A stroke is analogous to a heart attack, and can be called a brain attack. In a heart attack and stroke, the blood supply is cut off, the downstream tissues are deprived of oxygen and nutrients, and they can rapidly die. Atherosclerosis, or the build up of plaque from cholesterol and other fat-like molecules, is one cause of stroke. Strokes affecting the brainstem cause a number of problems. The brainstem is responsible for numerous autonomic functions, including breathing. In addition, the nerves that communicate down to the spinal cord and receive signals from the body pass through the brainstem. It is important to consult with a physician for the diagnosis and treatment of your disease.
Types
There are two basic types of strokes. In an ischemic stroke, a blood vessel is plugged, cutting off the blood supply to a region of the brain, or the blood pressure is too low to maintain an adequate blood supply to the brain. Cholesterol can cause this through the build up of plaques in the arteries. In a hemorrhagic stroke, a blood vessel bursts, and the artery further down does not receive blood. This is more likely to be caused by high blood pressure, and less likely to be caused by cholesterol, but it can develop if the plaque and immune cells weaken the walls of the artery, making it prone to rupture.
Development
A collection of arteries is shaped similarly to a hollow tree. Over time, high cholesterol and plaques narrow the round inside of the artery through which the blood passes. Ischemic strokes in the brain stem can be caused by plaque building up, breaking, and causing the sudden development of a blood clot that blocks the artery. This is called thrombosis. The part of the brainstem served by that artery is deprived of a blood supply and no longer functions. Alternatively, a plaque further away can dislodge, travel through the blood stream and become lodged in a narrower artery; this is called an embolism.
Syndromes
There are many syndromes caused by strokes to the brainstem. A given syndrome depends on the location of the stroke, which determines the subsequent loss of function. For example, in lateral medullary syndrome, also called Wallenberg syndrome, blockage of the posterior inferior cerebellar artery cause deficits in sensation on the same side of the face as the stroke and the opposite side of the body. This leads to problems that include difficulty swallowing, slurred speech, trouble walking, facial pain, vertigo and double vision.
Diagnosis
The diagnosis of a brainstem stroke takes into account many aspects of your present and past medical history, physical exam, labs and imaging. Of these, the clinical history, exam and imaging are generally the most helpful. Imaging usually starts with a rapid CT scan, which uses a series of x-rays to construct images of the brain, followed by an MRI, which uses magnets to construct a very detailed picture of the brain.
Treatment
There is generally no cure for a stroke once it has occurred. However, if it is caught soon enough, in some cases it is possible to give a drug that breaks down blood clots, a process called thrombolysis, or have a surgeon or interventional radiologist attempt to remove the a blockage, a procedure called a thrombectomy. Sometimes a stent, or tube, can be placed to open the artery. If the stroke cannot be reversed, then the symptoms are treated with interventions such as physical therapy, speech therapy, and other rehabilitative and supportive measures.
References
- "Neuroscience"; Dale Purves; 4th Ed. 2007
- "Harrison's Principles of Internal Medicine"; Anthony S Fauci, et al.; 17th Ed 2008
