clinical correlations #4 med micro 2008 upper respiratory tract infections
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Upper Respiratory Tract InfectionsUpper Respiratory Tract Infections
Divya Ahuja, M.D.
November 2008
Clinical correlations #4
Med Micro 2008
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Burden of URIBurden of URI
Significant morbidity anddirect health care costs
Direct costs of $ 17
billion annually
Occasionally leads tofatal illness
Excessive use of
antibiotics a major issue
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The Common ColdThe Common Cold
s Children average 8 per year, adults 3s Parainfluenza isolated in 1955s Rhinoviruses 30 to 35%; coronaviruses about 10%,
miscellaneous known viruses about 20%, presumedundiscovered viruses up to 35%, group A streptococci 5% to
10%s Seasonal variation
Rhinovirus early fall Coronavirus- winter
s Day cares are culture medias Sinusitis often present by CT scan; rhinosinusitis might be a
better term
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s Common symptoms are sore throat, runny nose,
nasal congestion, sneezing,
s Sometimes accompanied by conjunctivitis,
myalgias, fatigue
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The common coldThe common cold
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Transmission of rhinovirusesTransmission of rhinoviruses
s
Direct contact is the most efficient means oftransmission: 40% to 90% recovery from
hands.
s Infectious droplet nuclei
s Brief exposure (e.g., handshake) transmits in
less than 10% of instances
s Kissing does not seem to be a common mode
of transmission.
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Clinical characteristicsClinical characteristics
s Incubation period 12-72 hours
sNasal obstruction, drainage, sneezing,
scratchy throat
s Median duration 1 week but 25% can last 2weeks
s Pharyngeal erhema is commoner with
adenovirus
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Diagnosis and treatmentDiagnosis and treatment
s Main challenge is to distinguish between uncomplicatedcold and streptococcal pharyngitis or bacterial sinusitis Good examination
s Marked exudate suggests Streptococcal infection
Adenovirus Diphtheria
s Rapid antigen tests for group A streptococcuss Rapid techniques for influenza, RSV, parainfluenzas Treat with NSAIDs and whatever else your grandmother
advises
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Acute bacterial sinusitisAcute bacterial sinusitis
s Viral infection--> obstruction of ducts and compromiseof mucocilary blanket--> acute infection from virulentorganisms (most often S. pneumoniae andH.influenzae)--> opportunistic pathogens
s Nose blowing generates high intranasal pressures that
deposit bacteria into the sinus cavitys Complicates 0.5% of common URI
s More common in adults than in children
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Paranasal sinusesParanasal sinuses
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Waters view (left); Coronal CTWaters view (left); Coronal CT
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Acute sinusitis: complicationsAcute sinusitis: complications
sMaxillary: usually uncomplicated
sEthmoid: cavernous sinus thrombosis(40% mortality)
s Frontal: osteomyelitis of frontal bone;cavernous sinus thrombosis; epidural,subdural, or intracerebral abscess;
orbital extension
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Acute sinusitis: complications (2)Acute sinusitis: complications (2)
Sphenoid: Rare, but usually misdiagnosed,with grave consequences; extension to internal
carotid artery, cavernous sinuses, pituitary,
optic nerves; common misdiagnoses include
ophthalmic migraine, aseptic meningitis,
trigeminal neuralgia, cavernous sinus
thrombosis
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CaseCase
s BR 59 year old white female
s Diplopia and left temporal headache
s Thought to have temporal arteritis
s
Started on Prednisone 100mg once dailys Noted to have 6th nerve palsy
s MRI 9/03 normal
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CaseCase
s Persistent headaches
s CT 10/03 normal, ESR 12 (on steroids)
s Repeat MRI 3/04 showed (2.3/1.5cm) mass in the left
orbital apex involving the sinus
s Developed left Ptosis, left fixed dilated pupil and left
2nd to 6th nerve palsies
s CT head showed 1.5/2 cm hypo dense mass in the left
basal ganglia
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Chronic sinusitisChronic sinusitis
Bacterial: Cultures show a variety of
opportunistic pathogens including
anaerobes but problem is mainly anatomic,
not microbiologic Fungal: suspect especially when a single
sinus is involved; syndromes associated
with nasal polyposis can have high
