Pneumonia is an acute infection of the lung parenchyma including the alveolar spaces and interstitial tissue. It can involve the entire lobe (lobar pneumonia), a segment of a lobe (segmental or lobular pneumonia), alveoli contiguous to bronchi (bronchopneumonia), or interstitial tissue (interstitial pneumonia). These distinctions can be made based on an X-ray.
Classification
- Community-acquired (pneumonia contracted outside a health-care institution)
- Nosocomial (acquired in a hospital or other long-term health care facility).
Other types of pneumonia include:
- Aspiration pneumonia
- Atypical pneumonia
- Bacterial pneumonia
- CMV pneumonia
- Legionella pneumonia
- Mycoplasma pneumonia (walking pneumonia)
- Necrotizing pneumonia
- Pediatric pneumonia
- Pneumocystis carinii pneumonia
- Pneumonia in an immunocompromised host
- Pneumonia with lung abscess
- Pyogenic pneumonia
- Viral pneumonia.
Signs and Symptoms
- Chills
- Fever
- Cough
- Chest pain
- Labored breathing
- Fatigue
- Anorexia
- Headache
- Leucocytosis
- Bloody sputum
- Aspiration of gastric contents, water, or other irritants.
Pneumonia is not a single disease. It can have over 30 different causes. There are five main causes of pneumonia:
- Bacteria
- Viruses
- Mycoplasmas
- Other infectious agents, such as fungi - including pneumocystis
- Various chemicals
Risk Factors
- Upper respiratory tract infections
- Advanced age
- Alcoholism
- Cigarette smoking
- Institutionalization
- Malnutrition
- Immunosuppression
- Cancer
- Liver or kidney disease
- Congestive heart disease
- Cerebrovascular disease
DIAGNOSIS
Clinical examination reveals bronchial breathing, crepitations decreased breathing sounds and dullness to percussion.
Investigations
- Chest X-ray
- Gram's stain and culture of the sputum
- CBC
- Arterial blood gases
- Bacterial cultures of mucus produced by coughing
- Mantoux skin test
- Serological tests
TREATMENT
Goal
- Eradication of the microorganism involved.
- Identification and treatment of underlying precipitating factors.
- Prevention of hypoxia and hypercapnia.
- Prevention and early treatment of complications.
- Nutritional support.
- Symptomatic and supportive treatment.
Supportive therapy includes oxygen and respiratory treatments to remove secretions if needed. With treatment, most types of bacterial pneumonia can be cured within 1 to 2 weeks. Viral pneumonia may last longer. Mycoplasmal pneumonia may take 4 to 6 weeks to resolve completely.
Non-Pharmacological Treatment
Small frequent feeds are given by nasogastric tube, if necessary. IV fluids/alimentation given if enteral feeds are not tolerated
Pharmacological Treatment
Organism-Streptococcus pneumonia Pen MIC<2.0 5g/mL
1st line agents - Cephalosporins, Quinolones
2nd line agents - Vancomycin
Organism- Haemophilus influenza
1st line agents - Cephalosporins-2nd & 3rd Generation
Tetracyclines, penicillins, macrolides, Co-trimoxazole
2nd line agents Quinolones, macrolides
Organism - Moraxella catarrhalis
1st line agents Cephalosporins
2nd & 3rd generation co-cotrimoxazole, macrolides, penicillins
2nd line agents-Quinolones
Organism- Anaerobes
1st line agents Penicillins
2nd line agents - Imipenem, meropenem
Organism - Staphylococcus aureus (Methicillin-susceptible)
1st line agents - Nafcillin, oxacillin, cloxacillin, flucloxacillin w/or w/o rifampicin or gentamicin
2nd line agents - Cephalosporins
Organism-Staphylococcus aureus (Methicillin-resistant)
1st line agents Vancomycin w/ or w/o rifampicin, gentamicin
Organism- Enterobacteriaceae; Coliforms:
E Coli, Klebsiella, Proteus, and Enterobacter
1st line agents -cephalosporins
