Brain tumors: Nursing

Brain tumors are abnormal growths that can be broadly classified into primary tumors, which originate from cells within the nervous system, and secondary or metastatic tumors originating and spreading from cells outside the nervous system.

Okay, let’s start by looking at the physiology of the nervous system, which is divided into the central nervous system, that includes the brain and spinal cord, while the peripheral nervous system includes all the nerves that connect the central nervous system to the muscles and organs.

Zooming in, the brain is made up of different types of cells. First, there are neurons, which receive and send electrical impulses to one another. Then there are neuroglial cells, which help support and protect the brain, and can be classified into astrocytes, which are the most abundant, as well as ependymal cells, microglia, and oligodendrocytes.

Astrocytes have long processes with enlarged terminal ends that surround blood vessels of the brain as part of the blood-brain barrier. so that only certain molecules can slip through. Astrocytes also help provide nourishment to neurons, and recycle neurotransmitters. Next are ependymal cells, which line up the ventricles of the brain, and produce CSF. Then, microglia are the immune cells of the central nervous system. Lastly, there are oligodendrocytes, which have cellular processes that wrap themselves around axons to form a myelin sheath. In the peripheral nervous system, the myelin sheath is similarly formed by another type of cells, called Schwann cells. Additionally, there are cells that secrete hormones into circulation. These cells are found in the pituitary gland, located at the base of the brain.

Some brain cells have a limited ability to be replaced, especially after injury, and they do it by having undifferentiated stem cells, called neural stem cells and glioblasts, which activate and mature into neurons or neuroglia, respectively.

Now, brain tumors occur when any of these cells acquire mutations, which can arise due to a variety of risk factors. Environmental risk factors include exposure to ionizing radiation, which can come from radiotherapy for cancer, or diagnostic imaging like CT scan or MRI. Another risk factor is exposure to N-nitroso compounds found in tobacco, beer, and food products treated with nitrite like fish or cured meats. Genetic risk factors include hereditary conditions like tuberous sclerosis, neurofibromatosis, and von-Hippel-Lindau disease, where affected clients are genetically predisposed to develop brain tumors even without the presence of environmental risk factors. Finally, immunocompromised clients, like organ transplant recipients or clients with AIDS are at higher risk for certain types of brain tumors.