Meeting 3 Nervous System PDF

The Nervous System Stroke & Parkinson’s Disease By: Rahmad Abdillah What is a Stroke?  Specific arteries supply blood to specific areas of the brain. A stroke occurs when one of these arteries to the brain is either blocked or bursts.  As a...

The Nervous System Stroke & Parkinson’s Disease By: Rahmad Abdillah What is a Stroke?  Specific arteries supply blood to specific areas of the brain. A stroke occurs when one of these arteries to the brain is either blocked or bursts.  As a result, part of the brain does not get the blood it needs, so it starts to die. Blood Flow in Normal and Blocked Arteries NORMAL ARTERY Blood flows easily through a clear artery BLOCKAGE An artery can become blocked by plaque (a fatty substance in the wall of the artery) or a blood clot, which reduces blood flow to the brain and causes a stroke. This picture shows atherosclerosis, a hardening of the arteries. Atherosclerosis is caused partly by cholesterol or plaque buildup. Blood Flow in Normal and Blocked Arteries CLOT DISSOLVES A transient ischemic attack or TIA has the same signs and symptoms of a stroke, but they only last a short time. The plaque or blood clot breaks up and blood flow is restored to the brain and there is no permanent damage. A TIA is serious and needs to be evaluated by a health care provider. This picture shows a blood clot blocking an artery in the brain. Without enough blood flow, brain cells begin to die. Ischemic Stroke Ischemic Stroke Ischemic stroke is the most common type of stroke. An ischemic stroke happens when an artery in the brain is blocked. There are two types of ischemic stroke: 1. Embolic Stroke: In an embolic stroke, a blood clot or plaque fragment forms, usually in the heart or the large arteries leading to the brain, and then moves through the arteries to the brain. In the brain, the clot blocks a blood vessel and leads to a stroke. 2. Thrombotic Stroke: A thrombotic stroke is a blood clot that forms inside an artery that supplies blood to the brain. The clot interrupts blood flow and causes a stroke. Transient Ischemic Attack (TIA) If an artery in the brain or one that goes to the brain is blocked for a short time, blood flow slows down or stops. This can cause a transient ischemic attack, sometimes called a mini- stroke. A TIA’s major symptoms include sudden: Numbness, weakness or paralysis of the face, arm or leg, usually on one side of the body Loss of vision in one or both eyes or double vision Trouble speaking or difficulty understanding others Loss of balance or coordination Severe headache with no known cause Hemorrhagic Stroke  A hemorrhagic stroke happens when a blood vessel in the brain bursts and spills blood into or around the brain. High blood pressure and aneurysms can make blood vessels weak enough to burst.  There are different types of hemorrhagic stroke, including intracerebral hemorrhage and subarachnoid hemorrhage. Intracerebral Hemorrhage One kind of hemorrhagic stroke is called an intracerebral hemorrhage. This kind of stroke is caused when a burst blood vessel bleeds into brain tissue. The bleeding causes brain cells to die and the part of the brain that is affected stops working correctly. High blood pressure (hypertension), is the most common cause of this type of stroke. Subarachnoid Hemorrhage Another kind of hemorrhagic stroke is called a subarachnoid hemorrhage. In this type of stroke, a blood vessel bursts near the surface of the brain and blood leaks into the space between the brain and the skull (the subarachnoid space). Blood that collects in this space puts pressure on brain tissue and causes blood vessels to spasm. This type of stroke can be caused by different things but is usually caused by a burst aneurysm.  Aneurysm An aneurysm is a weak spot on the wall of an artery that bulges out into a thin bubble. As it gets bigger, the wall may weaken and burst. If it bursts, blood leaks inside or around the brain. How a Stroke Affects You The Sides of the Brain A stroke on the left side of the brain affects the right side of the body and you may experience some of the following: Speech and language problems Inability to read, write and learn new information Impaired ability to do math or to organize, reason and analyze things A stroke on the right side of the brain affects the left side of the body and you may experience some of following: Problems with depth perception or directions, such as up or down, and front and back Inability to be creative, such as painting a picture, or to appreciate art and music Failure to recognize the emotion in someone’s voice  Moving and Sensing Things The human brain has different areas that control how the body moves and feels. When a stroke damages a certain part of the brain, that part may not work as well as it did before. This can cause problems with walking, speaking, seeing or feeling. There may be challenges with basic self-care such as bathing or dressing, eating, swallowing, memory, emotions and understanding surroundings that should be familiar.  