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Interpretation of Renal Function Tests- PART 2

May 31 | 3:30 PM

The kidneys are involved in the excretion of waste products and toxins like urea, creatinine, and uric acid, as well as the regulation of extracellular fluid volume, serum osmolality, and electrolyte concentrations, and the production of hormones like erythropoietin, 1,25 dihydroxy vitamin D, and renin. The nephron, which includes the glomerulus, proximal and distal tubules, and collecting duct, is the functional unit of the kidney. Renal function testing is crucial in the treatment of patients with kidney disease or diseases that impact renal function. Renal function tests are useful for detecting renal disease, monitoring the kidneys' response to treatment, and determining the development of renal illness. Join us live with Dr. Mahadev Desai in this super amazing #backtoschool series on basic investigations.

[Music] good evening dear doctors thank you so much for joining in i am dr fatima on behalf of the entire team of netflix welcome you all to this amazing session on matrix so tonight we have the interpretation of renal function test part 2 by our awesome netflix select faculty and mentor dr mahadev desai now dr mahadev desai earlier on has taught about on netflix has covered sessions on interpretation of cbc lfts all these sessions are available in the replay section for all of you to watch tonight in continuation of the interpretation of renal function test this is part two of the amazing session our faculty doctor madhya desai is senior consultant physician at um sir is also extremely passionate about teaching medicine and it is truly an honor to be learning from you tonight sir thank you so much for joining us yeah good evening dr fatima and all the viewers i'm very happy to see a large number gathered on dot and that's what we would like to maintain we already talked about the renal interpretation of renal function test part one which was about and tell about urine analysis so today we will not be talking about the urine analysis as the inner function and before we begin i thought let's have some thing like a quiz so that we recapitulate what is very important part of the so oligaria is defined as an x amount of ml of urine for 24 hours that is is it less than 100 is it more than less than 400 less than 700 or less than 1000 ml per day your time starts now yeah so i am happy that most of the people who voted favor that less than 400 ml per 24 hours is considered as oligaria less than 100 ml per 24 it's called anuria and there is a subset of patients with acute kidney injury or which used to be called as a ketone and failure where the urine output may be more than 400 but the laboratory parameters suggest acute kidney injury or acute anal failure they are called non-oligary criminal failure we move on to the next that is glomerular filtration rate of which i am going to talk in more detail because that is one of the most important function of the kidney is to filter so it depends on the age gender and weight of a person is it true or false so we know that bromine filter syringe does not does depend on the age and weight of a person so we'll be talking more about it when we move on first let me tell you what we discussed last time we discussed about the functions of the kidney and about the urine analysis today i am going to focus mainly large part almost half of the time i will be talking about the governmental filtration rate then the difference between the acute kidney injury and chronic kidney disease how we categorize them how we grade them and then depending on the time other functions we began last time with the what are the functions of the kidney we know that kidney is a master organ and in order to remember all the functions major functions of the kidney i give the mnemonic a wet blade wet bed we know that kidney is one of the most important organ for the balancing act so it maintains the acid-base balance it maintains the water balance it maintains the electrolyte balance mainly the sodium potassium and many other calcium phosphates and all and it also helps in removal of the toxins then it is one of the important organ for maintaining the blood pressure and through the volume as well as through the renin then it also helps in the blood formations in the form of erythropoies in secretion by the kidneys and very important functions of vitamin d metabolism through the production of 125 dihydroxyl colic also feral or called active vitamin d or kelsey travel so kidney is very very important how does kidney bring about all this function by the efficient filtration we know that gromyl filtration rate is indicative of the rate of filtration of functioning nephrons kidney is made up of n number of nephrons and each nephron is carrying out the same function of filtrations over a period of 24 hours almost 180 liters of plasma is subjected to the glomeruli and out of which almost 178.5 liters that is almost 99 is the absorbed and the only resulting into 1 to 1.5 liters of the urine so that's how the kidney is efficient how do we measure this normally we do not measure the glucose rate because of any cumbersome procedure and if you remember your physiology class when we used to talk about how do we measure the glomeral filtration rate we have to have a substance which is if it is given orally it should be completely metabolized it should not have any metabolism at the liver level and it should come to the blood in the amount that is ingested then it should be completely secreted by the basement membrane and it should not be secreted in