What was the theoretical basis for the pathophysiology of classic brain tumor headache?
Brain tumor headache is believed to be caused by two processes: The first is the regional traction and stimulation of pain-sensitive structures including cranial nerves, blood vessel, and dura. The second is the global and generalized traction of the brain structures from high intracranial pressure, which is worsened by recumbency position and physiological states that increase intracranial pressure such as CO 2 retention, cerebral vasodilation, and peritumoral edema. The mild CO 2 retention caused by hypoventilation during sleep is believed to be the inciting factor for the increased pain associated with brain tumors early in the day.
The progressive nature of brain tumor headache is believed to correspond to the transition from local to global traction of cranial structures as brain tumor size increases. In addition, the positional change in brain tumor headache is due to changes in the intracranial pressure in which venous outflow congestion such as laying down increases intracranial pressure. Conversely, ambulation and upright position increase venous outflow and decrease intracranial pressure, and hence improve brain tumor headache.
