Infectious Corneal Conditions Flashcards
What type of agar is gonoccocal keratoconjunctivitis cultured on?
- Chocolate Agar
2. Thayer-Martin Medium
WIT: Hyperacute conjunctivitis w/ alot of purulent discharge. Eyelid edema, conj hyperemia/chemosis, lymphadenopathy, peri corneal ulceration w/ central extension
Gono Keratoconjunc.
How do you treat gonoccocal keratoconjunctivitis?
- Topical FQ (moxi or gati)(q1h)
- IM Ceftriaxone
- Tx underlying infection & screen for chlamydia
- Erythro, Tetra, Doxy
When would you send a patient to the hospital w/ gonoc. kerato. ?
If their cornea perforates
This bacteria is found in soil, vegetation, moist environments in hospitals, GI tract. Gram (-)
Pseudomonas Aeruginosa
This bacteria has been linked to 60% of bacterial keratitis and known to be commonly found in CL wearers
Pseudomonas Aeruginosa
Corneas are made more susceptible to pseudomonas by what 3 things?
- Hypoxia
- Trauma
- Surface Disease
What type of bacteria is pseudomonas aeruginosa?
Gram (-) bacillus (rod)
What is the main risk factor for Acanthamoaeba? Where is it mainly found?
Soft contact lens wear
Water
Pt presents with paracentral ring-like stromal infiltrate, epithelial haze w/ defects, dendritiform ulcers, uveitis and the beginning of scleritis. What is it?
Acanthamoeba infection
What’s the first thing you should do to an acanthamoeba patient to help with drug penetration in the eye?
Debride epithelium to help w/ drug penetration
What’s contraindicated in acanthamoeba patients?
Steroids
WIT: Allergic, cell-mediated response; often hypersensitivity to staph. exotoxin; found mainly in young patients
Phylctenular Keratoconjunctivitis
What is phlyctenular kerato. caused by?
- Staph Blepharitis
- Tuberculosis
- Helminth (worm)
- Rosacea
What are the main signs of Phlyctenular Keratoconjunctivitis?
- Small white nodule at limbus
- Conj. injection
- Corneal ulceration or neo
- Scar of healed phlycten
How do we treat Phlyctenular Keratoconj.?
- Treat specific etiology
2. Topical steroid/antibiotic combo (helps w/ healing)
How long does it take for phlyctenular kerato. to resolve?
2-3 weeks
What is the incubation period for inclusion conjunctivitis?
1 week
How is inclusion conjunctivitis transmitted?
- Systemic chlamydial infection is transmitted by autoinoculation
Chlamydia cells cannot ___ extracellularly; they depend on host cells.
replicate
Inclusion Conjunctivitis presents how?
- Subacute onset
- Uni or Bilateral Redness
- Watering
- Discharge
Inclusion Conjunctivitis Signs:
- Watering/Mucopurulent Discharge
- Large Follicles in Inf. Fornix & Tarsal Conj
- Peripheral Infiltrates (2-3 wks after onset)
- PAN swelling
Established inclusion conjunctivitis will have what signs?
- Less follicles, some papillae
- mild conj. scarring
- Superior pannus
What disease is the leading cause of preventable blindness in the world assoc. with poverty, overcrowding and poor hygiene?
Trachoma
WIT: Chronic, conjunctival inflammation caused by C.Trachomatis (chlamydial family)
Trachoma
What is the most important vector in Trachoma?
Flies
How can trachoma be directly transmitted?
From eye or nasal discharge
What are the signs of the active Trachoma disease?
- Mixed follicular/papillary rxn
- Mucopurulent discharge
- Herbert Pitts
- Sup. epithelial keratitis & pannus
What are the signs of the chronic Trachoma disease?
- Linear conj. scars (mild)
- Arlt’s LIne
- Upper Tarsus involvement
WIT: Superior conjunctival follicles at the upper limbus that may resolve and leave shallow depressions
Herbert’s Pitts
WIT: Thick band of scar tissue in the conjunctiva of the eye, near the lid margin, that is associated with eye infections
Arlt’s Line
What are the complications of Trachoma?
- Trichiasis/Distichiasis
- Corneal vascularization
- Entropion
- Dry Eye
How can we PREVENT trachoma?
Regular face washing and control of flies
How can we TREAT trachoma?
- Single dose Azithromycin 1g
- Z-Pak (if 1g is too strong)
- Erythromycin (for preg)
What’s the purpose of surgery in trachoma?
Relieving trichiasis and maintaining complete lid closure
WIT: Inflammation of the corneal stroma without primary involvement of the epithelium or endothelium
Interstitial Keratitis
Interstitial keratitis is most commonly associated with what disease?
Congenital Syphillis
What are the other causes of interstitial keratitis?
