Pneumonia - Causes, Symptoms and Treatments
An acute infection of the lung parenchyma, pneumonia often impairs gas exchange. The prognosis is generally good for people who have normal lungs and adequate host defenses before the onset of pneumonia; however, pneumonia is the sixth leading cause of death in the United States.
Causes of Pneumonia:
Pneumonia can be classified in several ways:
. Microbiologic etiology - Pneumonia can be viral, bacterial, fungal, protozoal, mycobacterial, mycoplasmal, or rickettsial in origin.
. Location- Bronchopneumonia involves distal airways and alveoli; lobular pneumonia, part of a lobe; and lobar pneumonia, an entire lobe.
. Type - Primary pneumonia results from inhalation or aspiration of a pathogen; it includes pneumococcal and viral pneumonia. Secondary pneumonia may follow initial lung damage from a noxious chemical or other insult (superinfection), or may result from hematogenous spread of bacteria from a distant focus.
Predisposing factors to bacterial and viral pneumonia include chronic illness and debilitation; cancer (particularly lung cancer); abdominal and thoracic surgery; atelectasis; common colds or other viral respiratory infections; chronic respiratory disease (chronic obstructive pulmonary disease [COPD], asthma, bronchiectasis, cystic fibrosis); influenza; smoking; malnutrition; alcoholism; sickle cell disease; tracheostomy; exposure to noxious gases; aspiration; and immunosuppressant therapy.
Predisposing factors to aspiration pneumonia include old age, debilitation, nasogastric tube feedings, impaired gag reflex, poor oral hygiene, and decreased level of consciousness.
Signs and symptoms of Pneumonia:
The five cardinal symptoms of early bacterial pneumonia are coughing, sputum production, pleuritic chest pain, shaking chills, and fever. Physical signs vary widely, ranging from diffuse, fine rales to signs of localized or extensive consolidation and pleural effusion.
Complications include hypoxemia, respiratory failure, pleural effusion, empyema, lung abscess, and bacteremia, with spread of infection to other parts of the body resulting in meningitis, endocarditis, and pericarditis.
Diagnosis of Pneumonia:
Clinical features, chest X -ray showing infiltratcs, and sputum smear demonstrating acute inflammatory cells support this diagnosis. Positive blood cultures in patients with pulmonary infiltratcs strongly suggest pneumonia produced by the organisms isolated from the blood cultures.
Pleural effusions, if present, should be tapped and fluid analyzed for evidence of infection in the pleural space. Occasionally, a transtracheal aspirate of tracheobronchial secretions or bronchoscopy with brushings or washings may be done to obtain material for smear and culture. The patient's response to antimicrobial therapy also provides important evidence of the presence of pneumonia.
Other conditions to consider are lung cancer, heart failure, Wegener's granulomatosis, and tuberculosis.
Treatment of Pneumonia:
Antimicrobial therapy varies with the causative agent. Therapy should be reevaluated early in the course of treatment.
Supportive measures include humidified oxygen therapy for hypoxia, mechanical ventilation for respiratory failure, a high-calorie diet and adequate fluid intake, bed rest, and an analgesic to relieve pleuritic chest pain. Patients with severe pneumonia on mechanical ventilation may require positive end-expiratory pressure to facilitate adequate oxygenation.
Special considerations and prevention tips of Pneumonia:
Advise the patient to avoid using antibiotics indiscriminately during minor viral infections because this may result in upper airway colonization with antibioticresistant bacteria. If the patient then develops pneumonia, the organisms producing the pneumonia may require treatment with more toxic antibiotics.
Encourage annual influenza vaccination and Pneumovax for high-risk patients, such as those with COPD, chronic heart disease, or sickle cell disease.
Urge all bedridden and postoperative patients to perform deep-breathing and coughing exercises frequently. Position such patients properly to promote full aeration and drainage of secretions.
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