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Unit 5- Semester 2 > Eye Infections 1 > Flashcards

Eye Infections 1 Flashcards

1
Q

Noncontagious inflammation of the lower portion of the eyelids and eyelashes

A

Blepharitis

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2
Q

Causes blepharitis

A

Poor eyelid hygiene
Excess oil produced by the glands in the eyelids

Bacterial infection: Staphylococcus aureus
Allergic reaction

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3
Q

Decryocystitis

A

Inflammation of the lacrimal sac

Partial or complete obstruction within the sac or nasolacrimal duct. Bacteria are trapped initiating acute or chronic infection
Older patients are predisposed d/t lacrimal drainage system loses elasticity & tears fail to flush debris

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4
Q

Conjunctivitis

A

Inflammation of the conjunctiva (Outermost layer of the eye covering the sclera)

Could extend to the eyelids
Cornea (keratitis)
Or sclera (episcleritis)
Progressive keratitis can lead to ulceration, scarring, and blindness

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5
Q

Bacterial conjunctivitis

A

Adults: Staphylococcus aureus

Both: (Streptococcus pneumoniae, Haemophilus influenzae)

infants: Neisseria gonorrhoeae

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6
Q

viral conjunctivitis

A

Viral usually associated with an upper respiratory infection

Cold, sore throat

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7
Q

Sx viral/ bacterial and allergic conjunctivitis

A 
Bacterial 
Stringy discharge
Swelling of the conjunctiva
Redness, tearing
Irritation (gritty feeling)
Can spread to other eye
Viral 
Watery discharge
Red eye
Irritation
Can spread to other eye

Allergic: both eyes, itching, swollen eyelids

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8
Q

Microorganisms that cause ophthalmia neonatorum

A

Microorganisms that typically cause this type of conjunctivitis are the sexually transmitted microorganisms which cause gonorrhea and chylamidia
Neisseria gonorrhoeae, Chlamydia trachomatis, Herpes simplex virus

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9
Q

Ophthalmia neonatorum

A

Ophthalmia neonatorum
Severe conjunctivitis of newborns
Can acquire the infection at birth

Microorganisms that typically cause this type of conjunctivitis are the sexually transmitted microorganisms which cause gonorrhea and chylamidia
Neisseria gonorrhoeae, Chlamydia trachomatis, Herpes simplex virus

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10
Q

Endophthalmitis

causative agents

A

Caused commonly by normal flora of the eyelids
Staphylococcus epidermidis
Caused less commonly by gram-neg microorganisms
Pseudomonas sp.
Prognosis poor

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11
Q

Endophthalmitis

A

Rare, intraocular infection
Infection of the aqueous or vitreous humor
Usually caused by bacteria or fungi
Occurs most commonly after cataract surgery

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12
Q

Etiological agent of Post-surgical endophthalmitis:

A

Pseudomonas

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13
Q

uveitis

description and types

A 
Inflammation or swelling of the eye structures responsible for the eye’s blood supply
Iris, ciliary body, choroid
Three types of uveitis
Iritis (or anterior uveitis)
Intermediate uveitis (cyclitis)
Posterior uveitis
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14
Q

Iriitis and periorbital cellulitis

A

Redness, pain, photophobia due to painful movement of inflamed iris
Blurred vision in severe inflammation

Periorbital cellulitis
Acute infection of the tissues surrounding the eye
Can lead to orbital cellulitis and protrusion of the eyeball
Complications include meningitis

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15
Q

Orbital Cellulitis common agents (bacterial)

A

Bacterial
Staphylococcus aureus, Staphylococcus epidermidis
Streptococcus pneumoniae, Streptococcus pyogenes
Haemophilus influenzae
Moraxella catarrhalis
Eikenella corrodens, Pasteurella multocida
Associated with dog bites
Mycobacterium tuberculosis
MOTT

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16
Q

Orbital Cellulitis agents (fungal and parasites)

A 
Common agents
Fungal
Rhizopus sp.
Aspergillus sp.
Penicillium sp.
Candida paropsilosis

Parasitic
Trichinella spiralis
Echinococcus granulosus
Fly larvae (maggots)

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17
Q

Haemophilus influenza

A 
Gram-negative, bacillus (rod)
Non-motile, non-spore forming
Fastidious, facultative anaerobe
Haemophilus – “blood loving”
Requires 2 erthrocyte factors for growth
X – hemin
V – nicotinamide adenine dinucleotide
Both of these factors are released from lysed RBCs
Therefore H. influenzae is grown on chocolate agar
Lysed erthrocyte medium

