4. PATHOGENESIS
Pneumonia results from
Proliferation of organism at alveolar level Host response
Micro-organism gain access to lower respiratory tract in several ways
* Aspiration from oropharynx
* Inhalation (Contaminated droplets)
* Haematogenous (Rare)
* Extension from infected pleura & mediastinum (Rare)
5. Alveolar level
Macrophage
Local protein
Engulf and Cleared
Inflammatory response
Capillary leak
Haemoptysis
Rediographic
change
Crepitations
Hypoxemia
Tracheobronchial tree
Particle trapped by cells
Mucocilliary clearance
Local antibacterial factor
Oropharynx
Gag reflex
Cough
Normal flora
Nasopharynx
Hair + tubinate
(Larger particle)
SIRS- increase Respiratory drive
Respiratory distress due to:
Decrease compliance due to capillary leak
Increase Respiratory drive
Hypoxemia
Increase Secretion
Increase Bronchospasm
PATHOGENESIS
6. CLINICAL FEATURES
Indolent to Fulminant in onset
Mild to Fatal in severity
Common Symptoms
Systemic :
Fever, rigor, shivering & malaise predominate & delirium may present.
Loss of appetite
Headache
Pulmonary :
Cough initially short , painful & dry, but later is accompanied by the expectoration of mucopurulent
sputum.
Chest Pain occasionally referred to shoulder & ant. Abdominal wall.
( Less typical presentation in very young & elderly)
7. Signs:
Inspection
Tachypnoea , Central cyanosis (if severe), ↓ movement of chest
Palpation
↓ chest Expansion
Trachea deviated (if upper lobe)
Percussion
Dull
Auscultation
Bronchial breath sounds & ↑vocal resonance over consolidation & whispering pectoriloquy
Crepitation
Pleural rub if pleurisy
8. PARTICULAR CLINICAL FEATURE SUGGESTING UNDERLYING CAUSE
Streptococcus pneumonia:
Preceded by Flue Like symptoms
Herpes labialis
Rusty sputum
Occasional haemoptysis
Bacteremia common in women/COPD/DM
Mycoplasma Pneumonia:
Young patient
Haemolytic anaemia
Meningoencphalitis
Erythema Multiforme/ Erythema Nodosum
GBS
Stevens Johnson Syndrome
9. PARTICULAR CLINICAL FEATURE SUGGESTING UNDERLYING CAUSE
Legionella:
Associated with cooling system
Neurological symptoms
Diarrhea
Common in Patient of CKD, Haematological malignancy, DM, steroid use.
Elevated liver enzyme
Hyponatraemia
Staphy. Aureus:
Recent influenza infection
Bilateral infiltrate
Endocarditis/Brain Abcess/osteomyelitis
Associated with high mortality rate
10. PARTICULAR CLINICAL FEATURE SUGGESTING UNDERLYING CAUSE
Chlamydia Pneumoniae
Prolong prodrome
Mild disease
Haemophilus influenza
Elderly patient with pre-existing lung disease
Chlamydia psittaci
From birds - Occupational Pneumonia
Dry cough
11. PARTICULAR CLINICAL FEATURE SUGGESTING UNDERLYING CAUSE
Coxiella Burnetti:
Dairy farms - Occupational Pneumonia
Endocarditis (in chronic cases)
Klebsiella:
Male Alcoholic / DM/Hospitalized Patient
Poor dental hygiene
Low platelet count
Low WBC count
Pseudomonas aeruginosa:
Cavitation /Abcess
Common in Immunosupression
12. INVESTIGATION
Blood: CBC > High neutrophil count
> Low neutrophil count
> Evidence of Haemolysis (Mycoplasma)
Urea + Electrolytes (Hyponatremia)
Lever function test (Hypoalbuminemia)
Procalcitonin
ESR/CRP
Blood culture > Disappointing
> 5% to 14% of CAP will be positive
> indicated for High risk patient – Neutropenia
– Asplenia
– Complement deficiency
– CLD
– Severe CAP
ABG (Arterial blood gas)
15. SEVERITY ASSESSMENT
1. CURB-65 score
&
2. Pneumonia severity index (PSI)
CURB-65 score
C: confusion present
U: (Plasma) urea level >7 mmol/L
R: respiratory rate >30/min
B: systolic BP <90 mmHg; diastolic BP <60 mmHg
65: age >65y
1 point for each of the above:
Score 0-1: Treat as outpatient
Score 2: Admit to hospital
Score 3+: Often require ICU care
Mortality rates increase with increasing score.
