Microbiology II Flashcards
What are the different sites for eye infections?
Conjunctiva: conjunctivitis
Eyelid: blepharitis
Iris: Irisitis
Cornea: keratitis
Iris, ciliary body, choroid (uvea): uveitis
Sclera: scleritis
Aqeous or vitreous humor: endophalmitis
Retina: retinitis
Choroid and Retina: Chorioretinitis
What is Blepharitis? Symptoms? Most common infectious cause?
Inflammation of eyelid margin
- *Symptoms:**
- Itchiness
- redness
- can lead to lid thickening and loss of eyelashes
Cause:
Staph aureus
Treatment:
Lid scrubs
warm compress
Severe: topical or oral antibiotics
What is Conjunctivitis? Symptoms? Causes?
Inflammation of the conjunctiva
Symptoms:
Red eye
Pain, burning, sandy and/or gritty feeling in eye
Discharge with eye “stuck shut” in morning
Viral Causes:
Adenovirus *most common*
HSV
Measles
Varicella
Bacterial Causes:
Staphylococcus aureus
Strep pneumoniae
Haemophilus influenzae
How do symptoms and treatment differ between bacterial and viral conjunctivits?
Bacterial: treat with topical Abx
Usually unilateral
Purulent discharge
Purulent discharge appears soon after wiping lids
Min to severe conjunctival edema
Node not typical
Discharge continuous
Viral: Topical lubricating agent
Typically bilateral
Watery or mucoserous discharge
Profuse tearing
little edema
Preauricular lymph node common
Discharge improves in AM
What is Keritis? Symptoms? Causes?
Infection of cornea
Symptoms:
Red eye
foreign body sensation
photophobia
trouble keeping eye open
corneal opacity
infiltrate
Causes:
Bacterial (S. aureus, Pseudomonas, Corynebacteria, chlamydia, more)
Virus (adenovirus, HSV1)
Fungi (fusarium)
Protozoa (Acanthamoebae)
Helminths (onchocerca volvulus)
Keritis require urgent referral to an opthalmologist
What is trachoma? What is the pathogenesis?
**Bacterial keritis** due to **Chlamydia Trachomatis** #1 infectious cause of blindness
Ocular serovars A, B, Ba, C
Pathogenesis:
Recurrent palpebral conjunctivitis that scars
–> contraction of eyelid and inturnign of eyelashes (entropion)
–> eyelashes scratch cornea (trichiasis)
Overtime: keratits, corneal opacification, and blindness
What are some common causes of external eye disease in newborns?
Chlamydia trachomatis
Neisseria ghonnorhea
HSV
What is endophthalmitis? Symptoms? Treatment?
Inflammation of vitreous or aqeous humor
Symptoms:
Decreasing vision
eye ache
fever uncommon
decreased visual acuity
hypopyon (layering of WBC in anterior chamber)
view of retina is hazy
Causes: (usually bacterial or fungi)
Complication of surgery (post-cataract)
Post-traumatic
Hematogenous spread
What can cause acute, subacute, or chornic endophthalmitis due to complication of surgery?
acute:
S. epidermidis
S. aureus
Strep species
Subacute:
Aspergillus (uncommon)
dimorphic fungi
**Chronic:** Propionibacterium acnes (G+ rod)
What is Chorioretinits? Causes?
Inflammation of choroid and retina
Congenital:
Toxoplasmosis
CMV
Adults: (esp. immunocompromised)
Virus: HSV, VZV, CMV
fungi: candida, aspergillus, histoplasmosis, fusarium
protozoa: toxoplasmosis
helminths: toxocara canis
bacteria: mycobacteria tuberculosis
What is otitis externa? Symptoms? Common causes?
- *Inflammation of external auditory canal**
- -> only skin lined cul-de-sac in body
- -> predisposed to becoming moist, dar, warm
Symptoms:
Ear pain
Discharge
Signs:
Pain upon application of tragal pressure (pulling ear)
ear canal edematous and erythematous
possible debris in ear canal (yellow/brown/white)
Tympanic membrane: mobile (may be red)
Causes:
Pseudomonas aeruginosa
Staph aureus
Fungal (candida, aspergillus)
What are risk factors for otitis externa?
Local trauma
foreign objects
high environmental temperatures
chronic skin disease
Excessive moisture
(swimmer’s ear)
What is Otitis media? Symptoms? Causes?
infection of middle ear
Symptoms:
Ear pain
hearing loss
vertigo
ear discharge (perforated ear drum)
fever
Findings of tympanic membrane:
Erythematous
Opaque
Bulging or immobile (fluid in middle ear)
Causes:
Bacteria: Strep pneumoniae, H. influenzae, Moraxella catarrhalis, pseudomonas aeruginos
Virus: RSV, rhinovirus, influenza, adenovirus
What is the pathogenesis of otitis media?
- Inflammation of nasopharynx due to infection or allergy
- Congestion of nares and eustachian tube with obstruction of eustachian tube
- Secretions produced by middle ear accumulate in middle ear space
- Growth of viruses or bacteria that colonize the upper respiratory tract
What is the usual cause of sinusitis?
Usually due to viruses causign a cold (viral rhinosinusitis)
Small percentage are bacterial
