Microbio Quiz: eye infections

Streptococcus Pneumoniae: gram

gram-positive lancet shaped dilococci

Streptococcus Pneumoniae: virulence

polysaccharide capsule, pneumolysin

Streptococcus Pneumoniae: infections

bacterial conjunctivitis (pink eye)

keratitis

Streptococcus Pneumoniae: clues

painful central ulcer, hypopyon

Haemophilus Influenza: gram

gram-negative coccobacillus

Haemophilus Influenza: virulence

IgA protease, mucosal adherance

Haemophilus Influenza: infections

purulent conjunctivitis

Haemophilus Influenza: clues

thick purulent discharge, common in children

Adenovirus: family

• adenoviridae

• dsDNA

• non-enveloped

Adenovirus: infections

viral conjunctivitis, keratoconjunctivitis 

Adenovirus: clues

watery discharge, lymphadenopathy, highly contagious

HSV1: family

herpesviridae, dsDNA, enveloped

HSV1: infections

herpetic keratitis, blepharoconjunctivitis

HSV1: clues

dendritic corneal ulcers on fluorescein

VZV (herpes zoster opthalmicus): family

herpesviridae, dsDNA

VZV (herpes zoster opthalmicus): infections

HZO, keratitis, conjunctivitis, uveitis

VZV (herpes zoster opthalmicus): clues

unilateral rash, hutchinson sign, corneal involvement

Acanthamoeba spp.: family

free living amoeba (not technically family)

Acanthamoeba spp.: infections

acanthamoeba keratitis

Acanthamoeba spp.: clues

• severe pain out of proportion

• ring infiltrate

• linked to contact lenses & contaminated water

Conjunctivitis: etiology

• adenovirus (most common viral)

• staph. aureus

• streptococcus pneumoniae

• haemophilus influenza

Conjunctivitis: symptoms

redness, irritation, tearing, purulent or watery discharge

Conjunctivitis: diagnosis

clinical; swab only if severe or recurrent

Conjunctivitis: treatment

• viral: hygiene/lubrication

• bacterial: topical antibiotics

Conjunctivitis: prevention

hand hygiene, avoid sharing towels/cosmetics

Conjunctivitis: notes

viral = feeling of sand in the eye

bacterial = purulent in the morning. allergic

Blepharitis: etiology

staph. aureus, eyelid margin inflammation

Blepharitis: symptoms

red swollen eyelids, crusting at eyelashes

Blepharitis: diagnosis

clinical

Blepharitis: treatment

warm compresses, eyelid hygiene ± topical antibiotics

Blepharitis: prevention

daily eyelid cleaning in predisposed individuals

Blepharitis: notes

other types of disease = seborrheic dermatitis or demodex infestation or Meibomian obstructed glands

Keratitis

• corneal infection

• vision-threatening

Keratitis: etiology

• pseudomonas aeruginosa → contact lens users (most dangerous type)

• staph. aureus

• streptococcus pneumoniae

• HSV-1

Keratitis: symptoms

pain, photophobia, corneal opacity/ulcer

Keratitis: diagnosis

slit-lamp exam + corneal scraping (microscopy, culture, PCR)

Keratitis: treatment

intensive topical antibiotics; antivirals for HSV

Keratitis: prevention

proper contact lens hygiene

Herpes Zoster Opthalmicus (HZO): etiology

reactivation of VZV in ophthalmic nerve (V1)

Herpes Zoster Opthalmicus (HZO): symptoms

unilateral vesicular rash, eye pain, photophobia

hutchinson sign: lesion on nose tip = high cornea risk

Herpes Zoster Opthalmicus (HZO): diagnosis

clinical; PCR if needed

Herpes Zoster Opthalmicus (HZO): treatment

systemic antivirals + pain control

Herpes Zoster Opthalmicus (HZO): prevention

zoster vaccination in older adults

Endophthalmitis:

• severe intraocular infection inside the eye (aqueous + vitreous humours)

Endophthalmitis: etiology

• staph. epidermidis

• staph. aureus

• pseudomonas aeruginosa

• candida spp.

Endophthalmitis: symptoms

sudden pain, redness, vision loss, hypopyon

Endophthalmitis: diagnosis

urgent ophthalmologic exam

vitreous + aqueous sampling

Endophthalmitis: treatment

intravitreal antibiotics ± vitrectomy in severe cases

Endophthalmitis: prevention

strict aseptic technique in ocular procedures