W15 URTIs Flashcards
rhinosinusitis - background
Incidence
Patho
SXS
Duration
Diagnosis
Etiology
incidence: affects ~1 in 8 adults annually
95% is viral!!!!!
pathogenesis: inflammation and infection of the nasal cavity and paranasal sinuses, resulting in
● rhinorrhea, nasal obstruction
● cough
● headache
● fever
varying duration of symptoms
● acute: < 4 weeks
● sub-acute: > 4 to 12 weeks
● chronic: > 12 weeks
diagnosis: clinical. CT can indicate inflammation but doesn’t
typically guide treatment (ie, supportive vs antibiotics)
viral (~95%): give supportive care
● rhinovirus
● influenza
● parainfluenza
● enterovirus
● adenovirus
● RSV
other than anti-influenza agents (which we’ll
cover later), there are no mainstream antiviral
agents to treat most cases of rhinosinusitis;
supportive care is key - review Wk 14 material (eg,
intranasal decongestants and corticosteroids)
bacterial (~5%)
● Streptococcus pneumoniae
● Haemophilus influenzae
● Moraxella catarrhalis
● Staphylococcus aureus
fungal (rare) - Aspergillus, Mucor
When to suspect and treat bacterial rhinosinusitis
S/S
ABX preferred empiric therapy?
Alternatives
Avoid?
likely bacterial if…
signs/symptoms persist > 10 days without improvement
severe signs/symptoms at onset:
● high fever, purulent discharge, and facial pain lasting for ≥3 consecutive days at the beginning of illness
● double-sickening (recovery from initial symptoms for several days followed by the return of similar/worsening symptoms)
empiric antibiotic therapy
● preferred: amoxicillin-clavulanate (Augmentin)
● alternative: doxycycline, levofloxacin, moxifloxacin
● severe infection requiring hospitalization (IV agents preferred):
ampicillin-sulbactam, levo/moxifloxacin, ceftriaxone, cefotaxime
● avoid macrolides d/t S.pneumo resistance
cultures are difficult to obtain and unlikely to be used to drive definitive treatment, so initial antibiotic choice and dosing is important
Pharyngitis
Presentation
Exam findings
Microbiology — etiology?
What should you rapid test for?
—sore throat that’s worse w/ swallowing
—low-grade fever is possible
other symptoms of URTI (eg, rhinorrhea, sinus or ear pain), but not typically associated w/ cough
exam findings
● inflamed pharynx, tonsils, and palate
● petechiae (suggestive of Grp A Strep)
● greyish exudate
● tender anterior cervical lymphadenopathy
viruses (~90%)
● rhinovirus
● adenovirus
● influenza
● enterovirus
bacterial (<10%)
● Streptococcus pyogenes (Group A strep, or GABHS, or GAS) if >3yo
● Chlamydia pneumoniae
● Mycoplasma pneumoniae
● can be sexually-transmitted, ie, N.gonorrhoeae
● S.pneumoniae and H. influenzae do not typically cause pharyngitis
Note:
after clinical diagnosis, your main goal is to determine whether it’s GAS, since it’s easily treatable with antibiotics and since you also want to prevent complications (ie, acute rheumatic fever, RHD)
● Rapid antigen test - fast turnaround time (15 min), most commonly used
● Rapid PCR – highly specific and sensitive, slower turnaround time (60 min)
● Throat culture if high suspicion but negative rapid antigen test
What is the Center Scoring System?
What is it evaluating?
What are the criteria?
pharyngitis treatment IF bacterial (90% is viral!)
