NURS-208 Final: Lecture 11 (Renal Pathophysiology)

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The Kidneys Kidney Anatomy 1.) We are going to focus on the cortex (outer layer) of the kidney first! → The renal cortex is a nice rim around the entire kidney → They contain all of these stru ... ctures called glomeruli, most of the proximal tubules and some segments of the distal tubule → Then there are the renal columns which are an extension of the cortex and they extend between the pyramid and the renal pelvis 2.) The medulla forms the inner part of the kidney → It consists of regions called pyramids Right and Left Kidney There is a little discrepancy of where the kidneys are in the body. 1.) One of the differences between the right and the left kidneys is that the left kidney is higher up → This is because the liver is in the way of the right kidney 2.) The thing that is most important that really helps us, especially when we take care of patients, is that you have two kidneys, but you only need one → The kidneys only share one blood supply (major vessel = aorta which branches off to the renal arteries) ↳ If your aorta is damaged (car accident/arteriosclerosis), the kidneys are going to feel that very quickly 3.) Everyday, you will be a lung and kidney nurse! → This is because these organs are usually the ones that every diagnosis touches 4.) The kidneys are located retroperitoneally 00:01 01:26 Retroperitoneal Bleed Some patients that take anticoagulants will come in with something called retroperitoneal bleed 1.) That encompasses on an x-ray (or a CAT scan) the abdomen area of the body 2.) When these patients come in they will have some non-specific complaint of pain → We would then like to get a diagnostic radiograph of the patient to try and find the source of this non-specific pain (we would like to see a chest x-ray) 3.) In this chest x-ray we do not really see much there, all of the organs seem to be normal size, so we ask more questions! → This is when we realize we need a stronger diagnostic film 4.) X-rays aren't that great, so the next diagnostic film used (to help us see a little bit more) is a CAT scan → A CAT scan can be taken two ways: We take a picture of you in the CAT scanner (it outlines with better definition all the organs and the bone), next we hook up contrast (radio opaque dye) to the patients IV (everyone in the hospital has an IV, it is apart of the admission agreement, and if you do not want one you have to sign a waver) and then take another picture in the scanner → What this radio opaque fluid does is it travels throughout the body within 10 seconds and it maps all the veins and arteries 5.) So you get a really clear picture of just organs with the first film and a really clear picture of what is happening to the veins and arteries in the second film → Especially the non-specific area that the patient is complaining of pain! → Sometimes we see leaks or small microvascular tears (hypertension causes small microvascular tears throughout the entire endothelium, from the head to the toe; the more velocity you have going through any vessel, if you are diagnosed, even though you are controlled on medications, you are going to have microvascular tears) 6.) So, a lot of these patients will come in with a retroperitoneal bleed → To help them you need to hold the anticoagulant (risk-benefit ratio; we know that we want to give people anticoagulants to help stop the formation of clots, especially when they are on bed rest; but, if they are covertly bleeding it is not worth the risk [even though they are at risk for forming a clot, you cannot make things worse; do no harm]!) → We fix this by keeping them for monitoring, make sure they have an IV site, and hold the anticoagulants 7.) Covert = hidden (we do not really know when it happens until the patient has symptoms); Overt = obvious 8.) Before the patient leaves we find out if they are having any other pain and we will probably repeat that CAT scan with contrast (this means you do two CAT scans) → That contrast needs to be a doctors order because it is a diagnostic substance that can cause the patient some harm → The kidneys have to filter out drugs so if they have really bad kidneys we will just take them off anticoagulants and not risk the CAT scan (we are not trained to know if it is safe or not) 9.) So if you see someone has a retroperitoneal bleed, you are going to think about the aorta as well as the structure of the kidney → Monitor kidney function! When someone has a retroperitoneal bleed, if it is going to be in this space and if there is microvascular tears in the aorta, the kidney is the first organ that is going to feel that effect (usually patients who have this retroperitoneal bleed all the sudden stop urinating). Kidney Blood Flow Blood flow is innervated by the sympathetic nervous system to the kidney. 1.) These pyramids extend to the renal pelvis and contain the loops of Henle and collecting ducts 2.) The minor and major calyxes are the chambers that receive the urine from the collecting ducts and form the entry into the renal pelvis (this is an extension of the upper ureter as well) 3.) The structural unit of the kidney is the lobe → Each lobe is composed of a pyramid and an overlying cortex (there is about roughly 14-18 lobes in each kidney) Filtration What is filtration? 