Burden of Upper respiratory tract infection (URI) Significant morbidity and direct health care...

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