hiperperfusion

Hyperperfusion is the state of increased blood flow to a tissue that exceeds its metabolic needs or normal baseline. It can be physiological, such as during neural activity or after a meal, or pathological, arising when perfusion becomes excessive relative to tissue demand or when regulation of blood flow is disrupted.

Physiology and mechanisms: In healthy tissue, cerebral and systemic blood flow is largely regulated by autoregulation to maintain stable capillary perfusion. Hyperperfusion occurs when this autoregulation is impaired or overwhelmed, leading to vasodilation and increased capillary flow. In the brain, excessive flow can contribute to edema, blood-brain barrier disruption, and, in vulnerable regions, hemorrhagic transformation.

Clinical contexts: Cerebral hyperperfusion syndrome (CHS) is a recognized complication after carotid revascularization procedures such as endarterectomy or stenting, presenting with headache, weakness, seizures, or evolving neurological deficits and possibly intracerebral hemorrhage. Hyperperfusion can also follow reperfusion after ischemia in other organs, resuscitation after cardiac arrest, or systemic inflammatory states such as sepsis. Functional hyperperfusion during normal activities is typically benign.

Diagnosis: Imaging modalities that quantify regional blood flow, such as perfusion MRI, CT perfusion, or PET/SPECT, help identify sites of hyperperfusion. Doppler ultrasound can assess large-artery flow, while clinical assessment focuses on symptoms and hemodynamic status. Distinguishing hyperperfusion from persistent hypoperfusion is important for management.

Treatment and prognosis: Therapy targets the underlying cause and aims to prevent secondary injury. In CHS, careful blood pressure control, avoidance of rapid reductions, and seizure management are common; supportive care is provided as needed. Prognosis varies by context and the risk of complications like edema or hemorrhage.