2. • is an infection of the pulmonary parenchyma.
• The context in which pneumonia develops is highly suggestive of the
likely organism(s) involved.
• Classification – Community acquired, Hospital acquired and ventilator
associated pneumionias.
• Lobar pneumonia - homogeneous consolidation of one or more lung
lobes, often with associated pleural inflammation;
bronchopneumonia - refers to more patchy alveolar consolidation
associated with bronchial and bronchiolar inflammation.
3. Pathophysiology
• Pneumonia results from the proliferation of microbial pathogens at the
alveolar level and the host’s response to those pathogens.
• Microorganisms gain access to the lower respiratory tract usually by
aspiration from the oropharynx, rarely via hematogenous spread (e.g.,
from tricuspid endocarditis) or by contiguous extension from an infected
pleural or mediastinal space.
• Small-volume aspiration occurs frequently during sleep (especially in the
elderly) and in patients with decreased levels of consciousness.
• Resident alveolar macrophages kill pathogens that manage to reach the
alveoli. Only when the capacity of the alveolar macrophages to ingest or
kill the microorganisms is exceeded does clinical pneumonia become
manifest.
4. Factors that predispose to pneumonia
• Cigarette smoking
• Upper respiratory tract
infections
• Alcohol
• Glucocorticoid therapy
• Old age
• Recent influenza infection
• Pre-existing lung disease
• HIV
• Indoor air pollution
6. Clinical features
• Presentation - Acute illness.
• Systemic features - fever, rigors, shivering and malaise. Delirium may be present.
Appetite ↓, Headache.
• Pulmonary symptoms – Cough; short, painful and dry, but later is accompanied by
the expectoration of mucopurulent sputum. Pleuritic chest pain may be a
presenting feature and on occasion may be referred to the shoulder or anterior
abdominal wall.
• Physical exam - ↑respiratory rate and use of accessory muscles of respiration.
Palpation may reveal increased or decreased tactile fremitus, and the percussion
note can vary from dull to flat, reflecting underlying consolidated lung and pleural
fluid, respectively.
• Elderly patients - Presentation may not be so obvious, May initially display new-
onset or worsening confusion and few other manifestations
7. Labs
• Haemogram - Very high (> 20 × 109/L) or low (< 4 × 109/L) WBC: marker of
severity, Neutrophil leucocytosis > 15 × 109/L: suggests bacterial aetiology,
Haemolytic anaemia: occasional complication of Mycoplasma
• Urea and electrolytes Urea > 7 mmol/L marker of severity, ↓Na: marker of
severity,
• Liver function tests - Abnormal if basal pneumonia inflames liver,
Hypoalbuminaemia: marker of severity
• ESR /CRP -non-specifically elevated
• Blood culture - Bacteraemia: marker of severity
• Pulse oximetry - SPO₂ < 93%, marker of severity.
8. • Sputum samples - Gram stain, culture and antimicrobial sensitivity
testing.
• Chest X-ray - Lobar pneumonia; Patchy opacification evolves into
homogeneous consolidation of affected lobe.
Bronchopneumonia - patchy and segmental shadowing
Complications - Para-pneumonic effusion, intrapulmonary abscess or
empyema.
• Pleural fluid - Always aspirate and culture when present in more than
trivial amounts, preferably with ultrasound guidance.
9. Lobar Pneumonia of the right middle lobe
bronchopneumonia: multifocal lung consolidation
bilaterally
10.
11. Management of pneumonia
• 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 SPO2 ≥ 92%.
• Fluid balance - iv fluids should be considered in those with severe
illness, in older patients and those with vomiting.
• Antibiotic treatment.
16. Indications for referral to ITU
• CURB score of 4–5, failing to respond rapidly to initial management
• Persisting hypoxia (PaO2 < 8 kPa (60 mmHg)), despite high
concentrations of oxygen
• Progressive hypercapnia
• Severe acidosis
• Circulatory shock
• Reduced conscious level
17. Prognosis
• Most patients respond promptly to antibiotic therapy.
• Fever may persist for several days, chest X-ray takes several weeks or
even months to resolve,
• Delayed recovery suggests either that a complication has occurred or
that the diagnosis is incorrect.
