Pneumonia

1
Pneumonia
2
Pneumonia is defined as inflammation and
consolidation of the respiratory part of lung
tissue (alveoli) due to an infectious agent.
3

• Community-acquired pneumonia remains a common
  illness. Pneumonia is the sixth leading cause of
  death in the the world and is the most common
  infectious cause of death.
• Pneumonia is the leading cause of death among
  hospital-acquired infections, and the mortality
  rates range from 20-50.
• Advanced age increases the incidence of pneumonia
  and the mortality from it.

4
Causes of bacterial pneumonia
include infection with respiratory pathogens.
Exposure to pulmonary irritants or direct
pulmonary injury causes noninfectious pneumonitis
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Intrinsic factors that predispose pneumonia
include

• 1)the host's immune response,
• 2)the presence of comorbidities
• 3) aspiration of oropharyngeal flora into the
  lung.
• 4) local lung pathologies

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• Aspiration is facilitated by altered mental
  status from intoxication, deranged metabolic
  states, neurological causes (eg, stroke), and
  endotracheal intubation.
• Local lung pathologies (tumors, chronic
  obstructive pulmonary disease, bronchiectasis)
  are predisposing factors for bacterial pneumonia.
  
• Smoking impairs the host's defense to infection
  by a variety of mechanisms.

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Classification

• 1. Community-acquired pneumonia
• typical
• atypical
• 2.Nosocomial pneumonia
• 3. Aspiration pneumonia.
• 4.Pneumonia in immunocompromised patients.

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• 1. Pneumonia that develops outside the hospital
  setting is considered community-acquired
  pneumonia.
• 2. Pneumonia developing 48 hours or more after
  admission to the hospital is termed nosocomial or
  hospital-acquired pneumonia.

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• 3. Aspiration pneumonia takes the special place
  due to high risk of lung tissue destruction and
  bad prognosis.
• 4. Pneumonia in immunocompromised patients (those
  who receive immunodepressants, such as
  cytostatics or system steroids, HIV-infected
  persons on last stage).

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Community-acquired pneumonia

• is caused most commonly by bacteria that
  traditionally have been divided into 2 groups,
  typical and atypical.

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A. Typical organisms in community-acquired
pneumonia

• (approximately 85) include
• Streptococcus pneumoniae (pneumococcus),
• Haemophilus influenzae (is associated with asthma
  and COPD), and
• Moraxella catarrhalis (in patients with chronic
  bronchitis).

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• S pneumoniae remains the most common agent
  responsible for community-acquired pneumonia.

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Rare bacterial pathogens in community-acquired
pneumonia are

• Klebsiella pneumoniae (in persons with chronic
  alcoholism),
• Staphylococcus aureus (in the setting of
  postviral influenza),
• Pseudomonas aeruginosa (in patients with
  bronchiectasis).

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B. Atypical pathogens in community-acquired
pneumonia

• (approximately 15) are
• Legionella pneumophila,
• Mycoplasma pneumoniae,
• Chlamydia psittaci,
• Coxiella burnetii.

15

• Do not mix community-acquired pneumonia due to
  atypical flora with
• atypical pneumonia due to virus (SARS severe
  acute respiratory syndrome)!.

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Typical (predominantly pneumococcal) pneumonia
produces the following

• a characteristic clinical pattern, with sudden
  onset of fever and shaking chills, pleuritic
  chest pain, and production of rust-colored sputum
  and
• radiological evidence of consolidation.
• examination of sputum in case of pneumococcal
  pneumonia shows gram-positive diplococci in
  chains.
• This clinical picture was recognized as typical
  (classical) pneumonia.

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Atypical" community-acquired pneumonia

• Most patients present with a gradual onset of the
  disease without shaking chills.
• A prodrome of it consists of headache,
  photophobia, sore throat, and eventually a dry,
  nonproductive cough.
• Their sputum does not contain gram-positive
  diplococci (pneumococci).
• Although these patients were not feeling well,
  they were not critically ill.
• Laboratory evaluations showed white blood cell
  counts to be normal.

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Hospital-acquired (nosocomial) pneumonia

• defines as pneumonia occurring more than 48 hours
  after admission to the hospital.
• It is a major cause of morbidity and mortality in
  hospitalized patients.

