Intracranial Hemorrhage: Intraparenchymal, Intraventricular, Hypertensive, and Transformation Hemorrhage

00:01 Now let's talk about the 4th type of hemorrhage. intraparenchymal hemorrhage which is also a type of hemorrhagic stroke in addition to an intracranial hemorrhage type. Intraparenchymal hemorrhages are hemorrhages as a result of intracerebral bleeding, bleeding within the brain parenchyma or brain tissue and we can see 2 basic types of intraparenchymal hemorrhage, lobar hemorrhages out in the lobes of the brain and deep subcortical hemorrhages which we see with hypertension.

00:31 When we think about intraparenchymal hemorrhages, these commonly arise from deep penetrating cerebral blood vessels and arteries either in the deep subcortical areas or out in the lobes of the brain. The deeper arteries, the deep subcortical hemorrhages, these arteries can be affected by lipohyalinosis, microaneurysm formation, or arteriosclerosis as a result of longstanding hypertension. Arteriosclerosis results from increase in the smooth muscle within and around the blood vessels as a result of longstanding hypertension and that increase in smooth muscle can result in damage to the blood vessels and ultimately hemorrhage. We can see 2 types of intraparenchymal hemorrhage, lobar and deep subcortical hemorrhages and here you see 2 examples on non-contrast head CT. On the left, we can see a lobar hemorrhage. This is an area of hyperdense signal out in the lobe, the frontal lobe of the brain and we see different causes for lobar hemorrhages than the deep subcortical hemorrhages which we see on the right. This is a deeper focus, again, of hyperdense signal consistent with hemorrhage which we commonly see the deep subcortical hemorrhages with hypertensive hemorrhage.

01:49 Let's talk about the types of intraparenchymal hemorrhages in our diagnostic investigation and why they occur. These hemorrhages occur from blood that is extravasating from ruptured arteries or vessels which results in a neurologic deficit. Patients typically present with a focal neurologic deficit, a stroke-like symptom, with or without headache and headache is common in these patients but not universal. So what happens when an intraparenchymal hemorrhage occurs? Well, the first thing is blood extravasates from the blood vessel from the ruptured artery and this results in development of a focal neurologic deficit. And these patients really present with focal neurologic deficits or stroke-like symptoms in addition to headache. Headache is common, but not universal.

02:33 It's much more common to see headache with an intraparenchymal hemorrhage or hemorrhagic stroke as opposed to a ischemic stroke. As that blood extravasates into the brain, there is adjacent brain tissue that is disrupted or displaced or compressed from local mass effect and swelling and deep hemorrhages occur in the same regions as lacunar infarcts. So we see hemorrhages in the caudate and putamen, in the thalamus, in the pons, or in the cerebella. Now let's talk about intraventricular hemorrhage.

03:00 in the pons, or in the cerebella. Now let's talk about intraventricular hemorrhage.

03:06 Intraventricular hemorrhage is bleeding or blood that forms from intracerebral bleeding in which there is blood in the ventricular system. This is the least common cause of intracranial hemorrhage, it's uncommon. And we see 2 types, primary intraventricular hemorrhage or secondary intraventricular hemorrhage. Primary IVH accounts for only about 3% of spontaneous intracranial hemorrhage so it's really rare. It may also occur secondary. You may have IVH secondary to subarachnoid hemorrhage, intraparenchymal hemorrhage, or any other type of intracranial hemorrhage. It can complicate those presentations. Patients present with symptoms of increased ICP, blood within the ventricles results in reduced CSF reabsorption. So we see increased intracranial pressure, symptoms of nausea, vomiting, headache and ultimately impaired consciousness.

03:57 Complications include obstructive hydrocephalus or cerebral vasospasm particularly when IVH is associated with subarachnoid hemorrhage. And we consider similar management strategies to other types of intracranial hemorrhage. We want to reduce blood pressure and prevent hemorrhage propagation but with IVH we have to be worried about hydrocephalus. These patients may need interventions to manage increased ICP such as external ventricular drains like an EVD or other management strategies to reduce increase in intracranial pressure and manage ICP. Now let's talk about the second step in causes of intraparenchymal hemorrhage. Now let's talk about step 2 in evaluating patients with an intracranial hemorrhage. The second step is working up the cause of the intracranial or intraparenchymal hemorrhage. And here we can consider 6 major categories that cause intraparenchymal hemorrhage. And many of these categories arise from risk factors for increase in intraparenchymal hemorrhage. That includes hypertension, hematologic disorders, disorders to increase likelihood of bleeding, cerebral amyloid angiopathy can increase the risk of bleeding anticoagulant use, alcohol use or abuse can increase the risk of particularly subdural hematoma formation both with and without trauma, and vascular abnormalities that are present on the brain.

05:13 The 6 categories I like to think about that are causes of intraparenchymal hemorrhage are hypertension, hemorrhagic transformation of an ischemic infarct, amyloid angiopathy, vascular lesions such as an AVM or aneurysm, tumor formation or tumor-like metastasis or primary brain tumors, and then there are a number of other causes like trauma, vasculitis, Moyamoya disease, and others. And these categories help me to think about the causes of the hemorrhage, what I need to do to evaluate them and ultimately the management strategy.