Notwithstanding the availability of potent antimicrobial drugs, pneumonia is still a major health problem. It is an infection of the lower respiratory tract that can be caused by a virus, bacteria or mycoplasma and is characteristically accompanied by cough, sputum production, fever, chills and pleuritic chest pain, all of which may be preceded by an upper respiratory tract infection. Physical examination reveals signs of consolidation of the lung parenchyma (increase tactile and vocal fremitus, bronchophony, egophony, bronchial breath sounds, fine rales over the consolidated area). Often there is also an associated pleural effusion, that can produce opposed features in physical examination (distant-to-absent breath sounds, pleural friction rubs which may fade as effusion becomes outstanding, decreased fremitus and flatness to percussion).
These signs are most recurrently found with bacterial pneumonia, whereas viral and mycoplasma pneumonias present with very few signs (often, only rales are heard).
1-aspiration of oropharyngeal secretions and associated bacterial flora;
2-hematogenous dissemination;
3-inhalation of infected aerosols;
4-proximity tiling parenchyma infection;
5-nosocomial infection; ·
Differential diagnosis is wide but can be much narrowed by the findings collected from a careful history and physical examination, sputum Gram’s staining and x-ray evaluation, being TB the most important one.
Occupational and social history should be carefully collected in order to determine whether there has been exposure to water-cooling facilities (Legionella), wild animals (anthrax or Q fever) or exposure to person with TB. Travel history is also important.
Simple and inexpensive test that also helps in determining the most appropriate therapy. The lack of dominant bacteria on the sample suggests the possibility of less common causes of pneumonia (Legionella, TB, fungi);
leukocytosis with left shift;
Its major purpose is to establish whether pneumonia is present or not. Diagnosing the ineffective agent is virtually impossible based on radiological features. Basic radiological feature of pneumonia are one or more consolidated areas.
x-ray patterns
Bacterial pneumonia :
consolidation of an entire or the majority of a lobe (lobar consolidation), producing an opaque lobe, except for air bronchograms.
Viral and mycoplasma pneumonia:
widespread ill defined consolidation with loss of clarity of vascular markings or localized consolidation. Pleural effusion is rare and radiological abnormalities can still be seen many weeks after clinical recovery.
Radiologically, it can be difficult to distinguish between pneumonia, pulmonary edema and pulmonary infarction, being clinical features much more important in deciding the issue.
In patients presenting with consolidation of one or two lobes supplied by a common bronchus, mainly if loss of volume is also present, obstruction of a major bronchus should be considered (remember carcinoma is a common cause of obstruction).
1-age over 65;
2-important coexisting illnesses (COPD, DM, neurologic disease, alcoholism, cardiac failure);
3-alteration in vital signs;
4-leuukopenia or important leukocytosis;
5-evidence of respiratory failure;
6-septic appearance;
7-absence of supportive care at home;
1-Most common pathogens:
S. pneumoniae;
Mycoplasma pneumoniae;
Respiratory viruses;
Chlamydia pneumoniae;
Haemophillus influenzae;
Miscellaneous organisms (Legionella, S.aureus, M.tuberculosis, endemic fungi and anaerobic Gram- negative bacilli);
2-Treatment
-macrolide or tetracycline ( erythromycin) for 10 -14 days;
-intolerance of erythromycin or H.influenzae suspected (COPD): newer macrolides (clarithromycin*** azithromycin);
-intolerance or allergy to macrolides: tetracycline***;
*** must not be prescribed to pregnant women;
1-Most common pathogens:
-S.pneumoniae;
-respiratory viruses;
Haemophillus influenzae;
aerobic Gram-negative bacilli;
S.aureus;
Miscellaneous organisms (Legionella, M. catarrhalis, M.tuberculosis, endemic fungi);
2-Treatment
Second- generation cephalosporin or
trimethoprim- sulfamethoxazole or
Beta-lactam combined with á-lactamase inhibitor (amoxicilin - potassium clavulanate)
macrolide If Legionnaires’ disease suspected or X-ray shows interstitial pattern or
no improvement observed within 72 hours:
1-Most common pathogens:
-S.pneumoniae;
Haemophillus influenzae;
-aerobic Gram-negative bacilli;
-Legionella;
S.aureus;
-Chlamydia pneumoniae;
respiratory viruses;
Miscellaneous (Mycoplasma pneumoniae, M.catarrhalis, M.tuberculosis,endemic fungi )
2-Treatment
- second-generation cephalosporin or
third-generation cephalosporin or
Beta-lactam combined with á-lactamase inhibitor (amoxicilin - potassium clavulanate)
legionnaires disease suspected: macrolide
1-Most common pathogens:
-S.pneumoniae;
Legionella;
-aerobic Gram-negative bacilli;
-Mycoplasma pneumoniae;
-respiratory viruses;
-Miscellaneous (Haemophillus influenzae, M.tuberculosis endemic fungi)
2-Treatment
Macrolide plus a
third-generation cephalosporin with activity against Pseudomonas or
another anti pseudomonal agent;
1) Current - Mediacal Diagnosis & Treatment , Tierney, McPhee, Papadakis
2) Diagnostic Imaging- Armstrong/ Wastie
3) Cecil Textbook of Medicine- Bennett and Plum, 20th Edition.
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