Stroke - Symptoms

Stroke is a broad term that includes a range of conditions characterized by sudden disruption of brain function due to a disturbance in cerebral blood flow. The term cerebral ischemia is appropriate for the condition that follows cerebral vascular occlusion. Venous thrombosis can also cause ischemia, but is less common than arterial occlusion. This article does not cover intracranial hemorrhages (including subarachnoid and intracerebral hemorrhages), which are also considered types of stroke.

A stroke is characterized by a significant loss of neurological function that develops over minutes or hours. Sometimes stroke symptoms progress in stages over a longer period of time, sometimes over several days. Over time, the ischemic zone in the brain may expand, causing initially mild neurological symptoms to worsen over subsequent hours or days.

The key symptom that allows diagnosing cerebral ischemia is acute neurological deficit associated with loss of function of the brain area supplied with blood by a specific cerebral artery. Although diagnosis of the etiology of stroke and identification of risk factors are important, the affected vessel should be identified first.

Typically, with ischemic injury, neurological symptoms are most pronounced soon after the onset of the disease (unless there is a tendency for progression), and subsequently, the impaired function is restored. The most rapid recovery occurs in the first few days after the stroke and can sometimes lead to almost complete recovery of function. Although recovery slows after the first week, it can still be significant and continues for several months (sometimes years) after the stroke. Although patients and their relatives are often frightened by the loss of the ability to walk, speak, and move their limbs, it is important to inform them that improvement usually occurs over time and to reassure them of the prospect of possible gradual recovery.

Many patients recover completely within hours or days of the stroke, since arterial occlusion is often only temporary. If neurological symptoms persist for less than 24 hours, the episode is classified as a transient ischemic attack (TIA). If symptoms persist longer but subsequently resolve completely, a “reversible ischemic neurological deficit” is diagnosed. These terms are widely used to classify patients in research studies. The risk of recurrence is the same for both temporary and permanent arterial occlusion, since the underlying pathological process that leads to arterial occlusion is of decisive importance.

Initial symptoms of stroke

Most patients with ischemic stroke experience loss of motor or sensory function, often limited to one side of the body. Movement impairment may be characterized by true weakness (paresis) or loss of coordination (ataxia). Patients often describe motor symptoms as “awkwardness” or “heaviness.” Although any sensory system can be affected by stroke, somatosensory and visual functions are most often affected, while taste, smell, and hearing are usually spared.

While acute focal symptoms are a characteristic manifestation of ischemic stroke, general cerebral symptoms are not typical of focal ischemia. Therefore, in order to diagnose stroke in a patient presenting with vague complaints of general weakness, fatigue, dizziness, weakness in the limbs, migrating sensory disturbances involving both sides of the body, it is necessary to seek out clear focal symptoms. Diagnosis of stroke is impossible without characteristic specific complaints.

Transient loss of vision in one eye - amaurosis fugax - deserves special mention because it often occurs when the proximal portion of the carotid artery is affected. The ophthalmic artery, which supplies the retina, is the first branch of the internal carotid artery. Since surgical intervention is sometimes indicated in case of carotid artery pathology, an urgent examination of the carotid arteries is necessary in this situation.

In cerebral ischemia, cognitive functions are sometimes impaired. The loss of function may be obvious (for example, in aphasia, when the patient loses the ability to speak or understand speech addressed to him) or more hidden (for example, in isolated damage to the association areas of the cerebral cortex). In the latter case, the patient may develop hallucinations or confusion. Sometimes a patient with a speech disorder who does not have obvious motor or sensory impairments is mistakenly diagnosed with a psychiatric disorder. However, cognitive impairment rarely occurs in the absence of more typical focal motor or sensory impairments, which usually help in establishing the diagnosis of cerebral ischemia.

Acute vertigo is a particularly difficult symptom to evaluate because it may result from a loss of function in the brain (brainstem and cerebellum) or the peripheral vestibular apparatus (semicircular canals or eighth cranial nerve). The analysis is further complicated by the fact that the vestibular apparatus is partially supplied by the same vessel that supplies the brainstem. Thus, ischemia of the inner ear may be caused by the same mechanisms as ischemia of the brain.

Pain as such, including pain in the extremities, is not usually a manifestation of cerebral ischemia. An exception to this rule is headache, which is often noted with stroke. However, the presence, intensity, or location of pain is usually not helpful in establishing a diagnosis of stroke.

At the onset of a stroke, epileptic seizures or transient loss of consciousness may be observed, but the fact that they develop against the background of a newly developed persistent focal neurological defect is strong evidence that this episode is not just an epileptic seizure or syncope, but a manifestation of a stroke. Epileptic seizures and loss of consciousness are more often observed with intracranial hemorrhages, but they are also possible with arterial occlusion. Although they are more often observed with cardiogenic embolism of cerebral vessels, this pattern is not so absolute that, based on them, a conclusion can be made about the mechanism of stroke development.