Strokes can also vary according to another fundamental difference -- whether they involve a blocked blood vessel or a hemorrhage. Most strokes are due to the former in which brain-tissue damaged by lack of circulation is called an infarction. But 10-15% of strokes involve bleeding from ruptured blood vessels within the brain tissue, and while it's bad enough to have an infarction, hemorrhagic strokes (intracerebral hemorrhages) can be even more devastating.
One prominent figure with spontaneous intracerebral hemorrhage is Ariel Sharon, whose hemorrhagic stroke occurred while he was still prime minister of Israel. Although some patients with intracerebral hemorrhage recover to a point of being able to enjoy other people and regain some independence in functioning, Sharon's poor clinical outcome is all too common in patients with this disease.
The additional problem with hemorrhagic strokes is that the new deposit of blood occupies space -- sometimes a lot of it -- and there is only so much space within the skull (braincase) to go around. The fresh hemorrhage crowds and distorts the brain-tissue next to it, and additionally subjects the rest of the brain to increased pressure that can itself be damaging. Because of these distortions and pressure-changes, a patient with intracerebral hemorrhage often shows a decreased level of consciousness or even coma.
Another kind of spontaneous bleed within the braincase is subarachnoid hemorrhage, often caused by ruptured aneurysms outside the brain but inside the braincase. While this, too, is a very serious condition, it is not the focus of this particular essay, and spontaneous intracerebral hemorrhages are not caused by aneurysms of this kind. Yet another kind of bleed that can be confused with (primary) intracerebral hemorrhage is secondary hemorrhage. This occurs in some patients who started out with infarctions of the brain but who had subsequent bleeding from fragile blood-vessels around the infarction's edges. This kind of bleed is not quite as serious as that which occurs when the bleed is primary (the initial event).
How are intracerebral hemorrhages diagnosed? Since the 1970s when computed tomographic (CT) scans were introduced, this imaging technique has been the most effective and sensitive tool. A fresh hemorrhage within brain tissue is dramatically evident on CT scans. And unlike infarctions that can take a day or two to show up on CT scans, hemorrhages are already visible at the earliest moment a scan can be made.
Although surgical removal of blood-clots from the surface of the brain -- called subdural and epidural hematomas -- can be life-saving and function-sparing, surgery for a bleed (hematoma or blood-clot) within the brain tissue itself is another story. Some studies comparing outcome between operated and unoperated patients with intracerebral hemorrhage showed improved outcome, on average, for operated patients, while still others showed worsened outcome. Operated or unoperated, patients had high rates of death and disability.
Because of the limited prospects for meaningful improvement, surgery for intracerebral hemorrhage is often an act of desperation. One crusty old clinician was blunt about the direness of the situation, saying, "Show me a patient with intracerebral hemorrhage whose life was saved by surgery, and I'll show you a patient you wish you hadn't operated on." His point was that survivors of this operation usually show severe impairments.
However, one form of hemorrhage within brain tissue is probably a special case, and that is hemorrhage within the cerebellum, located within the bony braincase just above the nape of the neck. Surgical extraction of blood clots occurring within the cerebellum prevents excessive pressure on the nearby brainstem that handles a lot of basic and necessary functions, like breathing.
Administration of cortisol-type steroids is a nonsurgical treatment that has been studied in a scientific way, comparing treated patients to untreated patients with the same condition. The steroids didn't help. Decreasing the patients' blood pressures by administering medication has likewise been studied, but with the same outcome -- no benefit. However, in a preliminary study one nonsurgical treatment showed promise. Intravenous administration of activated factor VII (a natural component of the blood-clotting system) reduced expansion of the intracerebral blood-clot, death and disability when given within four hours of the initial hemorrhage. A larger study is underway to see if this benefit holds up under further analysis.
Otherwise, what can be done acutely for this condition? Individualizing treatment seems rational, even if unproved. For example, if the patient had a bleed while taking a blood-thinner (as was the case with Ariel Sharon) then it makes sense to stop the blood-thinner or reverse its effects. Supportive management, like administering intravenous fluids to prevent dehydration, monitoring for irregular heartbeats and protecting the patient's airway also make sense. If the patient can't consume food in the usual way, feeding through tubes or intravenous lines can be considered, though this decision can be postponed until the patient's prospects are more apparent.
Who is at risk for intracerebral hemorrhage? Neurologists at Malmo University Hospital in Malmo, Sweden, compared 147 patients with intracerebral hemorrhage with 1029 similar but stroke-free patients in order to determine risk factors. They found that hypertension (high blood pressure), diabetes, elevated triglyceride levels in the bloodstream, history of psychiatric problems, smoking and (surprisingly) short stature were more frequent in patients with intracerebral hemorrhage.
However, when it comes to modifiable risk-factors (those that one can do something about) a variety of studies indicate that hypertension is the single most important factor. Thus, treatment of hypertension, when present, is probably the single most effective thing that one can do in order to prevent this disease.
(C) 2006 by Gary Cordingley
