Week 3 - A. Prunuske (Eye Infections) Flashcards

0
Q

What is conjunctivitis an infection of?

A

Thin membrane (conjunctiva, obviously)

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1
Q

What is blepharitis an infection of?

A

Eye lid

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2
Q

What is an infection of the cornea called?

A

Keratitis

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3
Q

What is the medical term for an infection of BOTH the conjunctiva and the cornea?

A

Keratoconjunctivitis

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4
Q

What part of the eye is infected in Uveitis?

A

Middle Layer:

iris, ciliary body, and choroid

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5
Q

What part of the eye is infected in Chorioretinitis?

A

Choroid and retinal layers

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6
Q

What part of the eye is infected in Endophthalmitis?

A

Aqueous and vitreous humor

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7
Q

What kind of people are more likely to get trauma related to abrasions, scratches, and microabrasions?

A

Contact lens wearers

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8
Q

Why does dysfunctional tear states or decreased tear production increase the susceptibility of eye infections?

A

Tears are important defense mechanism.

Less tears –> more opportunity for pathogens to cause trouble.

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9
Q

How are deeper eye infections usually acquired?

A

Invaded from blood borne carriage

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10
Q

Chronic conjunctivitis is associated with what other common eye infection?

A

Blepharitis

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11
Q

What is overproduced in Blepharitis?

A

Too much oil is produced in the eyelid margin

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12
Q

What pathogen is most commonly associated with Blepharitis/Chronic conjunctivitis/Stye/Hordeolum?

A

Staphylococcus epidermidis

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13
Q

What is treatment for Blepharitis/Stye?

A

Keep lid clean, Warm compress, Erythromycin ointment

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14
Q

What two layers of the eye act as a physical barrier to prevent invasion?

A

Sclera & Cornea

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15
Q

What do tears contain for defense mechanism and lubrication?

A

sIgA and Lysozyme

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16
Q

What defense cells are present in the conjunctiva?

A

Lymphocytes, plasma cells, neutrophils, and mast cells

produce antibodies and cytokines

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17
Q

How does blinking act as a defense mechanism for the eye?

A

Inhibits microbial attachment

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18
Q

What causes red eye, irritation, and sensitivity in conjunctivitis?

A

Dilation and congestion of supepithelial vessels

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19
Q

What is the most common viral cause of conjunctivitis?

A

Adenovirus

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20
Q

What type of conjunctivitis most commonly causes mucopurulent discharge bilaterally?

A

Bacterial

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21
Q

What symptoms are typical in Allergic Conjunctivitis?

A

Bilateral eyes, Redness, Pruritic

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22
Q

What are some non-infectious causes of conjunctivitis?

A

Allergic rhinoconjunctivitis (hay fever), chemical reaction, prolonged use of ocular medications, neoplsm, irritation from contact lens, or foreign body.

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23
Q

What antibody response is most common in Allergic rhinoconjunctivitis (hay fever)?

A

IgE response

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24
Q

What things do you want to avoid in the management of allergic rhinoconjunctivitis?

A

Avoid antigen and glucocorticoid

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25
Q

Why do you want to avoid Steroids if possible when treating allergic rhinoconjunctivitis (hay fever)?

A

More likely to develop secondary infections.

Cause complications: glaucoma, cataracts

26
Q

What is the best treatment for allergic rhinoconjunctivitis?

A

Antihhistamines, mast cell stabilizers, nonsteroidal anti-inflammatory drugs

27
Q

What is the most common neonatal cause of viral conjunctivitis?

A

HSV

28
Q

What is the most common post-natal cause of viral conjunctivitis?

A

Adenovirus

29
Q

What are common indicators of viral conjunctivitis?

A

Watery/clear discharge, unilateral symptoms, recent URI

30
Q

What is the typical treatment for viral conjunctivitis?

A

Cold compress, topical vasoconstrictor

31
Q

What virus commonly causes conjunctivitis and is ds-DNA, non-enveloped, and highly contagious through fomites in swimming pools?

A

Adenovirus

32
Q

What determines the specificity of Adenovirus that infects the conjunctiva?

A

antigen ability to interact with cellular receptors

33
Q

What three pathogens most commonly cause acute bacterial conjunctivitis in children?

