Flashcards in Felton: Ear infections Deck (26):
What are some normal flora of the external ear?
about the same as the oily areas of the skin. Staphylococcus sp., mainly epidermidis, also Micrococcus, Corynebacterium, Propionibacterium
What typically causes acute diffuse external otitis? What are the clinical symptoms? some predisposing factors?
-caused by: almost always Gram-negative organisms, especially Pseudomonas aeruginosa. Proteus vulgaris and fungi are frequent secondary invaders
-predisposing? Elevated environmental humidity, High temperature, Maceration of skin following prolonged exposure to moisture, local trauma, Introduction of exogenous bacteria, especially Pseudomonas
-symptoms: Fullness, itching, pain, hearing loss due to occlusion of lumen, Erythema, green-tinted serous discharge***
What causes bullous external otitis (hemorrhagic external otitis)? what are some signs and what does it need to be differentiated from?
-normally pseudomonas aeruginosa
-Clinical signs - hemorrhagic bullae on osseus canal walls; rupture of bullae causes bloody discharge.
-differentiate from middle ear infection because this won't have a previous respiratory infection
What can result from untreated diffuse ottitis extern? What does this look like? What normally causes it?
-Granular external otitis
-Skin of meatus is raw and coated with scanty creamy pus and granulations on osseous meatus
-Proteus and Pseudomonas aeruginosa
-culture and sensitivity
What is the most serious case of external otitis? What normally causes it? What is a predisposing factor?
-necrotizing external otitis
-usually Pseudomonas aeruginosa alone; occasionally mixed.
-Predisposing factors - diabetes (plus diffuse external otitis which fails to heal)
-Necrosis with granulation tissue on floor of external auditory canal at junction of osseous and cartilaginous canals. It may spread through the clefts, expose bone and cartilage and spread into deep tissues, and even cause osteomyelitis and meningitis.
What are some infections of the outer ear caused by gram positive bacteria? what 2 gram + bacteria tend to cause these?
-Furuncle and carbuncle - Staphylococcus aureus
-abscess - usually Staphylococcus aureus
-Cellulitis - Streptococcus or Staphylococcus
-Erysipelas - Group A beta-hemolytic Streptococcus
-Ecthyma - Group A beta-hemolytic Streptococcus with an occasional coagulase-positive Staphylococcus aureus as secondary invader
-Impetigo Contagiosum - Group A beta-hemolytic Streptococcus or coagulase-positive Staphylococcus aureus
-Infectious eczematoid dermatitis, a consequence of perforated otitis media. The discharge from the primary affected area will irritate, sensitize, or infect adjacent skin. Etiology usually Staphylococcus aureus.
What are some characteristics of acute otomycosis? causes? predisposing factors? symptoms?
-caused by Apergillus niger and other fungi such as Mucor
-predisposing factors: hot weather, use of ear drops containing antibiotics and/or steroids over a period of weeks
-symptoms: early=itching and fullness, Lumen filled with waxy debris, and a velvety gray pseudomembrane lines the skin of the meatus and the tympanic membrane, Wet mount will show fungi, neutrophils, and epithelial cells
What are some causes of chronic or recurrent otomycosis? Symptoms? Predisposing factors?
-Etiology Aspergillus, Mucor, yeastlike fungi, dermatophytes, miscellaneous fungi
-Signs and Symptoms - at first asymptomatic, then itching, then mild pain, a slight seropurulent discharge and mild hearing loss
-Predisposing factors:chronic bacterial infection, foreign body or necrotic tumor, secondary to purulent discharge of the middle ear.
-Otoscope may reveal filamentous fungi and spores.
What are some predisposing factors to otitis media?
1. Upper Respiratory Tract Infection
2. Age of Child
3. Previous Otitis Media
5. Cigarette smoking by parents
6. Abnormality of middle ear or Eustachian tube
7. Exposure to other children in day care or to a sibling with recurrent otitis media
Why are middle ear infections more commonly seen in children than adults?
1. The Eustachian tube in adults enters the nasopharynx at an angle of up to 45 degrees from the horizontal; in children it enters an an angle of around 10 degrees from the horizontal.
2. In infants and young children, the amount and stiffness of the cartilage supporting the Eustachian tube is less than in older children and adults.
