General Intro CNS to PPT Flashcards
Where does the spinal cord end?
around L1-L2
Are there lymphatics in the CNS?
No
What are the meninges?
The meninges are the outer covering of protection for the brain.
What is the outermost membrane of the meninges?
The outermost membrane is the dura mater (tough mother), which is the strongest.
What is the structure of the dura mater?
The dura mater is a double-layered membrane that is continuous with the periosteum of the cranium.
What follows the contour of the dura mater?
The arachnoid membrane follows the contour of the dura mater.
What separates the pia mater from the arachnoid mater?
The subarachnoid space separates the pia mater from the arachnoid mater.
What is contained in the subarachnoid space?
The subarachnoid space contains cerebrospinal fluid (CSF) that circulates around the brain and spinal cord.
What is the function of CSF?
CSF provides further protection to the central nervous system (CNS).
What is the innermost layer of the meninges?
The innermost layer is the pia mater (delicate, tender mother), which is a highly vascular layer.
How does the pia mater relate to the brain?
The pia mater adheres closely to the contours of the brain.
What does BBB stand for?
BBB stands for Blood Brain Barrier.
What is the primary function of the BBB?
The primary function of the BBB is to protect the brain from potentially toxic compounds.
What type of substances can pass through the BBB?
Substances that can pass through the BBB must be lipid soluble.
Why can’t drugs reach tumor cells in healthy brain tissue?
Tumor cells that infiltrate healthy brain tissue cannot be reached by drugs that do not cross the BBB.
How is the separation of circulating blood and CSF maintained?
The separation is maintained by the choroid plexus in the CNS.
What do endothelial cells restrict?
Endothelial cells restrict the diffusion of microscopic objects (e.g. bacteria) and large or hydrophilic molecules into the CSF.
What type of molecules can diffuse through the BBB?
Small hydrophobic molecules can diffuse through the BBB.
What substances are actively transported across the BBB?
Cells of the barrier actively transport metabolic products such as glucose across the barrier with specific proteins.
CN 1?
Olfactory nerve
CN 2?
Optic nerve
CN 3?
oculomotor nerve
CN 4?
Trochlear nerve
CN 5?
Trigeminal nerve
CN 6?
Abducens nerve
CN 7?
Facial nerve
CN 8?
Vestibulocochlear nerve
CN 9?
Glossophsryngeal nerve
CN 10?
Vagus nerve
CN 11?
Accessory nerve
CN 12?
Hypoglossal nerve
What percentage of all cancers do primary brain tumors account for?
Primary brain tumors account for 1.5% of all cancers.
What is the distribution of primary brain tumors between the brain and spinal cord?
80% are brain tumors and 20% are spinal cord tumors.
What are the two peak ages for the incidence of primary brain tumors?
The two peak ages are 3-12 years and 50-80 years.
What types of tumors are commonly found in children aged 3-12 years?
Common tumors include Medulloblastoma, Cerebellar astrocytoma, and Ependymomas.
What types of tumors are commonly found in adults aged 50-80 years?
Common tumors include Malignant gliomas and meningiomas.
What percentage of cancer patients eventually develop brain metastasis?
Estimates suggest that 20%-40% of patients with cancer eventually develop brain metastasis.
What occupational exposures are associated with higher incidence rates of brain tumors?
Occupational exposure to chemicals, synthetic rubber, and pesticides is associated with higher incidence rates.
Which occupations have shown higher incidence rates of brain tumors?
Workers in agriculture and healthcare have shown higher incidence rates than other occupations.
What lifestyle and dietary factors are associated with brain tumors?
Factors include cell phones, nitrates, hair dyes, and smoking.
What medical conditions are associated with brain tumors?
Conditions include viral infections, certain drugs, and AIDS.
What genetic factors are linked to brain tumors?
Genetic factors include Neurofibromatosis (less than 5%), tuberous sclerosis, LI-Fraumeni syndrome, and von Hippel-Lindau syndrome.
What symptoms do benign tumors generally cause?
Benign tumors generally cause symptoms produced by pressure.
What can malignant tumors cause?
Malignant tumors can cause pressure and destruction of the CNS tissue.
What is intracranial pressure (ICP) caused by?
ICP is caused by the growth of the tumor itself, swelling of the brain, or blockage of the flow of CSF.
What is an initial symptom of increased intracranial pressure?
The initial symptom may be a headache, which is usually worse in the mornings.
What are some signs of increased intracranial pressure?
Signs of ICP include seizures and difficulties with balance, gait, and ambulation.
What symptoms may occur with glioma of the optic nerve?
Symptoms may include vision loss.
What symptoms can occur in the spinal cord?
Symptoms include pain, weakness, numbness in extremities, and bowel and bladder control problems.
What is necessary for patients with a sudden onset of symptoms of a spinal cord tumor?
Immediate treatment is necessary to prevent permanent paralysis.
How can ICP symptoms be managed?
Symptoms can be managed with corticosteroids.
What is the role of steroids in treating ICP?
Steroids help reduce swelling.
What are some neurological exam findings in CNS tumors?
Findings may include decreased level of alertness, poor memory, hyperactive reflexes, muscle weakness in extremities, visual field defects, and cranial nerve abnormalities.
What is the most important tool in diagnosis and grading of brain conditions?
MRI (with or without contrast) is the most important tool due to its superior image quality and ability to show chemical changes within the brain.
What is the contrast agent used in MRI for brain tumors?
The contrast agent used is gadolinium, which is a noniodine-based intravenous contrast agent.
What is the role of MRI contrast agents?
They help differentiate between edema and the tumor and can detect surface seeing.
What is the advantage of CT scans?
CT scans are more cost-effective and are used in follow-up after treatment.
What radionuclide does PET use?
PET uses the radionuclide F-fluorodeoxyglucose (FDG) to help detect lesions.
What is the utility of PET scans?
PET scans are useful in determining differences between necrosis and malignancy.
What are some other imaging studies?
Other imaging studies include arteriogram, EEG, MEG, and stereotactic biopsy.
What is the universal staging system for CNS tumors?
No universal staging system is currently used, leading to problems due to lack of standardization.
What are the routes of spread for tumors?
Local invasion, along pre-existing pathways defined by white matter tracts, and spread via the CSF.
Tumors do not spread hematogenously.
What is the treatment of choice for most brain and spinal cord tumors?
Surgery.
The primary goal for surgery is to remove the tumor and obtain a histologic diagnosis.
What factors can limit surgery for brain and spinal cord tumors?
Tumor location and extent, patient status, and risk of debilitating neurological deficits.
Does partial removal of a tumor enhance the patient’s chances for survival?
No, the patient’s chances for survival are not enhanced with partial removal of the tumor.
What follows surgery to prevent tumor regrowth or recurrence?
Adjuvant Radiation Therapy.
What is an important option for patients with isolated CNS tumors and solitary brain metastases?
Stereotactic Radiosurgery (SRS).
What factors have limited the use of chemotherapy in CNS treatment?
The presence of the BBB, the low number of effective drugs, lack of change in progression of disease with introduction of adjuvant therapy, and lack of adjuvant chemotherapy to increase the survival rate.
