Burden of Upper respiratory tract infection (URI)
Significant morbidity and direct health care costs
Direct costs of $ 17 billion annually
Excessive use of antibiotics a major issue
Occasionally leads to fatal illness
Common cold - DefinitionThe common cold is a viral infection
upper respiratory tract, nose, and throat
More than 100 viruses can cause a common coldsigns and symptoms tend to vary greatly
Preschool children are at greatest risk of frequent coldschildren average 8 per year, adults 3
Most people recover from a common colda week or two
The Common Cold - CausesEtiologies
Rhinoviruses 30 to 35%Coronaviruses about 10%Miscellaneous known viruses about 20%Influenza and adenovirus-30%Presumed undiscovered viruses up to 35%Group A streptococci 5% to 10%
Parainfluenza was the first respiratory virus isolated (1955)
Seasonal variationRhinovirus early fallCoronavirus- winter
Transmission of Rhinoviruses
Direct contact is the most efficient means of transmission40% to 90% recovery from hands
Brief exposure (e.g., handshake) transmits in less than 10% of instances
Kissing does not seem to be a common mode of transmission
Transmission through droplet Transmission through droplet dispersiondispersion
(Courtesy-American Assoc. for the Advancement Of Science)
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Molecular surface of a Human rhinovirus, showing protein spikes
Risk factorsCold viruses are almost always present in the
environment
But the following factors can increase your chances of getting a cold:
AgeImmunityTime of year
Clinical characteristicsIncubation period 12-72 hours
Nasal obstruction, drainage, sneezing, scratchy throat
Median duration 1 week - but 25% can last 2 weeks
Pharyngeal erythema is commoner with adenovirus than with rhino or coronavirus
Common Cold - SymptomsCommon symptoms are
sore throatrunny nosenasal congestionsneezing
Sometimes accompanied byconjunctivitismyalgias fatigue
Sinusitis often present by CT scan; “rhinosinusitis” might be a better term
Common Cold - Complications
Acute ear infection (otitis media)
Wheezing
Sinusitis
Other secondary infections
The common cold
Diagnosis and treatmentMain challenge is to distinguish between uncomplicated
cold and streptococcal pharyngitis or bacterial sinusitis
Marked exudate or pharyngeal erythema suggests
Streptococcal infectionAdenovirusDiphtheria
Rapid antigen tests for group A streptococcus
Rapid techniques for influenza, RSV, parainfluenza
Treat with NSAIDs and whatever else your grandmother advises
A Rapid Strep Test kit
Acute sinusitis - DefinitionAcute sinusitis
causes the cavities around your nasal passages to become inflamed and swollen
With acute sinusitis, it may be difficult to breathe through the nose
Acute sinusitis is most often caused by the common cold
Acute sinusitis - CausesAcute sinusitis can be caused by:
Viral infection Bacterial infectionFungal infection
Some health conditions can increase the risk of getting a sinus infection include:
Allergies Nasal polyps or tumorsDeviated nasal septum Tooth infectionOther medical conditions
Acute bacterial sinusitisEpidemiological studies suggest 1 billion cases of viral
rhinosinusitis occur annually in the USOf these 0.5 – 2 % are complicated by bacterial sinusitis
Acute sinusitis typically starts with viral infection that paves the path for pathogenic bacteriaThe major pathogens are Streptococcus pneumoniae and
Haemophilus influenzae
Nose blowing generates high intranasal pressures that deposit bacteria into the sinus cavity
More common in adults than in children
Acute bacterial sinusitis - CausesCommunity acquired bacterial sinusitis
S. pneumoniaeH. influenzaeS. pyogenes
Nosocomial sinusitisSeen in critically ill, mechanically ventilated
S. aureus Pseudomonas aeruginosa Serratia marcescens
Fungal
Bacterial sinusitis - Clinical featuresClinical features
SneezingNasal dischargeFacial pressureFeverPurulent drainageHeadache
Sinus imaging not routinely recommended
Chronic sinusitis
Chronic sinusitis
a common condition in which the cavities around nasal passages (sinuses) become inflamed and swollen
for at least eight weeks, despite treatment attempts
Chronic sinusitis - Causes 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
