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Micro Exam 5 > Lecture 54 Eye Infections > Flashcards

Lecture 54 Eye Infections Flashcards

1
Q

Orbital Cellulitis characteristics

A

Painful swelling of the eyelids
Globe looks normal, but has restricted/painful motion
Fever > 102

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2
Q

Orbital Cellulitis causes

A

Often a spread of infection from another location:
Sinusitis (90%) => Staph/Strep/H. influenzae spread
Fungal
Arthropod bite
Trauma
Complication of dental extraction
Septicemia

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3
Q

Treatment for Orbital Cellulitis

A

Hospital
IV antibiotics or antifungal
Surgery

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4
Q

Blepharitis signs/symptoms

A

Inflammation of the eyelid
Red/itchy/gritty/burning/foreign body sensation
Excessive tearing, or dry eye
Eyelashes matted, crusted, missing, or misdirected

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5
Q

Blepharitis Causes

A

Staph: most common, overgrowth of normal flora, usually bilateral
Virus: HSV, VZV, Molluscum Contagiosum, assoc. with lesions, usually unilateral
Ectoparasite: Follicle Mites, Crab Lice

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6
Q

Blepharitis Treatment

A 
Warm compress
Clean eyes regularly
Contacts can be worn
Antibiotic, antiviral, tea tree oil (mites)
Avoid steroids for viral infections
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7
Q

Hordeolum and Chalazion

A

Hordeolum: infection that is painful to palpation, usually caused by Staph
External Hordeolum: infection of gland of Zeiss
Internal Hordeolum: infection of Meibomian gland

Chalazion: granuloma formation in Meibomian gland, often not painful
can follow an internal hordeolum

Treatment: warm compress, generally resolve within days to weeks; otherwise, antibiotics or surgery can be implemented

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8
Q

Conjunctivitis

A 
Red/Pink Eye
Can have viral or bacterial cause
Adenovirus is most common
Usually self-limited to 2-4 weeks
Transmitted by secretions: hand to eye
Hand washing important for control
Viral infection tends to be >12 y/o, itching, burning, watery, FB sensation, lymphadenopathy, hemorrhaging, longer course
Bacterial infection tends to be
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9
Q

Follicular Conjunctivitis

A

Least severe type
Doesn’t involve the cornea
Usually caused by Adenovirus
Can be caused by HSV, VZV, Molluscum Contagiosum

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10
Q

Pharyngoconjunctival fever (PCF)

A

Adenovirus caused (Serotypes 3&7)
Follicular conjunctivitis with additional symptoms:
Fever, sore throat, headache, malaise
If bilateral, second eye becomes infected 1-3 days later and is less severe
Most often in kids

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11
Q

Epidemic Keratoconjunctivitis (EKC)

A 
Adenovirus caused (Serotypes 8, 19, 37)
Symptoms initially like PCF or the Flu
Subepithelial corneal infiltrates
Pseudomembrane may form
Transmitted on contaminated equipment in clinics
Rule of 8
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12
Q

Acute epidemic hemorrhagic conjunctivitis

A

Viral cause: Coxsackie virus A24, Enterovirus 70, (Adenovirus)
Acute onset, rapid course, self-limited 5-7 days
Subconjunctival hemorrhage prominent
Topical steroid use => bac superinfection
Assoc. with crowding and poor hygiene
More common in developing areas

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13
Q

Bacterial Conjunctivitis

A

Mucopurulent discharge

Actue: generally self-limited, antibiotics shorten course, but not necessarily needed
Common agents: S. aureus, S. pneumoniae, H. influnzae, Moraxella spp.