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The most common organisms responsible for
nosocomial pneumonia are

• Staphylococcus aureus
• Klebsiella pneumoniae
• Gram-negative pathogens
• Enterobacter,
• Pseudomonas aeruginosa, and
• Escherichia coli.

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• S. aureus pneumonia generally occurs in those who
  abuse intravenous drugs in hospitalized patients
  and patients with prosthetic devices it spreads
  hematogenously to the lungs from contaminated
  local sites.
• Infection by Pseudomonas aeruginosa tend to cause
  pneumonia in the patients, requiring mechanical
  ventilation.

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Essentials of diagnosis of community-acquired
pneumonia

• Occurs in healthy person
• Sudden onset of fever and shaking chills, cough,
  and production of rust-colored sputum sometimes
  accompanied by pleuritic chest pain due to
  pleurisy
• Physical examination detects signs of
  consolidation
• Crackles in auscultation
• Pulmonary infiltrate on chest x-ray.

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Essentials of diagnosis of hospital-acquired
(nosocomial) pneumonia

• Occurs more than 48 hours after admission to the
  hospital.
• One or more clinical findings (fever, cough,
  leukocytosis, purulent sputum) in most patients.
• Especially frequent in patients requiring
  intensive care and mechanical ventilation.
• Pulmonary infiltrate on chest x-ray.

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Clinical presentation in patients with pneumonia

• varies from a mildly ill ambulatory patient to a
  critically ill patient with respiratory failure
  or septic shock.
• Typically, patients with pneumonia present with
  variable degrees of fever they may report rigors
  or shaking chills.
• Pleuritic chest pain secondary to pleurisy is a
  common feature of pneumococcal infection, but
  these may occur in other bacterial pneumonias.

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Clinical presentation in patients with pneumonia

• A productive cough is characteristic feature of
  pneumonia. The character of sputum may suggest a
  particular pathogen.
• Patients with pneumococcal pneumonia produce
  rust-colored sputum.
• Infections with Pseudomonas and Haemophilus are
  known to expectorate green sputum.
• Anaerobic infections produce foul-smelling
  sputum.
• Currant-jelly sputum suggests pneumonia from
  Klebsiella.

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Clinical presentation in patients with pneumonia

• Malaise, myalgias, and exertional dyspnea may be
  observed.
• Patients may complain of other nonspecific
  symptoms, which include
• headaches,
• nausea, and
• vomiting.
• These symptoms are accompanied by intoxication.

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A detaled past medical history and history of
environmental and occupational exposures should
be obtained

• This history should include whether the patient
  has recently traveled or had contact with animals
  that might serve as a source of an infectious
  agent.
• Patients may report
• exposure to turkeys, chickens, ducks in case of
  Chlamydia psittaci infection
• exposure to contaminated air-conditioning
  cooling towers in case of Legionella pneumophila
  infection.

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Evaluation of host factors often provides a clue
to the bacterial diagnosis

• Diabetic ketoacidosis may lead to S. pneumoniae
  or S. aureus infection.
• Alcoholism may indicate Klebsiella pneumoniae
  infection.
• Chronic obstructive lung disease may lead to
  Haemophilus influenzae or Moraxella catarrhalis
  infection.
• HIV infection may lead to Cryptococcus
  neoformans, Mycobacterium avium-intracellulare
  infection or Pneumocystis pneumonia.

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Precise clinical diagnosis of nosocomial
pneumonia

• is much more difficult than community-acquired
  pneumonia.
• It is because of the absence of a typical
  clinical picture against the background of the
  disease, which was the reason for
  hospitalization.
• The subclinical course without clear typical
  picture is widespread.
• However, one or more clinical findings (fever,
  leukocytosis, purulent sputum), and a pulmonary
  infiltrate on chest x-ray are present in most
  patients.

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Physical

• A.The common symptoms and signs (due to
  intoxication and respiratory failure) are as
  follows
• Fever (temperature gt38.5C)
• Tachypnea
• Tachycardia
• Central cyanosis
• These symptoms are non-specific and indicate
  severity of the disease, not etiology. They cant
  help to diagnose pneumonia, but they determine
  therapy and prognosis.

