Transcript Upper and lower airway infections

Upper and lower airway
infections
Semmelweis University
First Department of Medicine
Dr. Szathmári Miklós
01. February 2010.
The most common airway infections
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Common cold
Acute pharyngitis
Acute bronchitis
Chronic obstructive lung disease
Pneumonias
– Community aquired pneumonia
– Health care associated pneumonia
• Ventilator associated pneumonia
• Hospital aquired pneumonia
The common cold in adults
• Most frequent benign self-limited acute illness
(syndrome) caused by members of several
families of viruses
• The term refers to a mild upper respiratory viral
illness involving, to variable degrees, sneezing,
nasal congestion and rinorrhea, sore throat,
cough, low grade fever, headache and
malaise
• The average incidence of the common cold is
two to three per year by adulthood
The common cold in adults
• Rhinoviruses are the most common viruses
associated with cold symptoms. Coronaviruses
cause 10-15%, influenza virus cause 5-15%,
and parainfluenza and RSV virus are
responsible for about 5 %
• Influenza and parainfluenza tipically cause
more symptoms than other cold viruses.
• Seasonal pattern:
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Rhinovirus, parainfluenza: in fall and late spring
RSV and coronavirus in winter and spring
Enteroviruses: in the summer
Adenoviruses: outbreaks in military facilities, and
hospital wards.
The common cold in adults
• Transmission: hand contact (direct and
indirect contact with a contaminated
environmental surface. Cold inducing
viruses may remain viable on human skin
for at least two hours.
• Droplet transmission is the most
common means of transmission for
influenza viruses.
The common cold in adults
clinical features and pathogenesis
• Incubation period for most common cold viruses is 24 to
72 hours.
• The symptoms vary from patient to patient: rhinitis and
nasal congestion are most common. The sore throat is
frequently the most bothersome symptom on the first day
of illness, but it is usually short lived. Cough becomes
troublesome on the fourth or fifth day of illness. Nasal
discharge may appear to be purulent in the absence of a
secondary bacterial infection. Fever is uncommon in
adults.
• Risk factors for increased severity of disease include:
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Chronic disease
Congenital immundeficiency disorders
Malnutrition
Cigarette smoking
The common cold in adults
• Complications
– Sinusitis: viral sinusitis occurs more frequently than
secondary bacterial sinusitis
– Lower respiratory tract disease: Viral upper
respiratory infections (rhinovirus) have been linked
to up to 40 percent af acute asthma attacks in
adults. The increased airway hyperreactivity (may
explain the persistent cough following upper
respiratory tract infections) can be a consequence of:
• Local viral infection of lower airway epithelial cells, or
• Inflammatory mediators acting distantly in the lower airways
– Otitis media (Eustachian tube dysfuction; impaired
clearance and pressure regulation)
Acute pharyngitis
• One of the most common conditions
encountered in office practice.
• The major treatable pathogen, group A
Streptococcus is the cause of pharyngitis in only
10 percent of adults who seek medical care.
• The vast majority of patients receive antibiotic
therapy. The overtreatment of acute pharyngitis
represents one of the major causes of
antibiotic abuse.
• Acute rheumatic fever, an important complication
af acute streptoccoccal pharyngitis, has nearly
disappeared from the most developed countries.
Common causes of acute
pharyngitis
Pathogens
Frequency
Examples
Viruses
50%
Rhinovirus, Adenovirus, Influenza A
and B, Parainfluenza, Coxsackievirus,
Coronavirus, Echovirus
Primary
pathogens
10-15%
Group A Streptococcus
Group C Stretococcus
Group G Streptococcus
Neisseria gonorrheae
Possible
primary
pathogens
<5%
Chlamidophilia pneumoniae
Mycoplasma pneumoniae
Archanobacterium haemolyticum
No microbe
identified
Appr.30%
Identifying group A streptococcal
pharyngitis
• Clinical prognostic score (sensitivity and spesificity
range from 55-75%, respectively. Centor criteria:
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Tonsillar exudates
Tender anterior cervical adenopathy
Fever by history
Absence of cough
• Diagnostic tests
– Rapid streptococcal antigen test (RSAT)- ELISA method with 8090% sensitivity and 90-100% specificity
– Throat culture (low sensitivity, time delay in obtaining actionable
result)
– Antistreptolysin titer (peak value within two to three weeks.
