Suppurative Pneumonia & Pneumonia in Immunocompromised Patients!

SUPPURATIVE PNEUMONIA (ASPIRATION PNEUMONIA) AND PNEUMONIA IN IMMUNOCOMPROMOISED PATIENTS 

SUPPURATIVE PNEUMONIA

Definition:

"Suppurative pneumonia is characterized by destruction of the lung parenchyma by inflammatory process and although microabscessation formation is characteristic histological feature, pulmonary abscess" is usually taken to refer lesion which is a large, localized collection of pus or a cavity lined by chronic inflammatory tissue from which pus has escaped by rupture into bronchus".

Etiology:

1. Inhalation of septic material during operations on the nose, mouth, throat under general anesthesia
2. Bulbar
3. Vocal cord palsy
4. Esophageal reflux
5. Alcoholism

Infecting Organism:

• Bacterioder melaninogenicus
• Anaerobic/microaerophilic cocci
• B. fragilis
• S. aureus (most common)
• K.pneumoniae
• S.pneumonia.

*Leimerres Syndrome is a rare cause of pulmonary abscesses. Usually, causative agent is F.secrophorum. Illness signs include sore throat, painful swollen neck, fever, rigors, dyspnea.

A non-infective form of Aspiration pneumonia is exogenous lipid pneumonia may follow aspiration of animal, vegetable, mineral oil.

Clinical Features:

1. Cough with sputum
2. Pleural pain
3. Pyrexia
4. Systemic upset
5. Weight loss

Investigations:

1. Chest Pain: to confirm the diagnosis and exclude complication.
2. Pulse Oximetry: to monitor response to oxygen therapy, if SaO2 < 93% features of sever pneumonia, identify ventilatory failure or acidosis.
3. Cell count: ESR, Neutrophil leukocytosis
4. Microbiological studies: for severe CAP and those that do not respond to initial therapy (Gram stain, sputum culture, blood culture)
5. Renal Function test: Urea and Electrolytes
6. Liver Function test: Elevated C-Reactive protein
7. Complete Blood Count (CBC)
8. Chest X-Ray

Management:

The goal for management involves:

• Oxygen therapy
• Fluid balance
• Antibiotic therapy
• In severe illness--Nutrition support

1. Oxygen Therapy:

• Oxygen should be administered to all the patients with tachypnea, hypoxemia, hypotension with the aim of maintaining SaO2 at >92%.
• Indicated for: Referral to Intensive Therapy Unit (ITU) including.

1. Persistent hypoxia SaO2 <90% despite high concentration of O2.
2. Severe acidosis
3. Circulatory shock
4. Reduced conscious level.

2. IV Fluids:

• should be considered in patients with severe illness, older patients, those who are vomiting. Oral fluid intake is encouraged.

3.Antibiotic Therapy:

IV Co-Amoxiclav 102g three times daily.

• If anaerobic bacterial infection;

            Oral Metronidazole 400mg three times daily.

• If Community acquired MRSA suspected;

           Oral non-beta lactam antibiotics used- Tetracycline, Clindamycin

• Treatment for 4-6 weeks - patients with lung abscess

4. Physiotherapy

5. Surgery (if no improvement)

PNEUMONIA IN IMMUNO-SUPPRESSED HOST:

• Patients immunocompromised by drugs or disease are at a high risk of pulmonary infection.

Etiology:

• Defective phagocytic function: caused by;

       Acute leukemia

       Cytotoxic drugs

      Agranulocytosis

Infecting organisms:

       Gram positive bacteria ( S.aureus)

       Gram negative bacteria

       Fungi (e.g.: Aspergillus fumigatus)

• Defects in Cell-mediated Immunity: caused by;

       Immunosuppressive drugs

      Cytotoxic drugs

      Chemotherapy

  Infecting organism:

     Virus (Adenovirus)

     Fungi

• Defects in Antibody Production: caused by;

      Chronic lymphocytic pneumonia

       Infecting organism:

       H.influenza

Clinical Features:

Fever

Investigations:

1. Bronchoscopy
2. BAL
3. Surgical lung biopsy
4. Transbronchial biopsy
5. Microbiological tests
6. High Resolution Chromatography (HRCT): for differentiating likely cause such as cavitation seen with mycobacteria and fungi)

Management:

The goal for management involves:

• Oxygen therapy
• Fluid balance
• Antibiotic therapy
• In severe illness--Nutrition support

1. Oxygen Therapy:

• Oxygen should be administered to all the patients with tachypnea, hypoxemia, hypotension with the aim of maintaining SaO2 at >92%.
• Indicated for: Referral to Intensive Therapy Unit (ITU) including.

1. Persistent hypoxia SaO2 <90% despite high concentration of O2.
2. Severe acidosis
3. Circulatory shock
4. Reduced conscious level.

2. IV Fluids:

• should be considered in patients with severe illness, older patients, those who are vomiting. Oral fluid intake is encouraged.

3.Antibiotics:

Brad spectrum antibiotics- 3rd Generation Cephalosporin and Antisaphylococcal antibiotic

                                                                          or

                        Antipseudomonal penicillin and Aminoglycosides