3. • Pneumonia is an infection of the pulmonary
parenchyma.
• caused by acute infection, usually bacterial,
characterized by clinical and/or radiographic
signs of consolidation of a part or parts of one
or both lungs.
4.
5.
6.
7. • ‘Lobar pneumonia’ is a radiological and
pathological term referring to homogeneous
consolidation of one or more lung lobes, often
with associated pleural inflammation.
• Bronchopneumonia’ refers to more patchy
alveolar consolidation associated with
bronchial and bronchiolar inflammation, often
affecting both lower lobes.
8.
9. PATHOPHYSIOLOGY
• proliferation of microbial pathogens at the
alveolar level and the host’s response to those
pathogens.
• aspiration from the oropharynx
• Pathogens are inhaled as contaminated
droplets.
10. • hematogenous spread (e.g., from tricuspid
endocarditis) or by contiguous extension from an
infected pleural or mediastinal space.
• Once engulfed, the pathogens—even if they are
not killed by macrophages—are eliminated via
either the mucociliary elevator or the lymphatics
and no longer represent an infectious challenge.
• Only when the capacity of the alveolar
macrophages to ingest or kill the microorganisms
is exceeded does clinical pneumonia become
manifest.
11. • Alveolar macrophages initiate the
inflammatory response to bolster lower
respiratory tract defenses.
• Inflammatory mediators released by
macrophages and the newly recruited
neutrophils create an alveolar capillary leak.
• The capillary leak results in a radiographic
infiltrate and rales detectable on auscultation,
and hypoxemia results from alveolar filling.
13. • Edema- with the presence of a proteinaceous
exudate - and often of bacteria—in the alveoli.
• This phase is rarely evident in clinical or
autopsy specimens because it is so rapidly
followed by a red hepatization phase.
14. • red hepatization - presence of erythrocytes in
the cellular intraalveolar exudate gives this
second stage its name, but neutrophils are
also present and are important from the
standpoint of host defense.
• Bacteria are occasionally seen in cultures of
alveolar specimens collected during this
phase.
15. • gray hepatization - no new erythrocytes are
extravasating, and those already present have
been lysed and degraded.
• The neutrophil is the predominant cell, fibrin
deposition is abundant, and bacteria have
disappeared.
• This phase corresponds with successful
containment of the infection and
improvement in gas exchange.
16. • Resolution - the macrophage is the dominant
cell type in the alveolar space, and the debris
of neutrophils, bacteria, and fibrin has been
cleared, as has the inflammatory response.
18. • Clinical features – patient is frequently febrile,
with a tachycardic response, and may have
chills and/or sweats and cough that is either
nonproductive or productive of mucoid,
purulent, or blood-tinged sputum.
• Pleuritic chest pain, gastrointestinal symptoms
• increased respiratory rate, use of accessory
muscles of respiration.
19.
20. • Palpation may reveal increased or decreased
tactile fremitus
• percussion note can vary from dull to flat,
reflecting underlying consolidated lung and
pleural fluid.
• Crackles, bronchial breath sounds, and
possibly a pleural friction rub may be heard on
auscultation.
27. Management
• Oxygen should be administered to all patients
with tachypnoea, hypoxaemia, hypotension or
acidosis, with the aim of maintaining the PaO2
at or above 8 kPa (60 mmHg) or the SaO2 at
or above 92%.
28.
29. • Intravenous fluids – severe illness, older
patients and those who are vomiting.
Inotropic support may be required in patients
with shock.
30.
31. Discharge and follow-up
• depends on their home circumstances and the
likelihood of complications.
• Clinical review should be arranged around 6
weeks later and a chest X-ray obtained if there
are persistent symptoms, physical signs or
reasons to suspect underlying malignancy.
32. Prevention
• Current smokers should be advised to stop.
• Influenza and pneumococcal vaccination.
• Tackling malnourishment and indoor air
pollution, and encouraging immunisation
against measles, pertussis and Haemophilus
influenzae type b are particularly important in
children.