Critical for the diagnosis of acute rheumatic fever but is not
helpful for management of streptococcal pharyngitis
Acute bronchitis (etiology)
• The usual causes of acute bronchitis are viral
infections of the upper airways including influenza A and
B, parainfluenza, coronavirus, rhinovirus, respiratory
syncytial virus, and human metapneumovirus.
• Bacterial pathogens that cause pneumonia, such as
Streptococcus pneumoniae, Haemophilus influenzae,
Staphylococcus aureus, Moraxella catarrhalis do not
cause acute bronchitis, with exception of patients with
airway violations such as tracheostomy or endotracheal
intubation, or those with exacerbations of chronic
bronchitis.
• Influenza, as the cause of acute bronchitis merits special
consideration because of its morbidity and potential for
specific therapy. It is treatable with neuroaminidase
inhibitors, although these drugs must be given within 48
hours of symptoms onset for demonstrable clinical benefit.
• Other pathogens: Mycoplasma pneumoniae,
Chlamydophila pneumoniae, Bordatella pertussis
Acute bronchitis (clinical symptoms)
• Self-limited inflammation of the bronchi
• Clinical sypmtoms: cough, usually with sputum
production, and evidence of concurrent upper airway
infection. Fever is unusual sign, when accompannying
cough, suggest either influenza or pneumonia. The
cough often lasts from 10 to 20 days. Purulent sputum
in 50% of patients, this usually represents sloughing of
cells from the tracheobronchial epithelium, along with
inflammatory cells, and does not signify bacterial
infection, as is often assumed. The patient often have
significant bronchospasm. Airway hyperreactivity
improves over five to six weeks.
Acute bronchitis
(diagnosis and treatment)
• Diagnostic tests:
– In case of abnormal vital signs (fever, tachypnoe, tachycardia) –
chest X-ray – diff. diag. Penumonia. Over 75 years of age the
patient may have pnemonia with normal vital signs.
– Microbiology:
• in patients with severe paroxysmal cough should be evaluated for
pertussis regardless of the immunization history
• Diagnostic studies for mycoplasma and C. pneumoniae
• Rapid tests for the diagnosis of influenza
• Bacterial cultures of expectorated sputum in patients with negative
chest X-ray are not recommended.
• Treatment:
– Symptomatic treatment using nonsteroidal antiinflammatory
drugs and nasal decongestants.
– The patients with acute bronchitis do not have benefit from
antibiotic treatment, except patients with serious preexisting
comorbidity). Pertussis can be treated with macrolide antibiotic
Chronic obstructive pulmonary disease
(COPD)
• Definition: a disease state characterized
by airflow limitation that is not fully
reversible.
• COPD includes
– Emphysema: destruction and enlargement of
lung alveoli
– Chronic bronchitis: a clinically defined
condition with chronic cough and phlegm
– Small airway disease: a condition in which
small bronchioles are narrowed
COPD risk factors
• The causal relationship between cigarette smoking and the
development of COPD has been absolutely proved, Although packyears of cigarette smoking is the most significant predictor of FEV1,
only 15% of the variability in FEV1 is explained by pack-years.
• Airway responsiveness: increased bronchocontriction in response
to a variety of exogenous stimuli
• Respiratory infections: important causes of exacerbations of
COPD, but the association of infections to the development and
progression of COPD remains to be proven
• Occupational exposures: Several specific occupational dusts and
fumes are likely risk factors for COPD, the magnitude of these
effects appears to be less important than the effect of smoking
• Ambient air pollution: The prevalence of COPD in urban areas is
higher than in the rural areas in connection with the increased
pollution in the urba settings.
