Brain cancer develops within two main groups of cells: the nerve cells, or neurons of the brain, or the glia that support and nourish neuron functioning. Cancer of the brain stem--brain matter close to the spinal cord--leads to development of tumors at the base of the skull. Damage to essential brain centers within the brain stem due to cancer can lead to harmful symptoms.
Vomiting
A common symptom of cancer growth in the brain stem is vomiting. The American Brain Tumor Association indicates that while vomiting due to brain stem cancer can be persistent throughout the day, patients usually feel the worst in the mornings upon awakening. Vomiting can occur from damage to the brain stem itself or from stress on the brain as a whole. Tumors within the brain stem can disrupt the flow of cerebrospinal fluid, leading to a buildup of fluid within the skull that can increase intracranial pressure. As a result, tissue throughout the entire brain experiences abnormal pressure, which can contribute to nausea and vomiting. Patients experiencing unexplained vomiting, especially in combination with other symptoms of brain cancer, should seek medical attention.
Muscle Weakness
During brain cancer progression, brain tissue around the tumor becomes damaged. The increased pressure due to tumor growth can interfere with normal nerve functioning within the brain stem, leading to abnormalities. In addition, cancer cells often seek out and destroy healthy tissue along the periphery of a tumor, causing further nerve damage and inhibiting proper brain function. Since the brain stem contains the motor control centers of the brain--collections of nerves that signal to muscles throughout the body--patients with brain cancers may develop muscle weakness, according to Harvard University. Patients may have difficulty beginning, completing or controlling muscle movements and may develop problems with fine motor control.
Abnormal Gait
Another possible symptom of cancer growth in the brain stem is the development of an abnormal gait. Repetitive motions, such as walking, are controlled by collections of nerves called central pattern generators, or CPGs. The CPGs each contain nerves within the brain stem that work to continue a pattern of motion without conscious thought, allowing a person to continue to walk without consciously planning each footstep. Brain stem cancers can damage the cells that make up CPGs, leading to abnormal muscle movement and the development of an abnormal gait. Disruptions in motor control, such as the development of an abnormal gait, often require immediate medical attention.