16. Other markers of severe community-acquired pneumonia
Chest X-ray: more than one lobe involved
PaO2 <8 kPa
Low albumin (<35 g/L)
White cell count (<4109/L or >20109/L)
Blood culture – positive
Presence of other co-morbidities
Absence of fever in the elderly.
20. Complications
• Para-pneumonic effusion – common
• Empyema
• Retention of sputum causing lobar collapse
• Deep vein thrombosis and pulmonary embolism
• Pneumothorax, particularly with Staphylococcus aureus
• Suppurative pneumonia/lung abscess
• ARDS, renal failure, multi-organ failure
• Ectopic abscess formation (Staphylococcus aureus)
• Hepatitis, pericarditis, myocarditis, meningoencephalitis
• Arrhythmias (e.g. atrial fibrillation)
• Pyrexia due to drug hypersensitivity
21. Management of CAP
Oxygen Administration
Pt with tachypnoea, hypoxia, hypotension & acidosis
Target PaO2 ≥ 60 mmHg Or SaO2 ≥ 92%
Fluid Balance : adequate fluid balance
Treatment of Pleural Pain: Paracetamol , Tramadol or Combination, NSAIDs, Opiates with caution
CPT: helpful to assist expectoration of sputum
22. Antibiotic Treatment for CAP
Low Severity CAP (CURB-65 score 0-1)
Amoxicillin 500mg 3 times daily orally (or IV if necessary)
If patient is allergic to penicillin
Doxycyline 200 mg loading dose then 100 mg/day orally
or
Clarithromycin 500 mg twice daily orally
Moderate severity CAP (CURB-65 score 2)
• Amoxicillin 500 mg-1gm 3 times daily orally (or IV if oral medication not
possible) plus clarithromycin 500 mg twice daily orally/IV
or
benzylpenicillin 1.2g 4 times daily IV
plus clarithromycin 500 mg twice daily orally/IV
23. Antibiotic Treatment for CAP
If patient is allergic to penicillin
Doxycycline 200 mg loading dose then 100 mg/day orally
or
Levofloxacion 500 mg/day orally
Severe CAP (CURB-65 score 3-5)
Co-amoxiclav 1.2g 3 times daily IV or Cefuroxime 1.5g 3 times daily IV
or Ceftriaxone 1-2 g daily IV plus clarithromycin 500 mg twice daily IV
or
benzyplenicillin 1.2 g 4 times daily IV plus Levofloxacin 500 mg twice
daily
If legionella is strongly suspected
Consider adding Levofloxacin 500 mg twice daily IV
25. PNEUMONIA IN IMMUNOCOMPROMIZED PATIENT
Immunocompromized by drugs/disease
Organisms > Common pathogens
Opportunistic infection: Gm-ve Bacteria
Mycobacteria
Fungal
Protozoal
Helminthic
Viral
26. Two clinical tools helps us to narrow the D/D
1. Underlying immunological defect
2. Time course of infection
1. Underlying immunological defect
Causes of immune suppression-associated lung infection
Cause Probable organism
Defective
Phagocytic function
Acute leukaemia
Cytotoxic drugs
Agranuloytosis
Gram-positive bacteria,
including Staph. aureus
Gram-negative bacteria
Fungi e.g. Candida albicans
and Aspergillus fumigatus
Defects in Cell-
mediated immunity
immunosuppressive drugs
Cytotoxic chemotherapy
lymphoma
Thymic aplasia
Viruses
Cytomegalovirus
Herpesvirus
Adenovirus
Influenza
Fungi
Pneumocysitis jirovecii
Candida albicans
Aspergillus fumigatus
Defective effects in
antibody production
Multiple myeloma ,Chronic
lymphocytic leukaemia
Haemophilus influenzae
Mycoplasma pneumoniae
27. 2. Time course of infection
Fulminant pneumonia-Bacterial
Insidious pneumonia –viral/fungal/protozoal
Pneumonia within 2-4 weeks of organ transplantation
- Usually Bacterial
Several months or more later of organ transplantation
- P. Jirovecii
- CMV.
