Diagnosis and Treatment of Late Neurological Ischemic Deficit in Patients Suffering From Subarachnoid Hemorrhage

Aneurysmal subarachnoid hemorrhage (aSAH) is a particular form of hemorrhagic stroke characterized by blood spillage into the intracranial subarachnoid spaces due to the rupture of an aneurysm of a large cerebral arterial vessel of the circle of Willis. It can cause sudden and intense symptoms, such as violent headache, nausea, vomiting, neck stiffness and sensitivity to light, but also loss of consciousness, cardiac arrest and death.

The pre-hospital mortality rate in the literature remains high (22-26%), even if it is lower than in previous decades. However, the number of patients discharged from hospital with permanent disabilities is increasing, especially those of working age (the average age at onset of symptoms is 55 years), contributing significantly to public health costs.

The incidence of aSAH worldwide is approximately 6.1 cases per 100,000 people per year, but there are national differences. In Italy, for example, it is 11.2 (10.5-12.4) cases per 100,000 inhabitants per year.

At the onset of symptoms, once the aneurysmal origin of the cerebral hemorrhage has been confirmed through radiological examinations, it is essential to promptly ensure treatment of the ruptured aneurysm. Early repair of the ruptured aneurysm is recommended within 24 to 72 hours, via endovascular coiling or neurosurgical clipping. This allows to prevent any rebleeding and reduce the risk of cerebral vasospasm, as it reduces the amount of blood distributed in the subarachnoid space. The latter, in fact, represents the main inflammatory stimulus on large cerebral arteries, favoring the vasoconstriction reaction which manifests itself angiographically and/or ultrasonographically in 70% of cases. Cerebral vasospasm is very often clinically silent, since the reduction of the vascular lumen is not sufficient to generate the conditions of discrepancy between the arterial flow of the perfused brain parenchyma and its metabolic demand.

However, in 20-30% of cases a neurological deterioration also occurs, called delayed ischemic neurological deficit or DIND (Delayed Ischemic Neurological Deficit), defined as a focal neurological deterioration (appearance of at least one of the symptoms including hemiparesis, aphasia, hemianopsia or neglect) or global (sudden neurological worsening leading to at least a two-point decrease in the Glasgow Scale or the appearance of anisocoria or pupillary reactivity). DIND is not always immediately evident after securing the aneurysm, and it is necessary to exclude other causes of neurological deterioration, such as hydrocephalus, convulsions, rebleeding and hyponatremia in order to confirm it.