3rd Generation Cephalosporin w/or w/o aminoglycoside or imipenem or meropenem
2nd line agents- Penicillins, amoxicillin/clavulanate, ampicillin/sulbactam, quinolones
Organism- Pseudomonas aeruginosa
1st line agent- Aminoglycoside, penicillin ceftazidime, ciprofloxacin, cefepime
2nd line agents-Ciprofloxacin and Aminoglycoside or ciprofloxacin and penicillin
Organism- Legionella
1st line agents
azithromycin w or w/o rifampicin, ciprofloxacin, levofloxacin, erythromycin, clarithromycin,
2nd line agents Doxycycline w/ or w/o rifampicin
Organism- Mycoplasma pneumonia
1st line agents Tetracyclines, macrolides, quinolones
Organism- Chlamydia pneumonia
1st line agents Tetracyclines, macrolides, quinolones
Organism- Streptococcus pneumonia Pen MIC<2.0 5g/mL
1st line agents Penicillins
2nd line agents - Cephalosporins, tetracyclines, penicillins
Organism- Streptococcus pneumonia Pen MIC 2.0 5g/mL
1st line agents-Cephalosporins, quinolones
2nd line agents-Other Antibiotic: Vancomycin
Organism- Haemophilus influenza
1st line agents 2nd & 3rd Generation Cephalosporins
Tetracyclines, penicillins, macrolides
- Azithromycin
Combination Antibiotics
- Co-trimoxazole
2nd line agents-Quinolones, macrolides
Organism- Moraxella catarrhalis
1st line agents- Cephalosporins 2nd & 3rd Generation, Co-trimoxazole
2nd line agents - Quinolones
Organism- Anaerobes
1st line agents - Penicillins
Other Antibiotic: Clindamycin
2nd line agents-Other Antibiotics Imipenem, meropenem
Organism- Staphylococcus aureus (MethicillinsUsceptible)
1st line agents Nafcillin, Oxacillin, Cloxacillin,
Flucloxacillin w/or w/o Rifampicin or Gentamicin
2nd line agents Cephalosporins
- Others-Clindamycin, Co-trimoxazole
Organism- Staphylococcus aureus (Methicillin-resistant)
1st line agents-Vancomycin w/ or w/o Rifampicin, gentamicin
Organism- Enterobacteriaceae Coliforms: E Coli, Klebsiella, Proteus, and Enterobacter
1st line agents-3rd Generation Cephalosporin w/or w/o Aminoglycoside or imipenem or meropenem
2nd line agents-Aztreonam
Penicillins, quinolones
Organism- Pseudomonas aeruginosa
1st line agents-Aminoglycoside and Ticarcillin, Piperacillin
2nd line agents-Ciprofloxacin and Aminoglycoside or Mezlocillin, Ceftazidime, Cefepime, Aztreonam Ciprofloxacin, and Ticarcillin, Piperacillin or Mezlocillin
Organism- Legionella
1st line agents Erythromycin, Clarithromycin, Azithromycin or Dirithromycin w/or w/o Rifampicin, Ciprofloxacin, Levofloxacin, Gatifloxacin or Moxifloxacin
2nd line agents Doxycycline w/or w/o Rifampicin
Organism- Mycoplasma pneumonia
1st line agents-Tetracyclines, macrolides
2nd line agents Quinolones
Organism- Chlamydia pneumonia
1st line agents Tetracyclines, macrolides
2nd line agents Quinolones
Surgical Treatment
Large or symptomatic pneumothoraces require drainage by a chest tube. Needle aspiration is used to relieve a tension pneumothorax, and followed by chest tube placement.
Empyema and most large pleural effusions require chest tube drainage. More aggressive surgical procedures such as open drainage or decortication are rarely indicated for empyema.
Complications
- Acute respiratory failure
- Death
- Empyema
- Pleuritis
- Pleural effusion
- Pneumothorax
- Bronchiectasis
- Lung abscess
Prevention
Vaccination (polyvalent pneumococcal vaccine, flu vaccine, Hib vaccine) may help prevent some types of pneumonia.
Coughing and deep breathing may help prevent some forms of nosocomial pneumonia.
Prognosis
- Most patients will respond to treatment and improve within two weeks.
- Elderly or debilitated patients who fail to respond to treatment may die from respiratory failure.