Nontraumatic intraparenchymal hemorrhage most commonly results from hypertensive damage to blood vessel walls e.g.:

- hypertension

- eclampsia

- drug abuse,

but it also may be due to autoregulatory dysfunction with excessive cerebral blood flow e.g.:

- reperfusion injury

- hemorrhagic transformation

- cold exposure

- rupture of an aneurysm or arteriovenous malformation (AVM)

- arteriopathy (e.g. cerebral amyloid angiopathy, moyamoya)

- altered hemostasis (e.g. thrombolysis, anticoagulation, bleeding diathesis)

- hemorrhagic necrosis (e.g. tumor, infection)

- venous outflow obstruction (e.g. cerebral venous sinus thrombosis).

Nonpenetrating and penetrating cranial trauma can also be common causes of intracerebral hemorrhage.

Acquired cerebrovascular diseases are those that are obtained throughout a person's life that may be preventable by controlling risk factors. The incidence of cerebrovascular disease increases as an individual ages. Causes of acquired cerebrovascular disease include atherosclerosis, embolism, aneurysms, and arterial dissections. Atherosclerosis leads to narrowing of blood vessels and less perfusion to the brain, and it also increases the risk of thrombosis, or a blockage of an artery, within the brain. Major modifiable risk factors for atherosclerosis include:

Controlling these risk factors can reduce the incidence of atherosclerosis and stroke. Atrial fibrillation is also a major risk factor for strokes. Atrial fibrillation causes blood clots to form within the heart, which may travel to the arteries within the brain and cause an embolism. The embolism prevents blood flow to the brain, which leads to a stroke.

An aneurysm is an abnormal bulging of small sections of arteries, which increases the risk of artery rupture. Intracranial aneurysms are a leading cause of subarachnoid hemorrhage, or bleeding around the brain within the subarachnoid space. There are various hereditary disorders associated with intracranial aneurysms, such as Ehlers-Danlos syndrome, autosomal dominant polycystic kidney disease, and familial hyperaldosteronism type I. However, individuals without these disorders may also obtain aneurysms. The American Heart Association and American Stroke Association recommend controlling modifiable risk factors including smoking and hypertension.

Arterial dissections are tears of the internal lining of arteries, often associated with trauma. Dissections within the carotid arteries or vertebral arteries may compromise blood flow to the brain due to thrombosis, and dissections increase the risk of vessel rupture.

It is also possible to classify angiopathy by the associated condition:

- Diabetic angiopathy

- Congophilic angiopathy

In younger patients, vascular malformations, specifically AVMs and cavernous angiomas are more common causes for hemorrhage. In addition, venous malformations are associated with hemorrhage.

In the elderly population, amyloid angiopathy is associated with cerebral infarcts as well as hemorrhage in superficial locations, rather than deep white matter or basal ganglia. These are usually described as "lobar". These bleedings are not associated with systemic amyloidosis.

Hemorrhagic neoplasms are more complex, heterogeneous bleeds often with associated edema. These hemorrhages are related to tumor necrosis, vascular invasion and neovascularity. Glioblastomas are the most common primary malignancies to hemorrhage while thyroid, renal cell carcinoma, melanoma, and lung cancer are the most common causes of hemorrhage from metastatic disease.

Other causes of intraparenchymal hemorrhage include hemorrhagic transformation of infarction which is usually in a classic vascular distribution and is seen in approximately 24 to 48 hours following the ischemic event. This hemorrhage rarely extends into the ventricular system.

Intracerebral bleeds are the second most common cause of stroke, accounting for 10% of hospital admissions for stroke. High blood pressure raises the risks of spontaneous intracerebral hemorrhage by two to six times. More common in adults than in children, intraparenchymal bleeds are usually due to penetrating head trauma, but can also be due to depressed skull fractures. Acceleration-deceleration trauma, rupture of an aneurysm or arteriovenous malformation (AVM), and bleeding within a tumor are additional causes. Amyloid angiopathy is a not uncommon cause of intracerebral hemorrhage in patients over the age of 55. A very small proportion is due to cerebral venous sinus thrombosis.

