Pneumonia vs. "Chest Cold"

[Reasonable Rascal]

How do we (reliably) differentiate between true pneumonia and a simple "chest cold" when x-ray studies are not in the picture? What are the differentials between the two?

Is there a way to differentiate bacterial from viral pneumonia without lab studies, i.e. characters of the disease process?

RR

[Craig]

Its can be verging on impossible to 100% to differeniate between pneumonia and bronchitis / "chesty colds".

Pneumonia is inflammation and congestion of the air sacs and small airways themselves. Other chest infections tend to inflammation and congestion if the medium sized airways

Generally speaking, its more likely to be pneumonia if

1) increased respiratory rate
2) an area of dullness to percussion on exmination of the chest
3) bronchial breathing - extra loud breath sounds when the surrounding sounds are soft.

2 and 3 suggest lung consolidation

4) if BP is low, particularly distolic values less than 60 or 65
5) they look sick - they have an increased work of breathing ie they are working hard to breath - using extra muscles, indrawing.

Fortunately assessing the respiratory system is one of the easiest without high tech gadgets and investigations - it would be rare that a CXR surprises me - 95% + of the time you know what you are going to see from clinical exam.

A viral pneumonia may look like either and your best bet would be trying to decide on the basis of history - but almost all severe viral infections have a superimposed bacterial infections.

hope that helps

Craig

[themadmedic]

There are some physical exam findings that might be suggestive-such as signs of consolidation of the lung parenchyma (increase tactile and vocal fremitus, bronchophony, egophony, bronchial breath sounds, fine rales over the consolidated area). Often there is also an associated pleural effusion that can produce opposed features in physical examination (distant-to-absent breath sounds, pleural friction rubs which may fade as effusion becomes outstanding, decreased fremitus and flatness to percussion).

These signs are most recurrently found with bacterial pneumonia, whereas viral and mycoplasma pneumonias present with very few signs (often, only rales are heard).

If lab is available you can try sputum cultures and stains...but truth be told many of these will likely be treated empirically.