ophthalmology Flashcards
Conjunctivitis summary
Conjunctivitis (pinkeye) is a very common inflammation of the conjunctiva (the mucus membrane that lines the inside of the eyelids and the sclera). It is most commonly caused by viruses or bacteria but can also have noninfectious (e.g., allergic) causes. It is also commonly associated with corneal inflammation (then referred to as keratoconjunctivitis). Conjunctivitis is the most common cause of ocular hyperemia. Other classic features are burning, foreign body sensation, excessive tearing, and photophobia. Additionally, in infectious conjunctivitis, general signs of viral or bacterial infection (e.g., fever) may be seen, while itching is particularly common in allergic conjunctivitis. Dry eye is a hallmark feature of keratoconjunctivitis sicca. In most cases, local pharmacologic therapy with anti-infective, anti-inflammatory and/or antiallergic agents is sufficient. However, bacterial conjunctivitis can lead to blindness in newborns; therefore, strict and rapid treatment and prevention is vital. Surgical intervention is only rarely useful or necessary (e.g., correction of eyelids). An important differential diagnosis of conjunctivitis is subconjunctival hemorrhage, which is a collection of blood between the conjunctiva and the sclera that typically appears as a focal, red region on the surface of the eye.
Conjunctivitis
Clinical features
General signs and symptoms of conjunctivitis
Conjunctival injection: conjunctival hyperemia with dilatation of blood vessels → ocular hyperemia and reddening
Discharge and crust formation
Chemosis: edema of eyelids and/or conjunctiva.
Burning or foreign-body sensation
Photophobia
Itching (most intense in seasonal allergic conjunctivitis)
differential between bac and viral conjunctivitis on table.
Virala conjunctivitis
Epidemiology
Most common type of conjunctivitis
Incidence rises during the late fall and early spring
Etiology: adenoviruses (most common), herpes simplex virus (HSV), varicella-zoster virus (VZV), picornavirus, molluscum contagiosum, HIV (highly contagious), measles, zika
Epidemic keratoconjunctivitis (“pinkeye”)
Pathogen: specific adenovirus subtypes
Transmission: direct contact, fecal-oral route, or contaminated water (e.g., swimming pools)
Pharyngoconjunctival fever (PCF)
Pathogen: adenovirus 3
Transmission: direct contact, fecal-oral route, or contaminated water
Herpes simplex conjunctivitis
Pathogen: usually HSV-1 in children (most common) and adults (HSV-2 infection may occur in neonates)
Transmission: close personal contact with inoculation into conjunctiva
Clinical features
See “Clinical features” above
Epidemic keratoconjunctivitis
Sudden onset, fulminant course (lasts 7–21 days)
Subconjunctival and petechial hemorrhage
Eyelid ecchymosis
Multifocal epithelial punctate keratitis → anterior stromal keratitis
Unilateral preauricular lymphadenopathy
Increased lacrimation
Severe cases
Membrane or pseudomembrane formation → conjunctival scarring
Anterior uveitis
Vision loss (rare)
Pharyngoconjunctival fever: fever, pharyngitis, acute follicular conjunctivitis (unilateral or bilateral), tender preauricular lymphadenopathy
Herpes simplex conjunctivitis
Vesicular blepharitis
Dendritic epithelial keratitis of cornea or conjunctiva
Endothelialitis, trabeculitis, or uveitis
Diagnosis
Clinical diagnosis + history of upper respiratory infection, if present
Conjunctival smear and cultures (or viral isolation) if symptoms are recurrent/chronic
Treatment
Adenovirus: usually supportive (application of cold and moist compresses, artificial tears)
Herpes simplex: topical antiviral (e.g., ganciclovir)
Topical antibiotics if bacterial superinfection is suspected
Prognosis: usually self-limiting
Prevention: disinfect hands and instruments, avoid sharing towels, shaking hands, or touching eyes
Patient education regarding proper hygiene is essential to prevent an outbreak!
Bacterial conjunctivitis
General
Etiology: Staphylococcus aureus (most common in adults), Streptococcus pneumoniae, Haemophilus influenzae, Pseudomonas, Haemophilus, and Moraxella catarrhalis
Clinical features: see “Clinical features” above
Diagnosis
Clinical diagnosis
Conjunctival scrapings and culture (or PCR) required if persistent or severe disease (i.e., multiple or large corneal lesions), if the diagnosis is uncertain, and in newborn conjunctivitis
Treatment: Topical broad-spectrum antibiotics (e.g., erythromycin or trimethoprim-polymyxin B)
Special recommendations in newborn conjunctivitis
Neisserial and chlamydial infections require systemic treatment
Prevention
Proper hygiene
Treatment of pregnant women and prophylaxis in newborns
Public health programs (e.g., mass treatment)
Bacterial conjunctivitis
Neisserial conjunctivitis
Etiology
Pathogen: Neisseria gonorrhoeae
Route of infection (highly contagious)
Young, sexually active adults: direct contact to contaminated secretions (e.g., from the genitalia to the hand to the eye)
Newborns: perinatally
Clinical features
See “Clinical features” above; hyperacute conjunctivitis with marked eye swelling and profuse purulent discharge
Also preauricular lymphadenopathy
Diagnosis: gram stain shows intracellular gram negative diplococci
Treatment: IV or IM ceftriaxone plus oral azithromycin with saline irrigation (topical antibiotics may also be considered)
N.gonorrhoeae infection is an ocular emergency that can lead to keratitis, perforation, and blindess without prompt treatment!
Neisserial conjunctivitis
Trachoma (Granular conjunctivitis)
Etiology
Infection with Chlamydia trachomatis type A-C
Route of infection: direct (human-to-human contact with eyes or nose) or indirect (flies or towels) contact
Epidemiology
Most common cause of blindness due to chronic scarring worldwide
Predominantly affects young children and women
Clinical features: see “Clinical features” above
Can be divided into two stages which may occur simultaneously
Active phase : conjunctival follicles (with eventual involution forming Herbert pits), inflamed upper tarsal conjunctiva
Cicatricial phase : chronic/recurring inflammation in both eyes → conjunctival scarring → progressive conjunctival shrinkage → corneal ulcers and opacities, superficial neovascularization with cellular infiltration (corneal pannus), entropion, trichiasis
Diagnosis: clinical diagnosis
Treatment/Prevention
Antibiotics
Drug of choice: single oral dose azithromycin
Alternative: topical tetracycline (for six weeks)
Surgical intervention (eyelid correction in trichiasis)
Hygienic measures (particularly facial cleanliness) and environmental improvement (e.g., supply of clean water)
Prognosis: good (if treated early)
SAFE strategy (WHO) - Surgery, Antibiotics, Facial cleanliness, Environmental improvement
Inclusion conjunctivitis
Inclusion conjunctivitis (paratrachoma)
Epidemiology: more common in industrialized countries
Etiology
Pathogen: Chlamydia trachomatis types D–K
Route of infection: sexually , perinatally, or via swimming pools,
Clinical features: see “Clinical features” above
Conjunctival follicles
Papillary hypertrophy
Corneal pannus
Preauricular lymphadenopathy
Treatment/prevention: oral azithromycin, erythromycin, or doxycycline
Ddx:
Subconjunctival haemorrhage
