Transcript Upper and lower respiratory tract infectionsard

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 - Definition
 The common cold is a viral infection
 upper respiratory tract, nose, and throat
 More than 100 viruses can cause a common cold
 signs and symptoms tend to vary greatly
 Preschool children are at greatest risk of frequent colds
 children average 8 per year, adults 3
 Most people recover from a common cold
 a week or two
The Common Cold - Causes
 Etiologies
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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 variation
 Rhinovirus early fall
 Coronavirus- winter
Transmission of Rhinoviruses
 Direct contact is the most efficient means of transmission
 40% 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
dispersion
(Courtesy-American Assoc. for the Advancement Of Science)
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Molecular surface of a Human
rhinovirus, showing protein spikes
Risk factors
 Cold viruses are almost always present in the environment
 But the following factors can increase your chances of getting
a cold:
 Age
 Immunity
 Time of year
Clinical characteristics
 Incubation 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 - Symptoms
 Common symptoms are
 sore throat
 runny nose
 nasal congestion
 sneezing
 Sometimes accompanied by
 conjunctivitis
 myalgias
 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 treatment
 Main challenge is to distinguish between uncomplicated cold and
streptococcal pharyngitis or bacterial sinusitis
 Marked exudate or pharyngeal erythema suggests
 Streptococcal infection
 Adenovirus
 Diphtheria
 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 - Definition
 Acute 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 - Causes
 Acute sinusitis can be caused by:
 Viral infection
Bacterial infection
 Fungal infection
 Some health conditions can increase the risk of getting a sinus
infection include:
 Allergies
 Deviated nasal septum
 Other medical conditions
Nasal polyps or tumors
Tooth infection
Acute bacterial sinusitis
 Epidemiological studies suggest 1 billion cases of viral
rhinosinusitis occur annually in the US
 Of these 0.5 – 2 % are complicated by bacterial sinusitis
 Acute sinusitis typically starts with viral infection that paves the
path for pathogenic bacteria
 The 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 - Causes
 Community acquired bacterial sinusitis
 S. pneumoniae
 H. influenzae
 S. pyogenes
 Nosocomial sinusitis
 Seen in critically ill, mechanically ventilated
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S. aureus
Pseudomonas aeruginosa
Serratia marcescens
 Fungal
Bacterial sinusitis - Clinical features
 Clinical features
 Sneezing
 Nasal discharge
 Facial pressure
 Fever
 Purulent drainage
 Headache
 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 pharyngitis
 Inflammatory syndrome of the pharynx
 Most cases are viral
 Most 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 infection
 Gonococcal infection
 Diphtheria
 Yersinia entercolitica (can have fulminant
course)
 Mycoplasma pneumoniae
 Chlamydia 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 mainly
with travel or as secondary contacts
SARS coronavirus (SARS-CoV)
is causative of the syndrome
SARS: Radiographic findings
 Early: 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.
 Rhinorrhea, sore throat,
mild cough, fever
 Parainfluenzae and influenza
can be identified
by nasopharyngeal swab
 Rapid tests are available
 Treat with vaporizers,
nebulized adrenaline
 Systemic or nebulized
corticosteroids in the severely sick
The steeple sign as seen on an AP neck X-ray of a child with croup
Croup
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 media
 S. 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 cases
 Some 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 treatment
 Presence of fluid in the middle ear AND
 Ear pain, drainage, hearing loss
 The fluid may take weeks to resolve
 Amoxicillin remains the drug of choice
 Beta-lactamase producing strains of H. influenza will need
amoxicillin/clavulanic acid or cephalosporins
Otitis Media
Vesicular lesions
 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
 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