• Genetic considerations:
– Alfa-1 antitrypsin deficinecy (frequency appr. 1% in Caucasian
populations)
COPD clinical presentation
• History
– The three most common symptoms in COPD: cough,
sputum production and dyspnea
– The development of airflow reduction is a gradual
process
– Activities involving significant arm work, particularly at
or above shoulder level, are particularly difficult for
patients with COPD. The activities that allow the
patient to brace the arms and use accessory muscles
of respiration are better tolerated (pushing a shopping
cart, walking on a treadmill)
COPD clinical presentation
• Physical findings
– In the early stage entirely normal
– In patients wth more severe disease: prolonged
exspiratory phase and exspiratory wheezing. Signs of
hyperinflation of the lung: barrel chest, poor
diaphragma excursion, use of accessory respiratory
muscles, cyanosis.
– Systemic wasting, significant weight loss, loss of
subcutaneous adipose tissue
– Clubbing of the digits: not a sign of COPD.
Development of lung cancer is the most likely
explanation for newly developed clubbing
COPD clinical presentation
• Laboratory findings
– Spirometry : airflow obstruction with decreased FEV1
and FEV1/FVC. Increased total lung capacity,
functional residual capacity and residual volume
– Arterial blood gases and oximetry: hypoxaemia, Pco2
increased.
– Elevated hematocrit suggest present of chronic
hypoxemia
– Testing for α1AT deficiency
– Radiographic evaluation: may assist in the
classification of the type of COPD. Obviuos bullas,
paucity of parenchymal markings, or hyperlucency
suggest emphysema
COPD treatment
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Smoking cessation
Oxigen therapy
Lung volume reduction surgery
Inhaled glucocorticoids
Bronchodilatators
– Anticholinerg agents (tiotropium)
– Βeta-agonist (long-acting inhaled salmeterol)
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Theophyllin
N-acetyl cysteine
α1AT augmentation therapy
Antibiotic
Influence the
natural history
of patients with
COPD
Improve
symtoms and
decrease of the
frequency and
severity of
exacerbations
COPD antibiotic treatment
• Patients with COPD are frequently colonized
with potential respiratory pathogens, include
Streptococcus pneumoniae, Haemophilus
influenzae, and Moraxella catarrhalis. In addition
Mycoplasma pneumoniae and Chlamydiphila
pneumoniae are found in 5-10% of
exacerbations.
• The choice of antiobiotic should be based on
local patterns of antibiotic susceptibility of these
pathogens.
Community aquired pneumonia
• Definition: an acute infection of the
pulmonary parenchyma in a patient who
has acquired the infection in the
community, as distinquished from
– Hospital-acquired (nosocomial) pneumonia
– Healthcare-associated pneumonia (nursing
homes, dialysis center, outpatient clinics or
within 90 days of discharge from an acute or
chronic care facility.
Community aquired pneumonia
• Clinical features include:
– Cough and sputum
• Mucopurulant sputum in association with bacterial
pneumonia. Scant and watery sputum in case of atypical
pathogen
– Fever
• Chills in 40 to 50%. Frequently absent in older patients
– Pleuritic chest pain
• in 30% of causes
– Dyspnea and tachypnoe
• in 45 to 70% of patients, and may be the most sensitive sign
in elderly patients
– Nausea, vomiting, diarrhea
Community aquired pneumonia
(radiologic evaluation)
• Chest X-ray examination
– Radiographic appearence may include lobar
consolidation, interstitial infiltrates, and/or cavitation
– If the clinical evaluation does not support pneumonia
in a patient with an abnormal chest x-ray, other
causes must be considered, such as malignancy,
hemorrhage, pulmonary edema, pulmonary
embolism, etc.
– If the clinical syndrome favors pneumonia but the
radiograph is negative, the radiograph may represent
a false negative result (volume depletion may
produce an initially negative radiograph)
• CT scanning (not generally recommended for
routine use)
Community aquired pneumonia
(diagnostic testing for microbial etiology)
• Testing for a microbial diagnosis is usually not performed
in outpatients because empiric treatment is almost
always succesful.
