The pituitary gland is a small, pea-sized structure located at the base of the brain, often called the “master gland” because it produces hormones that regulate numerous body functions. A seizure is a sudden, uncontrolled episode of electrical disturbance in the brain, which can cause changes in behavior, movements, feelings, and consciousness. Although the pituitary gland and the brain areas responsible for seizures are not directly adjacent, a relationship exists between pituitary tumors and seizure activity, which physically and chemically disrupts normal brain function.
What Pituitary Tumors Are and Where They Occur
Pituitary tumors are abnormal growths that develop in the pituitary gland, which sits within a small, bony pocket at the base of the skull called the sella turcica. Most of these growths are benign and referred to as pituitary adenomas. They are classified by size: microadenomas are less than one centimeter, and macroadenomas are one centimeter or larger in diameter. Adenomas are also categorized by whether they secrete hormones in excess. Functional tumors, such as prolactinomas, overproduce specific hormones like prolactin or ACTH, while non-functional tumors cause problems due to their size and location.
How Pituitary Tumors Can Trigger Seizures
Pituitary tumors can trigger seizures through two pathways: direct pressure on nearby brain structures (mass effect) and indirect disruption caused by hormonal imbalance. The mass effect typically occurs with macroadenomas that have grown significantly, extending upward and pressing on the medial temporal lobe. The temporal lobe is one of the most seizure-prone areas of the brain, and this physical pressure disrupts normal electrical communication, creating an epileptogenic focus that leads to focal seizures. The indirect pathway involves hormonal changes caused by functional tumors, which can alter the brain’s overall electrical excitability, lowering the seizure threshold across the cortex. For instance, excessive ACTH production leads to high cortisol levels (Cushing’s disease), affecting neural stability and potentially causing generalized seizure activity. Hormonal imbalances can also cause severe electrolyte disturbances, such as hyponatremia (low blood sodium), which is highly disruptive to brain cell function and can induce generalized convulsions.
Identifying the Tumor-Seizure Connection
Confirming a pituitary tumor as the source of seizures requires a focused diagnostic process. Magnetic Resonance Imaging (MRI) is the procedure of choice for visualizing the tumor, providing detailed images that confirm its size, location, and proximity to sensitive brain areas like the temporal lobe. Electroencephalography (EEG) is essential for confirming the presence of seizure activity and localizing the focus of the abnormal electrical discharge. If the EEG suggests a focus near the area of tumor compression, it strengthens the case for a direct mass effect. Endocrine testing, performed through comprehensive blood, urine, and saliva analyses, checks for abnormal hormone levels (prolactin, ACTH, and IGF-1), which point toward the indirect hormonal mechanism.
Treatment Strategies for Tumor-Related Seizures
The treatment approach for seizures caused by a pituitary tumor is dual, focusing on controlling seizure symptoms and addressing the underlying tumor. Standard anti-epileptic drugs (AEDs) are used initially to manage seizures and prevent recurrence. For tumors causing a mass effect, surgical removal is often recommended, typically using a minimally invasive approach called transsphenoidal surgery. Removing the tumor relieves pressure on the temporal lobe, which often resolves the seizures. For functional tumors, medication is the primary treatment to shrink the tumor and normalize hormone levels, though radiation therapy may be used if surgery is not possible or ineffective.