Sunday, 12 September 2010

MRCP revision battle 9.5: Pneumothorax

A pneumothorax, as I'm sure you all know, is a collection of gas in the pleural cavity of the chest between the lung and chest wall.

I'm not about to insult you by going through the basic signs/symptoms of pneumothorax, but I will just briefly mention a rare sign that occasionally pops up in MRCP exams: a clicking sound at the sternal edge synchronised with the heart beat.  This rare sign of a pneumothorax is most commonly assocaited with small left sided pneumothoraces.

As a quick recap, its important to establish if the pneumothorax is primary (ie no underlying lung disease), secondary (=underlying lung disease) or traumatic (in which case as a medic you shouldn't be treating it!)

BTS guidelines state that in primary pneumothorax, if the patient is not breathless and the rim of air is <2cm you do not need to necessarily do anything and may consider sending the patient home.  If the rim of air is >2cm or the patient is breathless you should aspirate; try x2, if still unsuccessful insert a drain.

The guidelines for secondary pneumothorax are slightly more complex:
  • if >50yrs old AND breathless AND rim of air >2cm, insert a drain first line
  • if the above 3 criteria do not apply, try aspirating first
  • regardless of which category your patient falls into, patients with secondary pneumothorax should be admitted for 24 hours observation.

A random type of pneumothorax to be aware of is catamenial pneumothorax - this is a pneumothorax associated with menstruation, which is due to endometriosis of the lung.  90% of these occur on the right side.

As a complete aside, as well as recognising the 'click synchronised with heartbeat' as a possible pneumothorax it is worth learning that a 'crunching sound' in the chest can be due to a pneumomediastinum  and is called Hamman's sign.

Well those are todays battles over, but for those with residual enthusiasm the beat goes on with a war to test your memory of yesterday's topics...