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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
HSV Keratitis
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
Stromal HSV Keratitis
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
Epithelial HSV Keratitis
More common of HSV Keratitis types Usually no pain, but irritation and tearing common DENDRITIC ULCERS on corneal epithelium
28
VZV Recrudescence
Shingles outbreak from VZV in trigeminal will affect the eye in 50% of cases Sharp lines of demarcation on face with lesions
29
Adenovirus keratitis
Characteristic punctiform lesions on the cornea | punctiform= form of a point
30
What will be observed if scrapings from the cornea of an HSV infection are observed under a microscope?
Multinucleated giant cells
31
Treatment and outcomes of viral keratitis
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
Why is a central corneal ulcer that is not clearly due to HSV an emergency?
If not clearly due to HSV, it could be a bacterial infection. Bac. infections of the eye progress rapidly and cause damage quickly.
33
Causes of bacterial keratitis
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
Most common bacterial corneal pathogen in developing areas
Strep pneumoniae
35
Most common bacterial corneal pathogen in developed countries
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
What is quorum sensing
Some bacterial virulence factors are only expressed when the bacteria reach a certain density
37
What factors of contact lens use lead to increased chance of bacterial keratitis?
Soft contacts worse than others Extended wear Decreased O2 transmission Preserved solutions
38
Fungal keratitis
Usually only in immunocompromised or those using topical steroids in the eye Aspergillus Candida Fusarium solani
39
What should be suspected when a chronic case of keratitis does not respond to traditional therapy?
Acanthamoeba keratitis Usually only possible if there has been an abrasion of the corneal epithelium Therefore, generally unilateral
40
Most likely eye infection condition if patient's first complaint is visual field loss or lost visual acuity, and is most often unilateral
Retinitis or Chorioretinitis
41
Common infective agents of retinitis and chorioretinits
Viral: CMV, HSV, VZV Fungal: Histoplasma capsulatum Parasites: Toxoplama gondii, Toxocara canis/cati, Baylisascaris procyonis
42
CMV Retinitis
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
HSV and VZV retinitis
Generally only immunocompromised patients | Poor prognosis for sight retention even if immunocompetent
44
Ocular histoplasmosis syndrome
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
Exogenous Endophthalmitis
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
Endogenous Endophthalmitis
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
Components of immune privilege in the eye
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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