• Infection that inflames the air sacs in the lungs causing fluid or pus buildup

• Severity ranges from mild to life-threatening

• Affects all ages but especially the young, elderly, and immunocompromised

Bacterial:

– Streptococcus pneumoniae (80% of cases)

– Haemophilus influenzae (common in COPD)

– Mycoplasma pneumoniae

– Legionella pneumophila

Viral:

– Influenza viruses

– Respiratory syncytial virus (RSV)

– Coronavirus

Fungal:

– More common in immunocompromised individuals

– Pneumocystis jiroveci

Aspiration pneumonia is caused by the inhalation of foreign matter into the lungs.

• Age: Especially infants, young children, and the elderly

• Lifestyle factors: Smoking, alcohol use

• Preceding viral infections: Influenza, increasing susceptibility to bacterial infections

• Respiratory conditions: Asthma, COPD, bronchiectasis, cystic fibrosis, malignancy

• Immunosuppression: HIV/AIDS, cytotoxic therapy, organ transplantation

• Intravenous drug abuse: Associated with Staphylococcus aureus infection

• Hospitalization: Increases risk of Gram-negative bacterial infections

• Aspiration pneumonia: Impaired consciousness, neurological diseases, or esophageal obstruction

• Underlying diseases: Diabetes mellitus, cardiovascular diseases

– Respiratory conditions like asthma, COPD, bronchiectasis, cystic fibrosis, and lung cancer increase the risk.

– HIV/AIDS, cytotoxic therapy, and organ transplantation are key immunosuppressive conditions that heighten pneumonia risk.

– Intravenous drug abuse is associated with Staphylococcus aureus infections which can cause pneumonia.

1. Infection: Microorganisms (bacteria, viruses, or fungi) invade the lungs

2. Inflammatory Response: The immune system reacts, causing inflammation and increased blood vessel permeability

3. Fluid and Debris Accumulation: Increased permeability leads to fluid, pus, and debris accumulating in the air sacs

4. Impaired Oxygen Exchange: Accumulated fluid and debris hinder oxygen and carbon dioxide exchange, causing respiratory symptoms

5. Consolidation: Lung tissue may consolidate due to inflammation and immune activity

6. Symptoms: Individuals experience fever, cough, chest pain, difficulty breathing, and fatigue

• Common pathogens include Streptococcus pneumoniae, Staphylococcus aureus, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae, and respiratory viruses.

– Bronchitis
– Bronchiolitis
– Tuberculosis
– Pulmonary embolism
– Lung cancer
– Congestive heart failure
– Influenza
– COPD
– Asthma

• Bronchitis: Inflammation of bronchial tubes limited to airways not involving alveoli

• Bronchiolitis: Affects infants and young children characterized by inflammation and narrowing of bronchioles

• Tuberculosis: Bacterial infection primarily affecting lungs symptoms include cough, fever, night sweats; diagnosed with chest X-rays and sputum tests

• Pulmonary Embolism: Blood clot travels to lungs causing sudden shortness of breath, chest pain; diagnosed with CT scans

• Lung Cancer: Persistent cough, chest pain, weight loss; diagnosed with imaging studies and biopsies

• Congestive Heart Failure: Fluid accumulation in lungs due to heart failure leading to shortness of breath, coughing; diagnosed with echocardiogram and heart tests

• Influenza: Symptoms similar to pneumonia; diagnosed through rapid flu tests and clinical evaluation

• COPD: Chronic cough, shortness of breath; diagnosed with spirometry and lung function tests

• Asthma: Exacerbations lead to coughing, wheezing, shortness of breath; different mechanism and management from pneumonia

• Pneumonia is a significant cause of morbidity and mortality in the UK, affecting all age groups.

• More prevalent during winter months.

• Higher risk in the elderly, young children, and those with underlying health conditions.

• Includes community-acquired pneumonia (CAP) and hospital-acquired/ventilator-associated pneumonia.

• Affects 0.5-1% of the population annually.

• 22-42% of pneumonia cases are admitted to hospitals.

• 1.2-10% of hospitalized CAP patients require intensive care.

• Cough: With or without sputum

• Fever: Often with chills

• Dyspnea: Shortness of breath

• Chest Pain: Possibly pleuritic

• Fatigue

• Malaise

• Abnormal breath sounds

• Tachypnea: Increased respiratory rate

• Systemic inflammatory signs:

– Fever

– Tachycardia

• Hypoxemia: Reduced oxygen saturation

• Auscultation findings: Bronchial breathing

• Confusion

• Cyanosis

• Hemodynamic instability

• Nonspecific symptoms: Fever, cough, poor feeding, lethargy

• Additional symptoms: Abdominal pain may be present in young children

• New lung shadowing without an alternative explanation

• Common pathogens: Streptococcus pneumoniae, Staphylococcus aureus, Mycoplasma pneumoniae, Haemophilus influenzae, Chlamydophila pneumoniae, and respiratory viruses

