Ben Lovejoy's

Pulmonary Embolism page

pulmonary_embolism.jpg (157362 bytes)
Image borrowed from the excellent Mayo Foundation website

Having had a Pulmonary Embolism (PE), they are now pretty high on my list of Experiences I Recommend Not Having ...

Pulmonary Embolisms are a complication of Deep Vein Thrombosis (DVT), blood clots in the leg. DVTs can be caused both by leg injuries and by immobility, so if you've injured your leg and it's been put in plaster or you've spent some time in bed as a result, ask your doctor about precautions against DVT. These included elasticated surgical stockings and, sometimes, low doses of the blood thinner heparin. Definitely contact your doctor if you experience unexplained calf-pain, swelling or redness.

The danger with DVTs is that the clots break off and travel through the body. When a clot breaks off, it becomes known as an embolus, and it ends up either in the heart (where they can stop it) or the lungs.

A Pulmonary Embolism is what happens when the clot ends up in the lungs, blocking the passage of blood into one or both lungs. About 10% of PEs result in immediate death, and a futher 20% kill later if they're untreated. Once treated, the mortality rate drops to 3%.

The main symptoms of a Pulmonary Embolus are:

Chest pain
Typically under the breastbone or to one side
Typically a sharp stabbing pain
Typically made worse when breathing in
Shortness of breath
A mild temperature (typically 38°C), with sweating
Rapid pulse
A dry cough, sometimes with blood (usually small amounts, sometimes more)
A feeling of anxiety

If you think you may have a PE, go straight to hospital: remember that 30% mortality rate.

There are three main tests which can be performed:

Chest X-ray: helpful to eliminate other possibilities, but 25% of PEs don't show up on an ordinary x-ray
Ventilation Perfusion scan (V/Q scan): good initial screening test, but notoriously difficult to analyse
CT scan: what used to be a CAT scan, the definitive diagnostic tool

The usual treatment for PE (and DVT) is to thin the blood using anti-coagulants. This usually involves an initial injection of heparin, followed by a heparin infusion for several days. Once you've been on heparin for 24 hours or so, the risk level drops by a factor of ten. However, although heparin provides immediate protection, it has an extremely low half-life, so it only protects you while you're being infused with it. For this reason, a longer-lasting anti-coagulant is used for ongoing protection. The most common of these is warfarin. You have to stay on heparin until blood tests (known as an INR test) confirms that warfarin is keeping your blood two or three times thinner than usual.

Less common treatments include clot-filters, clot-busting drugs and surgery. These options are used when anti-coagulation is proving ineffective or where the clot is so severe that it is too dangerous to wait for the clots to dissolve in the thinned blood.

Good places for more detailed information include: