Intracerebral hemorrhage

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Introduction0:00–0:51

There are two main types of stroke: a hemorrhagic stroke, which occurs when an artery ruptures and bleeds within the brain, and an ischemic stroke, which occurs when an artery gets blocked.
Hemorrhagic strokes can be further split into two types, an intracerebral hemorrhage which is when bleeding occurs within the cerebrum, and a subarachnoid hemorrhage which is when bleeding occurs between the pia mater and arachnoid mater of the meninges - the inner and middle layers that wrap around the brain.
We’ll be focusing on intracerebral hemorrhages which are more common. An intracerebral hemorrhage that involves just the brain tissue is called an intraparenchymal hemorrhage, whereas if the blood extends into the ventricles of the brain which store cerebrospinal fluid, it’s called an intraventricular hemorrhage.

Anatomy0:51–3:26

The brain has a few regions - the most obvious is the cerebrum, which is divided into two cerebral hemispheres, each of which has a cortex - an outer region - divided into four lobes including the frontal lobe, parietal lobe, temporal lobe, and the occipital lobe.
There are also a number of additional structures - including the cerebellum, which is down below, as well as the brainstem which connects to the spinal cord.
The right cerebrum controls muscles on the left side of your body and vice versa. The frontal lobe controls movement, and executive function, which is our ability to make decisions.
The parietal lobe processes sensory information, which lets us locate exactly where we are physically and guides movements in a three-dimensional space.
The temporal lobe plays a role in hearing, smell, and memory, as well as visual recognition of faces and languages. Finally, there’s the occipital lobe which is primarily responsible for vision.
The cerebellum also helps with muscle coordination and balance. And finally, there’s the brainstem, which plays a vital role in functions like heart rate, blood pressure, breathing, gastrointestinal function, and consciousness.
The brain receives blood from the left and right internal carotid arteries, as well as the left and right vertebral arteries, which come together to form the basilar artery.
The internal carotid arteries turn into the left and right middle cerebral arteries which serve the lateral portions of the frontal, parietal, and temporal lobes of the brain.
Each of the internal carotid arteries also give off branches called the anterior cerebral arteries which serve the medial portion of the frontal and parietal lobes and connect with one another with a short little connecting blood vessel called the anterior communicating artery.
Meanwhile, the vertebral arteries and basilar artery give off branches to supply the cerebellum and the brainstem. In addition, the basilar artery divides to become the right and left posterior cerebral artery which mainly serve the occipital lobe and some of the temporal lobe as well as the thalamus.
Finally, the internal carotid arteries each give off a branch called the posterior communicating artery which attaches to the posterior arteries on each side.
So together, the main arteries and the communicating arteries complete what’s called the Circle of Willis - a ring where blood can circulate from one side to the other in case of a blockage.

Pathology3:26–5:50

There are a few ways that an intracerebral hemorrhage might happen. The most common one is through hypertension or high blood pressure.
Hypertension can lead to various vessel wall abnormalities. Hypertension can lead to hyaline arteriolosclerosis, which results from hydrostatic pressure pushing proteins out of the blood vessel lumen and into the interstitial space within the blood vessel walls.
Over time as more of these proteins deposit in the walls, the blood vessels become more stiff and brittle, and therefore more vulnerable to rupture.
Hypertension can also cause tiny bulges in the wall of small arteries, called microaneurysms. These microaneurysms are called Charcot-Bouchard aneurysms, and they’re most likely to be found on small arteries like lenticulostriate vessels which arise from the anterior part of the circle of Willis and supply the basal ganglia.
Intracerebral hemorrhages are sometimes associated with arteriovenous malformations. which are a tangle of blood vessels that directly connect an artery to a vein - a bit like a capillary bed, but with much, much larger blood vessels.
Over time these abnormal vessels can rupture causing a hemorrhagic stroke. Intracerebral hemorrhages are also associated with conditions that damage the arteries in the cerebrum themselves like vasculitis, an inflammation of the blood vessel walls, vascular tumors, like a hemangioma, which is a benign vascular tumor of the endothelial cells of blood vessels, and cerebral amyloid angiopathy, which is a degenerative disease where abnormal protein deposits in the walls of arterioles making them less compliant.
Intracerebral hemorrhage can also be secondary, arising after an ischemic stroke. An ischemic stroke is caused by a blockage of blood flow to a part of the brain, and within hours it usually leads to brain tissue death.
Arteries within the ischemic tissue are themselves made up of endothelial cells that die off - and that means that if there’s reperfusion or a return to blood flow, there’s an increased chance that the damaged blood vessel might rupture causing a hemorrhage.
If this happens, there’s bleeding into dead tissue, and it’s called a hemorrhagic conversion. Regardless of the cause, once there’s an intracerebral hemorrhage, blood starts spewing out from a damaged blood vessel creating a pool of blood which increases pressure in the skull and puts direct pressure on nearby tissue cells and blood vessels.

Symptoms5:50–7:34

It also means that less blood is flowing downstream to the cells that need it, which leaves the downstream tissue deprived of oxygen-rich blood.
Healthy tissue can die from both the direct pressure and the lack of oxygen within a few hours. Increased pressure within the skull can also lead to brain herniation, which is when the brain moves across structures in the skull.
These structures include the falx cerebri which divides the two halves of the brain, the tentorium cerebelli which divides the occipital lobes from the cerebellum, and the foramen magnum which is the hole in the base of the skull, where the spinal cord connects with the brain.
Stroke symptoms depend on the exact part of the brain that is affected. For example, an anterior or middle cerebral artery stroke can cause numbness and sudden muscle weakness.
If a stroke affects the Broca’s area, which is usually in the left frontal lobe, or Wernicke’s area, which is usually in the left temporal lobe, then it can cause slurred speech or difficulty understanding speech, respectively.
If there’s a posterior cerebral artery stroke, then it can affect vision. An acronym to remember some common stroke symptoms is FAST - Facial drooping, Arm weakness, Speech difficulties, and Time.
Time is obviously not a symptom but just a reminder to get help as quickly as possible to minimize cell injury and maximize the chance of a full recovery.

Diagnosis7:34–7:55

To diagnose and confirm the location and size of a hemorrhagic stroke, medical imaging with a CT or MRI can be used. Also, angiography, which uses contrast injected into the blood, can help to visualize the exact location where blood accumulates in the brain tissue.

Treatment7:55–8:37

Medical treatment of an intracerebral hemorrhage includes using drugs that help control hypertension and relieve intracranial pressure.
In terms of surgery, a craniotomy is often helpful at relieving intracranial pressure when there’s a bleed near the surface of the skull.
In a craniotomy, part of the skull bone is removed to drain any accumulated blood and relieve pressure. Alternatively, if there’s a bleed that’s located deep in the brain tissue, stereotactic aspiration can be done to aspirate off blood and relieve intracranial pressure.
Stereotactic aspiration is done under a CT scanner to help guide a needle to the exact spot where blood needs to be drained.
All right, as a quick recap. An intracerebral hemorrhage is a type of hemorrhagic stroke, where an artery breaks within the cerebrum.

Recap8:37–9:20

The result is that a pool of blood forms which increases intracranial pressure, and downstream tissue gets deprived of oxygen-rich blood.
Intracerebral hemorrhages can be treated with medications aimed at controlling the high intracranial pressure, as well as surgical interventions like a craniotomy and stereotactic aspiration which can help remove the pool of blood.
The goal is to identify symptoms and reestablish blood flow to prevent long-term damage. To help remember this a common acronym is FAST - Facial drooping, Arm weakness, Speech difficulties, and Time.