Download 10-Resiratory tract

Respiratory Infection
Ali Somily MD, FRCPC
OUTLINE
Resp Tract
URT
LRT
Upper Respiratory Tract
Infections
Etiologies
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Acute pharyngitis
Bacterial
– Streptococcal (GAS)
• Main
• Most common bacterial
– Diphtheria
• Rare
– N. gonorrhoeae,
– B. pertussis
Viral
• Most common
EBV Adenopathy
Adenovirus & EBV
GAS
How to collect throat swab ?
How to send it to the lab ?
 Bacterial
–Swab GAS
 Viral
–VTM
What is the diagnosis
Neck X-rays
Anatomy

Paranasal Sinuses
Sinusitis
What is sinusitis?
An acute inflammatory process involving
one or more of the paranasal sinuses.
 5%-10% of URIs in children.
 Maxillary and ethmoid sinuses are most
frequently involved.

Acute & Chronic Sinusitis
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Acute Sinusitis
>10 days but < 30 days.
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Subacute sinusitis
>30 days without improvement.

Chronic sinusitis
>120 days.
Etiology of Sinusitis
70% of bacterial sinusitis is caused by:
 Streptococcus pneumoniae
 Haemophilus influenzae
 Moraxella catarrhalis
Clinical Presentations of
Sinusitis
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Periorbital edema
Cellulitis
Nasal mucosa is reddened or swollen
Percussion or palpation tenderness over a sinus
Nasal discharge, thick, sometimes yellow or
green
Postnasal discharge in posterior pharynx
Difficult transillumination
Swelling of turbinates
Boggy pale turbinates
Pale, Boggy Turbinates
Diagnostic Tests
Radiographs
 Ultrasonograms
 CT scanning
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Laboratory studies, such as culture of
sinus puncture aspirates.
Pharmacological Plan of Care

Clarithromycin:15mg/kg/d in 2 divided
doses(>30kg, 250mg q12)
OTITIS MEDIA
 Definition: Presence of a middle ear
infection
 Acute Otitis Media: occurrence of
bacterial infection within the middle ear cavity.
 Otitis Media with Effusion: presence of
nonpurulent fluid within the middle ear cavity
Normal & abnormal tympanic
membrane
MICROBES
Streptococcus pneumoniae
 Haemophilus influenzae(non-typeable)
 Moraxella catarrhalis
 Group A Streptococcus
 Staph aureus
 Pseudomonas aeruginosa
 RSV assoc. with Acute Otitis Media

PATHOGENESIS
Otitis Media usually follows an URI in
which there is edema of the eustacian
tube, leading to blockage.
 Other factors: allergic rhinitis, nasal polyps,

adenoidal hypertrophy
Diagnosis
 Diagnostic tympanocentesis &
myringotomy
TREATMENT
 Amoxicillin: 20-40 mg/kg/day tid for
10-14 days or,
 Augmentin: 45 mg/kg/day po bid for
10-14 days
NASOPHARYNGEAL CULTURES

Carrier of
– Streptococcus
pyogenes,
– Corynebacterium
diphtheriae
– Neisseria meningitidis

Limited Practical
Value
– Otitis Media
– Sinusitis

For isolation of
– Bordetella pertussis
– Viral
Lower respiratory tract infection
Lung Anatomy
Classification
Typical Pneumonia
2. Atypical Pneumonia
1.
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According to the
following
1.
2.
3.
4.
5.
Organisms
Treatment
Presentation
X-rays
Prognosis
Etiology
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No agent isolated in 40 to 60% of cases
Culture sensitivity (50%) of sputum culture for S. pneumoniae,
Agents of pneumonia are difficult to grow
– Legionella,
– Chlamydia pneumoniae,
– Mycoplasma pneumoniae).

C. pneumoniae
– Second most common cause of pneumonia
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M. pneumoniae
– Most cases of ambulatory CAP (serologic methods)
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Haemophilus influenzae and Legionella
– The third and fourth most common bacterial causes of CAP requiring
hospitalization.
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Specimens are easily contaminated with upper respiratory secretions,
S.pneumo
Pneumonia
Staph.aureus
Lung abscess.
Pneumatocele and abscess
Transplant and CMV
Hematological malignancy and
Asp
lobar pneumonia
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Primarily caused by
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–
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Streptococcus pneumoniae,
Legionella pneumophila.
Klebsiella pneumoniae,
"currant jelly" sputum tissue damage and
hemorrhage into the alveoli
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Escherichia coli
– Often complicated by empyema and
septicemia.
Pseudomonas aeruginosa
 Serratia marcescens