• Mixed infections: Occur in about 25% of cases

• Chest X-ray: Identifies lung infiltrates or consolidation

• Complete Blood Count (CBC): Neutrophilia common in bacterial infections

• C-reactive Protein (CRP): Elevated in response to infection

• Procalcitonin levels: Assess infection severity

• Sputum culture

• Nasopharyngeal swab

• Bronchoalveolar lavage: Identifies the causative organism

• Arterial Blood Gas (ABG) Analysis

• Pulse Oximetry: Measures oxygen saturation

• Severity of illness

• Age

• Underlying health issues

• Social circumstances

• Confusion

• Respiratory rate ≥ 30 breaths/minute

• Systolic BP < 90 mm Hg or diastolic < 60 mm Hg

• Age ≥ 65 years

• Score 0: Low risk of mortality, consider home care

• Score 2+: Consider hospital admission

• Urea and Electrolytes: Checks for dehydration (related to CURB-65)

• Arterial Blood Gases (ABG): For low oxygen saturations or pre-existing respiratory disease like COPD

1. Chest X-ray: Identifies lung infiltrates or consolidation

2. Blood Tests:

– Complete Blood Count (CBC): Neutrophilia often seen in bacterial infections

– C-reactive Protein (CRP): Elevated in response to infection

– Procalcitonin levels: Assess infection severity

3. Microbiological Analysis of Respiratory Samples:

– Sputum culture, nasopharyngeal swab, or bronchoalveolar lavage: Identifies the causative organism

4. Additional Assessments:

– Arterial Blood Gas Analysis: Evaluates oxygenation status

– Pulse Oximetry: Measures oxygen saturation

• Avoid smoking

• Rest

• Increase fluid intake

• Oxygen therapy for hypoxia

• Analgesics (NSAIDs, paracetamol) for mild pleuritic pain

• Nebulized saline for expectoration

• Ventilation for severe hypoxia

• Amoxicillin

• Clarithromycin

• Erythromycin (in pregnancy)

• Doxycycline (for penicillin allergies or suspected atypical pathogens)

• Predicts pneumonia severity and influences treatment decisions based on confusion, urea levels, respiratory rate, blood pressure, and age

• Recommendations:

– Score 0: Consider home-based care (low risk)

– Score 2 or more: Consider hospital admission (intermediate risk)

– Score 3 or more: Consider intensive care assessment (high risk)

• CRB-65 score is used for risk assessment:

– Score 0: Low risk (consider home treatment)

– Score 1 or 2: Intermediate risk (consider hospital assessment)

– Score 3 or 4: High risk (urgent hospital admission recommended)

• CRP < 20 mg/L: Do not routinely offer antibiotic therapy

• CRP 20-100 mg/L: Consider delayed antibiotic prescription

• CRP > 100 mg/L: Offer antibiotic therapy

• Chest X-ray for all patients

• Blood and sputum cultures, pneumococcal and legionella urinary antigen tests for intermediate or high-risk patients

• CRP monitoring for admitted patients

• Delay discharge if specific findings are observed in the past 24 hours

• Temperature: Consider delaying discharge if the temperature remains elevated

• Expected symptom resolution timeline:

– 1 week: Fever should resolve

– 4 weeks: Chest pain and sputum production should substantially reduce

– 6 weeks: Cough and breathlessness should substantially reduce

– 3 months: Most symptoms should resolve; some fatigue may remain

– 6 months: Most individuals return to normal

• Repeat chest X-ray at 6 weeks after clinical resolution

• Varies by health, age, severity, and treatment timing: Prognosis depends on the individual’s overall health, age, severity of pneumonia, and how quickly treatment is initiated

• Response to treatment: Most patients respond well to antimicrobial therapy and supportive care

• Increased risk in severe cases or comorbidities: Patients with severe cases or underlying health conditions are at higher risk for complications and poor outcomes

• Mortality rates:

– <1% in community-acquired cases

– 5-10% in hospitalized patients

– 25% in intubated patients

– 50% in ICU patients requiring vasopressors

• Legionella pneumonia: Associated with severe outcomes, with mortality rates of 4% with quinolone treatment and 10.9% with macrolide treatment

• Health status

• Age

• Severity of the pneumonia

• Timing of treatment initiation.

• Community-acquired pneumonia (CAP): <1%

• Hospital-acquired pneumonia (HAP): 5-10%

• Intubated patients: 25%

• ICU with vasopressors: 50%.

• Most patients respond well to antimicrobial therapy and supportive care.

• Severe cases or those with comorbidities have an increased risk of complications.

• Specific pathogens, such as Legionella, have a higher mortality rate:

– 4% with quinolone treatment

– 10.9% with macrolide treatment.

• Prompt antibiotic treatment is crucial for improving outcomes.

• Vaccination against influenza and pneumococcal infections.

• Smoking cessation as a preventive strategy.

• Respiratory failure

• Sepsis

• Lung abscesses

• Empyema: Pus in the pleural cavity

• Pleural effusion

• Acute Respiratory Distress Syndrome (ARDS)

• Multiorgan failure

• Pleural effusion: Sterile accumulation of fluid

• Empyema: Serious reactive effusion after 4-5 days of antibiotic therapy

• Lung abscess: Especially in Klebsiella or Staphylococcal pneumonia

• Pneumatocele

• Pneumothorax

• Pyopneumothorax: Staphylococcal abscess rupture in pleural cavity

• Other systemic complications: Deep vein thrombosis, septicemia, pericarditis, endocarditis, osteomyelitis, septic arthritis, cerebral abscess, meningitis

• Postinfective bronchiectasis

• Acute kidney injury

• Post-infectious cough

• Bronchiectasis

• Increased susceptibility to recurrent infections