Persistant and Recurrent Pneumonia

I. Definitions

• Persistent Pneumonia: Persistence of clinical symptoms or radiological shadows for > 4 weeks despite appropriate antibiotic therapy.
• Recurrent Pneumonia:
  • 2 or more episodes in a single year, OR
  • 3 or more episodes in a lifetime.
  • Key Feature: There must be radiographic clearing between episodes.

II. Differential Diagnosis (Etiology)

The causes can be categorized based on the underlying mechanism.

A. Local/Anatomic Causes (Often focal recurrence)

1. Intraluminal Obstruction:
   • Foreign Body: Missed aspiration (Right lower lobe common).
   • Endobronchial TB or tumors (rare).
2. Extraluminal Compression:
   • Vascular rings/slings.
   • Enlarged lymph nodes (TB, Histoplasmosis).
3. Congenital Malformations:
   • Pulmonary Sequestration (recurrent infection in the sequestered lobe).
   • Congenital Lobar Emphysema.
   • Bronchogenic Cyst.
   • Tracheobronchial stenosis.

B. Aspiration Syndromes

1. Oropharyngeal Dysphagia: Cerebral Palsy, Bulbar palsy.
2. Gastroesophageal Reflux (GERD): Severe reflux + microaspiration.
3. H-type Tracheoesophageal Fistula: Presentation often delayed.

C. Generalized/Host Defense Defects (Often diffuse/multilobar)

1. Cystic Fibrosis (CF): Most common genetic cause of suppurative lung disease.
2. Primary Ciliary Dyskinesia (PCD): Recurrent pneumonia + Situs Inversus + Sinusitis (Kartagener syndrome).
3. Immunodeficiency:
   • Humoral: X-linked Agammaglobulinemia, Selective IgA deficiency.
   • Cellular: HIV/AIDS, SCID.
   • Phagocytic: Chronic Granulomatous Disease (CGD).

D. Specific Infections (Persistent)

• Tuberculosis: Always the first differential in endemic areas.
• Resistant Organisms: MRSA, Pseudomonas.
• Fungal: Aspergillosis, Histoplasmosis.

III. Diagnostic Approach

Step 1: Detailed History & Examination

• Choking history: Suspect Foreign Body.
• Site: Same lobe (Anatomic/FB) vs Different lobes (Immune/Aspiration).
• Associated features:
  • Greasy stools/Failure to thrive $\to$ Cystic Fibrosis.
  • Ear discharge/Dextrocardia $\to$ PCD.
  • Feeding difficulties $\to$ Aspiration.

Step 2: Phase I Investigations (Basic)

1. Complete Blood Count: Lymphopenia (Immune def), Neutropenia.
2. Chest X-Ray: Compare with previous films to confirm persistence vs recurrence.
3. Mantoux Test / IGRA: To rule out TB.
4. Sweat Chloride Test: Gold Standard for Cystic Fibrosis (Should be done in ALL cases of recurrent pneumonia).
5. Immunoglobulin Profile: IgG, IgM, IgA levels.
6. HIV ELISA.

Step 3: Phase II Investigations (Anatomic/Functional)

1. CT Scan Chest (CECT/HRCT):
   • Defines bronchiectasis, sequestration, or lymphadenopathy.
   • [Image of CT chest bronchiectasis]
2. Flexible Bronchoscopy:
   • Visualizes airway dynamics (malacia), foreign bodies, or compression.
   • Bronchoalveolar Lavage (BAL): For culture and lipid-laden macrophages (aspiration).

Step 4: Phase III Investigations (Specific)

• Barium Swallow: For vascular rings/TEF/GERD.
• Nasal Nitric Oxide / Ciliary Biopsy: For PCD.
• NBT Test / DHR Flow Cytometry: For CGD.

IV. Management

A. General Principles

1. Treat the Acute Episode: Culture-directed antibiotics.
2. Nutritional Rehabilitation: High-protein, high-calorie diet.
3. Airway Clearance: Chest physiotherapy and postural drainage (crucial for CF/PCD).
4. Vaccination: Pneumococcal (PCV/PPSV23) and Influenza vaccines.

B. Specific Management (Treat the Cause)

C. Follow-up

• Monitor growth velocity.
• Pulmonary Function Tests (PFTs) in older children.
• Repeat imaging only if clinical deterioration (ALARA principle).