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J Neurol Neurosurg Psychiatry 2003;74:1621-1626 Background: Basilar artery occlusion usually causes severe disability or death. Until the recent developments in local intra-arterial or systemic intravenous fibrinolysis, interest in early diagnosis [...]

Lyme disease is caused by infection with the bacteria Borrelia burgdorferi, which is transmitted to humans by tick bites. The resulting borreliosis can cause a wide range of symptoms, which may include neurological disorders. Three cases are presented in which the existence of borreliosis was not suspected at the time the neurological symptoms first appeared. Early stage borrelia infection without symptoms is difficult to diagnose; the diagnosis is generally made on the basis of detecting antibodies against B. burgdorferi; an increase in white blood cells in the cerebrospinal fluid; and living in an area where Lyme disease is endemic. Among the three cases presented here, the symptoms included fatigue, transient confusion, and difficulty walking. In two cases, penicillin treatment was instituted. This antibiotic treatment resulted in the normalization of the white blood cells in the cerebrospinal fluid, but did not reverse the neurological damage that had already taken place. In the third case, the diagnosis of borreliosis was not made until after the patient had died of pneumonia. In this case, pathological examination of the brain confirmed the diagnosis and revealed specific pathological changes. These changes included inflammation of the blood vessels, which obliterated some vessels and resulted in deprivation of oxygen in some regions of the brain. Similar changes are observed in the advanced stages of syphilis, in which the syphilis spirochetes enter the brain; these neuropathological findings underscore the similarity of both spirochetes, Borrelia and the syphilis organism, in their infection of the brain. The actual number of Borrelia spirochetes that could be identified in the brain of this patient was very small. (Consumer Summary produced by Reliance Medical Information, Inc.)

An embolus is any insoluble matter which blocks a blood vessel. The most common cause of stroke is a thromboembolus, an embolus formed from a blood clot. Most often, such a blood clot arises from another artery. For example, an atherosclerotic plaque in the internal carotid artery in the neck might rupture and provide a spot for a clot to form. If part of this clot should break off, it would then travel up into the head and very likely lodge in the brain. However, the second most common cause of thromboemboli which result in strokes is an abnormality of the heart. Clots may form in the hearts in patients with ventricular fibrillation or in patients with abnormal heart valves, as well as other cardiac abnormalities. To gain insight into the ways in which cardiac abnormalities might contribute to a stroke, the records of 1,311 patients who had experienced their first stroke were examined. Of these patients, 305 individuals had some cardiac abnormality which may have contributed to their stroke. In 76.7 percent of these cases, no other factor predisposing the patient toward a stroke could be found. Therefore, the heart may be presumed to be the source of the stroke in these patients. It was found that the parts of the brain most likely to be affected were different when the heart was the source of the thromboembolus. A blood clot traveling into the brain through the internal carotid artery is most likely to then proceed to the middle cerebral artery and become lodged in a smaller branch. In most cases, the clot is more likely to lodge in the more forward areas served by this artery. However, among the patients with a potential cardiac source for their embolus, the clot lodged with the same frequency in the anterior and the posterior areas. Is it suspected that this is due to that fact that, in patients with serious disease of the carotid artery, the dynamics of blood flow in this region of the brain would be different and would be likely to carry a floating clot in different directions. Furthermore, the cerebellum and the portion of the brain served by the anterior cerebral artery were more likely to be affected when the heart was the source of the embolus, rather than when the embolus was associated with atherosclerotic disease of the carotid artery. (Consumer Summary produced by Reliance Medical Information, Inc.)

Bulbar palsy results from damage to clusters of nerve cells located in the medulla oblongata (bundle of nerve tissue in the brain, connected to the spinal cord); the term continues to be used although the term 'bulb' for the medulla has long been antiquated. This palsy, or paralysis, affects muscles controlled by the cranial nerves such as facial muscles and muscles of the tongue. The same symptoms as bulbar palsy may result despite intact nuclear groups of nerve cells in the medulla if the input to those neurons is somehow disrupted. The term ''pseudobulbar palsy'' was coined to describe this state of affairs. Since the damaged nerve cells in pseudobulbar palsy are higher up in the nervous system than the medulla, the same condition is also called ''suprabulbar'' by some authorities. Pseudo- or suprabulbar palsy generally develops as a result of multiple infarctions (tissue death caused by reduced blood supply). That is, a single stroke is unlikely to hit all the necessary brain centers to result in pseudobulbar palsy. As a result, suprabulbar palsy usually develops in fits and starts, as several strokes in succession contribute to the final outcome. However, in some instances it is possible to develop suprabulbar palsy as a result of a single stroke. The authors present 13 cases in which suprabulbar palsy had an acute onset, indicating that a single stroke had done the damage. These cases illustrate that suprabulbar palsy resulting from a single stroke may by more common than has been previously suspected. Brain imaging revealed that 12 patients had infarctions and one suffered a small cerebral hemorrhage. The damage tended to be located in the opercular portion of the frontal cortex, which is the part of the brain hidden from view on gross inspection by the overlying temporal lobe. This location of the infarction or hemorrhage may disrupt nerve fibers connecting the cerebral cortex with the medulla, but may spare nearby nerve fibers that run from the cerebral cortex to the spinal cord to control the movement of the body. All but two patients in the present series were sufferers of hypertension. (Consumer Summary produced by Reliance Medical Information, Inc.)