A

Staph aureus, Strep pneumoniae, and Haemophilus influenzae

34
Q

What common pathogen causes acute bacterial conjunctivitis in Adults?

A

Staph aureus

35
Q

What is the typical treatment for acute bacterial conjunctivitis?

A

Empiric treatment for BOTH Gm -/+
Polytrim (Trimethoprim and polymixin)
Fluorquinolone (moxifloxacin)

36
Q

What is MOA of trimethoprim?

A

Bacteriostatic - inhibits bacterial dihydrofolate

37
Q

What is MOA of Polymyxin B?

A

Binds to lipopolysaccharid –> creating holes in membrane –> release cellular contents
(Gm -)

38
Q

What is MOA of Moxifloxacin?

A

Topo II inhibitor

39
Q

What is the pathogen that causes Hyperacute bacterial conjunctivitis?

A

Neisseria gonorrheoeae (less often Neisseria meningitidis)

40
Q

What special agar is used to identify gram-negative diplococci like Neisseria gonorrhoeae?

A

Chocolate agar (nom nom)

41
Q

What antibiotic is a cell wall inhibitor and is used promptly to treat hyperacute bacterial conjunctivitis?

A

Ceftriaxone

42
Q

What condition can occur if conjunctivitis or keratonconjunctivitis is acquired within the first four weeks of birth?

A

Ophthalmia neonatorum! (thats why all new babies get erythromycin ointment on their eyes)

43
Q

Erythromycin and Azithromycin are Macrolides that inhibit translation by binding to what part of the ribosome?

A

BIG SUBUNIT (50S)

44
Q

What are common adverse side effects of Macrolides like Erythromycin and Azithromycin?

A

GI discomfort, hepatic failure, and prolonged QT

check other meds due to cytochrome P450 inhibition

45
Q

What is the leading cause of blindness WORLDWIDE?!?

A

Trachoma caused by Chlamydia (serotypes A-C)

46
Q

Inclusion conjunctivitis is caused by serotypes D-K of what pathogen?

A

Chlamydia trachomatis

47
Q

What is preferred treatment for eye infections caused by Chlamydia?

A

Azithromycin

48
Q

What form of Chlamydia trachomatis enters epithelial cells?

A

Elementary bodies

49
Q

What form does Chlamydia convert to after it has entered the epithelial cells?

A

Reticulate body

50
Q

Which form of Chlamydia has a more rigid outer membrane?

A

Elementary bodies

51
Q

What eye infection does HSV-1 cause?

A

Keratoconjunctivitis

52
Q

What is the typical presentation of Keratoconjunctivitis caused by HSV-1?

A

unilateral infection, similar to adenovirus, with PAINFUL corneal lesions

53
Q

What do you want to avoid with corneal lesions/penetrations in treating keratoconjunctivitis?

A

Corticosteroids are bad for the cornea!

54
Q

What topical drug and systemic antibiotic should you use if there is corneal involvement in keratoconjunctivitis caused by HSV-1?

A

Trifuridine and Acyclovir

55
Q

Why is Trifluridine a more toxic drug?

A

It can be phosphorylated by the host kinases to become active (not viral specific kinases like acyclovir)

56
Q

What conditions can increase your risk of getting keratitis?

A

Trauma, drying of epithelia, and hypoxia

57
Q

What is viral keratitis caused by?

A

HSV-1 (also adenovirus & VZV)

58
Q

What are common pathogens in bacterial keratitis?

A

Staph. aureus/epidermis, Pseudomonas aerugrinosa, and Bacillus cereus

59
Q

What is the treatment for bacterial keratitis?

A

Moxifloxacin eye drops

60
Q

What is cool about Pseudomonas?

A

Produces a blue/green pigment (pyocyanin) that inhibits mitochondrial enzymes that disrupt ciliary beating in the eye => Virulence factor

61
Q

What cell surface adherence factors produced by Pseudomonas destroy corneal epithelium in bacterial keratitis?

A

Cytotoxins like elastase and alkaline protease

62
Q

What process actually damages the cornea leading to scarring and loss of visual acuity during a keratitis caused by Pseudomonas aerginosa?

A

host immune response