Causes of Increased and Decreased Ccr

00:02 This is a table here. It is a nice table to summarize the things that we have talked about.

00:05 Let me dissect this for you. In general, this is all about creatinine clearance. First and foremost, we will talk about two ends of the spectrum. We will talk about increased creatinine clearance and common causes for that and possibly why and then as we complete the high yield or most common cause of increased creatinine clearance, we will then go into what is known as decreased creatinine clearance. Let us begin. So normal pregnancy. Close your eyes.

00:33 Think about a pregnant lady. Next, what might you be thinking about? Her plasma volume.

00:39 As soon as she becomes pregnant in general, what about her plasma volume? It increases.

00:43 Does it not? So in a normal pregnant woman with an increase in plasma volume, I am now delivering increased amounts of plasma to my afferent arteriole thus to my glomerulus.

00:58 What Starling force are you now increasing? Good. Hydrostatic pressure. Excellant. Which pressure is that? The pulling or the pushing pressure. So you have increased the amount of plasma volume arriving at the afferent arteriole in the glomerulus, it is going to push more substances or in other words filter more. So now if you filter more with a normal kidney, what will you then expect at the end of the first trimester when usually the plasma volume might increase as much as 50 percent. Obviously an increase in creatinine clearance. From physiology, a concept that you must keep in mind also dealing with pregnancy important for renal function is something called renal threshold for glucose and we will spend some time with that and all that I wish to say about this at this point so at least I plan to seed in your head and then we will further discuss this as how the renal threshold for glucose decreases in a pregnant woman? Fact, the renal threshold for glucose decreases in a pregnant woman. There is more glucose in the urine of a pregnant lady on purpose. In general, when you have a pregnant lady, what is her plasma glucose? It will be elevated in general because you want to feed the little bit of baby. The fetus is hungry. So it will be fun when we get to that point. Move on. So now that is a normal pregnancy. Let us talk about diabetic early on and with diabetes, there is going to be two major issues within the renal region and here it would be the blood vessels that are affected much more so with efferent interesting enough. So now think about where you are and don't just read.

02:45 Conceptualize the efferent arteriole. Where are you? Distal to the glomerulus. Correct and if it is diabetes, what kind of blood vessel change do you find in general? Tell me about diabetes mellitus. Is that a chronic issue? Is that an acute issue? It is a chronic issue. 10, 15, 20 years have taken place. You may or may not have controlled your glycemic control maybe you didn't monitor properly. Really difficult at times. You think about HbA1c and all these things and so, therefore, the type of pathology that takes place with diabetes mellitus is called non-enzymatic glycosylation or you might notice it as being advanced glycosylated end products for the most part similar and more importantly is that the blood vessels are undergoing a process. Please highlight in your head. Hyaline arteriolosclerosis.

03:37 How important is that? Very. Hyaline, what does that mean? Accumulation of protein. Now the enzymatic glycosylation might then contribute to this hyaline, which is what color? H&E stain eosinophilic and it will be pinkish and this is accumulating in the lumen of the blood vessel causing what? Constriction okay great not so much for the patient, but the concept is great. Isn't it? So you are going to constrict, constrict and constrict pathologically the efferent arteriole. Are you picturing this? So what may then happen proximally? You added a resistor in a series, what then happens proximally? An increase in pressure.

04:18 When increase in pressure, then what happens to hydrostatic pressure? It increases. Let me ask you something. You want to discipline your child. You discipline your child and maybe you lose respect or whatever, but then you spank. What if you continue spanking, spanking, spanking, spanking? My goodness at some point you are going to damage the buttocks of that baby with enough spanking. Well with efferent arteriole constriction you are spanking the glomerulus.

04:46 Spank, spank, spank, spank and so, therefore, are you now perhaps causing damage. Yes, you are and what is the first thing that you will be looking for in dipstick in a patient that you suspect diabetic nephropathy. It is called microalbuminuria. You should never have albumin in your urine. So when the time is right and we talked about dipsticks, we will talk about the microalbuminuria and say that now the glomerulus is damaged apart from the protein that might be passing through is it possible that you might have increased creatinine clearance? Absolutely. That is my topic. You see as to how you are going to use this information but then also clinical application in terms of overall what is happening. May I ask you one other thing that you may or may not have thought of. As soon as you have microalbuminuria, what kind of drug that you might you want to give your patient. It is called a renal protective drug or an ACE inhibitor and I will introduce that here. At some point, we will reinforce that and you will have seen that in pharmacology and that is an important drug so that you can protect the efferent arteriole in the glomerulus from further kidney damage. Let us continue, please.

06:03 Increased GFR, damage of glomerulus, hyperfiltration injury is what you are looking at as being part of early diabetic nephropathy. So if this is increased creatinine clearance, then let us take a look at decreased creatinine clearance. Elderly people, as we get older what we will say beyond the age of 50, there is a drop in GFR one milliliter per minute.

06:28 So, therefore, elderly people will have an automatic decrease in creatinine clearance and why is that important to you. We just discussed earlier as to how it is important that you measure or assess kidney function by using the clearance formula UV/P. Once you do so, you will get renal function assessment and you want to make sure that you understand an adjust the dose of your nephrotoxic drug. Acute and chronic renal disease once again now with acute renal disease or acute renal failure, we will talk about different phases as you will see. Acute renal failure is going to be a completely different manifestation than chronic and that is important as a distinguishing point and I wish to point out here and I will keep repeating it until it becomes firmly etched in your head, but there are times with acute and definitely chronic in which because you can’t filter properly. What then may happen to creatinine clearance? Well here if you can’t filter properly, you will then be decreasing creatinine clearance. So what does that mean? That means less has been cleared there is more that ends up being wear in your plasma. Let us continue.