Etiology
As far as the non-traumatic ICH there are several etiologies:
- Hypertension
- Cerebral amyloid angiopathy (most important cause of ICH in elderly)
- Vascular malformations (most important cause of ICH in children)
- Hemorrhagic infarction (also venous sinus thrombosis)
- Ruptured saccular aneurysm
Risk Factors
- Hypertension
- Older age
- Alcoholism
- Black ethnicity (interact with the age)
- Lower cholesterol and lower LDL cholesterol
- Lower triglycerides
- Street drugs (cocaine, amphetamine)
Pathogenesis
The hypertension has effects on penetrating vessels because they branch off from the intracerebral vessels with a 90° angle: so the high pressure is transmitted rapidly distally without a gradual increase. If this situation is perpetuated for very long time (chronic hypertension), the arteries could be predisposed to the rupture of their wall: this situation is called “pseudoaneurysm” and account for a small quantitative of blood in the hemorrhage (so it causes a subclinical leaks of blood).
If the patient suffers for a bleeding disorder the hemorrhage doesn’t’ stop and a severe ICH occurs. The site of the microscopic bleed is different according to the etiology: hypertensive microbleeds arise from the deep subcortical and infratentorial regions, amyloid microbleeds arise in superficial lobar regions.
Pathophysiology
After a ICH occurs, there is the formation and expansion of a blood clot and the brain is damaged firstly because of the mechanical injury.
In the area surrounding the lesion there is a perilesional edema that is rich of cytotoxic molecules.
Both the edema and the blood clot contribute to generate mass effect and to increase the intracranial pressure (ICP). As a consequence, the cerebral perfusion was reduced causing an ischemic injury. If the ICP raise to higher levels a cerebral herniation develops.
Clinical Presentation
Note that the symptoms don’t begin abruptly (like in SAH) but they increase during minutes or in a few hours.
Most of the ICH occurs during the normal people activity.
Diagnosis
If there is a suspect of intracerebral hemorrhage, there are two different strumental tests:
Authors
Giannantonio Spena, MDNeurosurgeon Consultant
|
Giorgio Saraceno, MSMedical Student |