Prevent Another Stroke If you have high blood pressure, lower it. Measurement of 130/80 mm Hg and above is considered high blood pressure, work with your health care provider to manage it. Find out if you have atrial fibrillation (AFib). AFib is a quivering or irregular heartbeat that can lead to blood clots and cause a stroke. Your health care provider can tell you if you have AFib and help you manage it. If you smoke, stop. Smoking doubles the risk for stroke. If you drink alcohol, do so in moderation. Heavy drinking can increase your risk for stroke. Lower your cholesterol (the fat-like substance in your blood). Studies suggest ideal total cholesterol levels at about 150 mg/dL, which equals about 100 mg/dL for low-density lipoprotein cholesterol (LDL-C). Lower cholesterol levels are linked with lower rates of heart disease and stroke. If you have diabetes, follow your health care provider’s advice carefully to get your blood sugar level under control. Having diabetes puts you at an increased risk for stroke. Talk to your health care provider about a diet that will help you manage your diabetes, such as limiting foods high in added sugars. Exercise daily. Even a little exercise—a brisk walk, swim or yard work—can improve your health and may reduce your stroke risk. Check with your health care provider before starting a new exercise regimen. Cut down on sodium and saturated and trans fat. By reducing these, you can lower your risk for stroke, high blood pressure and heart disease.  Parkinson’s Disease What is Parkinson’s disease? Parkinson’s disease (PD) is movement disorder of the nervous system that worsens over time. As nerve cells (neurons) in parts of the brain weaken or are damaged or die, people may begin to notice problems with movement, tremor, stiffness in the limbs or the trunk of the body, or impaired balance. As these symptoms become more obvious, people may have difficulty walking, talking, or completing other simple tasks. “Not everyone with one or more of these symptoms has PD, as the symptoms appear in other diseases as well” No cure for PD exists today, but research is ongoing and medications or surgery can often provide substantial improvement with motor symptoms What are the symptoms of the disease? The four primary symptoms of PD are: Tremor. Tremor (shaking) often begins in a hand. The tremor associated with PD has a characteristic rhythmic back-and-forth motion that may involve the thumb and forefinger and appear as a “pill rolling”. It is most obvious when the hand is at rest or when a person is under stress. This tremor usually disappears during sleep or improves with a purposeful, intended movement. Rigidity. Rigidity (muscle stiffness), or a resistance to movement, affects most people with PD. The muscles remain constantly tense and contracted so that the person aches or feels stiff. The rigidity becomes obvious when another person tries to move the individual’s arm, which will move only in ratchet-like or short, jerky movements known as “cogwheel” rigidity. What are the symptoms of the disease? Bradykinesia. This slowing down of spontaneous and automatic movement is particularly frustrating because it may make simple tasks difficult. The person cannot rapidly perform routine movements. Activities once performed quickly and easily—such as washing or dressing—may take much longer. There is often a decrease in facial expressions. Postural instability. Impaired balance and changes in posture can increase the risk of falls. Do symptoms get worse? PD does not affect everyone the same way. The rate of progression and the particular symptoms differ among individuals. PD symptoms typically begin on one side of the body. However, the disease eventually affects both sides, although symptoms are often less severe on one side than on the other. Early symptoms of PD may be subtle and occur gradually. Affected people may feel mild tremors or have difficulty getting out of a chair. Activities may take longer to complete than in the past. Muscles stiffen and movement may be slower. The person’s face may lack expression and animation (known as “masked face”). What other changes may occur with PD? Depression. Some people lose their motivation and become dependent on family members. Emotional changes. Some people with PD become fearful and insecure, while others may become irritable or uncharacteristically pessimistic. Difficulty with swallowing and chewing. Problems with swallowing and chewing may occur in later stages of the disease. Food and saliva may collect in the mouth and back of the throat, which can result in choking or drooling. Getting adequate nutrition may be difficult. Speech changes. About half of all individuals with PD have speech difficulties that may be characterized as speaking too softly or in a monotone. Some may hesitate before speaking, slur, or speak too fast. Urinary problems or constipation. Bladder and bowel problems can occur due to the improper functioning of the autonomic nervous system, which is responsible for regulating smooth muscle activity. Sleep problems. Common sleep problems in PD include difficulty staying asleep at night, restless sleep, nightmares and emotional dreams, and drowsiness or sudden sleep onset during the day. Another Dementia or other