Risk factors for ICH include:

- Hypertension (high blood pressure)

- Diabetes mellitus

- Menopause

- Cigarette smoking

- Excessive alcohol consumption

- Severe migraine

Traumautic intracerebral hematomas are divided into acute and delayed. Acute intracerebral hematomas occur at the time of the injury while delayed intracerebral hematomas have been reported from as early as 6 hours post injury to as long as several weeks.

Diseases associated with cerebral atherosclerosis include:

- Hypertensive arteriopathy

This pathological process involves the thickening and damage of arteriole walls. It mainly affects the ends of the arterioles which are located in the deep gray nuclei and deep white matter of the brain. It is thought that this is what causes cerebral microbleeds in deep brain regions. This small vessel damage can also reduce the clearance of amyloid-β, thereby increasing the likelihood of CAA.

Diseases cerebral atherosclerosis and associated diseases can cause are:

- Alzheimer's disease

Alzheimer's disease is a form of dementia that entails brain atrophy. Cerebral amyloid angiopathy is found in 90% of the cases at autopsy, with 25% being severe CAA.

- Cerebral microbleeds (CMB)

Cerebral microbleeds have been observed during recent studies on dementia sufferers using MRI.

- Stroke

Strokes occur from the sudden loss of blood flow to an area of the brain. The loss of flow is generally either from a blockage or hemorrhage. Studies of postmortem stroke cases have shown that intracranial athreosclerotic plaque build up occurred in over half of the individuals and over one third of the overall cases had stenotic build up.

Prognostics factors:

Lower Glasgow coma scale score, higher pulse rate, higher respiratory rate and lower arterial oxygen saturation level is prognostic features of in-hospital mortality rate in acute ischemic stroke.

There are two types of angiopathy: macroangiopathy and microangiopathy.

In macroangiopathy, atherosclerosis and a resultant blood clot forms on the large blood vessels, sticks to the vessel walls, and blocks the flow of blood. Macroangiopathy may cause other complications, such as ischemic heart disease, stroke and peripheral vascular disease which contributes to the diabetic foot ulcers and the risk of amputation.

In microangiopathy, the walls of the smaller blood vessels become so thick and weak that they bleed, leak protein, and slow the flow of blood through the body. The decrease of blood flow through stenosis or clot formation impairs the flow of oxygen to cells and biological tissues (called ischemia) and leads to cellular death (necrosis and gangrene, which in turn may require amputation). Thus, tissues which are very sensitive to oxygen levels, such as the retina, develop microangiopathy and may cause blindness (so-called proliferative diabetic retinopathy). Damage to nerve cells may cause peripheral neuropathy, and to kidney cells, diabetic nephropathy (Kimmelstiel-Wilson syndrome).

Asymptomatic individuals with intracranial stenosis are typically told to take over the counter platelet inhibitors like aspirin whereas those with symptomatic presentation are prescribed anti-coagulation medications. For asymptomatic persons the idea is to stop the buildup of plaque from continuing. They are not experiencing symptoms; however if more build up occurs it is likely they will. For symptomatic individuals it is necessary to try and reduce the amount of stenosis. The anti-coagulation medications reduce the likelihood of further buildup while also trying to break down the current build up on the surface without an embolism forming. For those with severe stenosis that are at risk for impending stroke endovascular treatment is used. Depending on the individual and the location of the stenosis there are multiple treatments that can be undertaken. These include angioplasty, stent insertion, or bypass the blocked area.

70% of patients with carotid arterial dissection are between the ages of 35 and 50, with a mean age of 47 years.