Hyperacute: more severe, requires systemic antibiotics
Spreads to cornea if untreated
Neisseria gonorrhoeae, menigitidis
Often concurrent infection with Chlamydia trachomatis

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14
Q

Inclusion conjunctivitis and trachoma

General info

A

Both caused by Chlamydia trachomatis (gram (-) obligate intracellular bacteria)

IC: serotypes D-K (assoc. with genital infections), named for inclusion bodies seen in infected cells, in neonates called neonatal conjunctivitis

Trachoma: serotypes A-C, can lead to complete vision loss, leading cause of preventable blindness in the world

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15
Q

Adult inclusion conjunctivitis

A

Usually unilateral, little to no discharge, transmitted by contact with infected fluids
Numerous papillae on lower conjunctival membrane
Scarring of cornea very rare

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16
Q

Trachoma general characteristics

A

Disease progression is slow
Lymphoid follicles and papillae develop on superior conjunctiva, papillae necrose and lead to scarring of the cornea and inversion of eyelids and lashes
Repeat infections required to lead to end stage blindness

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17
Q

Trachoma epidemiology

A

Assoc. with poverty and unsanitary conditions
Disease of the creche
Infection spread by vectors like flies, or infected fomites like dirty towels
Clean water and handwashing important to prevent trachoma and IC

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18
Q

Diagnosis of IC and Trachoma

A

Clinical signs

Scrapings and microscope looking for inclusion bodies

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19
Q

Treatment of IC and Trachoma

A

SAFE Strategy:
S: Surgery (limits scarring)
A: Antibiotics (Oral azithromycin, Topical Tetracycline) (IC only needs A)
F: Facial Cleanliness
E: Environmental Change (water supply and sanitation, improve community and personal hygiene)

20
Q

Most likely organism and mechanism of neonatal conjunctivitis (ophthalmia neonatorum

A

Conjunctivitis in newborns less than 28 days old generally caused by inoculation during delivery by:
Neisseria gonorrhoeae
Chlamydia trachomatis

21
Q

Ophthalmia neonatorum from Neisseria gonorrhoeae

A 
50% of kids born to infected mothers
Appears within 24-48 hours
Often bilateral
Purulent discharge
Rapidly destructive
Treat with systemic antibiotics
22
Q

Ophthalmia neonatorum from Chlamydia trachomatis

A

70% of kids born to infected mother
5-15 days after birth
Unilateral or Bilateral

23
Q

Keratitis general characteristics

A

Infection of the cornea
Unilateral, but can be bilateral
Severe pain, photophobia, impaired vision from scarred or damaged cornea
Correlated with use of immuno-suppressive agents for the eye

24
Q

Keratitis pathogens

A

Viral:
HSV 1
VZV (shingles)
Adenovirus

Bacterial:
S. pneumonia
Pseudomonas aeruginosa

Fungal:
Candida
Aspergillus
Fusarium solani

Parasitic:
Acanthamoeba

25
Q

HSV Keratitis

A

Leading cause of infectious blindness in developed countries => corneal transplant
Rare in kids, mostly adults
Many kinds: Stromal and Epithelial

Remember that HSV is known to remain latent in the trigeminal ganglia

26
Q

Stromal HSV Keratitis

A

More sever of the HSV Keratitis types
Two types:
Non-necrotizing: also known as Immune Stromal Keratitis (ISK)
Necrotizing: immune response to viral infection causes necrotizing damage to the cornea

27
Q

Epithelial HSV Keratitis

A

More common of HSV Keratitis types
Usually no pain, but irritation and tearing common
DENDRITIC ULCERS on corneal epithelium

28
Q

VZV Recrudescence

A

Shingles outbreak from VZV in trigeminal will affect the eye in 50% of cases
Sharp lines of demarcation on face with lesions

29
Q

Adenovirus keratitis

A

Characteristic punctiform lesions on the cornea

punctiform= form of a point

30
Q

What will be observed if scrapings from the cornea of an HSV infection are observed under a microscope?

A

Multinucleated giant cells

31
Q

Treatment and outcomes of viral keratitis

A

Common treatment is Acyclovir or ganciclovir
HSV keratitis will resolve without treatment, but treatment can minimize corneal damage
Shingle patients need treatment within 3 days of lesion appearance

32
Q

Why is a central corneal ulcer that is not clearly due to HSV an emergency?

A

If not clearly due to HSV, it could be a bacterial infection.
Bac. infections of the eye progress rapidly and cause damage quickly.

