brains and clots

Monday, January 7, 2013

Practicing medicine by reading press releases is not necessarily the right thing to do, but using the news to teach medical issues is an important public service. That said, there should always be a large print disclaimer that the writer and the patient have never met.

Secretary Hillary Clinton is back to work after a difficult couple of weeks. It began with a viral infection that left her dehydrated.  Due to her weakness, she fell, hit her head and sustained a concussion. Here the story gets murky. According to the press release, she underwent a routine head MRI that revealed a thrombus or blood clot in one of the large veins in her brain and was treated by anticoagulation, or thinning her blood with medication to prevent further clot formation.

Cerebral vein thrombosis is a rare occurrence and is difficult to diagnose. Often the only symptom is progressive headache and vision change but the big worry is that CVT can cause stroke, but not in the classic way. A “normal” stroke occurs when an artery that supplies part of the brain gradually narrows with cholesterol plaques until one day, the plaque ruptures, a clot forms and that part of the brain loses blood supply, turns off and the part of the body that it controls, stops working. In CVT, a vein fills with clot and blood can’t get from the brain back to the heart. This causes blood to back up behind the clot causing brain congestion and affecting brain function.

CVT is often found by mistake, as an incidental finding on CT or MRI scans of the head. The doctor and patient are usually trying to diagnose the cause of unusual headaches or neurologic symptoms and stumble upon the clot. It would be very unusual for a doctor to make the diagnosis based on history and physical examination.

These clots are most commonly found in brains after trauma or surgery and in patients who are hypercoaguable, a situation where the blood has a tendency to clot inappropriately. The common reasons for this condition include pregnancy, tumors and genetic conditions associated with abnormal clotting proteins in the blood. Screening for the cause of the clot is as important as making the diagnosis and starting treatment.

Anticoagulation is the treatment and is a two step process. First, heparin injections are used to immediately thin the blood while, at the same time, warfarin (Coumadin) therapy by mouth is begun. It takes a few days for warfarin to be effective and the patient is maintained on both drugs until that occurs. Anticoagulation does not dissolve the clot but instead prevents the clot from growing in size. Over time, the body will figure out how to get blood past the clot and will gradually resolve the issue.

Back to Secretary Clinton.  In most patients with minor head injury or concussion, brain imaging is not required; no CT, no MRI unless the patient has an abnormal neurologic exam, a depressed skull fracture or persistent vomiting. Ottawa and New Orleans CT guidelines have been developed to decide what patient needs an operation for bleeding in the brain and who is safe to go home. There is no “routine” reason to do an MRI regardless of the press release. The Secretary must have been complaining of something.  Once the diagnosis of cerebral vein thrombosis is made, screening for a hypercoaguable state might be appropriate because Secretary Clinton has had at least two previous blood clots in her legs. If there are genetic causes, not only would she have to be on blood thinners for a much longer period of time, but it might help assess potential risks for her daughter.

Of course, this is all speculation and one shouldn’t practice medicine by press release, should one.




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