Eye Infections Flashcards

1
Q

Defense mechanisms of the eye (2)

A
  1. Tears: Lysozyme, IgA
  2. Conjunctiva: barrier protection, blood supply
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2
Q

Blepharitis definition

A

Non-contagious inflammation of the eyelash follicles and tiny oil glands along the margins of the eyelid

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3
Q

Dacrocystitis definition

A

inflammation of the lacrimal sac

(elderly are at a risk as their system loses elasticity)

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4
Q

Three types of conjunctivitis

A
  1. Bacterial
  2. Viral
  3. Allergic
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5
Q

What is unique to bacterial conjunctivitis compared to viral and allergic?

A

Stringy discharge

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6
Q

What is a unique symptom of viral conjunctivitis compared to bacterial and allergic?

A

Watery discharge

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7
Q

What is a unique symptom of allergic conjunctivitis compared to viral and bacterial?

A

Typically affects both eyes

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8
Q

Define opthalmia neonatorum

A

Severe eye infection contracted in the birth canal of a woman with gonorrhea or chlamydia

(organisms: N. gonorrhoeae, C. Trachomatis, HSV)

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9
Q

Endophthalmitis definition & prognosis

A

Inflammation of internal tissues of the eye

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10
Q

Orbital cellulitis definition

A
  • Diffuse infection of tissues in the orbit
  • causes grossly swollen eyelids and red eye
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11
Q

Haemophilus influenzae: characteristics

A

Gram-negative rod

Nasopharyngeal mucosa resident

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12
Q
A
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13
Q

Haemophilus influenzae pathogenesis (3)

A
  1. Polysaccharide capsule (type B capsule is Polly ribitol phosphate) - most virulent factor
  2. IGA protease
  3. Pili attachment of respiratory epithelial cells
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14
Q

Haemophilus influenzae growth requirements (2)

A
  1. X (hemin) and V (NAD) from lysed RBCs
  2. use of chocolate agar
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15
Q

Streptococcus pneumoniae

A
  1. Gram positive diplococci
  2. Catalase negative
  3. Alpha-hemolytic
  4. Encapsulated IGA protease
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16
Q
A
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17
Q

Streptococcus pneumoniae colony morphology

A

Alpha hemolytic on blood agar

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18
Q

Endophthalmitis treatment

A
  1. Typically requires surgery
  2. usually hospitalization

(usually caused by bacteria or fungi)

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19
Q

Endophthalmitis causative organisms (2)

A
  1. Normal flora of the eyelids (epidermidis)
  2. Gram-negative microorganisms (pseudomons, poor prognosis)
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20
Q

Uveitis definition

A

Inflammation or swelling of the eye structure is responsible for the eyes blood supply

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21
Q

Structure is responsible for the eyes’ blood supply (3)

A
  1. Iris
  2. Ciliary body
  3. Choroid
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22
Q

Iritis symptoms

A
  1. Photophobia
  2. Blurred vision in severe inflammation

(also common sx: redness, pain)

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23
Q

Uveitis: 3 types

A
  1. Iritis
  2. Intermediate uveitis (cyclitis)
  3. Posterior uveitis
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24
Q

What is a complication of periorbital cellulitis

A

It can lead to orbital cellulitis and develop into meningitis

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25
Q

How do microorganisms gain entry into the orbit?

A
  1. Trauma
  2. Surgery
  3. URI
  4. Dental caries

(drainage system is not very effective)

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26
Q

Haemophilus influenzae characteristics

A
  1. Gram-negative
  2. Bacillus, rod
  3. Fastidious
  4. Facultative anaerobe
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27
Q

Haemophilus influenzae: culture requirements

A
  1. X - hemin
  2. V - nicotinamide adenine dinucleotide
  3. Chocolate ogre

(both X & V factors are from lysed blood. Neisseria also requires these)

28
Q

Which 2 microorganisms require X & V factors from lysed blood?

A
  1. H. Influenzae
  2. Neisseria
29
Q

Haemophilus influenzae pathogenicity

A
  1. Pili attached to respiratory epithelial cells
  2. Endotoxic (to ciliated cells)
30
Q

What is the most virulent strain of haemophilus influenzae?

A

HiB (haemophilus influenzae type b)

(we have a vax for this; prevents meningitis, pneumoniae)

31
Q

Non encapsulated or nontypeable strains of Haemophilus influenzae cause which infections?

A
  1. Otitis media
  2. Conjunctivitis
  3. Bronchitis
  4. Pneumoniae
32
Q

Patients at risk of H. influenzae?

