A college student has been experiencing frequent headaches that he describes as throbbing and complaining of difficulty concentrating while studying

Question

Upon cerebral angiography, he is found to have an arteriovenous malformation. Which of the following pathophysiological concepts is likely responsible for his symptoms?
A)
Increased tissue perfusion at the site of the malformation
B)
Hydrocephalus and protein in the cerebral spinal fluid
C)
High pressure and local hemorrhage of the venous system
D)
Localized ischemia with areas of necrosis noted on CT angiography

Answer 1

Ans:
C

Feedback:

In arteriovenous malformations, a tangle of arteries and veins acts as a bypass between the cerebral arterial and venous circulation, in place of the normal capillary bed. However, the capillaries are necessary to attenuate the high arterial blood pressure before this volume drains to the venous system. As a result, the venous channels experience high pressure, making them to hemorrhage and rupture more likely; the lack of perfusion of surrounding tissue causes neurologic deficits such as learning disorders. Headaches are severe, and people with the disorder may describe them as throbbing (synchronous with their heartbeat). Increased tissue perfusion means that more oxygenated blood is brought to the area, which is not the case. The elevated arterial and venous pressures divert blood away from the surrounding tissue, impairing tissue perfusion. Answer choice B is incorrect since arteriovenous malformation is associated with blood vessels and not the fluid within the ventricles of the brain. Answer choice D is incorrect in that there is blood flow to the area. Ischemia is associated with decreased arterial flow resulting in death to brain tissue.