no gram stain; Giemsa stain = inclusion bodies (neonates); IFA detection of IgG or IgM
- tx w/ oral azithromycin; can be combined w/ topical doxycycline
- for neonates: tx = oral erythromycin
- prevention = SAFE - surgery, antibiotics, facial cleanliness, environmental improvement
11
Q
N. gonorrhoeae
A
- severe purulent conjunctivitis in neonates; transmitted during birth
- eye pain, redness, discharge; can go blind if not treated
- dx: gram (-) diplococcic, culture on Thayer-Martin agar
- tx = IV penicillin G, ceftriaxone if resistant strain
- prevention: topical silver nitrate, erythromycin, tetracycline
12
Q
Brazilian purpuric fever
A
- in peds caused by H. flu aegyptius
- purulent conjunctivitis then several weeks of fever, purpura, vascular collapse
- rapidly fatal
- probably distractor; don’t pick it
13
Q
adenovirus
A
- enveloped double-stranded DNA virus
- school-aged kids –> swimming pools!
- fever, sore throat, conjunctivitis
- respiratory spread; ocular secretions
14
Q
keratoconjunctivitis
A
- caused by adenovirus
- no pharyngitis (diff serotypes of adenovirus)
- transmission by hands and fomites; highly contagious in households
- classical “pink eye”
- redness, photophobia, tearing, pain
15
Q
to dx adenovirus? tx?
A
- could run PCR but more practical to r/o other causes
- rapid Strep tests, cultures for respiratory viruses, etc.
- tx: most infections self-limited = supportive and symptomatic tx
16
Q
herpes simplex virus
A
- neonates: HSV-2; transmission during birth; causes red eye, watery discharge
- keratoconjunctivitis = HSV-1 in adults; acute onset pain, red eye, watery discharge, itching, blurred vision, lid swells
- dx: MULTINUCLEATED GIANT CELLS (synctitia) on Tzank smear
- tx: IV acyclovir
17
Q
CMV
A
- most common in AIDS pts
- decreased VA, floaters, loss of visual fields, retinal necrosis = retinal detachment; associated w/ intraretinal hemorrhages
- dx: owl’s eye inclusions; IgM serology; PCR
- tx = IV ganciclovir; use foscarnet for AIDS pts
18
Q
herpes zoster ophthalmicus
A
- caused by reactivation of VZV
- eye pain, red eye (unilateral), decreased vision, skin/lid rash and pain, fever, malaise
- typical zoster lesions around nose
- dx: Tzank smear and Wright stain; IFA
- tx = oral acyclovir
19
Q
Coxsackie A24 & Enterovirus E70
A
- acute hemorrhagic conjunctivitis seen in undeveloped countries
- rapid onset painful conjunctivitis; petechiae that become subconjunctival hemorrhages; almost always resolves in 5-7d
- dx w/ PCR
- tx: symptomatic w/ topical steroids
20
Q
measles
A
- seen in unvaccinated people; usually kids
- high fever, cough, coryza, CONJUNCTIVITIS, photophobia
- buzzword = koplik spots = red bump w/ blue dot in the middle
21
Q
rubella
A
- fetal infection: 1-8 wk gestation
- cataract, glaucoma, microphthalmia
- salt and pepper change in retina
22
Q
bacterial keratitis
A
- infection of cornea; rapid progression
- risk factors = contact lenses, trauma, surgery, immunocompromised
- symptoms: pain, redness, swelling, impaired vision
- dx: gram stain, culture corneal scraping
- tx: depends on causative organism; topical fluoroquinolones, ciprofloxacin
23
Q
ocular fungal infections
A
- Fusarioum species in southern states
- Candida albicans (yeast) and Aspergillus (mold) in norther states
- Fusarium & Aspergillus = filamentous fungi
- spread through blood to eye or direct inoculation
- not common but will lead to blindness
24
Q
Fusarium species
A
- more common in southern states
- causes keratitis: hx of trauma (contact lenses, foreign body)
- symptoms: foreign body sensation, pain, discomfort, decreased vision, hypersensitivity to light
- filamentous fungi
- dx: KOH prep of eye scrapings cultured on Sabouraud dextrose agar
- tx = topical natamycin
25
Q
Candida albicans
A
- causes endophthalmitis
- exogenous (accidental or post-op inoculation) or endogenous (hematogenous seeding of eye) spread
- ocular pain, photophobia, floaters, fever
- budding yeast w/ pseudohyphae and germ tubes
- dx w/ funduscopic exam
- tx = amphotericin B
26
Q
causes of ocular parasitic infections
A
- protozoa: acanthamoeba, toxoplasma
- metazoan (worms): Trichinella spiralis, Taenia solium, Onchocerca volvulus, Loa loa
27
Q
Acanthamoeba species
A
- parasitic; causes amebic keratitis
- associated w/ contact lens use: contaminated solution, improper cleaning/storage, swimming in FRESH water w/ contacts
- photophobia, blurred vision, foreign body sensation, severe pain
- can cause cataracts and vision loss
- dx w/ Giemsa stain; culture contact solution; will see motile amoeba on wet prep
- tx = topical propamidine, micronazole, neomycin
28
Q
ocular toxoplasmosis-
A
- Toxoplasma gondii = cause
- AIDS pts but could be congenital (one of the TORCH bugs that crosses placenta)
- can cause spontaneous abortions; if kid born w/ it you won’t see symptoms until teen yrs (means mom got it late in pregnancy)
- severe scarring = irreversible vision loss
- tx = pyrimethamin, sulfonamide drugs
29
Q
Trichinella spiralis
A
- worm infections; larvae can be cyst in eye
- periorbital edema
- no good tx for larvae: corticosteroids and mebendazole
30
Q
Ocular cysticercosis
A
- caused by Taenia solium
- cysticerci lodge in the eye = loss of visual acuity and visual field defects
- dx: you can see the cyst in the eye
- tx = praziquantel or albendazole
- surgically remove ocular cysts; if it’s in your eye it’s probably other places (brain)
31
Q
African River Blindness
A
- Onchocerca volvulus; transmitted by black fly
- early signs: itching, redness, photophobia, blurred vision
- late disease = vision loss and blindness
- tx = ivermectin
32
Q
Loa loa
A
- transmitted by Chrysops fly (W. Africa)
- DOES NOT CAUSE BLINDNESS
- tx = diethylcarbamazine