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Physical

• B. The most important information on physical
  examination is connected with signs of lung
  tissue consolidation due to local inflammation
• Dullness to percussion
• Increased tactile fremitus
• Decreased intensity of breath sounds
• Crackles (crepitation) at the beginning and
  resolving of inflammation
• Local rales
• Pleural friction rub

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The main doctors task on physical examination

• is revealing of asymmetric pathology.
• Pneumonia is local respiratory pathology.
  Therefore, the presence of focal area of lung
  tissue consolidation has the most diagnostic
  value.
• It is direct indication for chest radiograph.

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Imaging Studies

• The diagnosis of pneumonia is impossible without
  X-ray investigation.
• Direct indication for chest X-ray is not only
  focal acoustic pathology but also any clinical
  situation accompanied by chronic or prolonged
  cough.

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Imaging Studies

• In chest medicine 80 of information is on the
  developed film.
• Chest radiograph findings in typical case of
  pneumonia indicate a segmental or lobar opacity,
  or infiltration corresponding to the impaired
  area.

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Left low lobe pneumonia
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Low lobe pneumonia
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Right upper lobe lobar pneumonia secondary to
Streptococcus pneumoniae infection
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Bacterial pneumonia. Bilateral airspace
infiltration secondary to community-acquired
pneumonia, subsequently confirmed to be
Legionella pneumonia
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Bacterial pneumonia. Rarely, severe pneumococcal
infection may be associated with necrotizing
pneumonia.
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Chest radiographs showing right middle lobe
pneumonia
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Hospital-acquired right lower lobe pneumonia
sputum culture confirmed this to be secondary to
gram-negative organisms
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Aspergillus pneumonia
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Pneumonia caused by Chlamydia psittasi
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Aspiration pneumonia
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CT in case of pneumonia
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Lab Studies

• Complete blood count
• Leukocytosis with a left shift is commonly
  observed in case of pneumonia.
• These findings may be absent in elderly or
  debilitated patients.
• Leukopenia is an ominous sign of impending sepsis
  and a poor outcome.

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Lab Studies

• Sputum examination
• provides an accurate diagnosis in approximately
  50 of patients. A single pathogen present on the
  Gram stain is typical for pneumonia.
• The main value of sputum examination is to
  exclude the presence of such microorganisms as
  mycobacteria, fungi, Legionella, and Pneumocystis
  through special smears and cultures.

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Bacterial pneumonia. Pneumococci on sputum Gram
stain.
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Bacterial pneumonia. Histopathological micrograph
of bacterial pneumonia showing extensive
infiltration with inflammatory cells
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Bacterial pneumonia. Klebsiella pneumoniae on
sputum Gram stain
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Lab Studies

• The diagnosis of pneumonia cannot be based solely
  on the results of culture of expectorated sputum.
  
• 100 sputum cultures are impossible in most
  clinics. No ordinary lab can ensure 100
  etiological diagnosis of pneumonia in time.
• The standard lab limits sputum investigation by
  Gram-stained smear.
• That is why diagnosis of pneumonia is
  clinical-radiological, not etiological.

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Lab Studies

• Additional lab tests are necessary when diagnosis
  is unclear and the treatment based on the
  findings of standard tests has no effect.
• Other tests may include serology, which is
  essential in the diagnosis of unusual causes of
  pneumonia such as Legionella, Mycoplasma,
  Chlamydia, and other.
• Blood cultures are of a limited value, as they
  are positive only in approximately 40 of cases.

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Other Tests

• Arterial blood gas (ABG) determination
  Evaluation of the patient's gas exchange is
  essential in order to decide if hospital
  admission, oxygen supplementation, or other
  efforts are indicated.
• Pulse oximetry of less than 90 indicates
  significant hypoxia an ABG determination should
  be performed in these patients.

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Procedures

• Bronchoscopy
• Bronchial washing specimens can be obtained.
  Protected brush and bronchoalveolar lavage can be
  performed for quantitative cultures.
• Thoracentesis
• This is an essential procedure in patients with
  a parapneumonic pleural effusion.
• Obtaining fluid from the pleural space for
  laboratory analysis allows for the
  differentiation between simple and complicated
  effusions. This determination helps guide further
  therapeutic intervention.

