Introduction
A cerebral hemorrhage (intracranial hemorrhage) is a hemorrhage within the skull. A distinction is made between an intracerebral hemorrhage (bleeding into the brain tissue) and a subarachnoid hemorrhage (bleeding between the middle and inner layers of the cerebral membrane). In both cases, the bleeding causes compression of surrounding brain areas, a reduced supply of blood to the brain tissue supplied by the affected vessel and an increase in pressure within the skull. The causes of a cerebral hemorrhage are manifold. In addition to trauma (fall, blow), vascular diseases, tumors and coagulation disorders can also trigger a cerebral hemorrhage.
Causes
There are numerous causes for cerebral hemorrhage. One can distinguish between traumatic and non-traumatic causes: Craniocerebral trauma (fall, blow, traffic accident) Aneurysms (bulging of the vascular walls) Hypertensive microangiopathy (damage to the vascular walls caused by high blood pressure) (brain) tumors Coagulation disorders (with increased bleeding tendency) Amyloid angiopathy (disease with deposition of proteins in the vessels of the brain, which causes stenoses – narrowing of the vessels – and aneurysms – protrusions of the vessel wall). (e.g.
AV malformation with formation with short circuit connections between arteries and veins in the brain) Vasculitis (chronic inflammation of the vessel walls)
- Craniocerebral traumas (fall, blow, traffic accident)
- Aneurysms (bulging of the vessel walls)
- Hypertensive microangiopathy (vascular wall damage due to high blood pressure)
- (brain) tumors
- Coagulation disorders (with increased bleeding tendency)
- Amyloid angiopathy (disease with deposition of proteins in the vessels of the brain, resulting in stenoses – narrowing of vessels – and aneurysms – protrusions of the vessel wall)
- Congenital vascular malformations (e.g. AV malformation with formation with short circuit connections between arteries and veins in the brain)
- Vasculitides (chronic inflammation of the vascular walls)
A common cause of cerebral hemorrhages is craniocerebral trauma (SHT). In the course of severe falls or blows to the skull, the brain vessels rupture and bleed into the brain tissue. A distinction is made between primary and secondary brain damage in craniocerebral trauma.
First, the force applied during a fall or impact causes a fracture of the skull and compression of or damage to the underlying brain tissue (primary brain damage). In addition, a rupture of the superficial brain vessels often results in bleeding into the tissue. Secondary brain damage describes the complications of craniocerebral trauma that occur in the further course of the disease.
These can occur either directly after the trauma or after a few days or weeks. Secondary brain damage includes hematoma (blood accumulation), brain edema (swelling of the tissue due to fluid retention), brain swelling, hypoxia (oxygen deprivation) and hypotension (low blood pressure). Particularly due to the increase in pressure caused by haematomas, brain edema or brain swelling, there is a risk of the brain stem and midbrain becoming trapped in the bony skull with loss of vital functions (e.g. due to compression of the respiratory center).
Another common cause of cerebral hemorrhages is vascular damage caused by chronic high blood pressure (hypertensive microangiopathy). The permanently elevated blood pressure values lead to arteriosclerotic remodelling with hardening of the vessel walls (increase in wall thickness). This process is intensified by other risk factors (such as diabetes mellitus, smoking or increased LDL cholesterol concentrations).
As a result, the vessels lose the ability to regulate the vessel diameter depending on the blood pressure value. In the final stage of this process, the calcified vessel walls become brittle, which promotes the formation of aneurysms (bulging of the vessel wall) or blood clots. Due to the weakened wall stability, there is also an increased risk of rupture of the vessel wall.
The small vessels supplying the brain are often affected. Aneurysms are by far the most common cause of subarachnoid hemorrhage (SAH). This is a bleeding from the vessels supplying the meninges into the superficial layers of the brain tissue.Aneurysms are a bagging of a blood vessel, which additionally stretches and thins the vessel walls.
As a result, there is an increased risk of rupture of the vessel wall with bleeding into the surrounding tissue. There are numerous causes for the development of aneurysms. A large proportion of them are predisposed at birth and are increased in the course of life by risk factors (e.g. high blood pressure, smoking).
Chronically elevated blood pressure in particular leads to further dilation and bulging of the vessel. If the blood pressure is very high, the vessel wall can no longer compensate for the blood pressure and a rupture occurs. An aneurysm before rupture usually causes no discomfort or symptoms and is therefore difficult to diagnose.
Tumors are another cause of brain hemorrhages. Tumors that have metastasized to the brain can also lead to cerebral hemorrhages. Due to their partially displacing growth, they can damage and infiltrate (penetrate) the surrounding vascular walls.
This increases the risk of bleeding into the brain tissue. Cerebral hemorrhages can be the first symptom of brain tumors or brain metastases. Numerous coagulation disorders also increase the risk of cerebral hemorrhage.
Due to an increased tendency to bleed, even slight lesions or fractures in the area of the skull can lead to massive bleeding. This is due to the fact that even very small wall defects cannot be closed when there is an increased tendency to bleed and the bleeding is therefore not stopped. A distinction is made between medically induced coagulation disorders and congenital coagulation disorders.
Drugs that lead to an increased bleeding tendency include blood thinners (anticoagulants) such as heparin, Marcumar, Apixaban and Rivaroxaban. Antiplatelets such as ASA or clopidogrel can also promote cerebral hemorrhage by increasing the tendency to bleed. Congenital coagulation disorders with an increased bleeding propensity include diseases of the blood platelets (thrombocytopathies or thrombocytopenia), hemophilia (hemophilia) or vWF syndrome. Protein C deficiency, liver failure
