Respiratory system

UK figures suggest that an estimated 5-11/1000 adults suffer from CAP each year, accounting for around 5-12% of all lower respiratory tract infections. The incidence varies with age, being much higher in the very young and very old, in whom the mortality rates are also much higher. World-wide, CAP continues to kill more children than any other illness.

Pneumonia usually presents as an acute illness in which systemic features such as fever, rigors, shivering and vomiting predominate . Pulmonary symptoms breathlessness and cough, painful and dry, but later accompanied by the expectoration of mucopurulent sputum. Proteinaceous fluid and inflammatory cells congest the airspaces, leading to consolidation of lung tissue. This improves the conductivity of sound to the chest wall (bronchial breathing and whispering pectoriloquy). Crackles are often also detected

The objectives are to exclude other conditions that mimic pneumonia ,assess the severity, and identify the development of complications. A chest X-ray usually provides confirmation of the diagnosis. In lobar pneumonia, a homogeneous opacity localised to the affected lobe or segment usually appears within 12-18 hours of the onset of the illness . Radiological examination is helpful if a complication such as parapneumonic effusion, intrapulmonary abscess formation or empyema is suspected.


Oxygen: should be administered to all patients with tachypnoea, hypoxaemia, hypotension or acidosis with the aim of maintaining the PaO2 ≥ 8 kPa (60 mmHg) or SaO2 ≥ 92%. High concentrations (≥ 35%), preferably humidified, should be used in all patients who do not have hypercapnia associated with COPD. Assisted ventilation should be considered at an early stage in those who remain hypoxaemic despite adequate oxygen therapy.Noninvasive Ventilation (NIV ) may have a limited role but early recourse to mechanical ventilation is often more appropriate

Fluid balance: Intravenous fluids should be considered in those with severe illness, in older patients and in those with vomiting. Otherwise, an adequate oral intake of fluid should be encouraged. Inotropic support may be required in patients with circulatory shock.


Most patients respond promptly to antibiotic therapy. However, fever may persist for several days and the chest X-ray often takes several weeks or even months to resolve, especially in old age. Delayed recovery suggests either that a complication has occurred or that the diagnosis is incorrect . Alternatively, the pneumonia may be secondary to a proximal bronchial obstruction or recurrent aspiration. The mortality rate in adults managed at home is very low (< 1%); hospital death rates are typically between 5 and 10%, but may be as high as 50% in severe illness