between our metabolism the kidney and it should be excreted as it is the only substance that is an inulin but again it has to be given in an injectable form so it's a substance which is not metabolized somebody is rightly said that it's an inert substance correct so it is not metabolized by the liver when we inject intravenously inulin and we have to measure every hourly the amount of inulin cleared by the kidney that is in the urinary inline concentration it's a very cumbersome procedure very expensive one and not routinely available so we do not use the inulin clearance what we use is the substance which is endogenously produced but again at almost a constant rate an indicative fair indicating of the removal filtration rate and that is why you use the we usually use creatinine clearance case again clear and clear stage also requires the measurement of 24 hours of urinary creatinine urinary volume and we know the formula uv by p or where the v is the volume of the unit for 24 hours the we know there are 100 140 m minutes so that is why the that is mentioned here e stands for the urinary creatinine and p stands for the plasma creatinine and 1.17 is the standard surface area that is measured and in actual patient write the actual a sense for the surface area of the person so if you want the exact creatine clearance rate we need this formula this gradient clearance is slightly higher than the true glomerular filtration rate because part of the creatinine unlike inulin is also secreted by the proximal tubules so the urinary recovery of the cradle is slightly higher so the urinary creatine clearance would be higher than the actual gfr but all said and done creating clearance or the measurement of the creatine is one of the most important indicator of brumal filtration rate so what is serum creatine why we measure serum creatine and how does it come from the normal values mentioned is 0.8 to 1.1 milligram per deciliter this is usually in the male in the female it is around slightly less because of the less muscle mass and less creatinine excretion creatinine comes from the creatine which is the muscle protein skeletal muscle protein it also comes from the dietary protein meat intake so creatinine is formed by the creatine which is the muscle protein or the dietary meat intake which is fairly released at a constant rate and that is why it doesn't change on day to day basis and it is freely filtered across the collimate line and it is not re-absorbed unlike the other that we are going to talk next about the urea that we use routinely with urea and creatinine the creatine is not re-absorbed or it is not metabolized by the kidney but the only small negative part as we mentioned earlier is that there is some degree of secretion of the creatine in the proximal tubules which gives slightly higher values of the bloom filtration by this method but creatine values are lower in the women as we mentioned another test that we use routinely is the blood urea you might see some of the reports especially the reports which masons come from the usa or many of the new laboratories also started using blood urea nitrogen practically it is the same thing that they measure only thing in blood urea one uses the urea as a whole molecule which has a molecular weight of 60 as against that in blood here and nitrogen only the nitrogen content of the urea molecule is measured and that's why it is obviously the nitrogen compound is almost half of the total urea molecule it is the molecular weight is 28 so the normal value of blood urea is 20 1.4 or say 20 and the blurrier nitrogen is around 10. so the blood area is approximately you can say twice that of the bloodier and nitrogen it does not make any difference in the interpretation whether it is bu and or bu laboratories give different normalities i agree with that so you have to see the by and large the values are almost around the same and what we see is a cross difference and remember i agree with these comments that laboratories have a different values and that is why patients keep on coming so the value mentioned is 40 or mentioned is 13 and now this is 15 is it high this is more common in creatinine when the values go right up to 1.5 milligram and in fact that's a very very high values we'll see when we talk in more detail about the creatinine part so you have to see the normal values by the laboratories and the important thing is that blood urea or blood urine nitrogen interpretation is same whether it is bun or bu you compare with the upper value of the normal of that particular parameter important thing is that the blood urea blood and nitrogen as against creatinine are changing according to the independent of the gfr if the person is taking more protein diet or if the person has to break down injuries hemorrhage bleeding then the blood urea production would be increased which will be reflected in the serum or blood urea levels of blood urine nitrogen levels and as against that if the person has lope is on low protein diet or patience chronic liver disease then the urea level will be less and if the patient is a liver disease irrespective of the global filtration the values will be on the lower side in spite of patients having a significantly low gfr so there is one thing we have to always remember the chronic liver disease when evaluate the cruel filtration by the creatinine or the urea levels but there is an importance of the measurement of blood urea or blood urine nitrogen and the normal blood urea bloody nitrogen is around 20 to 1 or 21 10 to 1 mostly but the blood area to creatinine ratio the title should have been blurred area to create