Secretary of State Hillary Clinton has been hospitalized at New York Presbyterian Hospital for a blood clot.

Mrs. Clinton had contracted a stomach flu in mid-December after returning from an overseas trip. This caused her to become dehydrated. She fainted while at home, hitting her head, and causing a concussion. Clinton had to postpone her testimony before Congress concerning the investigation into the problems at the US Embassy in Benghazi, Libya because of this.

Philippe Reines, deputy assistant Secretary of State, told reporters:

Her doctors will continue to assess her condition, including other issues associated with her concussion. They will determine if any further action is required.

Although Reines did not specify where the blood clot was, he did confirm that she is being treated with anticoagulants (blood thinners). Because of this, it is probably safe to say that Clinton did not have a blood clot in her brain, as she would not be treated with this kind of medication.

Dr. Sanjay Gupta, CNN chief medical correspondent, agrees:

I think it’s very unlikely this is a blood clot on top of the brain or around the brain specifically, because you just don’t treat blood clots on the brain that way…. That would worsen the bleeding.

However, if the concussion caused Secretary Clinton be become sedentary, she could be at risk for deep vein thromboses (DVTs). DVT’s are blood clots that forms in a vein deep in the body. Blood clots occur when blood thickens and clumps together. Although DVTs can occur anywhere in the body, most deep vein blood clots occur in the lower leg or thigh.

A blood clot in a deep vein can break off and travel through the bloodstream. The loose clot is called an embolus. It can travel to an artery in the lungs and block blood flow. This condition is called pulmonary embolism, or PE.

PE is a very serious condition. It can damage the lungs and other organs in the body and cause death.

What Causes Deep Vein Thromboses?

Blood clots can form in your body’s deep veins if:

• A vein’s inner lining is damaged. Injuries caused by physical, chemical, or biological factors can damage the veins. Such factors include surgery, serious injuries, inflammation, and immune responses.
• Blood flow is sluggish or slow. Lack of motion can cause sluggish or slow blood flow. This may occur after surgery, if you’re ill and in bed for a long time, or if you’re traveling for a long time.
• Your blood is thicker or more likely to clot than normal. Some inherited conditions (such as factor V Leiden) increase the risk of blood clotting. Hormone therapy or birth control pills also can increase the risk of clotting.

What are the Symptoms of Deep Vein Thrombosis?

Only about half of the people who have DVT have signs and symptoms. These signs and symptoms occur in the leg affected by the deep vein clot. They include:

• Swelling of the leg or along a vein in the leg
• Pain or tenderness in the leg, which you may feel only when standing or walking
• Increased warmth in the area of the leg that’s swollen or painful
• Red or discolored skin on the leg

We’ll report back if more details are available about Secretary Clinton’s condition.

UPDATE 12/31/12 5:50 pm

We are now being told that the blood clot IS in Hillary Clinton’s head- in a vein in the space between the brain and skull behind the right ear.

The clot was apparently found on a follow-up MRI. In a statement, her doctors, Drs. Lisa Bardack and Gigi El-Bayoumisaid, said that Clinton did not suffer a stroke or any neurological damage, and:

She will be released once the medication dose has been established. In all other aspects of her recovery, the secretary is making excellent progress and we are confident she will make a full recovery. She is in good spirits, engaging with her doctors, her family, and her staff.

Dr. Larry Goldstein, a neurologist and Director of the Duke University Stroke Center, explained that the clot developed in “‘a drainage channel, the equivalent of a big vein inside the skull — it’s how the blood gets back to the heart.” He added that this is an uncommon event after a concussion, and that is it one of the few types of clots in the head where anticoagulants (blood thinners) are appropriate treatment.

It should also be noted that Mrs. Clinton has a history of deep vein thrombosis. In 1998, a clot was found behind her right knee and she was treated with anticoagulants. This may mean that she is more predisposed to forming blood clots.

More info, as it becomes available.