One cause of microangiopathy is long-term diabetes mellitus. In this case, high blood glucose levels cause the endothelial cells lining the blood vessels to take in more glucose than normal (these cells do not depend on insulin). They then form more glycoproteins on their surface than normal, and also cause the basement membrane in the vessel wall to grow abnormally thicker and weaker. Therefore they bleed, leak protein, and slow the flow of blood through the body. As a result, some organs and tissues do not get enough blood (carrying oxygen & nutrients) and are damaged, for example, the retina (diabetic retinopathy) or kidney (diabetic nephropathy). Nerves and neurons, if not sufficiently supplied with blood, are also damaged, which leads to loss of function (diabetic neuropathy, especially peripheral neuropathy).

Massive microangiopathy may cause microangiopathic hemolytic anemia (MAHA).

The risk of death from an intraparenchymal bleed in traumatic brain injury is especially high when the injury occurs in the brain stem. Intraparenchymal bleeds within the medulla oblongata are almost always fatal, because they cause damage to cranial nerve X, the vagus nerve, which plays an important role in blood circulation and breathing. This kind of hemorrhage can also occur in the cortex or subcortical areas, usually in the frontal or temporal lobes when due to head injury, and sometimes in the cerebellum.

For spontaneous ICH seen on CT scan, the death rate (mortality) is 34–50% by 30 days after the insult, and half of the deaths occur in the first 2 days. Even though the majority of deaths occurs in the first days after ICH, survivors have a long term excess mortality of 27% compared to the general population.

The incidence of RCVS is unknown, but it is believed to be "not uncommon", and likely under-diagnosed. One small, possibly biased study found that the condition was eventually diagnosed in 45% of outpatients with sudden headache, and 46% of outpatients with thunderclap headache.

The average age of onset is 42, but RCVS has been observed in patients aged from 19 months to 70 years. Children are rarely affected. It is more common in females, with a female-to-male ratio of 2.4:1.

Once considered uncommon, spontaneous carotid artery dissection is an increasingly recognised cause of stroke that preferentially affects the middle-aged.

The incidence of spontaneous carotid artery dissection is low, and incidence rates for internal carotid artery dissection have been reported to be 2.6 to 2.9 per 100,000.

Observational studies and case reports published since the early 1980s show that patients with spontaneous internal carotid artery dissection may also have a history of stroke in their family and/or hereditary connective tissue disorders, such as Marfan syndrome, Ehlers-Danlos syndrome, autosomal dominant polycystic kidney disease, pseudoxanthoma elasticum, fibromuscular dysplasia, and osteogenesis imperfecta type I. IgG4-related disease involving the carotid artery has also been observed as a cause.

However, although an association with connective tissue disorders does exist, most people with spontaneous arterial dissections do not have associated connective tissue disorders. Also, the reports on the prevalence of hereditary connective tissue diseases in people with spontaneous dissections are highly variable, ranging from 0% to 0.6% in one study to 5% to 18% in another study.

Internal carotid artery dissection can also be associated with an elongated styloid process (known as Eagle syndrome when the elongated styloid process causes symptoms).

It is usually associated with amyloid beta.

However, there are other types:

- the "Icelandic type" is associated with Cystatin C

- the "British type" is associated with ITM2B

Research is currently being conducted to determine if there is a link between cerebral amyloid angiopathy and ingestion of excessive quantities of aluminum.

Can occur due to autosomal dominant diseases, such as hereditary hemorrhagic telangiectasia.

Susceptibility weighted imaging has been proposed as a tool for identifying CAA-related microhemorrhages.

Biopsies also play a role in diagnosing the condition.

The direct cause of the symptoms is believed to be either constriction or dilation of blood vessels in the brain. The pathogenesis is not known definitively, and the condition is likely to result from multiple different disease processes.