in ratio which is normally around 20 to 1 but if the patient has acute kidney injury because of the severe volume depletion like hypovolemia because of the diarrhea vomiting excessive diuretic use or the buns in that case because of the hypovolemia decreased tissue perfusion the kidneys would definitely reabsorb more salt and water sodium and water and urea is also is cosmetically active substance and it can get reabsorbed in parallel with the sodium so the urea will rise more than the creatinine in case of volume depletion that what we classically called as a prional cause of acute kidney injury whenever we interpret urea and creatinine if the suppose the urea patient's area is 100 and the creatine is 1.1 we can say that because it's very high the urea to create and ratio is high we can say that it's a pre-renal cause and you have to find out the cause for the hypovolemia and hypoperfusions but what we see classical in chronic kidney disease is urea may be around 40 50 60 and the creatine is 33.54 so whenever the urea is higher than the creatinine in the ratio of 40 to 1 you can see that probably it's a pre-renal cause and we have to look for that now we come to the actual global filtration rate we do not measure the actual but we always go for the estimated uh dramaal filtration rate and we go with the help of the serum creatinine with many formulas we take into account the race age gender and weight the national kidney foundation which is the authentic organizations which is having a large volume of experience they have many formulations or these formulas or the calculations for measuring the estimated gfr what we call it egfr but the nkf suggests that ideally one should use 2009 ckd epidemiology creatine equation to estimate egfr now how do we get this we all have smartphones right today i don't think that anybody would practicing without the help of the smartphone all these smartphones the advantage is that we have so many calculators available that one click we can get any type of calendar that we want to use it and it's very very important that next time when you see a created in serum creating levels always always measure the egfr because we have to have the practice of measuring egf for each and every person each and every visit so depending on whether you have got an android or a iphone you can go to the play stores or the i app stores and look for egfr calculators by national kidney foundation this is a very very handy and very useful tool the moment you download it it will come as this is the first page where there is a national kidney foundation egfr and the moment you click it you will get different options you have got four different types of calculators whether it is a secret epi which is suggested by the national candy foundations or mdrd study equations which was a last study which measured the with a particular formula then there is another one is where they use not only the creatine but also another substance called systasine cysteine and what we use routinely in our practice is what is called cockroft cold formula which is as many of our nephrologist friends suggest that it is very good for indian patients and we'll see all these different i tried putting the values of creatinine age and weight with all different formulas and let me tell you the difference would be about 1 to 2 ml per minute right so practically you can use any one of them and use continue the same one and that should be fine so these are the different options available the moment you click on the cockroft goal formula you will get this particular page where you have to mention the serum creating values in the milligram then weight can be pounds or there is a drop down menu and you can get convert into kilograms then 18 years and whether the patient is a male or a female and if you put suppose the values as 1.2 milligram right you can zoom if you want pinch and zoom if you want to see the slide clearly and if the patient's serum creatine is 1.2 patients weight is 70 kg and the age is 66 and his male is a male patient then if you click done then you will get the values of egfr as 60 ml per minute so this is how you get egfr we must start measuring all patients egfr especially the patients whom we are following for a long term like the diabetic patients or chronic kidney disease patients we must have it and we know that we use so many drugs where the dose should be adjusted to the egfr or the creatine clearance and that is why it's very very important to measure irrespective of weather means looking at the patients with kidney injury acute or chronic injury but more so for all patients management and for the correct pharmacological treatment we must measure the egfr the now one point about the new terminologies we no longer use the word acute renal failure we call acute kidney injury and instead of chronic renal failure we use the word chronic kidney disease so next time please avoid the word arf or crf because the failure indicates an irreversibility part which is not the case in most of the cases actually is in acute kidney injury and there are many different subsets and the treatment depends on at what stage we intervene chronic kidney disease also has a treatment in the form of maintenance dialysis as well as transplantation so better avoid term failures and use the term acute kidney injury and chronic kidney disease aki and ckd now how do we grape acute kidney injury there is a beautiful trial called the rifle criteria here the rifle is an acronym for the first letter of each criteria for the kidney injuries r stands for the risk i for the injury f for failure l for loss