Brain Imaging in Hypertensive Hemorrhage

Introduction:

The brain is a complex organ comprising various glands and a rich vascular network. The arteries in the brain are responsible for the rich blood supply to the deep tissues of the brain. This intricate vascular system is the key to maintaining the integrity and vitality of the central nervous system. Certain conditions could weaken and damage the blood vessels within the brain resulting in a brain bleed. Brain bleeding is a life-threatening condition that requires prompt diagnosis and expedited treatment.

What Is an Intracranial Hemorrhage?

Hemorrhage refers to bleeding. Acute bleeding within the skull or the brain is known as intracranial hemorrhage. Intracranial hemorrhage is responsible for 15 % of strokes and is the chief reason for the increased mortality rates. The bleeding could result in a fatal condition known as stroke, where the brain is deprived of oxygen and blood, which could result in paralysis or death. Intracranial hemorrhage is more frequently seen in men than women. Various factors contribute to intracranial bleeding, such as trauma, hypertension, tumors, hereditary coagulopathy diseases, and vascular malformations.

What Are the Types of Intracranial Hemorrhage?

Intracranial hemorrhage can be categorized into four types:

• Epidural Hematoma: Epidural hematoma usually occurs after a trauma when the blood accumulates between the skull and the outermost protective covering of the brain (dura mater).

• Subdural Hematoma: Subdural hematoma refers to the bleeding between the dura mater and the brain surface.

• Subarachnoid Hemorrhage: Subarachnoid hematoma occurs when the bleeding happens between the brain and the meninges covering them.

• Intraparenchymal Hemorrhage: Intraparenchymal hemorrhage is when bleeding occurs within the brain. Hypertensive hemorrhages are usually intraparenchymal types.

What Is a Hypertensive Intracranial Hemorrhage?

Bleeding in the brain caused by high blood pressure is known as hypertensive intracranial hemorrhage. It usually affects people in their sixth or seventh decade. Hypertension causes the arteries supplying the brain to rupture, resulting in bleeding within the brain. Progressively, there is continued fluid build-up and formation of a blood clot. Since the brain is enclosed within the skull, the hemorrhage increases pressure within the brain. The blood clot can also compress the adjacent vital neurovascular bundles. As a result, the hemorrhagic area is deprived of oxygen and blood. In addition, the blood clot may degrade, releasing toxins and further damaging the tissues within the brain. These consequences collectively may result in a fatal condition called a stroke.

What Are the Causes of Hypertensive Brain Hemorrhage?

There are various risk factors associated with a hypertensive brain hemorrhage. They are described below:

• Trauma.

• Hypertension or increased blood pressure.

• Aneurysms (engorged and swollen blood vessels within the brain).

• Abnormalities in the blood vessel.

• Amyloid angiopathy (age-related blood vessel disorder where small vessels in the brain bleed).

• Bleeding disorders.

• Tumors or neoplasms in the brain.

• Liver diseases.

What Are the Symptoms of Hypertensive Hemorrhage?

The symptoms may develop gradually or may be spontaneous. The symptoms depend on the location and the severity of the damage caused by the bleeding. They are enlisted below:

• Persistent severe headache.

• Seizures.

• Altered vision.

• Vomiting.

• Weakness or numbness in the limbs.

• Difficulty in speaking, swallowing, urinating, or bowel movements.

• Confusion and disorientation.

What Is the Role of Imaging Techniques in Diagnosing Hypertensive Hemorrhage?

Brain hemorrhage is a life-threatening condition that requires prompt diagnosis and immediate treatment to prevent terminal damage. Unfortunately, clinical features are unreliable; hence imaging procedures are mandatory for a confirmatory diagnosis. Neuroimaging plays a crucial role in the diagnosis of intracranial hemorrhage. It helps understand the location and the cause of the bleed, the severity of the damage, the volume of the hemorrhage and guides the emergency treatment plan. Various imaging techniques that aid in the diagnostic workup of intracranial hemorrhage are discussed below:

• Computed Tomography (CT): CT is the most efficient and noninvasive technique to localize a brain bleed. Noncontrast CT is the most preferred technique as it is quick, widely available, and highly sensitive. The findings on CT are time-based; the findings progressively vary depending on the time elapsed since the bleeding initially occurred. An acute phase (within four hours of the bleed up to one week) is represented with areas of increased attenuation (appear bright on CT). This is due to the hemoglobin that is present in the extravasated blood. The hyperattenuated area may be surrounded by a low attenuated area representing the brain edema and the serum that may have been extruded. Within a week to ten days, the blood density usually starts decreasing from the periphery of the lesion, thus represented as hypoattenuating areas (gray) in the CT. In two to three weeks, once the clot is resolved, the intensity would be similar to that of the white matter in the brain. Over a few months, when the clot is entirely resolved, it would appear in the CT as a small slit-like cavity appearing hypointense (dark area), suggestive of hemorrhage.

• Magnetic Resonance Imaging (MRI): MRI is a vital test that can help in staging the hemorrhage based on the chemical changes that occur with the bleeding. These chemical changes can be assessed through the hemoglobin molecule in the extravasated blood. Chronic hypertensive hemorrhage usually appears as scattered and hypointense lesions in a multifocal plane. Serial head imaging by MRI can help to evaluate the secondary effects of the expanding clot on the adjacent neurovascular structures. Contrast MRI is more specific to determine any underlying pathology causing intracranial hemorrhage.

• Angiogram: Angiogram is an invasive procedure used to assess and evaluate the blood vessels within the brain. A catheter is introduced into an artery, and contrast material is injected through it. A CT or MRI is used to image the vessels in the brain. CT angiography is a highly reliable tool for diagnosing an intracranial hemorrhage. A spot sign in CT angiography (which appears as a hyperdense area within the blood clot) is usually considered a risk factor for hematoma expansion and poor prognosis.

How to Prevent Hypertensive Intracranial Hemorrhage?

Patients are required to monitor their blood pressure regularly. High blood pressure should be controlled with diet modification, exercise, and medications. In addition, patients should refrain from smoking and drinking alcohol. Any symptomatic changes, if observed, should be notified to the physician, and the necessary diagnostic tests should be performed.

Conclusion:

Intracranial hemorrhage is a fatal condition with high mortality rates. It is an emergency that requires prompt diagnosis and immediate treatment. Any delays could result in potential complications. Neuroimaging is considered the gold standard in diagnosing intracranial hemorrhage. Appropriate imaging techniques could result in an exact diagnosis and, thereby, better patient prognosis.