Up to two-thirds of RCVS cases are associated with an underlying condition or exposure, particularly vasoactive or recreational drug use, complications of pregnancy (eclampsia and pre-eclampsia), and the adjustment period following childbirth called "puerperium". Vasoactive drug use is found in about 50% of cases. Implicated drugs include selective serotonin reuptake inhibitors, weight-loss pills such as Hydroxycut, alpha-sympathomimetic decongestants, acute migraine medications, pseudoephedrine, epinephrine, cocaine, and cannabis, among many others. It sometimes follows blood transfusions, certain surgical procedures, swimming, bathing, high altitude experiences, sexual activity, exercise, or coughing. Symptoms can take days or a few months to manifest after a trigger.

Following a study and publication in 2007, it is also thought SSRIs, uncontrolled hypertension, endocrine abnormality, and neurosurgical trauma are indicated to potentially cause vasospasm.

Microangiopathy (or microvascular disease, or small vessel disease) is an angiopathy (i.e. disease of blood vessels) affecting small blood vessels in the body. It can be contrasted to macroangiopathy, or large vessel disease.

Cerebral small vessel disease refers to a group of diseases that affect the small arteries, arterioles, venules, and capillaries of the brain. Age-related and hypertension-related small vessel diseases and cerebral amyloid angiopathy are the most common forms.

Coronary small vessel disease is a type of coronary heart disease (CHD) that affects the arterioles and capillaries of the heart. Coronary small vessel disease is also known as cardiac syndrome X, microvascular dysfunction, non-obstructive coronary disease, or microvascular angina.

Cerebral edema can result from brain trauma or from nontraumatic causes such as ischemic stroke, cancer, or brain inflammation due to meningitis or encephalitis.

Vasogenic edema caused by amyloid-modifying treatments, such as monoclonal antibodies, is known as ARIA-E (amyloid-related imaging abnormalities edema).

The blood–brain barrier (BBB) or the blood–cerebrospinal fluid (CSF) barrier may break down, allowing fluid to accumulate in the brain's extracellular space.

Altered metabolism may cause brain cells to retain water, and dilution of the blood plasma may cause excess water to move into brain cells.

Fast travel to high altitude without proper acclimatization can cause high-altitude cerebral edema (HACE).

Cerebral edema is excess accumulation of fluid in the intracellular or extracellular spaces of the brain.

A few studies have worked on providing details related to the outlook of disease progression. Two studies show that each year 0.5% of people who have never had bleeding from their brain cavernoma, but had symptoms of seizures, were affected by bleeding. In contrast, patients who have had bleeding from their brain cavernoma in the past had a higher risk of being affected by subsequent bleeding. The statistics for this are very broad, ranging from 4%-23% a year. Additional studies suggest that women and patients under the age of 40 are at higher risk of bleeding, but similar conducted studies did not reach the same conclusion. However, when cavernous hemangiomas are completely excised, there is very little risk of growth or rebleeding. In terms of life expectancy, not enough data has been collected on patients with this malformation in order to provide a representative statistical analysis.

The estimated detection rate of AVM in the US general population is 1.4/100,000 per year. This is approximately one fifth to one seventh the incidence of intracranial aneurysms. An estimated 300,000 Americans have AVMs, of whom 12% (approximately 36,000) will exhibit symptoms of greatly varying severity.

Autosomal Dominant Retinal Vasculopathy with Cerebral Leukodystrophy (AD-RVCL) (previously known also as Cerebroretinal Vasculopathy, CRV, or Hereditary Vascular Retinopathy, HVR or Hereditary Endotheliopathy, Retinopathy, Nephropathy, and Stroke, HERNS) is an inherited condition resulting from a frameshift mutation to the TREX1 gene. This genetically inherited condition affects the retina and the white matter of the central nervous system, resulting in vision loss, lacunar strokes and ultimately dementia. Symptoms commonly begin in the early to mid-forties, and treatments currently aim to manage or alleviate the symptoms rather than treating the underlying cause. The overall prognosis is poor, and death can sometimes occur within 10 years of the first symptoms appearing.

