>> This is Frances Morrison, I'm doing a continuation of very mini med school to familiarize non clinicians with conditions, diseases, and medical concepts that would be found in patient data. Again, the goal of these series of lectures are to understand some of the more common diseases and conditions found in patients in the United States. Understand the basic physical processes behind these conditions, and the data elements you might find in a patient's record, including lab, radiology, and clinical finding data. There's a distinction between diseases and conditions, although it is a subtle one where a disease is something that causes a person to be ill, where a condition is potentially bothersome, and may lead to disease or be one of the things that are found in a disease, but not necessarily cause illness itself. Also, clinical finding is a symptom or a sign that indicates illness. Today I'm going to talk about stroke and diabetes, starting with stroke, which is a disease of the brain. You can see on the right side a, a stroke occurs in two different ways, a basic concept behind a stroke is that the brain is not getting the nutrients and oxygen that it needs to function, much like when the coronary arteries are blocked and the heart's not getting the resources it needs to function, this can also happen to the brain. There are two types of stroke that individuals experience, one is an ischemic stroke, where the blood is blocked and no blood can get to an area. A hemorrhagic stroke is when blood is coming out of the vessels into the tissue, this is not a way that the, the cells in the brain can actually use the blood, it can only use blood that's coming to it through the vessels because there are specific ways that the oxygen and nutrients transfer into the tissue so that blood flowing around the brain like you see on the right, does not actually provide any useful nutrients to the brain. ^M00:02:30 [ Background noise ] ^M00:02:35 >> Related terms for stroke include cerebral infarction, which is another term for stroke. And an infarct is a disruption in the blood vessel. Transient ischemic attack is a temporary reversible lack of flow to a brain tissue. Ischemia is lack of oxygen. A hemorrhage is a bleed, so basically, any kind of blood that gets outside of the blood vessels. Thrombosis is a blood clot inside a blood vessel. A plaque is a buildup of fatty and scar tissue inside the blood vessel. An embolism is a piece of material that comes from elsewhere, and it can occlude or block the lumen, or inside of the blood vessel. And an aneurysm is basically a ballooning out of the vessel that can result in a rupture, or a burst, causing a hemorrhagic stroke, potentially. Some important word roots, again, are cerebrum, when you say cerebral infarction that means a lack of blood getting to the cerebrum, since cerebrum is another word for brain. In Latin, heme, hemorrhage is two important word roots together, so the first one is heme, which means blood. And any time you see the letters rrh, it usually is referring to rrhea, as in you would say diarrhea is a flow, so a hemorrhage, or something similar to a hemorrhea would be the flow of blood. A thromb is another way of saying clot, so thrombus is a clot from elsewhere that lodges in a blood vessel. I'll discuss a little bit about imaging because it's an important detector of stroke particularly. There are different types of imaging that use different physical methods, so an x-ray is radiation that is sent through the body and a piece of material, almost like a photograph on the other side detects how dense different areas are, which is why you see bones very well on an x-ray, but you wouldn't see skin very well, so it doesn't -- the x-rays, or the radiation does not go through bone very well, which leaves that part of the photographic material white, or blank. CT, or computed tomography is really a fancy x-ray, it uses radiation, but it does it in a spiral, or a sectional method, where you take a lot more images and you can put it together in a three dimensional fashion. Sometimes these use dye, or contrast, which is injected into the blood vessels so you can see the blood vessels clearly, or areas of increased blood use. An MRI is a magnetic resonance imaging, using a large magnet to line up the cells and you have a way of detecting on the other side whether these cells are dense or not as dense by the way they line up. A functional MRI is an injection of some kind of material, usually a sugar or something that cells will use that's radioactive, and you can see where that's gathering, and it will change, for example, in the brain in certain areas that are using a lot of sugar, or when the brain is thinking in a particular area, it will light up much brighter. An ultrasound, as I mentioned before, an echocardiogram and an ultrasound are very similar, they both use sound, so echo is another way