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Information ⬇

Author: Ahmed Yousuf

Community-acquired pneumonia (CAP) (see Box 62.1 for definition) usually presents with acute respiratory symptoms, but should always be considered in patients with unexplained sepsis or delirium. Examination of the chest may be normal and, if you suspect pneumonia, a chest X-ray is need to make the diagnosis.

A broad range of pathogens can cause CAP. Streptococcus pneumoniae (pneumococcus) is the most common bacterial pathogen, accounting for up to 50% of cases. Other common pathogens are Staph. aureus, Legionella pneumophila and influenza.

Priorities ⬆ ⬇

Outline

Is This Pneumonia? How Severe is It?!!navigator!!

  • Suspect pneumonia in the presence of one or more of the following clinical features:
  • Consider the differential diagnosis (Table 62.1). A chest X-ray showing new focal shadowing is essential for the diagnosis (Table 62.2). Other investigations needed are given in Table 62.3. For low severity (CURB-65 = 0–1) urine antigen or serological investigations may be considered during outbreaks (e.g. Legionnaires' disease) or epidemic mycoplasma years, or when there is a particular clinical or epidemiological reason.
  • The severity of CAP can be assessed by the CURB-65 score (Table 62.4).

Choice of Initial Antibiotic Therapy for Cap!!navigator!!

  • Your initial therapy depends on the clinical setting, severity of pneumonia and local antimicrobial policy (Table 62.5).
  • Start antibiotic therapy as soon as diagnosis of CAP is suspected. Antibiotics should not be withheld if there is a delay in taking blood for culture.

Further Management ⬆ ⬇

Outline

Oxygen!!navigator!!

Humidified O2 should be continued to keep arterial PaO2 >8.0 kPa, oxygen saturation >92% (>88% in patients with chronic obstructive pulmonary disease).

Fluid balance

  • Insensible losses are greater than normal due to fever (allow 500 mL/day/°C fever) and tachypnoea.
  • Patients with severe pneumonia should receive IV fluids (2–3L/day), with daily assessment of fluid status and measurement of renal function. Adequate hydration also helps with expectoration of sputum.

Antibiotic therapy

  • Review this after 48h. If there has been clinical improvement, with a fall in C-reactive protein level, switch to oral therapy in those patients initially given IV therapy.
  • Management of patients who fail to improve after 48h antibiotic therapy is discussed below (see Problems).

Venous thromboembolism prophylaxis

Give prophylaxis with anti-embolism stockings and low-molecular-weight heparin.

Pain relief

Relieve pleuritic chest pain with paracetamol and/or NSAIDs, to facilitate sputum expectoration.

Chest physiotherapy

  • Chest physiotherapy is helpful if the patient is producing sputum but having difficulty expectorating it, and in bronchiectasis.
  • Nebulized hypertonic saline may be helpful when sputum is thick and difficult to expectorate, but tends to cause a greater degree of bronchoconstriction than normal saline. Give bronchodilator therapy before nebulized hypertonic saline.

Bronchodilator therapy

Nebulized salbutamol or ipratropium should be prescribed to patients with asthma or COPD if there is wheeze.

Checklist Before Discharge!!navigator!!

Clinically stable for >24h:

Problems!!navigator!!

Failure to improve after 48h antibiotic therapy

Address the following points:

  • Review the clinical, microbiological and radiological findings.
    • Are you confident the diagnosis is pneumonia (consider the diagnoses in Table 62.1), and that the patient's current antibiotic therapy is appropriate for the possible pathogens?
    • Consider broadening your antibiotic therapy, in case the organism is unusual or resistant: ask advice from a microbiologist.
  • Re-examine the patient, and check for signs of metastatic infection, such as septic arthritis, pericarditis or infective endocarditis.
  • Repeat the chest X-ray. Are there any new findings such as cavitation or pleural effusion? If pleural fluid is now present, this should be aspirated and sent for Gram stain and culture. If the fluid is cloudy rather than mildly turbid, drain completely and treat as empyema (discuss with a chest physician). A pH <7.20 also favours empyema rather than a parapneumonic effusion.
  • In an IV drug user or a patient with an indwelling venous cannula consider tricuspid valve endocarditis with septic pulmonary emboli.
  • Consider underlying airways or lung disease, such as chronic obstructive pulmonary disease, bronchiectasis, bronchial carcinoma and inhaled foreign body.
  • Consider pulmonary tuberculosis in patients with risk factors for TB. Send sputum for Ziehl-Neelsen stain. If no sputum is being produced, consider fibreoptic bronchoscopy. A Mantoux skin test (0.1 mL or 1 in 10,000 intradermally) may be performed, but interpretation can be difficult – a strongly positive test is good evidence of active infection, but a negative reaction can occur in the presence of active infection.
  • Consider HIV/AIDS. Test for HIV if this has not already been done.
  • Ask advice from a chest physician. CT or fibreoptic bronchoscopy may be indicated to clarify the diagnosis.

Further Reading ⬆

National Institute for Health and Care Excellence (2014) Pneumonia in adults: diagnosis and management. Clinical guideline (CG191). https://www.nice.org.uk/guidance/cg191

Prina E, Ranzani OT, Torres A. (2015) Community-acquired pneumonia. Lancet 386, 1097–1108.