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Key Medical Terms Associated with the Brain and Spinal Cord
Meningitis: Inflammation of the meninges due to an infection, usually caused by a bacterium or virus.
Symptoms include fever, headache, stiff neck, vomiting, confusion, lethargy, and drowsiness. The
meninges are the membranes which surround and cover the brain, spinal cord and nerve roots.
Myelitis: Inflammation of the spinal cord. Myelo means spinal cord.
Myelography (myelogram): Myelography provides a very detailed
picture (myelogram) of the spinal cord, nerve roots, subarachnoid
space and spinal column. The procedure uses a CT scan or x-ray
image of the spinal cord after injection of a radiopaque dye (contrast
medium) into the subarachnoid space. Allows the
radiologist to view and evaluate the status of the spinal
cord, the nerve roots and the meninges and to diagnose
abnormalities such as tumors and herniated intervertebral
discs.
Radiopaque dye introduced using a needle
Dementia: A term that describes a collection of symptoms
that include decreased intellectual functioning that interferes with normal life functions including
impairment of memory, judgment and abstract thinking, and changes in personality.
Encephalitis: An acute inflammation of the brain caused by either a direct attack by any of several
viruses or an allergic reaction to any of the many viruses that are normally harmless to the central
nervous system. If the virus affects the spinal cord as well, the condition is called encephalomyelitis.
Hydrocephalus: Enlargement of the brain due to an elevated
cerebrospinal fluid (CSF) pressure. The abnormal
accumulation of CSF may be due to an obstruction of CSF flow
or an abnormal rate of CSF production and/or reabsorption. In a
baby whose fontanels have not yet closed, the head bulges due
to the increased pressure. If the condition persists, the fluid
buildup compresses and damages the nervous tissue.
Hydrocephalus is relieved by draining the excess CSF. In adults,
hydrocephalus may occur after a head injury, meningitis, or
subarachnoid hemorrhage. Because adult skull bones are fused
together this condition can quickly become life-threatening and
requires immediate intervention.
Microcephaly: A congenital condition that involves the development of a small brain
and skull and frequently results in mental retardation.
Megacolon: An abnormally large colon. In congenital megacolon, parasympathetic
nerves to the distal segment of the colon do not develop properly. Loss of motor
function in the segment causes massive dilation of the normal proximal colon. The
condition results in extreme constipation, abdominal distention, and, occasionally,
vomiting.
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Vagotomy: Cutting the vagus (X) nerve near the organ that it is intended to treat. It is frequently done
to decrease the production of hydrochloric acid in persons with ulcers.
Concussion: An injury to the brain resulting from an impact to the head. A concussion does not
include injuries in which there is bleeding under the skull or into the brain. A mild concussion may
involve no loss of consciousness (person will feel”dazed") or a very brief loss of consciousness (being
"knocked out"). A severe concussion may involve prolonged loss of consciousness with a delayed
return to normal. A concussion produces no obvious bruising of the brain. Signs of a concussion are
headache, drowsiness, nausea and/or vomiting, a lack of concentration, confusion, or post-traumatic
amnesia (memory loss). Treatment involves monitoring the person as well as physical and cognitive
rest (reduction of such activities as school work, playing video games and reading). Symptoms
usually resolve within one to three weeks, though they may persist or complications may occur.
Repeated concussions may increase the risk in later life for dementia, Parkinson's disease, and/or
depression.
Contusion: A bruising of the brain due to trauma, and includes the leakage of blood from
microscopic vessels. It is usually associated with a concussion. In a contusion, the pia mater may be
torn, allowing blood to enter the subarachnod space. The area most commonly affected is the frontal
lobe. A contusion usually results in an immediate loss of consciousness (generally lasting no longer
than 5 minutes), loss of reflexes, transient cessation of respiration, and decreased blood pressure.
Vital signs typically stabilize in a few seconds.
Laceration: A tear of the brain, usually from a skull fraction or a gunshot wound. A laceration results
in rupture of large blood vessels, with bleeding into the brain and subarachnoid space.
Consequences include cerebral hematoma (localized pool of blood, usually clotted, that swells again
the brain tissue), edema, and increased intracranial pressure.
Alzheimer’s Disease (AD): A tale of Beta Amyloid Plaques, Tau Tangles (Neurofibrillary
tangles) and Dementia. AD is a disabling senile dementia (the loss of reasoning and ability to care
for oneself), that afflicts about 11% of the population over age 65. AD is the most common and most
costly neurological disorder of the CNS. AD is the fourth leading cause of death among the
elderly, after heart disease, cancer, and stroke. Individuals with AD initially have trouble
remembering recent events. They then become confused and forgetful, often repeating questions or
getting lost while traveling to familiar places. Memories of past events disappear and episodes of
paranoia, hallucination, or violent changes in mood may occur. As their minds continue to deteriorate,
they lose their ability to read, write, talk, eat, or walk. Death usually results from some complication
that afflicts bedridden patients, such as pneumonia.