- Lyme Disease
- TB
- Leprosy
- Parasitic/Viral infection
When/How does interstitial keratitis present from congenital symphillis?
Between the ages of 5-25 years w/ acute bilateral pain and severe blurred vision
All patients w/ IK should have ___ ___ to determine is syphilis is involved.
Treponemal Serology
What are the signs of IK?
Limbitis, Anterior Uveitis, Keratitis
What is the treatment for IK?
- Systemic PCN (if active)
- Topical Steroids
- Cycloplegic
What is the most common external ocular viral infection found in hospitals, schools and factories?
Viral Keratoconjunctivitis
Viral keratoconjuncitivitis is from ___ types of adenoviral infection found on dry surfaces.
51 types
Viral shedding may occur __-__ days before clinical disease is apparent and about ___ days after that.
4-10 days
12 days
What is the #1 type of viral keratoconjunctivitis?
EKC
What are the adenovirus serotypes for EKC?
8, 19, 37
What are 3 ways EKC is transmitted?
- Hand to Eye
- Instruments
- Solutions
Keratitis develops in what percent of EKC patients?
80%
What are the clinical signs of EKC?
- Eyelid Edema
- PAN Swelling
- Follicles
- Pseudomembranes w/ subconj hemorrhage
Stage 1 of EKC is how many days from onset? What ocular effect is found?
7-10 days from onset
PEK (resolves in 2 wks)
- contagious stage
Stage 2 of EKC; What ocular effect is found?
Subepithelial Opacities (corneal infiltrates) ,, Centrally
Stage 3 of EKC; What ocular effect is found?
Anterior Stromal Infiltrates (takes a long time to go away)(not contagious)
What’s the rule of 8 for EKC:
- Adenovirus 8
- 8 day latency between exposure & onset
- 8 days of PEK (contagious)
- 8 days of SEIs (not contagious)
Pharyngeal conj fever is adenoviral serotypes __ and __.
3 and 7
PCF is found in patients who have had a ____ recently?
Upper respiratory tract infection
What is the major cause of unilateral corneal scarring worldwide?
HSV (mainly HSV-1 = more common)
What is the most common infectious cause of corneal blindness in developed countries?
HSV
Reactivation of HSV is due to?
- Fever
- Hormonal change
- UV radiation
- Trauma
- Trigeminal Injury
What are the risk factors for HSV?
- Atopic eye disease
- Children
- AIDs
- Malnutrition
- Measles
- Malaria
- Abuse of steroids
What are the signs of HSV?
Central dendrite
Terminal Bulbs
Decreased corneal sensation
How do you treat HSV even though it spontaneously heals?
- Topical Antivirals (Zirgan)
- Oral Antivirals
- Debridement of dendrite
What is contraindicated in HSV?
Steroid use
What is the goal of treating HSV?
Heal with scarring of cornea
What are the 2 etiologies of disciform keratitis?
- HSV infection of keratocytes or endothelium
2. Hypersensitivity to viral antigen in the cornea
WIT: A patient presents with gradual onset of blurred vision with halos around lights.
Disciform keratitis
What are the signs of disciform keratitis?
- Central stromal edema
- KPs
- Wessley Ring
- Uveitis
How do we tx disciform keratitis?
If near visual axis, topical steroids w/ antiviral cover for at least 4 weeks… after 1 month topical steroid daily
HZV are found in patients of what age?
6th-7th decade
HZV affects what percentage of adults in the US population?
> 95%
What is the tx for HZV?
high dose of oral antivirals (acyclovir, famciclovir, valacyclovir)
What antiviral medication is best for HZV? Why?
Famciclovir = better bioavailability
Prodromal phase last how many days before the rash starts?
3-5 days
How does a HZV rash appear?
Red, maculopapular vescicles
When do the vesicles appear?
within 24 hours and come together over 2-4 days
When does the vesicles become pustular and dry up?
2-3 weeks
WIT: Enterovirus 70 infection. Seen in the tropics and warm climates. Rare in US. Pt presents w/ unilateral or bilateral acute red eye, tearing FBS, highly contagious
Acute Hemorrhagic Conjunctivitis
How do we treat acute hemorrhagic conjunctivitis?
Self-limiting, runs 2-3 weeks
Cold compresses
What is contraindicated in acute hemorrhagic conjunctivitis?
Steroids
What are the 6 bacteria that can penetrate an intact epithelium?
- N. Gonorrhea
- H. Influenzae
- N. Meningitis
- C. diphtheriae
- Listeria
- Shigella
How do we treat a bacterial ulcer?
4th gen FQ and add broad spectrum coverage (Tobramycin)
What is the major cause of vision loss in tropical and developing countries?
Fungal Keratits
What are the 2 types of fungi?
Filamentous
Yeast
Which type of fungi can penetrate the intact descemet’s membrane and perforation is common?
Filamentous fungi