Conjunctivitis drugs Flashcards

1
Q

Infection of the Eye lid

A

blepharitis

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2
Q

infection of the cornea

A

keratitis

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3
Q

endophthalmitis

A

aqueous and vitreous humor infection

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4
Q

defense mechanisms of eye

A

Sclera and cornea act as physical barrier
tears contain sIgA and lysozyme and provide lubrication
blinking inhibits microbial attachment

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5
Q

Common symptoms with bacterial conjunctivitis

A

Bilateral eyes - usually
Discharge - mucopurulent in young children
Redness- common in older children but not infants

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6
Q

common symptoms with viral conjunctivitis

A

not usually bilateral
watery discharge
usually red

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7
Q

common symptoms with allergic conjunctivitis

A

usually bilateral
no discharge
usually red

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8
Q

Treatment of allergic conjunctivitis

A

antihistamines

but no glucocorticoids - can lead to glaucoma, cataract and 2ndary infections

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9
Q

most common causes of viral conjunctivitis

A

Neonatal = HSV

post natal = Adenovirus

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10
Q

Describe the adenovirus

A

non-enveloped, double stranded DNA virus, Lytic in epithelial cells and latent in lymphoid
spreads through fomites

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11
Q

most common cause of acute bacterial conjunctivitis

A

Children - Staph aureus, strep pneumo and haemo influ

Adults - staph aureus

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12
Q

Empiric treatments of conjunctivitis

A

Trimethoprim and polymyxin (combined in drops) called polytrim
or
Moxifloxacin (more expensive)

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13
Q

Mechanism of moxifloxacin

A

topo II and IV inhibitor

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14
Q

Mechanism of trimethoprim

A

inhibits bacterial dihydrofolate reductase.

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15
Q

Mechanism of polymyxin B

A

Binds to LPS creating holes in membrane,

Used on Gram - multi-drug resistant bacteria

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16
Q

Hyperacute bacterial conjunctivitis cause

A

neisseria

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17
Q

Signs of neisseria conjunctivitis

A

Copious yellow green discharge
gram stain reveals gram negative intracellular diplococci
grows on chocolate agar

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18
Q

Treatment of hyperacute bacterial conjunctivitis

A

System ceftriaxone promptly

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19
Q

What is opthalmia neonatorum

A

conjunctivitis occurring within the first four weeks of birth

20
Q

Treatment of ophthalmia neonatorum

A

Prophaylaxis - erythromycin ointment

Treat - appropriate antimicrobial (usually erythromycin)

21
Q

Mechanism of erythromycin and azithromycin

A

inhibit translation by binding 23S rRNA of 50S subunit

22
Q

spectrum of macrolides

A

broad coverage of respiratory pathogens and chlamydia

23
Q

Resistance of macrolides

A

Methylation of binding site and increase efflux

24
Q

Adverse effects of macrolides

A

GI upset and hepatic failure

inhibitors of P450 enzymes

25
Q

Different serotypes of Chlamydia trachomatis

A

inclusion conjunctivitis = serotypes D-K
Trachoma = serotypes A-C
Trachoma is the leading cause of blindness worldwide due to multiple infections b/c no long lasting immunity

26
Q

Diagnosis of chlamydia trachomatis

A

direct fluorescent antibody

27
Q

treatment of chlamydia trachomatis

A

systemic azithromycin and improve hygiene

treat sexual partners and prophylaxis is being used to eliminate trachoma by 2020

28
Q

describe life cycle of chlamydia trachomatis

A

Elementary body (rigid outer membrane) enters epithelial cells -> converts to reticulate body -> replicates using binary fission

29
Q

Signs and symptoms of HSV keratoconjunctivitis

A

similar to adenovirus but lesions can be painful especially if scarring of the cornea occurs often and only one eye

30
Q

treatment of HSV keratoconjunctivitis

A

avoid corticosteroids
treat w/ topical trifluridine and systemic acyclovir
consider prophylactic treatment with erythromycin to prevent bacterial infection

31
Q

Mechanism of trifluridine

A

pyrimidine analog effective against acyclovir resistant virus because it can be phosphorylated by host kinases making it more toxic and should only be used topically

32
Q

signs and symptoms of keratitis

A

vision defects, photophobia, pain and foreign body sensation

33
Q

Causes of keratitis

A

Viral - HSV-1 usually but adenovirus and vzv too
Bacterial - staph, pseudomonas and bacillus cereus
Fungal can be seen in warm humid climate
acanthamoeba

34
Q

treatment of keratitis

A

bacterial - moxifloxacin eye drops

viral (HSV) - trifluridine and acyclovir

35
Q

Describe pseudomonas aeroginsoa

A

Gram -, aerobic rod w/ flagella
can use 75 different compounds for growth
usually opportunistic infection
naturally resistant to many antibiotics and disinfectants due to its ability to form biofilms

36
Q

what is pyocyanin and what does it do?

A

a blue pigment that inhibits mitochondrial enzymes which disrupts ciliary beating in pseudomonas keratitis

37
Q

Mechanism of keratitis

A

Bacterial cell surface adherence factors and secreted toxins like elastase and alkaline protease destroy corneal epithelium
The host response damages the cornea leading to scarring and loss of visual acuity

38
Q

Describe acanthamoeba

A

Single cell, eukaryote

can cause keratitis or granulomathous amebic encephalitis

39
Q

treatment of acanthamoeba

A

Azoles

40
Q

Mechanism of azoles

A

bind p-450 enzyme and block production of ergosterol

Can be very toxic

41
Q

describe uveitis

A

inflammation of uveal tract that can lead to blurred vision and permanent vision loss

42
Q

iritis

A

(also called anterior uveitis) often not infectious but has photophobia, pain and decreased visual acuity
caused by Treponema pallidum, herpes simplex and vzv

43
Q

Chorioretinitis

A

most common type of uveitis
has floaters and no pain
blurred vision and visual field defects

44
Q

Causes of chorioretinitis

A

usually manifestation of a systemic disease
most common causes are Toxoplamosis and CMV (looks like brushfire from periphery) esp in neonates and HIV positive individuals
Parasitic worms can also cause this (river blindness)

45
Q

describe toxoplama

A

Most common parasitic disease, late term congenital infections are more likely to lead to blindness
diagnose with IgM serology
treat with pyrimethamine and sulfadiazine

46
Q

Describe endophthalmitis

A

infection of vitreous and/or aqueous humors
Rare
Pain, redness and decreased vision
can be bacterial or fungal
Exogenous = recent intraocular surgery
Endogenous = spread from the blood
Treat w/ fluoroquinolone or vancomycin injected into the eye