Resident of the nasopharyngeal mucosa
Sometimes in the conjunctivae, genital tract

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18
Q

H. Influenza Path. mech.

A

Attachment to respiratory epithelial cells is accomplished using pili
It is suggested that there is a coordinated response between attachment and capsular development
Endotoxin in the cell wall is toxic to ciliated respiratory cells

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19
Q

Nonencapsulated (or non-typeable) strains of H. influenza cause

A

Otitis media, conjunctivitis, bronchitis, pneumoniae

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20
Q

Dz caused by the most virulent H. influenza (capsulated)

A

6 serotypes (a-f) based on biochemically different capsules
Haemophilus influenzae type b (HiB)
Most virulent strain
Responsible for such infections as bacteremia, meningitis, cellulitis, septic arthritis, pneumoniae

21
Q

H. influenza spread

A

Eustachian tubes to cause otitis media
Sinuses – sinusitis
Respiratory tract to cause bronchitis and pneumoniae.

Patients with COPD and cystic fibrosis
Non-typeable H. influenzae can colonize the lower respiratory tract and exacerbate these conditions

22
Q

Srep. pneumoniae

A

Gram-positive, cocci
Usually seen in pairs (diplo), but occur singly and in chains
Non-spore formers, non-motile
Fastidious, grows in 5% carbon dioxide
Facultative anaerobe
Under optimal conditions, S. pneumoniae’s generation time is 20-30 minutes

23
Q

Srep. pneumoniae growth

A

Growth on blood agar medium results in alpha-hemolysis
Green zone in the agar medium surrounding the colonies
Represents partial hemolysis of red blood cells

24
Q

Strep. pneumoniae virulence

A 
Capsule
Determinant of virulence
Interferes with phagocytosis
Blocks C3b opsonization
Antipneumococcal vaccines are designed based on pneumococcal capsular antigens
25
Q

The reaction to identify S. pneumoniae

A

Quellung reaction
Serotyping used to identify a particular capsule type
90 capsular types identified
Forms the basis of antigenic serotyping
Antibody which reacts with a particular capsule type will cause capsular swelling

26
Q

Staphylococcus aureus id

A

Gram-positive cocci, clusters

Virulence factors
Cytolytic toxins- affect red blood cells and leukocytes

Alpha-hemolysin- destroys platelets and causes severe tissue damage

Beta-hemolysin- acts on the sphingomyelin of red blood cell membranes
Staphylococcal leucocidin: Panton-Valentine leukocidin
exotoxin lethal to polymorphonuclear leukocytes.

Implicated in contributing to the invasiveness of S.aureus and suppressing phagocytosis`

27
Q

Staphylococcus aureus virulence factors (enzymes)

A

Coagulase - a critical virulence marker

Hyaluronidase: hydrolyzes hyaluronic acid which makes up connective tissues. Allows for easy spread of infection

Lipases :Act on fats and oil secreted by sebaceous glands. Allows for colonization of the microorganisms

28
Q

Protein A

A

Virulence factor of S. aureus
A cellular component in the cell wall of S. aureus
Able to bind the Fc portion of the antibody, thus avoiding phagocytosis

29
Q

Staphylococcus epidermidis id

A

Gram-positive cocci
Coagulase-negative (Staphylococcus aureus is coagulase-positive)

Indigenous to mammals
Normal skin flora
Most prevalent and persistent species on human skin and mucosal surfaces
Comprise 60-95% of all staphylococcal species

30
Q

S. epidermidis Abx resistance

A

Antibiotic-resistance is plasmid-mediated
-via conjugation

Certain aminoglycoside-resistance genes have been transferred from S. epidermidis to other S. epidermidis and S. aureus species

Penicillin, macrolides, tetracycline, chloramphenicol, trimethoprim, aminoglycosides. With few exceptions, almost all S. epidermidis infections are hospital-acquired

31
Q

Chlamydia trachomatis

A

Obligate intracellular parasites
Deficient in independent energy metabolism
Most common STD in the world. Cause of blindness and infertility.

Trachoma: Due to infection by Chlamydia trachomatis
Transmitted through infected secretions: eye discharge
eye-seeking flies.

Inflammatory reactions results in scarring on the conjunctiva
Forces the eyelid to turn inward where the eyelashes can rub the cornea

32
Q

Chlamydia trachomatis life cycle

A

Life cycle
Alternates between a non-replicating, infectious elementary body and a replicating, noninfectious reticulate body.

