Exam 4: Ear Infections Flashcards
What are the common etiologic agents of acute otitis media?
Strep pneumoniae, H. influenzae (non-typable), Moraxella catarrhalis, Viral (RSV, rhinovirus)
What are the characteristics of Strep pneumoniae?
Gram positive, diplococci (lancet shaped)
What can increase susceptibility to otitis media
chronic diseases: alcoholism, DM, chronic renal diseases
How is S. pneumoniae drug resistant?
Changes in the penicillin binding protein
What are virulence factors of S. pneumoniae
Capsule- blocks phagocytosis by interfering with complement, Choline binding proteins alters vascular permeability, Hydrogen peroxide- damage host cells and bactericidal, Neuraminidases- cleave host mucins, Pneumolysin- pore forming toxin, Iron acquisition proteins
What are the characteristic of H. influenze
gram-negative pleomorphic coccobacillus, anaerobic
How do you grow H. influenzae?
requires additional blood factors like NAD and hematin on chocolate agar
What is the penicillin resistance of H. influenzae?
Beta lactamases
What are characteristics of Moraxella catarrhalis
Gram-negative, aerobic, diplococcus, oxidase-positive, nonmotile, fastidious (chocolate agar), pili
What is the penicillin resistance in M. catarrhalis?
Produce beta lactamases
What are prevention strategies of acute otitis media?
Avoid cigarette smoke and sick children, breastfeed and avoid bottles before bed, wash hands frequently, stay up to date on vaccines
What is the recommended empiric treatment in 6 month-24 month olds? What does it cover?
Oral amoxicillin (provides coverage for Strep pneumoniae, H. influenzae)
If the patient to empiric treatment with amoxicillin, what should be added to the treatment?
Amoxicillin with clavulanate
What else can be prescribed, besides amoxicillin and clavulanate, to deal with a patient’s otitis media symptoms
Pain management (acetaminophen and ibuprofen) and decongestants
What is a good treatment for recurrent ear infections in children?
Ear tube insertion for recurrent infections
What are complications of otitis media?
Conductive hearing loss/delayed speech due to TM perforations, Cholesteatoma, Infection spreading to mastoid, inner ear, temporal bone and meninges
What is otitis externa also called?
Swimmer’s ear
What are risk factors for otitis media?
maceration- trauma, foreign bodies, excessive swimming, middle ear infxns, diabetes
What is the bodies natural defense to otitis media?
ear wax contains lysozymes and is slightly acidic to prevent microbial growth
What is the common etiology of acute localized otitis externa? Symptoms?
Staphylococcus; pustule or furuncle associated with hair follicles
What is the etiology of acute diffuse otitis externa? Symptoms?
Pseudomonas aeruginosa; itches, red ear canal, painful
What is the etiology of malignant otitis externa? Symptoms?
Pseudomonas aeruginosa; invasion of adjacent bone and cartilage which can progress to cranial nerve palsy and death
What populations is malignant otitis externa prevalent in?
Elderly, poorly controlled diabetes, immunocompromised
What are the fungal etiologies of otitis externa?
Aspergillus, Candida albicans
What is the management of otitis externa?
Cleansing with low pH topical solutions, don’t flush unless TM is intact, treat with analgesics (NSAIDs, acetaminophen), Topical antibiotics (unless cellulitis or fungal)- Ciprofloxacin + steroid, Neomycin + polymyxin + hydrocortisone
What is the bacterial cause of a patient who has green-yellow discharge from the eyes?
N. gonorrheae
What is the cause of patients with red, mild cold and clear drainage of the eyes?
Adenovirus
What is the cause of patients with visual field deficits, most commonly in HIV-infected individuals
CMV
What bacteria releases pneumolysin, a pore forming toxin?
S. pneumoniae