AD-RVCL (CRV) Acronym

Autosomal Dominance (genetics) means only one copy of the gene is necessary for the symptoms to manifest themselves.

Retinal Vasculopathy means a disorder that is associated with a disease of the blood vessels in the retina.

Cerebral means having to do with the brain.

Leukodystrophy means a degeneration of the white matter of the brain.

Pathogenesis

The main pathologic process centers on small blood vessels that prematurely “drop out” and disappear. The retina of the eye and white matter of the brain are the most sensitive to this pathologic process. Over a five to ten-year period, this vasculopathy (blood vessel pathology) results in vision loss and destructive brain lesions with neurologic deficits and death.

Most recently, AD-RVCL (CRV) has been renamed. The new name is CHARIOT which stands for Cerebral Hereditary Angiopathy with vascular Retinopathy and Impaired Organ function caused by TREX1 mutations.

Treatment

Currently, there is no therapy to prevent the blood vessel deterioration.

About TREX1

The official name of the TREX1 gene is “three prime repair exonuclease 1.” The normal function of the TREX1 gene is to provide instructions for making the 3-prime repair exonuclease 1 enzyme. This enzyme is a DNA exonuclease, which means it trims molecules of DNA by removing DNA building blocks (nucleotides) from the ends of the molecules. In this way, it breaks down unneeded DNA molecules or fragments that may be generated during genetic material in preparation for cell division, DNA repair, cell death, and other processes.

Changes (mutations) to the TREX1 gene can result in a range of conditions one of which is AD-RVCL. The mutations to the TREX1 gene are believed to prevent the production of the 3-prime repair exonuclease 1 enzyme. Researchers suggest that the absence of this enzyme may result in an accumulation of unneeded DNA and RNA in cells. These DNA and RNA molecules may be mistaken by cells for those of viral invaders, triggering immune system reactions that result in the symptoms of AD-RVCL.

Mutations in the TREX1 gene have also been identified in people with other disorders involving the immune system. These disorders include a chronic inflammatory disease called systemic lupus erythematosus (SLE), including a rare form of SLE called chilblain lupus that mainly affects the skin.

The TREX1 gene is located on chromosome 3: base pairs 48,465,519 to 48,467,644

The immune system.

- The immune system is composed of white blood cells or leukocytes.

- There are 5 different types of leukocytes.

- Combined, the 5 different leukocytes represent the 2 types of immune systems (The general or innate immune system and the adaptive or acquired immune system).

- The adaptive immune system is composed of two types of cells (B-cells which release antibodies and T-cells which destroy abnormal and cancerous cells).

How the immune system becomes part of the condition.

During mitosis, tiny fragments of “scrap” single strand DNA naturally occur inside the cell. Enzymes find and destroy the “scrap” DNA. The TREX1 gene provides the information necessary to create the enzyme that destroys this single strand “scrap” DNA. A mutation in the TREX1 gene causes the enzyme that would destroy the single strand DNA to be less than completely effective. The less than completely effective nature of the enzyme allows “scrap” single strand DNA to build up in the cell. The buildup of “scrap” single strand DNA alerts the immune system that the cell is abnormal.

The abnormality of the cells with the high concentration of “scrap” DNA triggers a T-cell response and the abnormal cells are destroyed. Because the TREX1 gene is identical in all of the cells in the body the ineffective enzyme allows the accumulation of “scrap” single strand DNA in all of the cells in the body. Eventually, the immune system has destroyed enough of the cells in the walls of the blood vessels that the capillaries burst open. The capillary bursting happens throughout the body but is most recognizable when it happens in the eyes and brain because these are the two places where capillary bursting has the most pronounced effect.

Characteristics of AD-RVCL

- No recognizable symptoms until after age 40.

- No environmental toxins have been found to be attributable to the condition.

- The condition is primarily localized to the brain and eyes.

- Optically correctable, but continuous, deterioration of visual acuity due to extensive multifocal microvascular abnormalities and retinal neovascularization leading, ultimately, to a loss of vision.

