Hemorrhagic stroke and aneurysm are often confused, though they are distinct medical conditions. Both involve blood vessels in the brain and can have severe consequences. This article clarifies their differences and the important connection between a cerebral aneurysm and a hemorrhagic stroke.
Understanding Hemorrhagic Stroke
A hemorrhagic stroke occurs when a blood vessel in the brain ruptures, causing bleeding into or around brain tissue. These strokes account for approximately 13% of all stroke cases and are medical emergencies. The bleeding disrupts normal blood flow, increasing pressure within the skull and damaging brain cells.
There are two primary types of hemorrhagic strokes. An intracerebral hemorrhage (ICH) involves bleeding directly within brain tissue. A subarachnoid hemorrhage (SAH) is bleeding into the subarachnoid space, the area between the brain and its protective outer membranes. Common causes include uncontrolled high blood pressure, head trauma, and blood vessel abnormalities like arteriovenous malformations (AVMs).
Understanding Cerebral Aneurysm
A cerebral aneurysm, also known as a brain aneurysm, is a weak, bulging spot on a blood vessel wall within the brain. This bulge resembles a small balloon or blister and fills with blood. Aneurysms typically form where arteries branch, as these areas often have weaker walls.
Cerebral aneurysms are classified by shape. Saccular aneurysms are the most common “berry” type, rounded and often found at the base of the brain. Fusiform aneurysms bulge on all sides of the artery, appearing as a dilated segment. Factors contributing to aneurysm formation include a family history, inherited connective tissue disorders, prolonged high blood pressure, and smoking.
The Connection: Aneurysm Rupture and Hemorrhagic Stroke
A ruptured aneurysm can directly cause a specific type of hemorrhagic stroke. When a cerebral aneurysm ruptures, it leads to a sudden, severe bleed into the subarachnoid space, resulting in a subarachnoid hemorrhage (SAH). The aneurysm is the underlying weakness, while the hemorrhagic stroke is the acute bleeding event.
Aneurysm rupture causes blood to spill into the space surrounding the brain. This influx creates significant pressure and can irritate surrounding tissues. Aneurysmal ruptures are a common cause of non-traumatic SAHs, accounting for approximately 85% of such cases. The resulting bleeding can lead to severe neurological deficits and requires immediate medical intervention.
Identifying Symptoms and Diagnosis
An unruptured cerebral aneurysm often remains asymptomatic, especially if small. Larger aneurysms might press on nearby nerves or brain tissue, potentially causing symptoms such as headaches, vision changes, or pain behind the eye. When an aneurysm ruptures, symptoms are sudden and severe, marking a medical emergency.
The most characteristic symptom of a ruptured aneurysm or hemorrhagic stroke is an abrupt, excruciating headache, often described as the “worst headache of my life.” Other symptoms include nausea, vomiting, a stiff neck, sensitivity to light, confusion, and sudden loss of consciousness. Diagnostic imaging, such as computed tomography (CT) scans, is typically the first step to identify bleeding. Further detailed imaging, like cerebral angiography or magnetic resonance imaging (MRI), helps pinpoint the exact location and size of the aneurysm or hemorrhage.
Medical Management and Treatment
Treatment for cerebral aneurysms and hemorrhagic strokes varies depending on whether the aneurysm has ruptured. For unruptured aneurysms, a healthcare team might recommend careful observation, especially for smaller, lower-risk cases. If treatment is necessary to prevent rupture, common procedures include surgical clipping or endovascular coiling. Surgical clipping involves opening the skull to place a small metal clip at the aneurysm’s base, blocking blood flow.
Endovascular coiling is a less invasive procedure where a catheter is threaded through blood vessels to the aneurysm, and platinum coils are deployed to fill and seal it. For ruptured aneurysms and resulting hemorrhagic strokes, immediate medical interventions focus on stopping the bleeding and managing brain pressure. This may involve securing the aneurysm through clipping or coiling, and administering medications to prevent complications like vasospasm (narrowing of blood vessels). Specialized neurosurgical care is important for optimal outcomes.