morbidity
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Spectrum of fungal sinusitisSpectrum of fungal sinusitis
Simple colonization
Sinus mycetoma (fungus
ball)
Allergic fungal sinusitis
Acute (fulminant) invasive
sinusitis (notably,
rhinocerebral mucormycosis)
Chronic invasive fungalsinusitis
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Otitis externaOtitis externa
Acute, localized: often S. aureus or
S. pyogenes Acute diffuse (swimmers ear):
gram-negative rods, especiallyPs.aeruginosa
Chronic: mainly with chronic otitismedia
Malignant: life-threateninginfection in diabetics;Pseudomonas
aeruginosa
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Malignant otitis externaMalignant otitis externa
Diabetes mellitus
Pseudomonas
aeruginosa
Osteomyelitis ofthe temporal bone
Involvement of
vital structures atbase of brain
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Acute otitis mediaAcute otitis media
s S. pneumoniae andH. influenzae theleading causes in all age groups
s Moraxella catarrhalis: ? emerging role
s
Some case may be viral (RSV, influenza,enteroviruses)
s Mycoplasma pneumoniae: inflammation ofthe tympanic membrane (bullous
myringitis)
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Acute otitis mediaAcute otitis media
Critical role ofeustachian tube asconduit betweennasopharynx, middle
ear, and mastoid aircells
Children have shorter,wider eustachian tubes
than adults
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Diagnosis and treatmentDiagnosis and treatment
s Presence of fluid in the middle ear AND
s Ear pain, drainage, hearing loss
s The fluid may take weeks to resolve
s Amoxicillin remains the drug of choice
s Beta-lactamase producing strains of H.
influenza will need amoxicillin/clavulanic
acid or cephalosporins
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Chronic otitis media and mastoiditisChronic otitis media and mastoiditis
s Prolonged middle ear effusions in
patients with previous episodes of
acute otitis media. Often skin flora or
anaerobic organismssMastoiditis: Less common nowadays.
formerly severe complications. Often
anaerobic.
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Acute pharyngitisAcute pharyngitis
s Most cases are viral
s Most important bacterial cause is
Streptococcus pyogenes (15-20%)
s Presents with sore or scratchy throats In severe bacterial cases there may be
odynophagia, fever, headache
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Acute pharyngitis: physical examAcute pharyngitis: physical exam
sViral: edema and hyperemia of tonsilsand pharyngeal mucosa
s Streptococcal: exudate and hemorrhage
involving tonsils and pharyngeal wallssEpstein-Barr virus (infectious mono):
may also cause exudate, withnasopharyngeal lymphoid hyperplasia
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Pharyngoconjuntival feverPharyngoconjuntival fever
sAdenoviral pharyngitis
s Pharyngeal erythema and exudate may
mimic streptococcal pharyngitis
sConjunctivitis (follicular) present in
1/3 to 1/2 of cases; commonly
unilateral but bilateral in 1/4 of cases
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Vesicular lesionsVesicular lesions
s Herpangina Uncommon
Due to coxsackieviruss
Small, 1-2 mm vesicles on the soft palate,uvula, and anterior tonsillar pillars which
rupture to form small white ulcers
Occurs mainly in children
s Herpes simplex virus
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Vincents angina and QuinsyVincents angina and Quinsy
s Vincents angina: anaerobic pharyngitis(exudate; foul odor to breath)
s Ludwigs angina- cellulitis of dental origin
s Quinsy: peritonsillitis/peritonsillar abscess.Medial displacement of the tonsil; often
spread of infection to carotid sheath
sDiphtheria
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Diphtheria
sfibrous pseudomembrane with necrotic epithelium and leukocytes
Di h h iDi hth i
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DiphtheriaDiphtheria
s
Classic diphtheria (Corynebacteriumdiphtheriae): slow onset, then marked toxicity
sArcanobacteriumhemolyticum (formerly
Cornyebacteriumhemolyticum): exudative
pharyngitis in adolescents and young adultswith diffuse, sometimes pruritic maculopapular
rash on trunk and extremities
Mi ll f h itiMi ll f h iti
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Miscellaneous causes of pharyngitisMiscellaneous causes of pharyngitis
s Primary HIV infectionsGonococcal infection
sDiphtheria
s Yersiniaentercolitica (can havefulminant course)
sMycoplasmapneumoniae
sChlamydiapneumoniae
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TreatmentTreatment
s Symptomatics Penicillin for Strep throat
s Macrolides for pen allergic patients
s Add an antianaerobic agent for Vincentsand Ludwigs angina
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Acute laryngotracheobronchitis (croupAcute laryngotracheobronchitis (croup)
s
Children, most often in 2nd years Parainfluenza virus type 1 most often in U.S.A. but other
agents are Mycoplasma pneumoniae, H. influenza
s Involvement of larynx and trachea: stridor, hoarseness,
coughs Subglottic involvement: high-pitched vibratory sounds
s Can lead to respiratory failure (2% get hospitalized)
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CroupCroup
s Rhinorrhea, sore throat, mild cough, fevers Parainfluenzae and influenza can be identified by
nasopharyngeal swab
s Rapid tests are available
s Treat with vaporizers, nebulized adrenalines Systemic or nebulized corticosteroids in the severely
sick
Acute epiglottitisAcute epiglottitis
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Acute epiglottitisAcute epiglottitis A life-threatening
cellulitis of the epiglottisand adjacent structures
Onset usually sudden (asopposed to gradual onset
of croup); drooling,dysphagia, sore throat
H. influenzae the usualpathogen both in children
(the usual patients) andadults
Acute suppurativeAcute suppurative
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Acute suppurativecute suppu at ve
parotitisparotitis
sUncommon, but highmorbidity and mortality
sUsually associated with
some combination ofdehydration, old age,malnutrition, and/orpostoperative state
s S. aureus the usualpathogen
Deep fascial space infections ofDeep fascial space infections of
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Deep fascial space infections ofDeep fascial space infections of
the head and neckthe head and neck
s Several syndromes according to anatomicplanes
s Can complicate odontogenic or
oropharyngeal infections Ludwigs angina: bilateral involvement of
submandibular and sublingual spaces
(brawny cellulitis at floor of mouth)
Deep fascial space infections ofDeep fascial space infections of
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Deep fascial space infections ofDeep fascial space infections of
the head and neck (2)the head and neck (2)
s Lemierre syndrome: suppurative thrombophlebitisof internal jugular vein (Fusobacterium
necrophorum)
s
Retropharyngeal space infection: contiguousspread from lateral pharyngeal space or infected
retropharyngeal lymph node; complications
include rupture into airway, septic thrombosis of
internal jugular vein
Severe acute respiratorySevere acute respiratory
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Severe acute respiratorySeve e cu e esp o y
distress syndrome (SARS)distress syndrome (SARS)
s Caused by a previously unrecognizedcoronavirusgenome has now been
sequenced.
s Clinical manifestations are similar to
those of other acute respiratory
illnessesnotably, influenza
s Cases in U.S.associated mainly
with travel or as secondary contacts
SARS CDC d fi iti (2003)SARS CDC d fi iti (2003)
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SARS: CDC case definition (2003)SARS: CDC case definition (2003)
s Respiratory illness of unknown etiology ANDs Measured temperature > 100.4 degrees F (38
degrees C) AND
s One or more clinical findings of respiratory illnessAND
s Travel within 10 days of onset of symptoms to anarea with documented or suspected cases OR close
contact with a case
SARS C d fi iti (2)SARS C d fi iti (2)
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SARS: Case definition (2)SARS: Case definition (2)
s Clinical findings of respiratory illness:cough, SOB, dyspnea, hypoxia, or
radiographic findings of either pneumonia
or ARDS
s Travel includes certain areas (mainland
China, Hong Kong, Hanoi, Singapore) and
also airports with documented or suspected
community transmission
SARS: Radiographic findingsSARS: Radiographic findings
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SARS: Radiographic findingsSARS: Radiographic findings
s Early: a peripheral/pleural-based
opacity (ground-glass orconsolidative) may be the only
abnormality. Look especially at
retrocardiac area.
s Advanced: widespread
opacification (ground-glass orconsolidative) tending to affect the
lower zones and often bilateral.
s Pleural effusions,
lymphadenopathy, and cavitation
are not seen.
D C l U b i (1956 2003)Dr Carlo Urbani (1956 2003)
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Dr. Carlo Urbani (1956-2003)Dr. Carlo Urbani (1956-2003)
s 2/28/03: RecognizedSARS while examining apatient in Hanoi.
s Identified outbreak andraises the alarm.
s Stayed caring patientsdespite multiple illnessesin staffsent wife andthree children back to Italy
s 3/29/03: Died of SARS
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