• Patients with severe CAP requiring ICU admission
should have blood cultures, urinary antigen tests, and
sputum culture
• Some microbes are critical to detect because they
represent important epidemiologic challenges and/or
serious conditions that require treatment different from
standard empiric regimen
– Legionella, Influenza A and B, community-associated methicillinresistant Staphylococcus aureus, and agent of bioterrorism
(Bacillus anthracis, Yersinia pestis, Francisella tularensis,
Coxiella burnetti, Legionella spp, Influenza virus, Hantavirus, and
ricin)
Microbial causes of community aquired
pneumonia, by site of care
Hospitalized patients
Outpatients
Non-ICU
ICU
Streptococcus
pneumoniae
Mycoplasma
pneumoniae
Haemophilus
influenzae
Chlamidophila
pneumoniae
Respiratory viruses
S.pneumoniae
M. pneumoniae
C. pneumoniae
H. Influenzae
Legionella spp.
Respiratory viruses
S. Pneumoniae
Staphylococcus
aureus
Legionella spp.
Gram-negative bacilli
H. influenzae
Harrison’s: Principles of Internal Medicine 17th edition. McGraw-Hill
Epidemiologic factors suggesting
possible causes of CAP
Factors
Possible pathogens
Alcoholism
S. pneumoniae, oral anaerobs, Klebsiella pneum.,
Mycobacterium tuberculosis, Acinetobacter
COPD/smoking
Haemophilus inf, Pseudomonas, Legionella, S.
pneum, Moraxella catarr.
Bronchiectasia, structural
lung disease
Pseudomonas aer., Staphylococcus aureus
Dementia, stroke
Oral anaerobs, gram-negative enteric bacteria
Lung abscess
Staphylococcus aureus, oral anaerobs, endemic
fungi, Mycobacterium tuberculosis
Stay in hotel or on cruise
ship in previous 2 weeks
Legionella spp.
Local influenza activity
Influenza virus, S. pneumoniae, S. aureus
Exposure to birds
Chlamidophila psittaci
Exposure to rabbits
Francisella tularensis
Empirical antibiotic treatment of CAP
• Outpatients
– Previously healthy and no antibiotic treatment in past 3 months
• A macrolide or doxycyclin (not in Hungary) or amoxicillin/clavulanate
– Comorbidities or antibiotics in past 3 months
• A respiratory fluoroquinolone p.o. or β-lactam + macrolide
• Inpatients
– Respiratory fluroquinolone p.o. or iv., or β-lactam + macrolide
• Special concerns
– Pseudomonas is a consideration (antistreptococcal,
antipseudomonas β-lactam (piperacillin/tazobactam, imipenem
plus ciprofloxacin or levofloxacin
– CA.MRSA is a consideration: add linezolid or vancomycin iv.
Health care-associated pneumonia
(ventilator associated pneumonia, VAP)
• Pneumonia is a common complication among
patients requiring mechanical ventilation (the
cumulative rate among patients who remain
ventilated for as long as 30 days is as high as
70%)
• Potential etiologic agents include both MDR
(multidrug-resistant) and non-MDR bacterial
pathogens.
– The non-MDR pathogens are identical to the
pathogens found in severe CAP. Such pathogens
predominates if VAP develops in the first 5-7 days of
the hospital stay
– The relative frequency of MDR pathogens vary
significantly from hospital to hospital (meany hospital
have problems with Pseudomonas aeruginosa and
MRSA)
Empirical treatment of HCAP/VAP
• Patient without risk factors for MDR
pathogens:
– Iv. ceftriaxon or respiratory fluoroquinolone or
amoxicillin-clavulinic acid or Ertapenem
• Patients with risk factors for MDR
pathogens:
– A β-lactam (cetazidine or piperacillin/tazobactam or
meropenem) plus a second agent active against
gram-negative bacterial pathogens (gentamycin,
amikacin, cipro- or levofloxacin) plus an agent active
against gram positive bacterial pathogens (Linezolid
or Vancomycin)
Hospital-acquired pneumonia (HAP)
• The HAP in nonintubated patient is similar to
VAP
• Higher frequency of non-MDR pathogens and
the better underlying host immunity in nonintubated patients allows monotherapy in a
larger proportion of cases HAP than of VAP.
• The anaerob infection is more common in the
non-VAP population
– Greater risk of macroaspiration
– Lower oxygen tension in the lower respiratory tract
• Because of the better host defenses, lower
mortality rate than in VAP