cognitive problems. Some people with PD develop memory problems and slow thinking. Cognitive problems become more severe in late stages of PD, and some people are diagnosed with Parkinson’s disease dementia (PDD). Memory, social judgment, language, reason Who gets Parkinson’s disease? Risk factors for PD include: Age. The average age of onset is about 70 years, and the incidence rises significantly with advancing age. However, a small percent of people with PD have “early-onset” disease that begins before the age of 50. Sex. PD affects more men than women. Heredity. People with one or more close relatives who have PD have an increased risk of developing the disease themselves. An estimated 15 to 25 percent of people with PD have a known relative with the disease. Some cases of the disease can be traced to specific genetic mutations. Exposure to pesticides. Studies show an increased risk of PD in people who live in rural areas with increased pesticide use. What causes the disease? The precise cause of PD is unknown, although some cases of PD are hereditary and can be traced to specific genetic mutations. Most cases are sporadic—that is, the disease does not typically run in families. Parkinson’s Etiology Parkinson’s disease occurs when nerve cells, or neurons, in the brain die or become impaired. Although many brain areas are affected, the most common symptoms result from the loss of neurons in an area near the base of the brain called the substantia nigra which produce dopamine. Dopamine responsible for transmitting signals between the substantia nigra and the next “relay station” of the brain, the corpus striatum, to produce smooth, purposeful movement. Loss of dopamine results in abnormal nerve firing patterns within the brain that cause impaired movement. “Studies have shown that most people with Parkinson’s have lost 60 to 80 percent or more of the dopamine-producing cells in the substantia nigra by the time symptoms appear” People with PD also lose the nerve endings that produce the neurotransmitter norepinephrine—the main chemical messenger to the part of the nervous system that controls many automatic functions of the body, such as pulse and blood pressure. The loss of norepinephrine might explain several of the non-motor features seen in PD, including fatigue and abnormalities of blood pressure regulation. Pathology Condition of Parkinson The protein alpha-synuclein. The affected brain cells of people with PD contain Lewy bodies— deposits of the protein alpha-synuclein. Researchers do not yet know why Lewy bodies form or what role they play in the disease. Some research suggests that the cell’s protein disposal system may fail in people with PD, causing proteins to build up to harmful levels and trigger cell death Genetics. Several genetic mutations are associated with PD, including the alpha-synuclein gene, and many more genes Environment. Exposure to certain toxins has caused parkinsonian symptoms in rare circumstances (such as exposure to MPTP, an illicit drug, or in miners exposed to the metal manganese). Mitochondria. The energy-producing components of the cell and abnormalities in the mitochondria are major sources of free radicals molecules that damage membranes, proteins, DNA, and other parts of the cell. This damage is often referred to as oxidative stress. Oxidative stress-related changes, including free radical damage to DNA, proteins, and fats, have been detected in the brains of individuals with PD How is Parkinson’s disease diagnosed? There are currently no specific tests that diagnose PD. The diagnosis is based on: Medical history and a neurological examination Blood and laboratory tests, to rule out other disorders that may be causing the symptoms Brain scans to rule out other disorders. However, computed tomography (CT) and magnetic resonance imaging (MRI) brain scans of people with PD usually appear normal. How is the disease treated? At present, there is no cure for PD, but medications or surgery can often provide improvement in the motor symptoms. Drug Therapy Medications for PD fall into three categories: Drugs that increase the level of dopamine in the brain. The most common drugs for PD are dopamine precursors—substances such as levodopa that cross the blood-brain barrier and are then changed into dopamine. Other drugs mimic dopamine or prevent or slow its breakdown. Drugs that affect other neurotransmitters in the body in order to ease some of the symptoms of the disease. For example, anticholinergic drugs interfere with production or uptake of the neurotransmitter acetylcholine. These can be effective in reducing tremors. Medications that help control the non-motor symptoms of the disease, that is, the symptoms that don’t affect movement. For example, people with PD-related depression may be prescribed antidepressants. Surgery Before the discovery of levodopa, surgery was an option for treating PD. Studies in the past few decades have led to great improvements in surgical techniques, and surgery is again considered for people with PD for whom drug therapy is no longer sufficient. Medications to Treat the Motor Symptoms of Parkinson’s Disease Thank You