engleski

CT scanning can differentiate between ischaemic attack and haemorrhage

I am concerned about Gunatilake's reports of cases in which rapid resolution of intracerebral haemorrhage occurred.1 The author's premise is founded on two erroneous statements. Gunatilake stated that "no one has reported resolution of the symptoms and signs of intracerebral haemorrhage within 24 hours, although the possibility has been recognised." The author obviously chose to ignore published data that showed a rapid resolution of neurological deficit after intracerebral haemorrhage.2-4 Gunatilake also stated: "Intracerebral haemorrhage ... is not included in the differential diagnosis of transient ischaemic attacks." In his work on vascular diseases of the central nervous system Ross Russell states: "With CT scanning it is now possible to be sure that a brief reversible focal disturbance is not due to a minor haemorrhage or to a cerebral tumour."5 He emphasises this statement with a diagnostic algorithm, which includes using computed tomography to differentiate between ischaemia and haemorrhage.5 Transient ischaemic attacks are agreed to be episodes of focal neurological deficit in a vascular distribution. They have been seen as a marker for the risk of cerebral infarction. This opinion has persisted despite the introduction of new diagnostic methods such as computed tomography, magnetic resonance imaging, and positron emission tomography. These methods have shown that even in people with normal findings on neurological examination there were often prolonged morphological, physiological, or metabolic disturbances. Therefore, the question is: should we classify these patients as having a transient ischaemic attack (on the basis of their history and the absence of neurological signs and symptoms) or as having a cerebral infarction (on the basis of neuroimaging)? Additionally, the unexpected frequency with which other causative factors which imitate a transient ischaemic attack are identified using the new neuroimaging techniques has created a need to redefine the differential diagnosis of transient ischaemic attacks. In an investigation carried out between 1991 and 1997 my colleagues and I identified 134 patients who had had a transient ischaemic attack and who were admitted on an emergency basis. Although we tried to use strict criteria, after undergoing computed tomography, 23% of patients were found to be misclassified (table).

ishemic stroke; cerebral haemorrhage; CT scanning

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