Eye Infections Flashcards
Defense mechanisms of the eye (2)
- Tears: Lysozyme, IgA
- Conjunctiva: barrier protection, blood supply
Blepharitis definition
Non-contagious inflammation of the eyelash follicles and tiny oil glands along the margins of the eyelid
Dacrocystitis definition
inflammation of the lacrimal sac
(elderly are at a risk as their system loses elasticity)
Three types of conjunctivitis
- Bacterial
- Viral
- Allergic
What is unique to bacterial conjunctivitis compared to viral and allergic?
Stringy discharge
What is a unique symptom of viral conjunctivitis compared to bacterial and allergic?
Watery discharge
What is a unique symptom of allergic conjunctivitis compared to viral and bacterial?
Typically affects both eyes
Define opthalmia neonatorum
Severe eye infection contracted in the birth canal of a woman with gonorrhea or chlamydia
(organisms: N. gonorrhoeae, C. Trachomatis, HSV)
Endophthalmitis definition & prognosis
Inflammation of internal tissues of the eye
Orbital cellulitis definition
- Diffuse infection of tissues in the orbit
- causes grossly swollen eyelids and red eye
Haemophilus influenzae: characteristics
Gram-negative rod
Nasopharyngeal mucosa resident
Haemophilus influenzae pathogenesis (3)
- Polysaccharide capsule (type B capsule is Polly ribitol phosphate) - most virulent factor
- IGA protease
- Pili attachment of respiratory epithelial cells
Haemophilus influenzae growth requirements (2)
- X (hemin) and V (NAD) from lysed RBCs
- use of chocolate agar
Streptococcus pneumoniae
- Gram positive diplococci
- Catalase negative
- Alpha-hemolytic
- Encapsulated IGA protease
Streptococcus pneumoniae colony morphology
Alpha hemolytic on blood agar
Endophthalmitis treatment
- Typically requires surgery
- usually hospitalization
(usually caused by bacteria or fungi)
Endophthalmitis causative organisms (2)
- Normal flora of the eyelids (epidermidis)
- Gram-negative microorganisms (pseudomons, poor prognosis)
Uveitis definition
Inflammation or swelling of the eye structure is responsible for the eyes blood supply
Structure is responsible for the eyes’ blood supply (3)
- Iris
- Ciliary body
- Choroid
Iritis symptoms
- Photophobia
- Blurred vision in severe inflammation
(also common sx: redness, pain)
Uveitis: 3 types
- Iritis
- Intermediate uveitis (cyclitis)
- Posterior uveitis
What is a complication of periorbital cellulitis
It can lead to orbital cellulitis and develop into meningitis
How do microorganisms gain entry into the orbit?
- Trauma
- Surgery
- URI
- Dental caries
(drainage system is not very effective)
Haemophilus influenzae characteristics
- Gram-negative
- Bacillus, rod
- Fastidious
- Facultative anaerobe