Pleural effusion w/o respiratory illness symptoms

[cltrunner]

I am a 31-yr old female runner, recently completed my second half marathon.  A few days after, I began having sharp pain with inhalation.  Pain was localized to left chest right below the breast with radiating pain in shoulder.  I was on vacation, so I waited a while before seeing a doctor (about a week and a half).  When I did, the pain had decreased quite a bit but I was still having trouble taking deep breaths and was unable to run my usual mileage.  Chest x-ray shows pleural effusion on left side, but I have had no cold symptoms or feelings of infection.  Could the running have irritated the lung somehow?  I'm puzzled/concerned by what could be causing my lung to do this.  My doctor says we'll check again in 10 days to see if it's better and proceed with CT scan if not.  I'm a healthy person, nonsmoker, no symptoms of connective tissue diseases.  Any ideas?

[National Jewish]

Your pain would not be due to a musculoskeletal problem since it started a few days after the half marathon and your chest x-ray shows a pleural effusion.  Both chest pain and pleural effusion can occur in a previously healthy young adult.

The lung is covered with a very thin membrane, called the pleura.  A similar membrane covers the inside of the chest wall, the ribs and muscles.  As the lungs expand and contract, these lubricated membranes glide over each other.  There is normally no space between them.  However it is possible for fluid to build up in between these 2 membranes.  There can be 1 to 2 liters of fluid in this area.  This collection of fluid is called a pleural effusion.  Sometimes there is no obvious reason for this to happen.  However possible causes are health problems, such as blood clots to the lungs or infection.

The lack of cold symptoms suggests that it is not an infection.  The sudden onset of this pain, without other respiratory symptoms, suggests that you may have had a blood clot in an artery of your lungs.  This is called a pulmonary embolus (PE).  It is important that the cause of the pain and effusion be found.  If you have had a PE, you remain at risk for recurrence.  This would be most likely to happen if you become dehydrated while running long distances.  Most of the time a PE comes from leg veins but blood clots can originate from any veins, especially pelvic veins.  With the passage of time, a blood clot in a vein may spontaneously dissolve.

A PE can be found using non-invasive tests.  An impedance plethysmography (IPG) uses ultrasound to find a blood clot.  The better test would be a CT scan of the chest, specifically a helical or spiral CT.  It would be a good idea to do this now, rather than to wait any longer.  If a blood clot is found to be the cause, you should then have a careful evaluation of your blood and how it clots.

More information can be obtained from a helical or spiral CT to find if something other than a blood clot is causing your pain and effusion.  If you have not had a blood clot to the lung and there is still fluid in your chest, the fluid should be removed and examined.  This may provide more clues about the cause.

[wftmed]

A related discussion, pleural effusion was started.