The brain stem, located between the cerebrum and the spinal cord, consists of three parts--the midbrain, the pons and the medulla. Symptoms of brain stem tumors vary according to the precise location of the tumor. The most common type of tumor in this area is a glioma, and the term brain stem gliomas is often used interchangeably with brain stem tumors. According to the Johns Hopkins Pediatric Brain Tumor Center, brain stem tumors are much more common in children than in adults, and they occur most frequently in school-age children.
Cranial Nerve Paralysis
According to "Adams and Victor's Principles of Neurology," weakness of a cranial nerve is often the first symptom of a brain stem tumor. The most common types of cranial nerve symptoms are a disturbance in gaze and weakness of the facial muscles on one side. As explained by the "Childhood Brain Tumor Foundation," double vision is the most common first symptom. Other symptoms of cranial nerve dysfunction include difficulty swallowing and loss of sensation in the jaw area.
Paralysis and Sensory Loss
Neurons from the cortex pass through the brain stem on their way to the body. A tumor in the brain stem disrupts these neurons and causes problems such as weakness, paralysis, unsteady gait and loss of sensation. Children can have a clumsy gait and lose motor functions they have just recently acquired. Patients may lose the ability to perceive how the body is balanced. Paralysis in the body typically occurs on the opposite side to the paralysis of facial muscles.
Intracranial Pressure
Intracranial pressure is increased and there can be blockage of the flow of cerebrospinal fluid, a fluid which bathes the brain. Through this mechanism, brain stem tumors can cause hydrocephalus, where there is an accumulation of fluid that then presses on normal brain structures. Difficulty speaking can occur. Children may tilt their head to one side. The midbrain regulates autonomic functions such as respiration and heart beat. Pressure on the centers responsible for these functions can cause death. According to the Childhood Brain Tumor Foundation, as of 2010, prognosis of many brain stems tumors is generally poor.
References
- Johns Hopkins Pediatric Brain Tumor Center: Brain Stem Gliomas in Children
- The Childhood Brain Tumor Foundation: Brain Stem Gliomas in Childhood
- "Adams and Victor's Principles of Neurology"; Maurice Victor and Allan Ropper; 2001