At autopsy, brains of AD victims shows 4 distinct structural
abnormalities:
1. Loss of neurons that liberate acetylcholine (ACh). A
major center of neurons that liberate ACh is the basal
nucleus. Axons of these neurons project throughout the
cerebral cortex and limbic system (includes the
hippocampus). Neuron death and loss of synaptic
communication are responsible for the ensuing dementia.
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2. Formation of beta amyloid plaques. Amyloid
plaques are clusters of abnormal proteins
deposited outside neuron that can inhibit their
function.
3. Formation of Neurofibrillary tangles.
Abnormal bundles of filaments inside neurons
in affected brain regions – especially in the
hippocampus. Neurofibrillary tangles are
made up of a protein called tau (TAW) that has
been hyperphosphorylated, meaning too may
phosphate groups have been added to it. The
neurofibrillary tangles cause microtubules
to disintegrate, destroying the structure of the
cell's cytoskeleton which collapses the neuron's
transport system.
4. Reduction of insulin and IGF I and II within
the cortex, hippocampus and hypothalamus.
Related to Type III Diabetes. Type III Diabetes
is a type of Insulin resistant diabetes
confined to the brain, characterized by a
decrease in brain insulin, insulin receptors,
insulin-like growth factors I and II (IGFs), and
mitochondrial dysfunctions. In the brain
insulin binds to receptors at a synapse and
turns on mechanisms necessary for nerve cells to survive and memories to form. Type III
diabetes represent a major pathogenic mechanism of Alzheimer’s disease (AD), which
involves brain shrinkage due to cell loss especially in the hippocampus which functions in
learning and memory formation.
Cause: Still uncertain but evidence suggests it is due to a combination of genetic factors,
environmental or lifestyle factors (history of head injuries), and the aging process.
Treatment: Drugs that inhibit acetylcholinesterase (AChE), the enzyme that breaks down ACh,
improve alertness and behavior. Research is currently working to develop drugs that will prevent
beta-amyloid plaque formation and reduce the formation of neurofibrillary tangles.
Stroke or Cerebrovascular accident (CVA): A stroke occurs when
the blood supply to your brain is interrupted or reduced. This
deprives your brain of oxygen and nutrients, which can cause your
brain cells to die. Types of strokes include Ischemic and
Hemorrhagic and are dependent on the cause of blood flow
interruption.
Ischemic Stroke: About 85 percent of strokes are ischemic strokes.
Ischemic strokes occur when the arteries to your brain become
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narrowed or blocked, causing severely reduced blood flow (ischemia). The most common ischemic
strokes include thrombotic and embolic.
1) Thrombotic stroke occurs when a stationary blood clot (thrombus) forms in one of the arteries
that supply blood to your brain. A clot often may be caused by fatty deposits (plaque) that build up in
arteries and cause reduced blood flow (atherosclerosis) or other
artery conditions.
2) Embolic stroke occurs when a moving blood clot (embolus) or
other debris forms away from your brain — commonly in your heart
— and is carried by the bloodstream to lodge in narrower brain
artery.
Hemorrhagic stroke occurs when a blood vessel in your brain
leaks or ruptures (ruptured aneurysm). Brain hemorrhages can
result from many conditions that affect your blood vessels,
including uncontrolled high blood pressure (hypertension) and
weak spots in your blood vessel walls (aneurysms).
Risk factors for developing a stroke include high blood pressure, high blood cholesterol, heart
disease, narrowed carotid arteries, transient ischemic attacks (TIAs), diabetes, smoking, obesity, and
excessive alcohol intake. Clot-dissolving drugs such as tissue plasminogen activator (t-PA) is
used to open blocked blood vessels in the brain but these drugs work best when administered within
three hours of the onset of the CVA and only work on blood clots.
Transient Ischemic Attack (TIA) – also called a ministroke: A brief episode (5 to 10 minutes) of
temporary cerebral dysfunction caused by impaired blood flow to part of the brain. Person has
a brief episode of symptoms similar to those you'd have in a stroke which include dizziness,
weakness, numbness, or paralysis in a limb or on one side of the body; drooping of one side of the
face; slurred speech or difficulty understanding speech; or partial loss of vision. Like an ischemic
stroke, a TIA occurs when a temporary blood clot or debris blocks blood flow to part of your brain.
A TIA doesn't leave lasting symptoms because the blockage is temporary and leaves no persistent
neurological deficits.