Question

Delayed cerebral ischemia after subarachnoid hemorrhage:
Diagnosis

Hint:

DCI is diagnosed through a combination of clinical monitoring, neuroimaging, and cerebral blood flow measurements, which helps identify at-risk patients early.

Answer 1

Delayed cerebral ischemia (DCI) is a common and serious complication after subarachnoid hemorrhage (SAH). It occurs several days after the initial hemorrhage and can lead to significant morbidity or mortality if not properly diagnosed and managed.
Step 1: Clinical Features of DCI:
1. Timing of Onset: DCI typically develops between 3 and 14 days after the hemorrhage. This delayed onset distinguishes it from early complications like rebleeding.
2. Neurological Deterioration: Patients with DCI may show signs of progressive neurological deterioration, such as confusion, hemiparesis, or loss of consciousness.
3. Clinical Symptoms: Symptoms can include new-onset focal neurological deficits (e.g., weakness, aphasia), decreased level of consciousness, and seizures.
Step 2: Diagnostic Tools:
1. Neuroimaging: - CT/MRI: Early CT or MRI scans may not detect ischemic changes, but subsequent imaging may reveal areas of hypodensity or infarction, especially in the watershed regions of the brain.
- CT Angiography (CTA): CTA can detect vasospasm, a common cause of DCI, by identifying areas of narrowed or occluded arteries.
- Magnetic Resonance Angiography (MRA): MRA can be used to assess the intracranial vasculature for vasospasm and identify areas at risk. 2. Cerebral Blood Flow Monitoring: Techniques such as transcranial Doppler (TCD) and brain tissue oxygen monitoring (PbtO2) are used to assess cerebral blood flow and oxygenation, helping to identify patients at risk for ischemia.