Tuesday, July 10, 2012
Getting the story right always difficult and even more so when the medical plot line is cobbled together from press releases and sports blogs. Such is the case of New York Mets pitcher Dillon Gee whose tingling hand ended up being a clot in the artery that supplies the arm with blood. Once the diagnosis is made, opening the artery by either removing the clot or dissolving it is a technical issue. The more interesting detective question asks why the blood clot happened in the first place. Caring for Mr. Gee requires more than restoring blood supply to his arm; it requires that if possible the underlying problem is fixed so blood clots won’t happen again.
Some background. The aorta is the large artery that leaves the heart carrying oxygen rich blood. The brachiocephalic artery is first major branch that splits off the aorta. It’s pretty short and then quickly divides into the right carotid artery to supply the brain and the subclavian artery that heads to the right arm. The subclavian gets renamed the axillary artery as it enters the armpit (or axilla) and then renamed again as the brachial artery when it enters the arm.
When the headlines read that Mr. Gee had a blood clot in his shoulder, they mean to say that there was a clot in either the subclavian, axillary or brachial artery. Classically, when arterial blood supply decreases to part of the body, it begins to ache with exercise and activity. This is the reason angina or chest pain happens as the coronary arteries to the heart narrow. In the bowel, ischemia, or loss of blood supply, can cause diarrhea and pain. In the arm, the symptoms can include weakness and numbness.
There are plenty of reasons to have a numb hand but let’s skip to the artery clot. It can happen because there is underlying damage to the lining of the artery and it can gradually narrow and clot off. Alternatively, a clot, or thrombus, can develop elsewhere in the body, break off and travel through the artery until it lodges and prevents blood from getting past. This is called an embolus and not uncommonly, a thrombus can develop in the heart because of a rhythm called atrial fibrillation and then dislodge and block blood flow to the brain ending up in a stroke. There is no reason that a clot couldn’t also travel to an artery in an arm, leg or intestine causing blood flow problems. Atrial fibrillation is a relatively easy diagnosis to make by EKG or heart monitor.
But there are other potential causes that Mr. Gee’s doctors will explore. When a blood clot occur in the veins of a leg, called a deep vein thrombosis, it can break off and travel to the lung causing a pulmonary embolism, but if there is a small “hole” in the heart so that returning blood can bypass the lung loop, a DVT can embolize to an artery. This could be an atrial septal defect (or a connection between the two upper champers of the heart), a ventricular septal defect or a patent foramen ovale. Even elite athletes can have structural heart problems and not appreciate them until something bad happens. And if a rhythm problem or structural issue is not the culprit, then perhaps a blood clotting disorder is the cause of Mr. Gee’s arterial thrombus. Regardless, there will be great expenditure of time, technology and detective work to sort out Mr. Gee’s arm.
Most often tingling in a hand is a primary nerve issue. You hit your funny bone and your hand goes numb. Irritation of a nerve root in the neck causes numbness. The saying goes: if you hear hoof beats, expect horses, not zebras. But in the case of Mr. Gee, his doctors decided to look in the zoo, not the pasture. We know that the blood supply to the pitching arm has been restored. It will be interesting to follow the detective work to find out the why.