Preferred
Alternative
Regardless of cause, what else to consider?
antibiotics for GAS
preferred:
●⭐️ IM penicillin G (Bicillin™) x1 dose
● ⭐️PO penicillin VK x 10 days
● ⭐️PO amoxicillin x 10 days
alternatives:
● cephalexin
● azithromycin
regardless of cause, also consider:
● saltwater gargle for soothing effect
● anesthetic sprays and lozenges (ie, benzocaine)
● analgesics (ie, acetaminophen, NSAIDs)
● not typically recommended, yet often used: short-course
corticosteroids
Scarlet fever
Patho
S/SXS — 2 main ones
pathogenesis
● typically accompanies pediatric strep pharyngitis (arise from 1 out of 10 cases)
● mediated by streptococcal pyrogenic exotoxin
● less common in the US in recent years, recent outbreaks in China and the UK
s/sxs (in additional to what you’d see w/ pharyngitis)
● sandpaper-like rash:
—by second day of illness
—spreads from upper trunk to extremities (spares the palms and soles)
—Pastia’s lines - more accented in skinfolds
—subsides after ~1 week, followed by desquamation of palms and soles
● “strawberry tongue” (similar to Kawasaki disease) and circumoral pallor
treat as you would strep pharyngitis (prev slide)
peritonsillar abscess (aka PTA or quinsy)
Invasive procedures
Which ABX?
the most common deep head and neck infection, usually arising from tonsillitis or pharyngitis
invasive procedures
● needle aspiration - easiest and most commonly done
● incision and drainage
● tonsillectomy
antibiotic treatment
like pharyngitis, but also consider anaerobes like Fusobacterium
● ⭐️preferred: amoxicillin-clavulanate or IV ampicillin sulbactam
(Augmentin or Unasyn)
● alternative: clindamycin
Acute otitis media (AOM)
Incidence
Risk factors
Patho
Hx
Diagnosis
PE: tympanic membrane, what do you see?
Rare complication
incidence:
most common infectious disease of childhood (affects up to 75% of children before the age of 2)
risk factors
● <2 years of age
● abnormal eustachian tube anatomy
● immunodeficiency
● environmental allergens, pollutants
pathogenesis:
congestion of the respiratory mucosa in the nasopharynx
and eustachian tube → obstruction of eustachian tube → aspiration of respiratory pathogens into the middle ear → infection and inflammation
history:
—recent URTI or allergic rhinitis
—otalgia, aural pressure, decreased hearing
—concomitant nasal congestion, headache, and/or fever
tympanic membrane on exam
● erythematous, engorgement of vessels
● opacification, loss of light reflex
● decreased mobility
● bulging suggests presence of middle ear empyema
● rupture and spillage of purulent material into the canal, can appear like otitis externa
Rare complication
—see image
AOM —
Microbiology
Treatment
viral (most cases, self-limiting)
● RSV
● influenza
● parainfluenza
● rhinovirus
● adenovirus
(aka, the same stuff that causes rhinosinusitis)
bacterial
● ⭐️Streptococcus pneumoniae (35% of cases)
● Haemophilus influenzae
● Moraxella catarrhalis
unless there is exudate due to TM perforation,
Gram stains and cultures are difficult to obtain
and unlikely to be used to drive definitive
treatment, so initial antibiotic choice and dosing
is important
most cases resolve without antibiotic therapy
and require only supportive care (ie, analgesics, decongestants)
NOTE: there is no topical analgesic for the ear
“watch and wait” approach (defer antibiotics
for 48-72h)
● recommended for mild disease in otherwise healthy children
● preferred over “just-in-case” antibiotic prescribing
antibiotics are NOT recommended in children >6 months who
● do not have severe symptoms (eg, moderate-severe otalgia >48h or febrile >102.2°F), and
● are not at high risk of complications (eg, abnormal
eustachian tube anatomy, immunodeficiency)
AOM - when to consider antibiotics
<6 months
6-23 months
>2 years
AOM
Which preferred abx?
