04-16 URI Flashcards
1. Identify the major infectious pathogens causing acute pharyngitis, acute bronchitis, and acute bacterial sinusitis. 2. Understand the clinical presentations of the principle syndromes associated with pharyngitis, bronchitis, and sinusitis. 3. Understand the differing biological pathways to clinical illness: receptor-mediated release of kinins in colds; invasive pyogenic bacterial infection with acute sinusitis; and immune-mediated rheumatic sequela in streptococcal pharyngitis. 4. Become f
CXR findings in pneumonia vs. bronchitis
Pneumonia: CXR w/ infiltrate
Bronchitis: normal or w/ peribronchial cuffing
Clinical presentation differences between viral and bacterial sinusitis
bacterial: more severe sx; more localized
viral: less severe sx; less localized (also present w/ or have h/o rhinorrhea, cough, +/- sore throat)
Red Flags on pneumonia imaging
—Kerley B lines (LHF)
—higher in lung? abscess? Ghon? (TB)
—multiple abscesses (SBE)
Major pathogens that cause acute pharyngitis? What is its clinical presentation of VIRAL pharyngitis? Diagnostics available? Epidemiology of principle cause?
PATHOGENS
—Tons: Rhino most common; 10% are Grp A Strep
—Viral: Rhino, Adeno, Para-flu, Flu, HSV, CoxA, EBV, CMV, HIV RSV (NOT Coronavirus)
—Bacterial: Grp A/C/G Strep, N. gon, Mycoplas, Chla. pneu, Corynebacterium diph, Arcanobacterium haemolyticum
CLINICAL PRESENTATION: Common Cold
—rhinorrhea/obst/sneeze; sore/scratchy throat; non-prod cough w/ Post-nas drip
—throat ery but no exudate; mild or no fever
—avg 1 week, but 25% last 2 wks; add 3 days for smokers
EPIDEMIOLOGY: Common Cold
—Rhino (most common): early fall or mid-spring; hand-to-hand transmission
—Corona (2nd) and RSV: winter;
—Incubation 2-3 days
Major pathogens that cause acute bronchitis?
—What is its clinical presentation?
—Epidemiology of principle cause?
—Treatment?
PATHOGENS
—MAJORITY = Viral: Rhino, Adeno, Flu A/B, Human metapnuemovirus, RSV
—Bacterial: Myco. pneu., Chla pneu., H.flu, Strep pneu., Branhamella catarrhalis
PRESENTATION
—cough for days-weeks +/- sputum +/- fevers
—crackles +/ wheezes but NO consolidation
MYCOPLASMA PRESENTATION
—cough: dry → green/yellow
—low-grade fever
—Pulm: rhonchi and coarse rales
EPIDEMIOLOGY
—Mostly viral
—Mycoplasma pneu (long incubation 3 wks w/ lots of sick contacts) and Chlamydia pneu on DDx
—Bordetella pertussis if outbreak
TREATMENT
—Supportive (consider albuterol or rapid roid taper)
—Abx (erythromycin or other macrolide like azithro or clarithro) only if highly-likely (exposure to infx’d person) or documented w/ IgM for M. pneumonia or PCR/culture of B. pertussis
Major pathogens that cause acute bacterial sinusitis? —What is its clinical presentation? —Diagnostics available? —Epidemiology of principle cause? —Treatment?
CAUSES
—Almost always rhino
—can also be acute bacterial (ACABS):
25-30% - Strep pneumo
15-20% - H. flu
15-20% - Moraxella catarrhalis (pedi)
< 5% for Strep pyo and < 5% for S. aureus
—or chronic bacterial:
Above + Staph, anaero Gm+, Gm- bacilli
—fungal in immunocompromised
PRESENTATION OF ACABS
—Usu overlap w/ URI
—Persistent cought, puruent boogers, h/a, FACIAL PAIN exacerbated by positional ∆s
—Bad breath w/ chronic
—Purulent discharge seen w/ otoscope, ↓ translum, pain w/ palpation
DIAGNOSIS —Gold Std: aspirate & culture —r/o allergic —Bacterial likely if classic sx (F >38°C, facial pain, erythema or swelling) OR if URI not improving after 10d —CT when suspect chronic
EPIDEMIOLOGY
—40-50% ACABS resolves spontaneously
TREATMENT
—Need to cover b-lactamase-producing H.flu, S.pneumoniae
—Amox-clav, cefuroxime, cefpodoxime; new quinolones (i.e. moxifloxacin)
—Anti-histamines and ibu, yes. Little evid. for Sudafed
Major pathogens that cause the common cold?
—30-50% rhinovirus —10-15% coronavirus —5-15% Influenza A/B —5% Parainfluenza —<5% Adenovirus —Also: RSV and human metapneumovirus
Pathophysiology of bacterial infection w/ acute sinusitis?
invasive, pyogenic infx
Pathophysiology post-infectious rheumatic disease?
immune-mediated
Pathophysiology of colds?
receptor-mediated release of kinins is the 1° cause of sx in common colds (i.e. those due to rhino)
—40% progress to viral sinusitis, but < 2.5% develop bacterial sinusitis
—triggers ~40% of asthma attacks in adults
—otitis media in kids or eustachian tube dysfxn in adults
Ibuprofen vs. APAP vs. ASA for common cold
choose ibuprofen; APAP and ASA may increase nasal s/sx, prolong viral shedding and decr. neutralizing Ab’s.
What is its clinical presentation of BACTERIAL pharyngitis? Diagnostics available? Epidemiology of principle cause? Treatment?
PRESENTATION
—abrupt onset
—painful swallowing
—systemic illness & malaise
—nasal congestion + cough in only 50%, not prominent
CENTOR SCORE
—Temp 100-104°F? +1
—Tonsillar exudate? +1
—Cervical adenopathy +1
—Absence of cough +1
—< 14 y/o +1
DIAGNOSIS
—Culture
—Rapid enzyme immunoassay (≥96% spec, only 80-90% sens)
EPIDEMIOLOGY
—Grp A Strep causes 5-15% sore throats in adults, and 20-30% in kids
TREATMENT
—P.O. PenV
—Erythromycin or other macrolide (clarith- or azith-romycin) if allergic to Pen
—IM Benzathine Pen x1 when compliance a problem
What is its clinical presentation of Infectious Mononucleosis pharyngitis? —Causative organisms? —Diagnostics available? —Epidemiology of principle cause? —Treatment?
PRESENTATION
—Exudative PHARYNGITIS/laryngitis in 1/2 of EBV-cases
—Systemic sx: FEBRILE, H/A, malaise, fatigue (usu signif)
—Onset: abrupt or w/ several day prodrome
—Cervical +/- systemic adenopathy
—Splenomegaly (50% pts)
CAUSATIVE AGENTS
—Usually EBV
—Also CMV, Toxoplasma gondii, and HIV
DIAGNOSIS —Lymphocytosis (atypical lymphocytes hallmark but not specific) —50% thrombocytopenia —Heterophile Ab's (e.g. monospot) —EBV-specific Abs
EPIDEMIOLOGY
—Prolly no epidemics
—Intimate contact
—2 age peaks: 0-5 y/o & 2nd decade (teens)
Antigenic Drift vs. Shift
shift (i.e. development of H1N1) is bigger ∆ than drift
Influenza Rx
—amantadine/rimantadine: reduces Flu A s/sx duration by 50%
—Neuraminidase inhibitors: oseltamivir and zanamivir
