How much do you know about Posterior Reversible Encephalopathy Syndrome?

Posterior reversible encephalopathy syndrome (PRES) is a relatively uncommon (but not rare) clinical syndrome. In recent years, with the popularization of imaging examinations, the understanding of this type of disease has become deeper and deeper. So how is it defined in medicine?

definition

Posterior reversible encephalopathy syndrome refers to reversible subcortical vasogenic edema caused by certain specific clinical conditions, often accompanied by various acute neurological symptoms.

Physiology and pathology

As we all know, due to the dynamic changes in human blood pressure and intracranial pressure, cerebral perfusion pressure is not constant. Under normal conditions, cerebral perfusion pressure is maintained between 50 and 100 mmHg. Through cerebrovascular pressure response, chemical regulation and autonomic nervous system regulation, cerebral blood flow can be in a stable state (see Figure 1). Especially the first two factors play a major role in regulating cerebral blood flow under physiological conditions.

Under pathological conditions, when blood pressure fluctuations are too large to exceed the self-regulatory capacity of blood vessels, or when excessive cytokine release in the circulation leads to endothelial dysfunction and the autonomic nervous system is insufficient to regulate perfusion pressure, a series of adverse consequences may occur, leading to changes in cerebral vascular permeability (see Figure 2).

Clinical manifestations

Onset may be acute or subacute, lasting from hours to days. Common clinical manifestations include: epilepsy, headache, visual impairment, changes in consciousness, etc.

Populations at high risk: patients with drastic fluctuations in blood pressure (fluctuations rather than simply high blood pressure; patients with low baseline blood pressure may have normal blood pressure when the disease occurs), renal failure, use of cytotoxic drugs, eclampsia and preeclampsia, immunosuppression after organ transplantation, autoimmune diseases, etc.