– Associated with a severe necrotizing
pneumonia in immunosuppressed patients
S.pneumoniae
Lung abscesses
Anaerobes
 Staphylococcus aureus
 Mycobacterium tuberculosis
 Mycoplasma pneumoniae
 Fungus
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Specimens
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A. Acceptable specimens
1. Sputum
2. Trachael and
transtracheal aspirates
3. Bronchial washings,
bronchial alveolar
lavage, bronchial
brushes, and bronchial
biopsy
4. Lung aspirate and
lung biopsy
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B. Unacceptable
specimens
1. Saliva submitted as
sputum
2. Twenty-four-hour
sputum collection .
3. Swabs
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A. Media
•1. BAP
•2. MAC
•3. CHOC
•4. Broth-BHI or THIO
Anaerobs
Invasive procedure
 Processed as rapidly as possible.
 Collected and transported anaerobically
 Cultured for anaerobes.
 Transtracheal aspiration
 Transbronchial biopsy
 Protected bronchial brushes
 Bronchalveolar
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Protected bronchoscopy brush send for
quantitative culture
– Quantitative culture: Plate 10 µL.
– Vortex the brush in 1 ml of BHI or steril saline
Sputum Specimens
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Teeth brush
– Contamination one log
less
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Mouthwash
– Avoid antiseptic
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Early morning
– Pooled overnight
secretions
– Discouraged 24 hr
collection
– Contamination
– Dilution
Induced sputum
 Sterile wide-mouth jar

– tightly fitted screwcap lid
– press the rim of the
container under the
lower lip
Translaryngeal (Transtracheal)
Aspiration
 1. The patient is debilitated
 2.Routine sputum samples have failed
to recover a causative organism in the
face of clinical bacterial pneumonia.
 3. An anaerobic pulmonary infection is
suspected.
Bronchoalveolar Lavage
 Injection of 30 to 50 mL
 The saline is then aspirated and
submitted for smear preparation and
culture
 The semiquantitative cultures
 >103 /mL that demonstrate intracellular
bacteria in more than 25% of the
inflammatory cells are indicators of
pneumonia that requires specific
treatment.
Other Tests

Blood cultures
– Streptococcus pneumoniae 25% to 30%
Direct fluorescent antibody tests
 Various Staining
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Pneumocystis carinii
The tissue forms of various fungi
Mycobacteria
Viral inclusions
Serological tests
V. MICROSCOPIC
 A. Smear preparation
 B. Microscopic screening
(sputum specimens only)
Legionella
Legionnaires' disease
Story
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In the summer of 1976, public attention was focused on
an outbreak of severe pneumonia that caused many
deaths in members of the American Legion convention in
Philadelphia.
231 people within a short time, and 34 of them died
After months of intensive investigations, a previously
unknown gram-negative bacillus was isolated.
Subsequent studies found this organism, named
Legionella pneumophila, to be the cause of multple
epidemic and sporadic infections.
The organism was previously not known to exist, because
it stains poorly with conventional dyes and does not grow
on common laboratory media.
Despite the initial problems with the isolation of
Legionella organisms, it is now recognized to be a
ubiquitous aquatic saprophyte.
Pneumophila
means "love
of the lungs"
and
Philadelphia
means "city
of brotherly
love",
200 - 216 South Broad Street - Bellevue - Stratford Hotel
(Fairmont Hotel) (1400 Walnut Street)]
Taxonomy

Taxonomic studies have shown that the family
Legionellaceae
– One genus, Legionella,
• 39 species
– > 60 serogroups. (Approximately half of these species and
serogroups have been implicated in human disease, with the
others found in environmental sources. )

L. pneumophila is the cause of almost 85% of
all infections;
– serotypes 1 is the most commonly isolated
Physiology and Structure
Slender, pleomorphic, gram-negative
bacilli.
 Stains poorly with common reagents.
 Nutritionally fastidious with requirement
for L-cysteine and enhanced growth with
iron salts.
 Nonfermentative.

Virulence
Capable of replication in alveolar
macrophages (and amoeba 'in nature).
 Prevents phagolysosome fusion.
 They enter the cell by

– C3b and mem.protein
– CR3 and bacterial surface
– Endocytosis to Macro and Mono comp
receptor
Epidemiology
Capable of sporadic and epidemic disease.
 Commonly found in natural bodies of water, cooling
towers, condensers, and water systems (including
hospital systems).
 Summer and autumn
 Estimated to be between 10,000 and 20,000 cases in
United States annually.
 Patients at high risk for symptomatic disease include
patients with compromised pulmonary function and
patients with decreased cellular immunity (particularly
transplant patients).
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Presentations
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Diseases
– Legionnaires' disease.
– Pontiac fever.
Diagnosis
– Culture on BCYE agar is the diagnostic test
of choice but positive titers develop late in
the course of disease.
Gram stain of Legionella pneumophila grown on
buffered charcoal-yeast extract agar
Legionella species may appear as characteristic
ground-glass colonies with iridescent edges,
which is typical of L. pneumophila.
Non-pneumophila species may appear as mucoid
protuberant colonies (C) or raised greyish white
colonies (D).
The colonies of certain species of Legionella autofluoresce
either blue-white (E) or red (F) under long-wavelength UV
light.
Immunofluorescent staining of either
respiratory specimens or culture isolates
should reveal short coccobacilli that stain a
bright (3 to 4+) apple green
Direct fluorescent antibody stain of Legionella
micdadei.
Treatment, Control, and
Prevention
Severe disease treated with azithromycin or
levofloxacin; less severe disease can be treated
with erythromycin or tetracycline.
 Rifampin can be added in sever cases
 Decrease environmental exposure to reduce
risk of disease.
 For environmental sources associated with
disease, treat with hyperchlorination,
superheating, or copper-silver ionization
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