Question

Why interventricular foramen blockage would create an increase in intracranial pressure? Explain in one paragraph

Answer 1

The human skull is a relatively fixed volume structure of approximately 1400 to 1700 mL. Physiologically its components consist of 80% brain parenchyma, 10% cerebrospinal fluid, and 10% blood. Since the skull is considered an unchangeable volume, any increase in the volume of components within the skull or an addition of a pathologic element will result in increased pressure within the skull. Pathologic structures that can cause increased ICP may include mass lesions, abscesses, and hematomas.The physiologic volume of the brain parenchyma is a relatively constant value in adults: however, it may be adjusted by mass lesions or in the setting of cerebral edema. Cerebral edema can occur with acute hypoxic encephalopathy, large cerebral infarction, and severe traumatic brain injury. CSF and blood volume in the intracranial space will vary on a regular basis as these are the primary regulators of intracranial pressure. CSF volume is primarily regulated via choroid plexus production at a rate of approximately 20 mL per hour physiologically and through its reabsorption at a similar rate by arachnoid granulations that drain into the venous system of the skull. The control mechanisms for maintaining appropriate CSF pressures may become damaged in neurological injuries such as stroke or trauma. Increased CSF production above the rate at which it can be reabsorbed such as in the presence of a choroid plexus papilloma leads to increased pressure.