of basically saying sound, or sound waves. An ultrasound uses sound waves to detect both flow as well as density in the body, they're often used in pregnancy to look at a fetus. A nuclear scan is injection of an, a radioactive material that lights up certain areas, especially in cancer, you can see where these materials gather by where the cells are very actively dividing. A PET, or positron emission tomography is similar to an FMRI in that you're injecting some kind of material that the cells will use quickly if they're dividing quickly, or, or doing a lot of activity. ^M00:07:31 [ Background noise ] ^M00:07:36 >> This is an example of CT's of a, of someone who's had a stroke, you can tell it's a CT, or computed tomography because the skull is very white, meaning it's almost like when you look at an x-ray you can see the bones as very white, so this is a CT. And if you look on A, as indicated as A, you can't really actually see anything, so most strokes in the beginning, you can't see anything, lack of blood flow to that area doesn't look like anything. But on the right, on the, the second image, B, the blood outside of the vessels, this is a hemorrhagic stroke on the right, you can see is very, very bright, so blood shows up, it's very bright when it's gathering abnormally in an area. Contrast would also look that bright, neither of these has contrast, but the contrast would be inside the blood vessels and look sort of like a branching, or dots, very delicately arranged throughout the brain. This is an example of a CT, versus an MRI in a stroke. Again, these are, these are images of the brain. On the left, you can see that's a CT. On the right, that's an MRI. These both, however, are ischemic strokes, meaning that they're not getting enough oxygen, causing damage to the brain. But on the left, you can tell that the CT does not pick up any evidence of this stroke, and on the right, the MRI picks up very clearly that that's an area of ischemic stroke, that is not blood in the MRI, that's an area of abnormality. A PET scan looks like this, where the areas of a lot of metabolism, or functioning are very red, and the areas that have less activity going on are blue, and you can see the inside part on the right, where Alzheimer's is, is you can see the brain is a little thinner and it's being filled in inside by fluid, cerebral spinal fluid, so there's less brain tissue, due to cellular damage. This is an example of an ultrasound that is demonstrating flow, and usually red is toward the viewer, and blue is away. But this is the heart, you can see the four chambers, the left and right sides of the heart where the blood is flowing through. And you can see how fast it's flowing, and whether there are abnormal areas of disrupted flow. Some labs you'll see, typically in stroke, include a chemistry panel, again, a complete blood count, end clotting tests are very important. The test you'll see, as I demonstrated were CT, MRI, people will do a carotid duplex, which is another, again, duplex is another way of saying ultrasound where you can detect flow through the carotid and see if there's anything either coming off of the carotid, if there are plaques that can break off into the brain and cause a lack of flow in different areas by lodging in the blood vessels. Or, if there is, is narrowing of the carotid and, and lack of blood flow to the brain. An angiogram can be done in the brain as well with imaging of the vessels, just like I described in the heart. I will discuss clotting tests, which are a very important test in stroke because they determine the clotting levels, or coagulation levels in blood. This often happens if the person is getting after, say, an ischemic stroke, they're trying to break up a clot in the brain, they'll give anti coagulation drugs, or blood thinning drugs, and follow the clotting test to make sure that they're not over... ^M00:11:57 [ Silence ] ^M00:12:24 >> Causes of stroke include smoking, again, you've seen that a few times, hypertension, high cholesterol, and sometimes if people are taking medication to break up a clot in another area, they can get a hemorrhagic stroke from that medication and too much blood thinning. Prevention includes diet and exercise, again, as well as if someone is having a, a clot elsewhere, it might end up in the brain, or if they're having clots in their brain they can take blood thinning medication like Coumadin and Heparin. Again, they can have an angiogram with angioplasty, as well as surgery to remove large obstructions in the brain. The next disease I'm going to talk about is diabetes, which is a very common disease causing a lot of different effects in the body. The reason diabetes causes problems is that it can damage the smaller vessels and this can affect blood flow and cause damage in the eyes, the heart, the kidneys, as well as the extremities, so the nerves and blood vessels in the