Bacterial, viral, and fungal pneumonia

1. C B U - S O M / N D O L A T E A C H I N G H O S P I T A L
I N T E R N A L M E D I C I N E
J U N E 2 0 2 2
PNEUMONIA
Dr C Nyirenda

2. Learning objectives
 At the end of this unit the student will be able to:
1. Define Pneumonia
2. List the etiologic agents of Pneumonia occurring in different
settings
3. Describe the mode of transmission of Pneumonia
4. Understand the epidemiology of Pneumonia.
5. Describe the pathophysiology of Pneumonia
6. Identify the clinical manifestations of Pneumonia
7. List the complications of Pneumonia
8. Describe the most common investigations for the diagnosis of
Pneumonia
9. Make an accurate diagnosis of Pneumonia
10. Manage most cases of Pneumonia appropriately
11. Refer complicated cases of Pneumonia

3. Definition
 Pneumonia is an acute infection of the lung parenchyma
including alveolar spaces and interstitial tissue.
 Involvement may be confined to an entire lobe -Lobar
pneumonia
 A segment of a lobe-Segmental or lobular pneumonia
 Alveoli contiguous to bronchi - Bronchopneumonia
 Interstitial tissue - Interstitial pneumonia
 These distinctions are generally based on x-ray
observations.

4. Risk factors
Predisposing factors for pneumonia include:-
 Preceding respiratory viral infections
 Alcoholism
 Cigarette smoking
 Underlying diseases such as Heart failure, COPD
 Age extremes
 Immunosuppressive therapy and disorders
 Decreased consciousness, comma, seizure etc.
 Surgery and aspiration of secretions

5. Pathogenesis
 The usual mechanisms to develop pneumonia are
either to inhale droplets small enough to reach the
alveoli, or to aspirate secretions from the upper
airways. Other means include
 hematogenous dissemination, via the circulation, or
directly from contiguous infections.

6. Epidemiology
CAP versus HAP
• Community-acquired pneumonia (CAP) is defined as
an acute infection of the pulmonary parenchyma in a
patient who has acquired the infection in the
community, as distinguished from hospital-acquired
(nosocomial) pneumonia (HAP).
• CAP is a common and potentially serious illness . It
is associated with considerable morbidity and
mortality, particularly in older adult patients and
those with significant comorbidities.

7. Pneumonia in special populations
 aspiration pneumonia,
 Hypostatic pneumonia
 Pneumonia in the immunocompromised patients,
 ventilator-associated pneumonia (VAP) etc.

8. Etiopathogenetic basis
 CAP; Streptococcus pneumonia, Haemophilus
influenza and Mycoplasma pneumoniae. Others-
Staph. Aureus, Legionella species
 HAP; Pseudomonas, Klebsiella, Bacteroides,
Clostridia and also Staph aureus
 Aspiration e.g in stroke, oesophageal disease,
myasthenia..; mainly oropharyngeal anaerobes but
also gram positives and possibly negatives
 Immunocompromised; PJP, other fungal species,
viruses (e.g HSV, CMV), Strep pneumonia, H.
Influenza, M. Pneumonia also

9. Clinical presentation
 Subjective: fever, rigors, malaise, anorexia,
dyspnoea, cough, purulent sputum, haemoptysis and
chest pains
 Objective: febrile, cyanosis, confusion, tachypnoea,
tachycardia, hypotension, reduced air entry,
crepitations,bronchial breath sounds and increased
vocal resonance

10. Investigations
 Laboratory; FBC/DC, U&E,LFT, CRP, blood cultures,
sputum m/c/s, urine Ag –legionella and
pneumococcus. Pleural fluid for culture??
 Bronchoscopy and bronchoalveolar lavage
 Radiological; CXR, CT or MRI in case of complicated
cases

11. Complications
 Pleural effusions, empyema, lung abscess,
respiratory failure, septicaemia, brain abscess
pericarditis, myocarditis etc

12. Severity scale
 CURB- 65 score
 C- confusion, U- urea> 7 mmol/l, R- rate >=30/min,
 BP < 90 systolic and /or 60 mmHg diastolic, age >
65
 Scores 0-1; home treatment; 2 hospitalization, >=3
severe pneumonia
 Increased mortality in co-morbidity and reduced
arterial partial pressure of oxygen e.g < 8 kpa

13. Management
 Oxygen therapy depending on severity; BLS as
appropriate
 IV fluids e.g in dehydration and shock.
 Antibiotic therapy; oral in mild disease e.g CURB 0-1
or if not vomiting. IVs in severe disease
 Empirical options:
 CAP; mild-penicillins or macrolides or
fluoroquinolones. Severe-Co-amoxyclav iv or
cephalosporin iv . Erythromycin iv in case of
Mycoplasma pneumonia

14. Management contn
 HAP; Aminoglycoside iv + penicillin or 3rd
generation cephalosporin iv
 Aspiration; Cephalosporin iv + metronidazole iv
 Others; PJP- high dose co-trimoxazole

15. END…
 Q/Cs??