Eye infections

Question 1

erythromycin/azithromycin

Answer 1

macrolides
inhibit translation by binding 23S rRNA of 50S subunit
Broad coverage

Question 2

trifluridine/acyclovir

Answer 2

trifluridine - pyrimidine analong effective against acyclovir resistant virus because phosphorylated by host kinases (toxic)
Acyclovir - virus specific enzymes required to phosphorylate (specific)

**inhibition of viral dna synthesis, chain termination

Question 3

moxifloxacin

Answer 3

Gram + and neg

Block DNA synthesis through binding to bacterial topo II and IV leading to formation of double strand breaks

Question 4

polymyxin B

Answer 4

Gram negative, multidrug resistant

Bind to LPS in membrane creating holds –> release of cell contents

Question 5

pyrimethamine/sulfadiazine

Answer 5

inhibit pteridine synthetase

and DHFR in purine synthesis

Question 6

eye lid infection

Answer 6

blepharitis

Question 7

conjunctiva infection

Answer 7

conjunctivitis

Question 8

cornea inf.

Answer 8

kertatitis

Question 9

conjunctiva and cornea inf.

Answer 9

keratoconjunctivitis

Question 10

middle layer - iris, ciliary body, choroid inf

Answer 10

uveitis

Question 11

choroid and retinal layers inf.

Answer 11

chorioretinitis

Question 12

aqueous and vitreous humor inf.

Answer 12

endophthalmitis

Question 13

agent of blepharitis

Answer 13

staphylococcus epidermidis

Question 14

eye defense mechanisms

Answer 14

sclera, cornea = physical barrier, conjunctiva has lymphocytes, plasma cells, neutrophils, mast cells, tears have sIgA and lysozyme, blinking inhibits attachement

Question 15

Main causes conjunctivitis

Answer 15

Bacterial, viral, allergic

Question 16

hallmarks bacterial conjunc.

Answer 16

bilateral, mucopurulent, redness in older children, often w/ ear infection, not itchy

Question 17

hallmarks viral conjunc.

Answer 17

Not always bilateral, mild/watery discharge, usually red, not usually with ear infection, not itchy

Question 18

hallmarks allergic conjunc.

Answer 18

usually bilateral, no discharge, usually red, no ear inf, very itchy

Question 19

allergic rhinoconjunctivitis is a _____ response

Answer 19

IgE response (type 1) - IgE bound to surface of mast cells, subsequent exposure to antigen –> release of histamines

Question 20

most common viral conjunc.

Answer 20

neonatal - HSV

Post natal - adenovirus* (also coxsackie, HSV1 and 2, VZV, EBV, mumps, rubella, flu)

Question 21

tx viral conjunc

Answer 21

cold compress and topical vasoconstrictors

Question 22

nonenveloped ds DNA virus, lytic in epithelial cells and latent in lymphoid cells

Answer 22

adenovirus (class 1)

Question 23

most common bacterial conjunctivitis children

Answer 23

staph aureus, strep pneumoniae, H. influenzae, also Moraxella lacunata

Question 24

most common bacterial conjunct. adults

Answer 24

staph aureous,

also strep pneumo, strep pyo, pseudomonas aeruginosa

Question 25

empiric tx bacterial conjunct.

Answer 25

empiric for gram pos and neg: trimethoprim + polymyxin moxifloxacin (more $$)

Question 26

trimethoprim

Answer 26

broad | bacteriostatic - inhibits bacterial DHFR

Question 27

hyperacute bacterial conjunctivitis agent

Answer 27

Neisseria gonorrhoeae (sometimes meningitidis)

Question 28

hallmarks hyperacute conjunc.

Answer 28

copious yellow-green discharge | preauricular adenopathy

Question 29

culture n. gonorrhoeae

Answer 29

gram negative, intracellular diplococci, growth on chocolate agar w/ vanco, colistin, nystatin and trimethoprim

Question 30

tx. n. gono in eye

Answer 30

systemic ceftriaxone, can augment with topical abx and irrigation

Question 31

conj, or keratoconjun w/in first four weeks of birth

Answer 31

ophthalmia neonatorum

Question 32

causative agents ophth. neonatorum

Answer 32

N. gono, C. trachomatic, Staph, strep, e.coli, H. simplex

Question 33

tx ophth neonatorum

Answer 33

prophylaxis w/ erythromycin ointment | tx w/ abx, usually erythromycin

Question 34

Chlamydia trachomatis prevalence, dx, tx

Answer 34

leading cause of blindness worldwide, dx w/ direct fluorescent ab, DNA probe systemic azithromycin inclusion conjunctivitis (D-K), trachoma (A-C)

Question 35

C. trachomatis intracellular cycle

Answer 35

elementary body enters epithelial cells, converts to reticulate body, then replicates using binary fission eb has more rigid outer membrane

Question 36

keratoconjunctivitis agent

Answer 36

HSV1 - similar presentation to adenovirus, painful if touching cornea

Question 37

keratoconjunctivitis tx

Answer 37

if corneal involvement (w/ HSV1) - topical trifluridine and systemic acyclovir, consider erythromycin

Question 38

vision defects, photophobia, pain, foreign body sensation

Answer 38

keratitis

Question 39

agents keratitis

Answer 39

viral - HSV1, adenovirus, pseudomonas Fungal acanthamoeba

Question 40

tx keratitis

Answer 40

bacteria - moxifloxacin eye drops | hsv-1 - trifluridine + acyclovir

Question 41

gram negative, aerobic rod, flagella

Answer 41

pseudomonas aeroginosa

Question 42

p. aeroginosa virulence factors

Answer 42

opportunistic secretes elastase and alkalin protease to destroy corneal epithelium, immune response --> scarring, vision loss Biofilms

Question 43

Single cell eukaryotic --> keratitis or granulomathous amebic encephalitis

Answer 43

acanthamoeba

Question 44

tx acanthamoeba

Answer 44

ketoconazole

Question 45

pathogens iritis

Answer 45

often not infectious | treponema pallidum, HSV, VZV

Question 46

chorioretinitis agents

Answer 46

toxoplasma gondii, CMV - HIV | Toxocara canis and ochocerca volvulus (parasites)

Question 47

tx toxoplasma

Answer 47

pyrimethamine + sulfadiazine

Question 48

endophthalmitis agents

Answer 48

bacteria/fungi exogenous (pseudomonas, staph, candida) or hematogenous spread * inject fluoroquinolone or vanco into eye

Question 49

5 signs to worry about --> ophthalmologist

Answer 49

1. Globe pain: suggests problem within the eye, eg iritis, uveitis, or glaucoma 2. Decreased visual acuity: this is bad – risk for permanent vision loss 3. Sluggish pupillary reflex: concerning for retinal or CNS disease 4. Dendritic corneal lesion: concerning for HSV keratitis 5. Vesicular lesions around the eye: concerning for herpes zoster

Question 50

ddx sudden painless unilateral vision loss

Answer 50

vitreous hemorrhage (dm, trauma) retinal detachment retinal vein occlusion central retinal artery occlusion

Question 51

flame shaped hemorrhages

Answer 51

retinal vein occlusion (squashed tomato, tomato soup)

Question 52

cherry red spot

Answer 52

central retinal artery occlusion