- Fungal (Aspergillus)
29. INVESTIGATION
HRCT
HRCT is useful in differentiating the likely causes:
Focal unilateral opacification- Bacterial infection,
Mycobacteria
Nocardia.
Bilateral opacification- P. jirovecii pneumonia
Fungi
Viruses
Unusual bacteria, e.g. nocardia.
Cavitation- N. asteroids
Mycobacteria
Fungi
The presence of a ‘halo sign’ suggest Aspergillus
Pleural effusions suggest a pyogenic bacterial infection and are uncommon in P.
jirovecii pneumonia.
31. Hospital Acquired Pneumonia (HAP)
2nd most common hospital- aquired infection (HAI)
Leading cause of Health care associated infection(HAI) associated death
It refers to a new episode of pneumonia occurring at least 2 days after
admission to hospital.
33. Features Suggesting of HAP
Unexplained fever
Increase O2 demand
New radiological infiltrate
Leucocytosis / Leucopenia
Antibiotic Treatment (HAP)
Early-onset HAP (occurring within 4–5 days of admission)
If Pt with no previous antibiotics: co-amoxiclav or cefuroxime - a sensible choice.
If the pt has received a course of recent antibiotics: piperacillin/tazobactam or a third-
generation cephalosporin should be considered
Late-onset HAP (pneumonia occurring > 5 days of hospitalization)
Wide range of Gram-negative bacteria & anaerobes are involved
Antipseudomonal : carbapenem (meropenem), an anti-pseudomonal cephalosporin or
piperacillin–tazobactam.
MRSA : glycopeptides such as vancomycin or linezolid.
Acinetobacter Baumannii : Usually sensitive to carbapenems but resistant cases may
require nebulised and/or intravenous colistin
35. Aspiration Pneumonia
It refers to the development of radiographic infiltrate in the setting of pt with risk factors for
increased oropharyngeal aspiration.
Risk factors :
Cerebrovascular disease
Degenerative neurologic disease
Alzheimer’s disease
Multi-infact dementia
Parkinsinson’s disease
MND
Multiple sclerosis
Head & Neck Cancer
Oropharyngeal, oral cavity, esophageal malignancy
Others: scleroderma,Diabetic gastroparesis,Reflux esophagitis,Achalasia etc.
36. Diagnosis:
No “gold standard” test to diagnose aspiration.
Presence of risk factors + Infiltrates in a characteristic bronchopulmonary segment
In recumbent position: common site of involvement are the posterior segments of upper lobes & apical
segments of lower lobes.
In upright or semirecumbent position: Basal segments of lower lobes are favored.
Treatment
Antimicrobial therapy: Choice should depend on the setting in which aspiration occurs ( eg: In the
community or Health care facility) & pt. characteristics such as alcoholism, IV drug abuse, bad oral
hygiene, recent use of antibiotics or acid suppressive therapy.
Involved organisms: Gram –ve enteric bacteria (most common), Anaerobes, Staph. Aureus.
Tube feeding
Maintaining oral hygiene
Endotracheal intubation (with cuffed tube) in some special circumstances like elderly with low GCS
ACE inhibitors may be beneficial in HTN pt.
37. Indication for ICU admission:
CURB- 65 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