extremities. Diabetes is caused by a lack of insulin. Insulin is a, a material or a chemical in your body that helps sugar or glucose get into, into your body's cells. Without insulin, glucose will only go into your brain, it's the only tissue that allows glucose in without this helped called insulin, and if you don't have insulin, the sugar will not get into the different parts of your body, including muscles, and all the other parts of your body that need glucose in order to function at all. So you'll see when there's less insulin, you'll see high levels of blood glucose and -- but the cells are not getting the glucose. Insulin is made in the pancreas, and there are many reasons why there can be problems with the pancreas, oftentimes the body's immune system, or the system that it helps fight off infection will think that the pancreas is some sort of a foreign body and attack it, causing damage to the cells, that's usually what happens, and nobody's quite sure why that occurs. So, if your own body's attacking your pancreas and destroying the cells that make insulin, you're not going to have enough insulin in your body, and you can see the pancreas there, wrapped around by the small intestine on the right. The pancreas is located right, right near the liver as you can see in the, in the middle image. Other terms you'll see related to diabetes is the full term for diabetes, which is diabetes mellitus. You'll hear about high blood glucose and high blood sugar, hyperglycemia, which, again, is just high sugar literally. Ketoacidosis is resulting increased acidity of the blood, due to the high blood glucose. Gestational diabetes is, is diabetes occurring when a woman is pregnant. And there are two types of diabetes, Type I or juvenile diabetes starts when an individual is very young, it's usually more severe and a lot younger and it can be genetic. Type II diabetes is more related to obesity and occurs generally in older individuals, although it's occurring younger and younger. And Metabolic Syndrome is another term you'll hear related to diabetes, which is a series of things that can increase your likelihood of death related to diabetes, and several other conditions. Important word roots include dia, which is through, so people who had diabetes mellitus would urinate or pee a lot because the glucose would draw the blood out of the body into the urine, so they would be drinking a lot of water and urinating large amounts, so they thought that there some almost like diarrhea, just the problem was the fluid flowing through the body. Gluc is a word root meaning sugar, as is glyc, G-L-Y-C. Hyper is a prefix that means high, and you'll also see hypo, hypoglycemia is when the blood sugar is too low, and that can cause coma if somebody takes too much insulin, for example, it can result in a coma because the brain is not getting enough sugar to it. Two concepts I want to talk about in a little more detail are autoimmune and inflammation. I mentioned that the body attacks its own pancreatic cells, causing diabetes. The immune system is the blood cells that fight off infection, they exist mostly in the blood, although there are some other tissues in the body that are involved in the immune system, including lymph nodes, the appendix they think is involved, the tonsils are also an area that has immune properties, and the lymph system, which is another very important concept that I mentioned before in terms of having lymphoma or cancer of the lymph system. The lymph system is parietal system to the blood vessels, and it really collects all the excess fluid, as well as all the, the immune cells flow through this lymph system. When there's inflammation or infection, the lymph nodes can get enlarged, as similar to I described, how I described in lymphoma. Inflammation is a very important medical concept, it is swelling, redness, and increased temperature, and it can be caused by the immune system fighting off an infection, or it can also be caused by immune system attacking itself. ^M00:19:49 [ Background noise ] ^M00:19:54 >> Causes of diabetes, again, include increasing age, as well as overeating and sedentary lifestyle, that's mostly Type II diabetes. Type I diabetes is more of an autoimmune disease. People can be genetically predisposed to diabetes. Some medications like steroids, not the kind that you take to build your muscles, but steroids one would take for decreasing the immune system, like in asthma, or in some of the arthritis diseases, so steroids end up increasing blood glucose and potentially can require treatment for diabetes. And pregnancy, as I mentioned, in gestational diabetes can be something that triggers diabetes. Diabetes can be treated and prevented with diet and medication. Two major types of medication are either shots, that would be insulin, or oral medication, that means like pills that you would take. Hypoglycemics, you can tell by