Pulse

Ambushed by a blood clot

When NBC News correspondent David Bloom died while traveling through the Iraqi desert with the U.S. Army's 3rd Infantry Division, people were shocked that a blood clot, not gunfire, killed him.

Bloom died April 6 when a clot lodged in an artery in his lung.

"I was mystified why a 39-year-old would die from a pulmonary embolism. They are rare in someone so young," says Dr. David Solomon, director of the division of pulmonary and critical care medicine at the University of South Florida College of Medicine.

Every year about 500,000 people in the United States suffer a fatal embolism, Solomon says. An embolus is a traveling clot; pulmonary means lung. When a pulmonary embolism occurs, a clot typically forms in a vessel in the leg or pelvic area and travels through the bloodstream, lodging in a narrow vessel in the lungs and blocking circulation. Sometimes the clot is small enough to permit some blood flow. A clot also may dissolve on its own, Solomon says.

Some medical experts speculate that Bloom's lengthy periods sitting atop a tank as it crossed Iraq toward Baghdad may have contributed to the clot's formation. Those most at risk are people confined to bed rest or recovering from surgery, says Solomon.

Although a clot cannot be predicted nor prevented, there are factors that increase the risk. The best general advice is to move.

"Use common sense," says Solomon. "If you're a retired person in Florida and you're going to Michigan for Easter, don't just drive straight through. Stop every couple of hours and walk around."

Lengthy trips by air and rail also call for getting up and walking the aisle or at least doing leg exercises in one's seat, he says.

Bloom had complained of pain behind his left knee in the days before his death. Symptoms of a clot may include localized or chest pain, difficulty breathing (particularly drawing a deep breath), faintness, coughing up blood or a racing pulse.

Discerning the difference between a muscle cramp and a life-threatening clot can be difficult.

"I don't think people should be talking to their doctor if they get a muscle cramp," says Solomon. But if the localized pain is accompanied by another symptom, a check is warranted.

In addition to long-haul travel, other risk factors include smoking, obesity, major surgery, high blood pressure and trauma. Women may be at particular risk during pregnancy and if they take hormones either in birth control pills or as hormone replacement therapy. Studies have found hormones increase the risk for clots, though the incidence remains extremely small.

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