Numerous microorganisms can be isolated from patients with chronic sinusitis
Mixtures of aerobic and anaerobic bacteria are common
The general conclusion at this time is that in most patients, no single microorganism can be assigned a pathogenic role
In some patients, however, P. aeruginosa or S. aureus seems to be clearly pathogenic
There are data suggesting roles for H. influenzae and Moraxella catarrhalis in children
In these instances, especially in children, Streptococcus pneumoniae and Haemophilus influenzae may be important
Numerous bacteria including gram-negative rods have been isolated with patients with post-operative sinusitis
Acute pharyngitisInflammatory syndrome of the pharynx
Most cases are viralMost important bacterial cause is Streptococcus
pyogenes (15-20%)
Presents with sore or scratchy throat
In severe bacterial cases there may be odynophagia, fever, headache
Miscellaneous causes of pharyngitis
Primary HIV infectionGonococcal infectionDiphtheriaYersinia entercolitica (can have fulminant course)
Mycoplasma pneumoniaeChlamydia pneumoniae
A case of strep throat
Severe Acute Respiratory Syndrome (SARS)Caused by a previously unrecognized coronavirus—
genome has now been sequenced
Clinical manifestations are similar to those of other acute respiratory illnesses—notably, influenza
Cases in U.S. associated mainlywith travel or as secondary contacts
SARS coronavirus (SARS-CoV)is causative of the syndrome
SARS: Radiographic findingsEarly: a peripheral/pleural-based
opacity (ground-glass or consolidative) may be the only abnormality. Look especially at retrocardiac area
Advanced: widespread opacification (ground-glass or consolidative) tending to affect the lower zones and often bilateral
Pleural effusions, lymphadenopathy, and cavitation are not seen.
CroupRhinorrhea, sore throat,
mild cough, feverParainfluenzae and influenza
can be identifiedby nasopharyngeal swab
Rapid tests are availableTreat with vaporizers,
nebulized adrenalineSystemic or nebulized
corticosteroids in the severely sick
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Acute Epiglottitis
A life-threatening cellulitis of the epiglottis and adjacent structures
Onset usually sudden (as opposed to gradual onset of croup); drooling, dysphagia, sore throat
H. influenzae the usual pathogen both in children (the usual patients) and adults
Acute suppurative parotitis
Uncommon, but high morbidity and mortality
Usually associated with some combination of dehydration, old age, malnutrition, and/or postoperative state
S. aureus the usual pathogen
Otitis externa Acute, localized: often S. aureus, S.
epidermidis or S. pyogenes
Acute diffuse (swimmer’s ear): gram-negative rods, especially Ps. Aeruginosa ; Rx: topical quinolones
Chronic: mainly with chronic otitis media
Malignant: life-threatening infection in diabetics, elderly, immunecompromised
Malignant otitis externa Diabetes mellitus
Pseudomonas aeruginosa
Osteomyelitis of the temporal bone
Involvement of vital structures at base of brain
Acute otitis mediaS. pneumoniae and H. influenzae the leading
causes in all age groups (most H. flu is from non-typable strains and not “B”)
Moraxella catarrhalis: 10% of casesSome cases may be viral (RSV, influenza,
enteroviruses)Mycoplasma pneumoniae: inflammation of the
tympanic membrane (“bullous myringitis”)
Acute otitis media Critical role of
eustachian tube as conduit between nasopharynx, middle ear, and mastoid air cells
Children have shorter, wider eustachian tubes than adults
Diagnosis and treatmentPresence of fluid in the middle ear ANDEar pain, drainage, hearing lossThe fluid may take weeks to resolveAmoxicillin remains the drug of choiceBeta-lactamase producing strains of H. influenza
will need amoxicillin/clavulanic acid or cephalosporins
Otitis Media
Vesicular lesionsHerpangina
UncommonDue to coxsackievirussSmall, 1-2 mm vesicles on the soft palate, uvula, and
anterior tonsillar pillars which rupture to form small white ulcers
Occurs mainly in children
Also think of Herpes simplex virus when you see vesicular lesions
Dr. Carlo Urbani (1956-2003)2/28/03: Recognized
SARS while examining a patient in Hanoi.
Identified outbreak and raises the alarm.
Stayed caring patients despite multiple illnesses in staff—sent wife and three children back to Italy
3/29/03: Died of SARS