Elementary body – dispersal form
Induces its own endocytosis with host cell
Once inside, it germinates into a vegetative, reticulate form

Reticulate body divides every 2-3 hrs
Incubation in host cell, 7-21 days
Reverts back to elementary bodies
Released from cell by exocytosis

33
Q

Chlamydia trachomatis

A

Immunofluorescence

Cell wall structurally similar to gram-neg; gram stain does not work well with this microorganism

34
Q

MOTT

A 
MOTT – (mycobacteria other than tubercle bacilli)
NTB (nontuberculous mycobacteria)
These infections are associated with
Trauma
Contact lens wear
Wound contamination with soil and water
Most common causes are
Mycobacterium chelonae
Mycobacterium fortuitum
35
Q

MOTT (mycobacteria other than tubercle bacilli)

A

NTB (nontuberculous mycobacteria)

These infections are associated with: trauma, contact lens wear, wound contamination with soil and water

Most common causes are:
Mycobacterium chelonae
Mycobacterium fortuitum

36
Q

etiological agent of

Keratitis and Corneal ulcers

A

M. fortuitum

37
Q

Eikenella corrodens

A

Microaerophilic, gram-negative rods.

Normal flora of human, mucosal surfaces
Culture requires CO2 environment and hemin in the medium.

Identification of this bacterium could be missed. For proper laboratory identification, lab must be notified if the wound is: head or neck result of human bites

Usually a part of a mixed infection, particularly with Streptococcus sp.

38
Q

Eikenella corrodens

is frequently associated with

A

chronic infections and abscess formation: orbital infections.

Not typically associated with eye infections
However, rare cases have occurred related to bite wounds.

Congenital lacrimal duct obstruction
Probing procedure resulted in an infection
Isolate identified as Eikenella corrodens

39
Q

Gets its name from the fact that it forms pits on the surface of agar medium on which it is grown
Gives it a corroded appearance

A

Eikenella corrodens

40
Q

Francisella tularensis
Path
Dx
Chrc

A

Chrc: gram - coccobaccilus, oxidase -, urease -, non motile
Path: tularemia (highly infectious- 10-50 organisms can infect)
Dx: growth on chocolate agar

41
Q

Tularemia

Sx and Path

A

Path: Francisella is primary a pathogen of squirrels and rabbits.
Humans infected by: bite of tick or deer fly, eating undercooked meat, handling infected rabbit carcasses

Sx: skin ulcers, swollen/painful lymph nodes, INFLAMED eyes, sore throat and mouth sores

42
Q

Cat scratch dz

agent andpt Hx

A 
Bartonella henselae (gram - bacillus)
Hx of exp to cats or being scratched
43
Q

Ocular Sx of cat scratch dz

A

Bartonella henselae
Parinaud’s oculoglandular syndrome ( conjunctivitis and neuroretinitis)
vitritis, pst uveitis
White retinal or choroidal lesions

44
Q

Moraxella catarrhalis

Characteristics

A

gram - diplococci
+ oxidase
Abx resistance: Penicilin, ampicillin, amoxicilin

45
Q

Moraxella catarrhalis
path
dx
Assoc infx

A

path: assoc with periorbital cellulitis, resp ( imp cause of bronchopulmonary inx), mid. ear, CNS, eye, joints

Dx: hocky puck test

Assoc infx: periorbital cellulitis

46
Q

HSV assc eye infections

A

Viral blepharitis (vesicles on lid margins and around the eye; later breaks open and forms lesions which can be come super infected by skin flora).

Occular herpes
Scleritis
infections of lacrimal apparatus
endophthalmitis

47
Q

Occular herpes

A

Caused by HSV(linsear, ds DNA, outer env)
HSV infx of conjunctiva
swelling of eylids
Herpes simplex Keratitis ( if cornea involved)–> destruction, ulceration and perforation of cornea [ denritic keratitis whn virus branches out in a dendritic pattern].

48
Q

Agents responsible for viral blepharitis, scleritis, infection of lacrimal apparatus, and endophthalmitis

A

HSV (in addition causes ocular herpes)- dsDNA w/ out env

Varicella zoster.
viral blepharitis: when then face is involved during chicken pox, then blisters form on the lid margins. wart like lesions (molluscom contagiosum) can form from the pox virus.

49
Q

Phalangeal conjunctival fever and epidemic keratoconjunctivitis are caused by:

A

adenovirus ( linear, dsDNA, icosah, non-env)

It also cause: tonsillitis, common cold, ear infx, conjunctivitis).

Unit 5- Semester 2 (2 decks)

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