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Differential diagnosis

• Any case of pneumonia requires excluding of 2
  other pulmonological problems.
• They are
• lung cancer and
• tuberculous.

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Complications

• Pleural effusion
• Empyema
• Pulmonary abscess
• Respiratory failure
• Acute heart failure
• Death

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Criteria for hospitalization

• The decision to hospitalize patients with
  community-acquired pneumonia is dictated by risk
  factors that increase either the risk of death or
  the risk of a complicated course of disease.

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Some of indications for hospitalization include

• Advanced age (over 65)
• comorbidity (alcoholism, diabetes mellitus, COPD,
  chronic renal or heart failure, chronic liver
  disease)
• suspicion of aspiration
• leukopenia or marked leukocytosis
• any evidence of respiratory failure
• septic appearance and
• absence of supportive care at home (social
  indications).

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Who can be treated at home?

• Only young people in case of mild course.
• If theres the smallest sign of a moderate
  course, the patient must be directed to the
  in-patient department immediately!

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Treatment

• Establishing a specific etiologic diagnosis of
  pneumonia is often difficult.
• In most cases of both community-acquired and
  hospital-acquired pneumonia no etiology was
  identified.
• Therefore, when organisms are not known, therapy
  should be empiric.

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The initial approach to treating patients with
?ommunity-acquired pneumonia

• involves a determination of 3 factors.
• Should the patient with pneumonia be treated in
  the hospital or as an outpatient?
• Does the patient have a serious coexisting
  illness or is the patient elderly?
• How severely ill is the patient at the time of
  the initial evaluation?

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Community-acquired pneumonia treatment

• Empiric therapy for pneumonia based on
  recommendations by the WHO (2000).
• Patients with community-acquired pneumonia are
  categorized into 4 groups because a different
  microbiologic spectrum is suggested in each group
  to choose the initial empiric therapy the most
  effectively.

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Community-acquired pneumonia treatment

• A. The 1st major category includes outpatients
  aged 60 years or younger without comorbidity.
• Antibiotic treatment with one of the newer
  macrolides (clarithromycin or azithromycin) is
  advised.

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Community-acquired pneumonia treatment

• B. The 2nd group combines community-acquired
  pneumonias occurring in outpatients with
  comorbidity or age 60 years or older.
• The recommended therapy is
• a 2nd-generation cephalosporin (cefuroxime), or
• a beta-lactam a beta-lactamase inhibitor
  (amoxicillin-clavulanate), or
• a newer fluoroquinolone (levofloxacin or
  moxifloxacin).

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Community-acquired pneumonia treatment

• C.Community-acquired pneumonia requiring
  hospitalization
• The recommended therapy is
• a 2nd-generation cephalosporin (cefuroxime), or
• a 3rd-generation cephalosporin (ceftriaxone), or
• amoxicillin-clavulanate.
• Combination therapy is advised with 2nd- or
  3rd-generation cephalosporin macrolide

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Community-acquired pneumonia treatment

• D. Severe community-acquired pneumonia requiring
  ICU care
• Combination therapy is advised with
• a macrolide plus a 3rd-generation cephalosporin
  (eg, ceftazidime), or
• triple therapy with
• (1) ceftazidime or carbapenem
• (2) amikacin
• (3) macrolide or fluoroquinolone (ciprofloxacin)

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Nosocomial pneumonia treatment

• Nosocomial pneumonia remains a prevalent
  hospital-acquired infection.

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Severe nosocomial pneumonia treatment

• The possible combinations are
• one of the following
• (1) aminoglycoside or ciprofloxacin
• (2) amoxicillin-clavulanate, or
• ceftazidime, or
• imipenemvancomycin

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NB!

• Pneumonia is not treated with gentamycin or
  penicillin!

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• Telithromycin (KETEK) is first antibiotic in a
  new class called ketolides.
• It keeps active against gram-positive cocci in
  the presence of resistance. Indicated to treat
  mild-to-moderate community-acquired pneumonia,
  including infections caused by multidrug-resistant
  S. pneumoniae.