In the cause-of-death statistics, strokes rank third in Western industrialized nations after heart disease and malignant tumor disease. Approximately one in ten inhabitants of a Western country dies of a sudden stroke, according to these statistics, with the risk of disease increasing markedly with increasing age. In the seventh decade of life, stroke is the second leading cause of death. Men and women are affected at about the same rate.
Transient Ischemic Attack and PRIND.
Depending on the extent and duration of acute circulatory disturbances in the brain, a wide variety of symptoms can occur, with smooth transitions between transient, fleeting symptomatology and lifelong persistent neurologic deficits:
- With only short-lasting complaints as a result of a circulatory disorder in the brain, one speaks of a transient ischemic attack (TIA), which may be the harbinger of a “major” stroke.
- The next level up in terms of intensity and duration of symptoms would be given by the so-called PRIND (prolonged reversible ischemic neurologic deficit), in which the deficits can last for hours or sometimes days, but then completely regress.
- In cases of irreparable damage to brain matter, neurologic damage usually persists for the rest of life.
Signs of a stroke
In accordance with the complex structure and function of the brain, acute circulatory disorders may present a wide variety of combinations of symptoms, depending on the area affected. To understand the particular failure symptoms, it is significant that the afferent and efferent nerve fibers that connect the brain to the “periphery” cross in the lower part of the brain, the brainstem. Accordingly, the left brain hemisphere is responsible for the right side of the body and vice versa. A sudden paralysis of the right half of the body as one of the possible symptoms, for example, consequently indicates an acute circulatory disturbance in the left half of the brain. Even more complex symptoms result from acute circulatory disturbances at the level of the brain stem, since numerous conduction fibers for both halves of the body and control centers are also located in close proximity here and can also be affected simultaneously. Typical symptoms when the brainstem is involved in the stroke event are:
- Occipital pain
- Double vision
- Twitching of the eyeballs
- Sensory disturbances of the hands or fingers
- Gait unsteadiness and speech disorders
Symptoms depending on the area of occlusion
From knowledge of brain anatomy and organizational structure, the experienced physician can draw conclusions from the symptom picture of a patient with acute stroke about the particular brain area affected, but not about the actual triggering cause. Basically, in this short review article by far not all conceivable symptom patterns and symptom combinations in strokes can be presented. Here are just a few typical symptoms of occlusion of an important vessel in individual regions of the brain:
- Vascular occlusion of the middle cerebral artery, middle cerebral artery (about 80 percent of vascular strokes): paralysis and sensory disturbances on the opposite side of the body, most pronounced in the fingers of the hand and in the face; in some cases, loss of vision in the opposite side of the face as well
- Vascular occlusion of the posterior cerebral artery, posterior cerebral artery (about 10 percent of vascular strokes): loss of vision in the opposite visual field, disturbances of consciousness, sensory disturbances on the opposite side of the body
- Vascular occlusion of the anterior cerebral artery, anterior cerebral artery (approximately 5 percent of vascular-related strokes): hemiplegia on the opposite side, affecting the leg more than the arm
- Vascular occlusion of one of the numerous brainstem vessels (20 percent of all vascular strokes, up to 50 percent in microvascular damage): Visual disturbances, motor disturbances, sensory disturbances, which can affect both halves of the body in different ways; in addition, occipital pain, double vision, twitching of the eyeballs, gait unsteadiness, speech disorders and, in severe cases, clouding of consciousness.
Diagnostics in the event of a stroke
The diagnosis of stroke results from the typical picture of sudden onset of new neurological deficits. If the symptoms are only mild, such as new-onset sensory disturbances of a hand or sudden double vision, other clinical pictures must also be included as possible causes. The final proof of a circulatory disorder in the brain can be provided by a computer tomography or magnetic resonance imaging of the skull. This examination procedure can also clarify the cause and location of damage in the brain in more detail. Additional diagnostic information after a stroke is provided by ultrasonography of the cerebral vessels, imaging of the entire cerebral circulation by contrast injection if necessary, a detailed examination of the heart for possible sources of embolism, and blood testing for possible coagulation disorders.
Stroke: prognosis
After a stroke has passed with new neurologic deficits, the degree of spontaneous regression of the damage is, of course, of the utmost interest. Although complete recoveries are conceivable in individual cases, in the majority of cases of large strokes, more or less pronounced persistent defects must be expected. Since numerous individual factors play a major role in the further course of the disease, prognoses are very difficult to make in individual cases. In principle, however, the acute functional deficits that occur even in major strokes can partially regress over the course of several weeks or months. Of decisive importance in such a stroke is the extent to which other, still intact brain areas can step in and take over the function of the brain tissue that has perished.
