Bacterial Pneumonia

Pneumonia is an infection that inflames respiratory bronchi, alveolar sacs and interstitium.

Symptoms

 * acute fever, cough, tachypnoea
 * immunocompetent patients may not seem severely ill (higher temperature, signs of toxic effect, cough - dry, later changes to productive, shortness of breath)
 * predisposition to bacterial pneumonia are immunodeficiency, congenital lung anomalies, cystic fibrosis, ciliary dysfunction...

Diagnosis

 * auscultation - bronchial breath sounds, crackles, rales, percussion dullness, increased pectoral fremitus
 * combined with pleural pathology – tight chest, shallow breathing, pain, pleural friction
 * when an effusion is present - percussion dullness, shallow or compressive breathing
 * sometimes it can manifest as abdominal pain or meningism
 * higher WCC - higher than 15× 109/l
 * chest X-ray: lobar consolidation, interstitial and air space opacification
 * when an effusion is present – opacity in lower and lateral parts of the lungs
 * it is important to make an imige of the patient lying down and on the patient's side

Differential Diagnosis

 * atelectasis (X-Ray - concave border, lobar pneumonia has convex border)
 * pleural effusion, lung, mediastinal or pleural tumors, foreign body aspiration, aspiration of gastric contents, lung infarction, lung congestion, chronic interstitial lung disease,...

Complications

 * lung abscess, empyema (staphylococci, beta-hemolytic streptococci group A)
 * meningitis, otitis media, sinusitis, pericarditis, septicemia
 * immunocompromised patients (for example splenectomy,...) - predisposition to sepsis

Therapy

 * antibiotics targeted against the agent
 * it is important to have an X-Ray, age of the patient, patient's immune status
 * pneumococcus – PNC, amoxicillin, ampicillin, erythromycin, clindamycin
 * symptoms of toxicity with breath shortness - crystal PNC i.v.
 * haemophilus influenzae – ampicillin, cephalosporins (7−10 days parenteral, 10−14 days oral),
 * staphylococcus – antistaphylococcal PNC (oxacilin, cloxacillin, methicillin), then cephalosporins and aminoglycosides
 * vancomycin for resistent staphylococcus
 * empyema – thoracentesis or chest drainage
 * oxygen therapy, rehydratation

Prognosis

 * usually good if the diagnosis and therapy is fast
 * mortality of a pneumonia without complications - lower than 1%

Prevention

 * vaccination,
 * children under 2 years, patients after splenectomy - pneumococcal vaccination

Staphylococcal Pneumonia

 * nowadays rare, more common with infants compared to older children
 * severe because of its progessive course and tendency towards complications - abscesses, pyopneumothorax
 * staphylococcus aureus - virulence factors - enzymes, toxins (hemolysin, leukocidin, staphylokinase, coagulase)
 * bronchogenic or hematic spread of the infection

Pathophysiology

 * inflammatory deposits merge, s. aureus quickly grows and destroys its surroundings, small abscesses are formed
 * rupture of a subpleural abscess creates pyopneumothorax
 * partial obstruction of small bronchi can lead to pneumatoceles' formation
 * septic thrombus can be formed in pulmonary veins

Symptoms

 * acute fever, shortness of breath
 * staphyloderma may appear
 * infants - peracute, sepsis
 * physical examination: in the early stages is the same as for pneumonia, when empyema or pyopneumothorax is formed then shallow breathing
 * laboratory tests: leukocytosis, neutrophilia, anemia, a left shift in blood count, high ESR and CRP, positive blood culture
 * chest X-Ray (lungs + heart): at first small bronchopulmonary deposits, they quickly grow and merge
 * exudate formation
 * abscesses – form cavities with with a wide border (filled with air after emptying the content into the bronchus)
 * complications: rare with targeted ATB therapy, younger infants - staphylococcal pericarditis, meningitis, osteomyelitis, metastatic abscesses

Diagnosis

 * complicated during early stages
 * anamnesis - information about staphyloderma or mother's mastitis
 * clinical symptoms, X-Ray, cultivation
 * differential diagnosis: pneumonias that could be complicated by empyema (agents: streptococci, klebsiella, haemophilus)

Therapy

 * antistaphylococcal ATB - oxacillin, vancomycin (3-4 weeks)
 * i.v. application of Ig or antistaphylococcal serum
 * empyema – chest drainage (max. 7 days)
 * prognosis – high mortality, it is influenced by the health status of the patient before the illness and by complications

Reference

 * BENEŠ, Jiří. Studijní materiály [online]. [cit. 2010]. < http://jirben.wz.cz >.