Respiratory InfectionRespiratory Infection

Ali Somily MD, FRCPC

OUTLINEOUTLINE

Upper Respiratory Tract Upper Respiratory Tract InfectionsInfections

EtiologiesEtiologies Acute pharyngitis Bacterial

– Streptococcal (GAS)•Main •Most common bacterial

– Diphtheria •Rare

– N. gonorrhoeae, – B. pertussis

Viral •Most common

EBV AdenopathyEBV Adenopathy

Adenovirus & EBVAdenovirus & EBV

GASGAS

How to collect throat swab ?How to collect throat swab ?

How to send it to the lab ?How to send it to the lab ?

Bacterial –Swab GAS

Viral –VTM

What is the diagnosisWhat is the diagnosis

Neck X-raysNeck X-rays

AnatomyAnatomy

Paranasal Sinuses

SinusitisSinusitis

What is 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 SinusitisAcute & Chronic Sinusitis

Acute Sinusitis>10 days but < 30 days.

Subacute sinusitis >30 days without improvement.

Chronic sinusitis>120 days.

Etiology of SinusitisEtiology of Sinusitis

70% of bacterial sinusitis is caused by:

Streptococcus pneumoniaeHaemophilus influenzaeMoraxella catarrhalis

Clinical Presentations of Clinical Presentations of SinusitisSinusitis 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 TurbinatesPale, Boggy Turbinates

Diagnostic TestsDiagnostic Tests

RadiographsUltrasonogramsCT scanning

Laboratory studies, such as culture of sinus puncture aspirates.

Pharmacological Plan of CarePharmacological Plan of Care

Clarithromycin:15mg/kg/d in 2 divided doses(>30kg, 250mg q12)

OTITIS MEDIAOTITIS 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 Normal & abnormal tympanic membranemembrane

MICROBESMICROBES

Streptococcus pneumoniaeHaemophilus influenzae(non-

typeable)Moraxella catarrhalisGroup A StreptococcusStaph aureusPseudomonas aeruginosaRSV assoc. with Acute Otitis Media

PATHOGENESISPATHOGENESIS

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

DiagnosisDiagnosis

Diagnostic tympanocentesis & myringotomy

TREATMENTTREATMENT

Amoxicillin: 20-40 mg/kg/day tid for 10-14 days or,

Augmentin: 45 mg/kg/day po bid for 10-14 days

NASOPHARYNGEAL NASOPHARYNGEAL CULTURESCULTURES Carrier of

– Streptococcus pyogenes,

– Corynebacterium diphtheriae

– Neisseria meningitidis

Limited Practical Value– Otitis Media– Sinusitis

For isolation of – Bordetella

pertussis– Viral

Lower respiratory tract Lower respiratory tract infectioninfection

Lung AnatomyLung Anatomy

ClassificationClassification1. Typical

Pneumonia2. Atypical

Pneumonia

According to the following1. Organisms2. Treatment3. Presentation4. X-rays5. Prognosis

EtiologyEtiology 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

M. pneumoniae – Most cases of ambulatory CAP (serologic methods)

Haemophilus influenzae and Legionella – The third and fourth most common bacterial causes of CAP

requiring hospitalization. Specimens are easily contaminated with upper

respiratory secretions,

S.pneumoS.pneumo

PneumoniaPneumonia

Staph.aureusStaph.aureus

Lung abscess.Lung abscess.

Pneumatocele and Pneumatocele and abscessabscess

Transplant and CMVTransplant and CMV

Hematological malignancy Hematological malignancy and Aspand Asp

lobar pneumonialobar pneumonia

Primarily caused by – Streptococcus pneumoniae,– Legionella pneumophila. – Klebsiella pneumoniae, – "currant jelly" sputum tissue

damage and hemorrhage into the alveoli

Escherichia coli – Often complicated by empyema

and septicemia.Pseudomonas aeruginosa Serratia marcescens

– Associated with a severe necrotizing pneumonia in immunosuppressed patients

S.pneumoniaeS.pneumoniae

Lung abscessesLung abscesses

Anaerobes Staphylococcus aureusMycobacterium tuberculosisMycoplasma pneumoniaeFungus

SpecimensSpecimens 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

B. Unacceptable specimens

1. Saliva submitted as sputum

2. Twenty-four-hour sputum collection .

3. Swabs

A. Media

•1. BAP•2. MAC•3. CHOC•4. Broth-BHI or THIO

AnaerobsAnaerobs

Invasive procedure Processed as rapidly as possible. Collected and transported

anaerobically Cultured for anaerobes. Transtracheal aspiration Transbronchial biopsyProtected bronchial brushesBronchalveolar

Protected bronchoscopy brush send for quantitative culture – Quantitative culture: Plate 10 µL. – Vortex the brush in 1 ml of BHI or

steril saline

Sputum SpecimensSputum Specimens Teeth brush

– Contamination one log less

Mouthwash– Avoid antiseptic

Early morning– Pooled overnight

secretions – Discouraged 24 hr

collection– Contamination– Dilution

Induced sputum Sterile wide-

mouth jar – tightly fitted

screw-cap lid – press the rim of

the container under the lower lip

Translaryngeal Translaryngeal (Transtracheal) Aspiration(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 Bronchoalveolar LavageLavageInjection 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 TestsOther Tests

Blood cultures – Streptococcus pneumoniae 25% to 30%

Direct fluorescent antibody tests Various Staining

– Pneumocystis carinii – The tissue forms of various fungi – Mycobacteria – Viral inclusions

Serological tests

V. V. MICROSCOPICMICROSCOPIC

A. Smear preparationB. Microscopic screening (sputum specimens only)

LegionellaLegionella

Legionnaires' diseaseLegionnaires' disease

StoryStory 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.

200 - 216 South Broad Street - Bellevue - Stratford Hotel (Fairmont Hotel) (1400 Walnut Street)]

Pneumophila means "love of the lungs" and Philadelphia means "city of brotherly love",

TaxonomyTaxonomy

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 StructurePhysiology 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.

VirulenceVirulence

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

EpidemiologyEpidemiology

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).

PresentationsPresentations

Diseases– Legionnaires' disease. – Pontiac fever.

DiagnosisDiagnosis

– Culture on BCYE agar is the diagnostic test of choice but positive titers develop late in the course of disease.

Gram stain of Gram stain of Legionella pneumophilaLegionella pneumophila grown on buffered charcoal-yeast grown on buffered charcoal-yeast

extract agarextract agar

Legionella Legionella species may appear as species may appear as characteristic ground-glass colonies characteristic ground-glass colonies with iridescent edges, which is typical with iridescent edges, which is typical of L. pneumophila. of L. pneumophila.

Non-pneumophila Non-pneumophila species may appear as species may appear as mucoid protuberant colonies (C) or raised mucoid protuberant colonies (C) or raised greyish white colonies (D). greyish white colonies (D).

The colonies The colonies of of certain species certain species of Legionella of Legionella autofluoresce either blue-white (E) or red (F) autofluoresce either blue-white (E) or red (F) under long-wavelength UV light. under long-wavelength UV light.

Immunofluorescent staining Immunofluorescent staining of of either respiratory specimens or either respiratory specimens or culture isolates should reveal short culture isolates should reveal short coccobacilli that stain a bright (3 coccobacilli that stain a bright (3 to 4+) apple greento 4+) apple green

Direct fluorescent antibody stain of Direct fluorescent antibody stain of LegionellaLegionellamicdadei.micdadei.

Treatment, Control, and Treatment, Control, and PreventionPrevention 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