Community Acquired Pneumonia (CAP)

Clinical Description

Pneumonia is inflammation of the lungs caused by infection. Causative organisms can be bacterial, viral or fungal. Community acquired pneumonia (CAP) is mostly caused by streptococcus pneumoniae. Other causes include Haemophilus influenza, staphylococcus aureus (in diabetes,in children after viral illness like measles), Atypical organisms: Mycoplasma pneumonia, chlamydia pneumoniae, Legionella pneumophila.

People at extra risk of CAP: HIV infected, elderly, diabetics, malnourished, smokers and alcoholics. Underlying bronchiectasis – increase risk of S. aureus or gram negative organisms (e.g. H. influenzae or Pseudomonas sp.) For all forms of pneumonia HIV testing is required.

Signs and Symptoms

• Cough
• shortness of breath
• fever,
• chest pain (can be pleuritic pain)
• Depends on severity, tachypnea, consolidation signs. Herpes labialis presence (suggests streptococcal pneumonia as cause of pneumonia)
• CAP Severity assessment important: determines management either as in patient or outpatient

CAP severity assessment score (CURB-65) in adult

Assign one point to each of the following factors (maximum 5 points):

• -Confusion, restlessness, or excessive
• Blood Urea Nitrogen (> 7 mmol/L)
• -Respiratory rate (≥ 30 per minute in adults)
• BP low (Systolic BP < 90 and/or diastolic BP < 60 mmHg)
• Age (extreme) ≥ 65yr
• 0-1:(Mild CAP): consider home treatment
• 2-3 (moderate CAP) consider short inpatient hospitalization
• 3 (severe CAP): admit and consider HDU/intensive care

Note: multilobar pneumonia, hypoxia, CAP with complications and presence comorbidities e.g. heart failure, CKD, diabetes mellitus necessitate in hospital treatment

Investigations

• FBC
• Urea, creatinine and electrolytes
• HIV test
• C-reactive protein (CRP)
• Blood culture
• Sputum gram stain and culture and sensitivity, Ziehl-Neelsen stain for acid-fast bacilli or MTB-RIF GeneXpert (to exclude TB)
• Chest X-ray
• FASH, CD4 and Urine TB LAM (if TB suspected)

Treatment

• Identify patients at greater risk who require in-hospital management
• Treat the infection and alleviate symptoms
• Prevent and management complications

Non-pharmacological

• Nurse in comfortable position
• Adequate oral hydration (if tolerated)
• Chest physiotherapy if CAP is complicated by lung abscess for
• Pharmacological treatment (depends on severity)

Pharmacological

COMPLICATIONS OF CAP

• Pleural effusion
• Empyema
• Lung abscess
• Pneumothorox (especially with staphylococcus aereus infection and Pneumocystis jiroveci pneumonia)
• Cavitating lesions (staphylococcal aereus, TB, klebsiella)
• Pericardial effusion/pericarditis
• Meningitis
• Septicaemia with shock/multi organ failure
• Adult respiratory distress syndrome (ARDS)