M6 Ear Infections Flashcards
What is the pathogenesis, the manner of development, of external ear infections?
There are two common pathogenesis:
1. Trauma including excessive moisture, damage to canal surface and ear wax.
2. Infection from middle ear can drain into external ear canal.
What damage of the internal ear is a pathogenesis to ear infections?
Deformed or defective eustachian (auditory) tube
What other body area infections can lead to inner ear infections (pathogenesis)?
Upper respiratory infections can lead to secondary infections in the ear.
What clinical manifestations of acute otitis externa can spread easily to the pinna?
inflammation of external auditory canal which can spread
to the pinna
What organisms could cause acute otitis externa of the pinna in the form of furuncle formation?
Localized infection of the pinna include furuncle formation
(like a superficial wound)= same pathogens:
Staphylococcus aureus/ Streptococcus pyogenes
What organism is likely to cause a diffuse infection related to softening of tissue due to swimming or hot/humid environment?
Diffuse infection is related to softening of tissue due to
swimming or hot/humid environment: Pseudomonas
aeruginosa or other GNB could play a role.
What can cause a chronic ear infection?
Chronic infections can occur from the irritation of drainage from the middle ear.
What area of the ear is affected in Otitis media?
Inflammation of area behind the eardrum (tympanic membrane)
What are the 3 conditions for inflammation behind the eardrum (or Otitis media) to occur?
3 conditions must be met
* adherence to nasopharynx
* entry to eustachian tube
* multiply at site
Who is Otitis media (or infections behind the eardrum) common in?
Most common in children.
What organisms are involved in Otitis externa and Otitis media chronic infections?
Externa: P. aeruginosa; anaerobes
Media: anaerobes
What organisms are involved in Otitis media disease?
Streptococcus pneumoniae,
Haemophilus influenzae
Moraxella catarrhalis
S. pyogenes
Respiratory syncytial virus
Influenza virus
What organisms are known to cause Acute Sinusitis in Young adults?
Young adults:
Haemophilus influenzae
Streptococcus pneumoniae
Streptococcus pyogenes
Moraxella catarrhalis
What organisms are known to cause Acute Sinusitis in children?
Children
S. pneumoniae
H. influenzae,
M. catarrhalis
Rhinovirus
What other body part is the Indigenous normal flora of the ear similar to?
Sparse & similar to conjunctiva
What organisms are more commonly found in the external ear canal?
Organisms more commonly found in external ear canal:
1. Strep. pneumoniae
2. Cutibacterium acnes
3. S. aureus
4. Enterobacterales
5. Candida spp.
6. Occasionally P. aeruginosa
Are middle ear infections typically diagnosed in the lab?
Usually, middle ear infections not diagnosed in Lab.
How are specimens for external otitis collected for the lab from the patient? What is the ideal method?
- External otitis: disinfect area and collect fluid after, specially
after spontaneous perforation of eardrum. - Ideal: needle aspiration (tympanocenthesis) of middle ear
What media are used to culture organisms suspected of causing ear infections?
External and Internal
* Choc (CA), BA, Mac (some labs add more selective media: PEA)
* direct smear
If an aspirate specimen from the ear is done, what additional type of culture can be done?
- If aspirated, anaerobic culture can be done (not on external swabs)
What are unacceptable specimens from the ear?
Unacceptable:
leaking,
improper transport media or time (less than 24 hours,
>2 hours refrigerate), clerical errors, etc
From the culture plates for external ear infection how do you determine significance of growth?
Determine significance of growth by:
* organism isolated
* amount of growth
* purity of culture
* All these factors combined will lead to lab protocol (varies)
Correlate growth with direct smear.
From the culture plates for internal ear infection how do you determine significance of growth?
Determine significance of growth by:
* organism isolated
* amount of pure growth if normal skin flora
Correlate growth with direct smear.
What and when do you report if there is no growth on the plates for external swabs? internal swabs?
External: 48 hours incubation before calling “no growth”
Internal: 72 hours incubation before calling “no growth”
When is an AST performed for an ear infection specimen for external and internal swabs?
AST to do if applicable to the organism