33
Q

Causes of bacterial keratitis

A

S. pneumonia and Pseudomonas aeruginosa
Bacterial infections of the cornea are not common, require a breach of the cornea from:
Surgery=> dry eyes
Abrasions
Or, just wearing contacts and allowing growth of Pseudomonas

34
Q

Most common bacterial corneal pathogen in developing areas

A

Strep pneumoniae

35
Q

Most common bacterial corneal pathogen in developed countries

A

Pseudomonas aeruginosa
Contact wearers–can live in some disinfectants, can’t otherwise bind to normal cornea without contact lenses
Formation of hypopyon (collection of leukocytes in anterior chamber)

36
Q

What is quorum sensing

A

Some bacterial virulence factors are only expressed when the bacteria reach a certain density

37
Q

What factors of contact lens use lead to increased chance of bacterial keratitis?

A

Soft contacts worse than others
Extended wear
Decreased O2 transmission
Preserved solutions

38
Q

Fungal keratitis

A

Usually only in immunocompromised or those using topical steroids in the eye
Aspergillus
Candida
Fusarium solani

39
Q

What should be suspected when a chronic case of keratitis does not respond to traditional therapy?

A

Acanthamoeba keratitis
Usually only possible if there has been an abrasion of the corneal epithelium
Therefore, generally unilateral

40
Q

Most likely eye infection condition if patient’s first complaint is visual field loss or lost visual acuity, and is most often unilateral

A

Retinitis or Chorioretinitis

41
Q

Common infective agents of retinitis and chorioretinits

A

Viral: CMV, HSV, VZV

Fungal: Histoplasma capsulatum

Parasites: Toxoplama gondii, Toxocara canis/cati, Baylisascaris procyonis

42
Q

CMV Retinitis

A

Characteristics: Opportunistic infection of immunocompromised patients
Often an end-stage condition in AIDS patients leading to blindness
Left untreated=> permanent retinal damage and blindness

Diagnosis: Characteristic lesions– “Cheese Pizza” lesions on the retina, these are large patches of red (hemorrhage) and white (necrosis) on the retina
No inflammation in the vitreous humor

Symptoms: Blind spots, blurred vision, floaters, dec visual acuity, loss of peripheral vision, can be asymptomatic

Treatment: Antivirals injected or implanted, often Ganciclovir or Fomivirsen
Surgery to treat retinal detachment

43
Q

HSV and VZV retinitis

A

Generally only immunocompromised patients

Poor prognosis for sight retention even if immunocompetent

44
Q

Ocular histoplasmosis syndrome

A

Fungal infection of the retina caused by Histoplasma capsulatum
Endemic in the midwest and south central US
Often asymptomatic, symptoms don’t appear until years after infection
Rare condition, resembles macular degeneration
Histo-Spots = tiny scares of inflammation on the retina

45
Q

Exogenous Endophthalmitis

A

Infection involving several layers of the eye and the vitreous/aqueous humors

Post-operative: most cases
Coagulase (-) staph–good prognosis
S. aureus, enterococci, Bacillus–poorer prognosis

Post-traumatic:
Staph most common, Bacillus cereus 2nd

46
Q

Endogenous Endophthalmitis

A

Usually immune compromised
Most common underlying disease: DM II
2nd most common: IV Drug use
Immunosuppressive meds

Break down of blood-ocular barrier=> infection

Fungal >50% of the time–C. albicans

Bacterial:
Gram (+): coagulase neg Staph, Bacillus
Gram (-): Klebsiella, E. coli,

47
Q

Components of immune privilege in the eye

A

Lack of blood and lymph vessels
Lack of MHC I receptors, but expression of HLA-G/E that suppress the function of NK cells
Increased expression of FAS ligand (used to signal apoptosis, helpful to tune down an immune response)
Anti-inflammatory/immunosuppressive proteins in the aqueous humor
ACAID–Anterior Chamber-Assoc. Immune Deviation

Micro Exam 5 (8 decks)

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