1.) The mass movement of water and solutes. It moves from our plasma to the renal tubule and this all occurs in the renal corpuscle 2.) About 20% of your plasma volume passes through the glomeruli at any given time and is filtered → This means 180L of fluid is filtered by our kidneys every day (that is a massive amount of fluid and work that your kidneys do every single day) 3.) If it can filter 180L of fluid a day without problem, you can image that if a patient is dehydrated, how the function of the kidney will definitely decrease (it wants to do its job) Effluent When you have someone that cannot make their own urine and we do dialysis, when the machine performs the filtration and removes all of the solutes and the toxins, we do not call that production from the machine urine. 1.) That urine is what you would make on your own 2.) Dialysis patients, who are on dialysis, do not make urine. They make effluent! → If the machine is making the product it is called effluent, but if the patient is making the product it is called urine 3.) Effluent is just another word for the dialysis machine removing the waste from the body (will be placed under output instead of urine for dialysis patients) Urine Formation How is urine made? 1.) Glomerular filtration → The movement of substances from the blood within the glomerulus into the capsular space 2.) Tubular reabsorption → The movement of substances from the tubular fluid back into the blood 3.) Tubular secretion → The movement of substances from the blood into the tubular fluid How and what is being placed in urine? Filtration, absorption, reabsorption and excretion. 1.) Filtration at the glomerulus 2.) Absorption into peritubular capillaries 3.) Reabsorption into tubule for excretion in urine Kidneys and Glucose Filtration 1.) You should not find glucose in urine because the molecule is too large → That extra glucose goes into the liver and the liver breaks it down and stores it either as glycogen or fat 2.) When carrier molecules for glucose become saturated (this sometimes happens in a state of hyperglycemia; this would be someone who is not making much insulin; a lot of people do not know that they are not making enough insulin) and a patient notices they are urinating a lot, one of the big problems is that glucose is being seen by the kidney every time the heart beats (the kidneys are seeing with every first of blood going through the renal artery into the glomeruli what is in the blood) → The kidney choses what to keep in the blood and what to excrete. It is doing that with all electrolytes (all electrolytes lead to your pH balance so not only are your kidneys changing your pH, but they are also altering your electrolytes and getting rid of excess water) → What happens with glucose though? I you ate food with a lot of glucose and you were not a diabetic, your body would take that all in and store it as either glycogen or fat ↳ But, if you were diabetic it would not go into the cell because you do not have any insulin, so it would circulate in your serum. But, the kidneys want to get rid of all this glucose so they will use water as a carrier molecule ↳ The only way for glucose to move out of the body if you do not make insulin is that the kidneys hook it up with H2O and it moves out of the body as a massive diuretic effect (so these patients, when they are hyperglycemic and don't take their insulin or do not make insulin, will be on the toilet almost urinating out their entire body volume to the point that they become so dehydrated they become comatose) → We know when the blood sugar is high and there is no insulin that you will have a massive diuresis (almost all of your blood volume) and you could go into hypovolemic shock and die → The kidneys do not notice that they are doing this to themselves is because there is no way for the kidney to stop (it cannot stop itself) ↳ There is no maximum rate of glucose filtration (there is no stop button). This is because circulating glucose is that bad! 3.) This is not saying that the kidneys regulate glucose it just means that the kidneys will try to rid the body of extra glucose when they detect it → Only insulin can help regulate glucose in Type I diabetics and food and exercise in Type II diabetics Clinicals (Patients) It is important on every shift with every patient to think about: 1.) Do they actually make urine? 2.) How much are they making? → An adult should make 30mL/hour at least (anything less than that is a reportable finding) What are the functions of the kidney? 1.) Regulate blood pressure 2.) Electrolyte balance 3.) Regulate pH 4.) Filter and excrete waste 5.) Release of Erythropoietin 6.) Synthesizes Vitamin D to its active form 7.) Regulates calcium and phosphorus 8.) Secretes prostaglandins → If you give NSAIDs and you stop the kidneys from producing prostaglandins, your kidneys are not going to be happy (so, prolonged use of NSAIDs cause renal failure; because it inhibits prostaglandin synthesis) → You need healthy kidneys to go into labor if you are pregnant. The prostaglandins help you contract your uterus (people in renal failure are usually not able to get pregnant) Secretion and Reabsorption in the Kidneys 1.) Renal tubules secrete H+ and K+ 2.) Na+ reabsorbed in proximal tubules 3.) Water reabsorption requires ADH in the distal tubule (I think this is wrong and is actually: Collecting ducts) [Show More]

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