Definition of Pneumonia

7/30/2019 Definition of Pneumonia

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Definition of Pneumonia

Pneumonia is defined as inflammation of lung parenchyma

The term pneumonitis is synonymous but is best avoided

During the process of inflammation of alveoli there occurs inflammatory exudate that fill up air

spaces and result in consolidation of lung.

Physical Signs & Symptoms

Cough (productive or non-productive)

Dyspnea

Pleuritic chest pain

Fever or hypothermia

Myalgias

Chills/Sweats

Fatigue

Headache

Diarrhea (Legionella)

URI, sinusitis (Mycoplasma)

Tachycardia

Tachypnoea

Hypotension

Creps

Bronchial breathing





Physical signs

Physical exam has a sensitivity of 47-60% and specificity of 50-75%

However in pt’s with creps, fever, cough and tachycardia the possibility of pneumonia increases

from 18 to 42%

Also, pt’s with none of RR>20, HR>100 and temp>37.8ºC have a <1% chance of having

pneumonia

Predisposing factors

Age

COPD

Diabetes

Heart failure

Immunocompromised states

Alcoholism

Smoking

Travel/occupational/recreational exposure



Classification of Pneumonias

LOBAR PNEUMONIA

INTERSTITIAL PNEUMONIA

BRONCHOPNEUMONIA

LOBAR PNEUMONIA

Organisms cause inflammatory exudate that fill up air spaces and result in consolidation of whole lobe

of lung



BRONCHOPNEUMONIA

Common cause is satphylococcal infection.

Bronchopneumonia is characterized by patchy exudative consolidation of lung parenchyma due

to terminal bronchiolitis with consolidation of peribronchial alveoli.

Common also with gram negative organisms



Pathogenesis of Bronchopneumonia

There is initial terminal bronchiolitis with patchy consolidation of peribronchial lung tissue.

Bronchioles are plugged by the swollen mucosa and their secretion. As a result, the air cannot

enter the alveoli.

The imprisoned air in the alveoli is absorbed causing collapse of the alveoli.

Collapsed areas are surrounded by areas of compensatory emphysema.

Consolidated areas are surrounded, from inside outwards, by areas of congestion, collapse and

emphysema .

Resolution of the exudate usually restores normal lung structure.

Organization may occur and result in fibrous scarring in some cases.

Aggressive disease may produce abscesses.





Atypical or Interstitial or viral Pneumonia

Atypical pneumonia as already said is caused by atypical bacteria that do not gram stain or do

not fit in any category like in virus or bacteria.some special fungi and rickettsia and most of

viruses can also cause this type of pneumonia .

The inflammation is confined to interalveolar septa or interstitial spaces between alveoli and

radiologically gives appearance of reticulonodular pattern.

In the next slide you will see white spaces that are alveolar spaces and are empty and clear.but

surrounded by swollen interstitial tissue infiltrated with inflammatory cells.

Atypical or Interstitial or viral Pneumonia

Causes



Mycoplasma

Legionella

Chlamydia

Pneumocystis carinni

. coxiella

Viruses

Investigation

Chest X-ray

FBC

CRP

U&E’s

ABG’s

Sputum culture

Blood culture (+ve in 1-16% of pt’s requiring admission)

Serology/PCR/antigen







Severity assessment

CURB-65

Confusion

Urea >7mmol/L

Respiratory rate >30

Blood pressure diastolic <60mmHg or systolic <90

≥65 years old

0-1-may be suitable for outpatient Rx

2 Hospital Rx, consider other features too (e.g. PaO2)

≥3 Severe disease

Treatment-Community acquired

CURB65 0-1

Amoxycillin 500-1g TDS

CURB65 2

Amoxycillin AND Clarithromycin 500mg BD

CURB65 ≥3

Co-amoxyclav 1.2g TDS AND Clarithromycin 500mg BD-Both given IV

Treatment-Specific organisms

S. pneumoniae

Benzylpenicillin or amoxycillin

S. aureus

Flucloxacillin

Legionella

Clarithromycin (or a quinolone e.g. Cipro)



Psitacosis or Q fever

Doxycycline

Mycoplasma

Clarithromycin

C. pneumoniae

Clarithromycin

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Definition of Pneumonia