- Elevated levels of alkaline phosphatase.

- Subtle vascular changes in the retina resembling telangiectasia (spider veins) in the parafovea circulation.

- Bilateral capillary occlusions involving the perifovea vessels as well as other isolated foci of occlusion in the posterior pole of the retina.

- Headaches due to papilledema.

- Mental confusion, loss of cognitive function, loss of memory, slowing of speech and hemiparesis due to “firm masses” and white, granular, firm lesions in the brain.

- Jacksonian seizures and grand mal seizure disorder.

- Progressive neurologic deterioration unresponsive to systemic corticosteroid therapy.

- Discrete, often confluent, foci of coagulation necrosis in the cerebral white matter with intermittent findings of fine calcium deposition within the necrotic foci.

- Vasculopathic changes involving both arteries and veins of medium and small caliber present in the cerebral white matter.

- Fibroid necrosis of vessel walls with extravasation of fibrinoid material into adjacent parenchyma present in both necrotic and non-necrotic tissue.

- Obliterative fibrosis in all the layers of many vessel walls.

- Parivascular, adventitial fibrosis with limited intimal thickening.

Conditions with similar symptoms that AD-RVCL can be misdiagnosed as:

- Brain tumors

- Diabetes

- Macular degeneration

- Telangiectasia (Spider veins)

- Hemiparesis (Stroke)

- Glaucoma

- Hypertension (high blood pressure)

- Systemic Lupus Erythematosus (SLE (same original pathogenic gene, but definitely a different disease because of a different mutation in TREX1))

- Polyarteritis nodosa

- Granulomatosis with polyangiitis

- Behçet's disease

- Lymphomatoid granulomatosis

- Vasculitis

Clinical Associations

- Raynaud's phenomenon

- Anemia

- Hypertension

- Normocytic anemia

- Normochromic anemia

- Gastrointestinal bleeding or telangiectasias

- Elevated alkaline phosphatase

Definitions

- Coagulation necrosis

- Endothelium

- Fibrinoid

- Fibrinoid necrosis

- Frameshift mutation

- Hemiparesis

- Jacksonian seizure

- Necrotic

- Necrosis

- Papilledema

- Perivascular

- Retinopathy

- Telangiectasia

- Vasculopathy

- Vascular

What AD-RVCL is not:

- Infection

- Cancer

- Diabetes

- Glaucoma

- Hypertension

- A neurological disorder

- Muscular dystrophy

- Systemic Lupus Erythematosis (SLE)

- Vasculitis

Things that have been tried but turned out to be ineffective or even make things worse:

- Antibiotics

- Steroids

- X-Ray therapy

- Immunosuppression

History of AD-RVCL (CRV)

- 1985 – 1988: CRV (Cerebral Retinal Vasculopathy) was discovered by John P. Atkinson, MD at Washington University School of Medicine in St. Louis, MO

- 1988: 10 families worldwide were identified as having CRV

- 1991: Related disease reported, HERNS (Hereditary Endiotheliopathy with Retinopathy, Nephropathy and Stroke – UCLA

- 1998: Related disease reported, HRV (Hereditary Retinal Vasculopathy) – Leiden University, Netherlands

- 2001: Localized to Chromosome 3.

- 2007: The specific genetic defect in all of these families was discovered in a single gene called TREX1

- 2008: Name changed to AD-RVCL Autosomal Dominant-Retinal Vasculopathy with Cerebral Leukodystrophy

- 2009: Testing for the disease available to persons 21 and older

- 2011: 20 families worldwide were identified as having CRV

- 2012: Obtained mouse models for further research and to test therapeutic agents

The incidence in the general population is roughly 0.5%, and clinical symptoms typically appear between 20 to 30 years of age. Once thought to be strictly congenital, these vascular lesions have been found to occur "de novo". It may appear either sporadically or exhibit autosomal dominant inheritance.