3. The Eustachian tube is longer in adults than in children.
What is the most important feature of the pathogenesis of infection of the middle ear?
Dysfunction of the Eustachian tube because of anatomical or physiological factors
How can viruses and bacteria enter the middle ear?
No normal flora, but bacteria and viruses may enter through the Eustachian tube or get to the middle ear via the lymphatics or blood.
What are some characteristics of Acute suppurative otitis media?
-common in children over 6 weeks.
-predisposing factors: Upper respiratory tract infection, Previous otitis media, age (6months-24 months for first attack), allergy, parental cigarette smoking, abnormal eustachian tube, child around other kids with otitis media.
-causes: Streptococcus pneumoniae (most common -35%), Haemophilus influenzae (25%), Moraxella catarrhalis (4-13%
-symptoms: unilateral, abrupt onset of fullness, pain and fever, reddening and bulging of the tympanic membrane, moderate leukocytosis,
-pathogenesis: upper resp infections 5-10 days before blocks eustachian tube--> negative middle ear pressure=> aspiration of organisms into tube=> infection, inflammation, swelling b/c neutrophil migration, increase pressure (may cause TM perforation)
How is Acute suppurative otitis media diagnosed?
-Signs and symptoms
-normally NOT aspirated for culture unless unsatisfactory clinical response or an unusual pathogen is suspected
-test for presence of fluid in the middle ear: pneumatic otoscope, tympanometry, acoustic reflectometry
What is the treatment for Acute suppurative otitis media?
Acetaminophen or ibuprofen for pain and fever
Appropriate antibiotics, 10 days or more
May need to do myringotomy to relieve pain and pressure; if so, perform cultures and antibiotic sensitivities from pus on sterile knife
What are some sequelae of acute suppurative otitis media?
acute mastoiditis or labyrinthritis from extension
What can cause acute suppurative otitis media in a newborn?
Streptococcus pneumoniae and Haemophilus influenzae, and organisms associated with neonatal sepsis, especially coliform organisms. Staphylococcus, or Chlamydia trachomatis
When is a culture essential in acute suppurative otitis media?
In the neonate, culture is essential for identification and antibiotic susceptibility testing
What is an importance virulence factor of streptococcus pneumonia?
capsule --> makes it look gooey on the culture (mucoid)
Is H. influenzae encapsulated? How is it grown in culture?
grown with factor X and V
What is Prevnar?
Conjugated 13-valent anti-pneumococcal vaccine
Intended to prevent invasive pneumococcal disease (meningitis and bacteremia) in young children
Side benefit is a 7% reduction in acute otitis media
What are some characteristics of Chronic Otitis Media with Effusion (OME) (Serous otitis media, secretory otitis media)?
Etiology, perhaps allergy, or virus infection, or previous acute suppurative otitis media. In one third of cases bacteria are present in the fluid - the same organisms that cause acute otitis media.
Predisposing factors - complete obstruction of Eustachian tube.
Usually there is a mild-to-moderate conductive hearing loss which is resolved with resolution of the middle ear effusion
What is the treatment for OME? Sequela?
-management of underlying allergy, infection, or obstruction
-WATCHFUL WAITING (no antibiotics or surgery for up to 3 months)
-myringotomy and tympanostomy tubes (after 4-6 months of hearing loss and no healing)
Sequela (rare)- glue ear (adhesive otitis media) - fluid becomes more viscous and adhesive, may be invaded by fibroblasts resulting in immobilization or destruction of ossicles and permanent hearing loss.
What is recurrent otitis media?
more than three acute episodes in six months
same etiology as acute otitis media but S. aureus may occur if there is a rupture of the TM
What can happen with an untreated case of chronic otitis media?
-anatomic changes in the structure of the middle ear that persist even in the absence of fluid in the middle ear cavity.
-Almost always associated with central or anterior perforation and mastoid infection.
-The skin of the external auditory canal and surface squamous epithelium of tympanic membrane may grow through the aperture and invade the middle ear.
-Symptoms and signs. There is pus, yellow to gray, and often extrusion of cheesy or greasy cholesteatomatous material.
-Often associated with Gram-negative bacteria, but may get periodic superinfection with pyogenic bacteria.
-Requires surgery to repair.