Alternatives
Duration
preferred: high-dose amoxicillin
● ⭐️amoxicillin 80-90 mg/kg/day
● amoxicillin/clavulanate 90 mg/kg/day if patient received amoxicillin within 30 days or previously failed amoxicillin
alternatives:
cefdinir, cefuroxime, cefpodoxime, ceftriaxone, azithromycin
duration of treatment:
● <2 years: 10 days
● 2-5 years: 7 days
● >6 years: 5-7 days
FYI: all based on amoxicillin component
pediatric amoxicillin-clavulanate
dosing is based on amoxicillin component
various formulations exist (know these rules
exist, no need to memorize for this class)
● for “high-dose” regimens (ie, 80-90 mg/kg/day), use the 14:1 formulation
(amoxicillin 600 mg/clavulanate 42.9 mg)
● for “standard dose” regimens (ie, 45
mg/kg/day), use 4:1, or 7:1 formulations
● the 4:1 formulation is divided to q8h,
while 7:1 and 14:1 are given q12h
otitis externa - background
Presentation
Microbiology
Treatment for mild/moderate/severe?
What do you need to cover for?
infection of the external auditory canal
Presentation
● painful erythema and edema of the ear canal skin
● possible purulent exudate
● recent history of water exposure (“swimmer’s ear”) or
trauma (scratching, Q-tips)
● in diabetic or immunocompromised patient, worse case
scenario can lead to osteomyelitis of the skull base
(“malignant external otitis”)
Microbiology: definitely bacterial
● Gram-negative bacteria (eg, Proteus, Pseudomonas)
● Fungal, incl Candida and Aspergillus (bottom-right image)
Mild
—antiseptic rinse + hydrocortisone 7 days
Moderate
—antiseptic rinse + corticosteroid + antibiotic 7 days
Severe
—antiseptic rinse + corticosteroid + antibiotic 7-14 days
If concern for malignant otitis externa, give systemic antibiotics with ⭐️good Pseudomonas coverage (and consider CT to r/o bone involvement)
otitis externa - topical treatment options
acidifying/antiseptic solution
—acetic acid 2%
—50/50 mix of isopropyl alcohol and white vinegar (can DIY this at home, great for prevention)
corticosteroids
—hydrocortisone (mildest)
—dexamethasone
—fluocinolone
antibiotics w/ GNR coverage
—aminoglycoside (eg, neomycin/polymyxin B)
—fluoroquinolones (eg, ciprofloxacin, ofloxacin)
(tend to be pricier but more tolerated)
combination products (more convenient)
—acetic acid/hydrocortisone
—ciprofloxacin/dexamethasone
—tobramycin/dexamethasone
—ciprofloxacin/hydrocortisone
—neomycin/polymyxin B/hydrocortisone
—neomycin/colistin/hydrocortisone
—gentamicin/prednisone
topical agents - treatment tips
❏ clear debris before applying topical meds, consider irrigation and suction
❏ protect from additional moisture and mechanical injury (ie, scratching)
❏ administration
● use drops abundantly (ie, 5 drops 3-4 times a day) to penetrate into the canal
● if significant edema of canal, use a wick to facilitate delivery of the meds
● administration isn’t easy; consider the help of a friend or loved one
● move outer ear back and forth for better penetration, lie for 3-5min after administration
❏ ⭐️if perforated TM ⭐️
● FQs > aminoglycosides (theoretically ototoxic)
● suspensions > solutions (low pH can can cause pain inflammation)
● acetic acid and vinegar can also cause discomfort
❏ ophthalmic agents are typically safe for the ear (if otic options not available)
❏ there is no FDA-approved topical analgesic for the ear
Influenza
transmitted via respiratory droplets
incubation period: 1-4 days
diagnosis via throat or nasal swabs
● rapid influenza diagnostic tests (RIDT) -widely available, high specificity but lower sensitivity (60-70%)
● reverse-transcriptase PCR - high sensitivity and specificity, differentiates between influenza A and B and different subtypes
● viral culture - high sensitivity and specificity, takes longer and not realistic for common use
unnecessary antibiotic prescribing
at least 28% of antibiotics prescribed in
the outpatient setting are unnecessary
(ie, not indicated) and contribute to local
resistance patterns
highest numbers of outpatient antibiotic
prescribing occur in the winter months
the most commonly prescribed antibiotics
are azithromycin and amoxicillin
acute respiratory tract infection (ARTIs)
are the most common indications for
which antibiotics are overprescribed
tips for unnecessary antibiotic prescribing