the word roots, you should recognize both hypo, which is decrease, and G-L-Y-C, which is another way saying sugar, and actually E-M in there would indicate heme, so hypoglycemic would be decreased sugar in the blood, so oral hypoglycemics decrease the blood sugars. People with diabetes tend to get a lot of food exams and eye exams because those are some of the areas that are affected by the disease. Individuals with diabetes tend to get a lot of labs, some from the blood, and some in the urine. The finger stick tests is a test of blood sugar by extracting blood out of a fingertip. A chemistry panel is important in diabetes to detect both acid and blood glucose. One main way to diagnose diabetes as opposed to a single increased blood sugar is a fasting plasma glucose. Hemoglobin A1C is an indicator of long term diabetes control. The red blood cells get slightly damaged by the glucose and you can tell with the hemoglobin A1C how much of an affect the blood glucose is having on the red blood cells over a long period of time. Diabetics, as I said, tend to get glucose in the urine, or sugar in their urine, so they're -- they tend to get a lot of urinalyses. Protein in the urine is also an indicator of kidney damage, and as I mentioned, diabetes can affect the kidneys, so they also check for protein the urine. A test that's not necessarily a lab test, but more or a diagnostic test that would happen in a, in an office is the oral glucose tolerance test, where people take time to glucose, and then followed by blood tests for sugar, and that's one way to definitively decided whether a person has diabetes or not. I'm going to talk a little bit more about chemistry panels, which is really a bread and butter laboratory exam, particularly in diseases like diabetes, where very close attention is paid to the electrolytes, meaning the different elements in the blood. The first two, BUN and creatinine indicate the kidney functioning, as I mentioned, diabetes can affect the kidneys, so it's important to know how well those are working, and that can be determined by a blood test that measures BUN and creatinine. Again, glucose indicates the level of sugar in the blood. HCO3, or bicarbonate can show the levels of carbon dioxide in the blood, and that's important for knowing whether a person's blood acidic, as happens in diabetes, or whether they have not enough oxygen, which also causes acidity. Serum potassium is important for the functioning of the heart, it allows the electrical impulses to go from one area to the other in the heart, and if that's not working, the heart does pump properly. Serum sodium and serum chloride are also important indicators of various diseases or conditions. An, an important distinction can be made between measuring blood and measuring serum. The serum blood test, or a serum, for example, a serum glucose is when all the blood cells are taken out of the blood and you just measure what's left. One example of why you would only use the serum is the serum potassium, if there are red blood cells in the specimen, or the, the blood to be tested, that if they're damaged, the serum potassium will appear a lot higher because there's potassium inside the cells, so it's important to remove those blood cells and then measure the serum elements like potassium, sodium, and chloride. I'm going to digress a little bit here and talk about hypertension, it's not on the list of the top 10 causes of mortality in the United States, but it's a very important cause of disease and morbidity, which means basically illness. Hypertension is high blood pressure, which is of unknown origin usually, meaning there isn't necessarily a well known reason why the blood pressure's high, although it can be caused by lack of exercise, stress, and poor diet, as well as increased sodium in the blood. High blood pressure's diagnosed by multiple blood pressure measurements, so if a person walks into a doctor's office and has one blood pressure that's high, that does not mean they have hypertension, they have to have repeated blood pressure measurements over a period of time that indicate that their, their blood pressure's high abnormally. Normal adults will have blood pressure of 120 over 80, anything too low means that the brain may not be getting enough oxygen, or other organs may not be getting enough oxygen, that the blood is not flowing properly to the entire body, and if it's too high, the blood vessels can be damaged over a long period of time. So the small arteries, in particular, can be damaged, causing organ damage, this is similar to what happens in diabetes where the arteries are being damaged over a long period of time. In summary, we discussed the basic processes related to stroke and diabetes, and some data elements you'll find that are relevant to these conditions, including lab, radiology, and clinical finding data related to stroke and diabetes. ^M00:27:53