A

with COPD and cystic fibrosis

33
Q

Streptococcus pneumoniae: characteristics

A
  1. Gram positive
  2. Diplococci
  3. Fastidious, facultative anaerobe
  4. capsule (interferes w/phagocytosis)
34
Q
A

Streptococcus pneumoniae

35
Q

Streptococcus pneumoniae: culture requirements

A
  1. Blood agar
  2. Alpha hemolytic
36
Q

Anit-pneumococcal vaccines are based on ________ (molecule).

A

pneumococcal capsular antigens

37
Q

Define Quellung reaction

A

Seroyping used to identify particular capsule type (there are about 90)

Antibody reacts with capsule type and causes capsular swelling

38
Q

Staph aureus characteristics

A
  • Gram positive
  • Grows in clusters
39
Q

Staphylococcus aureus virulence factors

A
  1. Alpha hemolysin
  2. Beta hemolysin
  3. Staphylococcal leukocidin
  4. Coagulase
  5. Hyaluronidase
  6. Lipases
  7. Protein A
40
Q

Alpha hemolysin

A

Destroys platelets and causes severe tissue damage

41
Q

Beta hemolysin

A

Acts on sphingomyelin of red blood cell membranes

42
Q

Staphylococcal leukocidin

A

Exotoxin lethal to polymorphonuclear leukocytes

(this is implicated in contributing to the invasiveness of staph aureus and suppression of phagocytosis)

43
Q

Hyaluronidase virulence factor works by ________.

A

Hydrolyzes hyaluronic acid in connective tissues to allow for easy spread of bacteria

44
Q

Virulence factor protein A (staph aureus) (2)

A
  1. Cellular component in the wall of staph aureus
  2. Able to buy into the FC portion of the antibody, inhibiting phagocytosis
45
Q

Staphylococcus epidermidis characteristics

A
  1. Gram positive cocci
  2. Coagulase negative (S. aureus is coagulase positive)
    3.
46
Q

Staphylococcus epidermidis is usually associated with which serious ophthalmic condition?

A

endolphthalmitis

47
Q

Almost all ______infections are hospital-acquired.

A

staphylococcus epidermidis

48
Q

Which microorganisms have acquired antibiotic-resistance through plasma mediated transfer?

A
  1. Staphylococcus epidermidis
  2. Staphylococcus aureus
49
Q

Chlamydia trachomatis characteristics

A
  1. Obligate intracellular parasite
  2. Most common STD
50
Q

Chlamydia trachomatis transmission (2)

A
  1. Eye discharge
  2. Eye-seeking flys
51
Q

Chlamydia trachomatis life cycle

A
  1. Alternates between a non replicating infectious elementary body and a replicating non-infectious reticular body
  2. incubation for 1-3 weeks
52
Q
A
53
Q

How do you diagnose chlamydia trachomatis?

A
  1. Apple green fluorescence on immunofluorescent slide
  2. Gram stain does not work well, but it looks like Gram-negative
54
Q

What does MOTT sound for?

A

Mycobacteria other than tubercle bacilli

55
Q

NTB

A

Non tuberculosis mycobacteria

56
Q

MOTT infection causes (3)

A
  1. Trauma
  2. Contact lens wear
  3. Wound contamination with soil and water
57
Q

Mycobacterium fortuitum causes which diseases (2)?

A
  1. Keratitis
  2. Corneal ulcers
58
Q

Eikenella corrodens characteristics

A
  1. Microaerophilic
  2. Gram-negative rods
  3. Normal flora of mucosal surfaces
59
Q

Eikenella corrodens culture requirements

A
  1. CO2 environment
  2. Hemin
60
Q

Please notify the lab if a wound is from the ______ (2).

A
  1. head or neck
  2. result of human bites
61
Q

Eikenella corrodens can develop into which disease(s)?

A

Orbital infections

(not typically associated with eye infections)

62
Q
A

Eikenella corrodens

(Note the pitting on the surface of the agar medium. This is where I can unlock where it ends gets its name due to the corroded appearance.)

63
Q

Francisella tularensis causes which disease?

A

Tularemia

(Highly infectious)

64
Q

Francisella tularensis causes

A
  1. Deer fly or tick
  2. Eating undercooked meat
  3. Handling rabbit carcass
    4.
65
Q

Tularemia symptoms

A
  1. Skin ulcers
  2. Swollen and painful lymph nodes
  3. Inflamed eyes, sore throat, mouth sores
66
Q

Francisella tularensis characteristics

A
  1. Gram negative coccobacilli
  2. Oxidase negative
  3. Urease negative
67
Q

Francisella tularensis is grown on _____.

A

Chocolate agar