and e for end-stage kidney disease or n-stage renal disease and there are two criteria for this one is the normal filtration rate criteria and another is the urine output criteria obviously when the patient is seen for the first time intensive care unit we may not have the values of the previous values of the creatinine so the urine criteria becomes very very important if the person's urine output is less than 0.5 ml per kg per hour in the six hours then he is definitely at the risk of developing acute kidney injury so any patient is admitted in the hospital especially in intensive care unit we must form the habit of getting the urine output an hourly measurement and see the first 6 hours how much is the green output if the urine output is less than 0.5 ml per kg per hour in 12 hours he is at the his kidneys are definitely having an injury pattern and these two criteria are more sensitive it may not be specific if the patient has hypotension for a short period also there can be a decrease during output as a part of compensation or to maintain the vital perfusion to the vital organs kidneys may have less urine output but the moment the patient's urine output becomes less than 0.3 ml per kg per hour for more than 24 hours or that what we call is an oliguria definitely the patient has kidney has injured significantly and if you use the gfr criteria if we know the patient's previous serum created in and it has gone up by 1.5 times or if we have the previous patient gfr values and it has decreased by 25 percent it is risk if it is more than twice the serum creatine than the previous values if you have it or gf are reduced by 50 percent patients kidneys are having an injury pattern and if there is creatinine of more than three times the previous value or the absolute value of more than four milligram or the rise in creatinine by more than 0.5 in the 24 hours then definitely the patience has the acute kidney injury or failure and persons having persistent acute renal failure or acute kidney injury for more than four weeks right is a loss and person is having this for more than three months is an aged kidney disease so very very very important that we measure the urine output as well as the creatine have a serial follow-up at least every once in 24 hours and if your slightest doubt about the somebody said that mdrd suggested it depends on what you follow but the national candy foundation suggests the ckd 2009 epi formula but as i said the difference will be of you can put down the values and you can see the differences of hardly one or two milliliters uh gfr if it is 60 it might be 61 or 62 by different formula so practically doesn't make my difference what i would suggest that keep on doing it by one particular formula and go for it and compare the previous readings every visit the another value another is for the ckd for ckd uh we take into account the chromo filtration rate as well as the urine albumin excretion last time we talked about the alvin excretion and we know that the urine albin excretion normally it is less than 30 milligram for 24 hours we call it moderately increase albuminuria if it is between 30 and 300 and it is more than 300 milligram per kilogram of milligram per gram of creatinine in 24 hours we collect severely increased albumeria the normal filtration rate we have already measured by the previous formula if the normal person's gfr is more than 90 it is g1 if it is between 60 and 89 it is g2 g3 is further divided into g3 a g3 b when it is between 45 and 59 uh it is g3 a and g3 b is between 30 and 44. kde igo is using the same formula security api so it's safe yes and g4 is 15 to 29 gfi and g5 is less than 15 g5 with an either the patient is on dialysis or the transplant then definitely the as an established kidney failure now if you add the albumin categories albino categories you can see that the same person who has a gfr in a normal range of more than 90 but if he has a moderately increasing that is between 30 and 30 300 then from green it becomes yellow and if it is more than 300 it becomes orange so the point is the albumin area and gfr if you combine we can have a better severity of the chronic kidney disease this is applied mainly the chronic kidney disease and it's important when we involve the nephrologist if the patient has albumen at any stage it is better that involved nephrology in the treatment of the patient and the patient who has got the albumin excretion of more than 300 at any given time it becomes a rate that means the chances of mortality kidney failure or patients having going into the dialysis or maintenance dialysis or transplant are very very high in all sick patients so very very important that every follow-up in the chronic patients like diabetic or high participation measure egfr and categorize them and we always adjust our dose of medicines according to the egfr serum creatinine and egf are very very important as you can see in this particular beautiful slide then the curve is the this shape is a carbon and if you see in the patient serum creatinine is up to one the gfr remains around 90 or above that is normal but the moment the serum creatine is just double to 2 milligram which for some people might feel that this is not difficult but the egfr comes to almost less than 50 percent of it that is 40 egfr and when the creatine goes from 2 to 3 the egfr has come to 25 that means his grade changes to almost grade 4 and when it is 4 milligram the egfr is less than 20 so never ever guided by only creatinine of course we have to take the other values and measure the egfr but going but only serum created in you might underestimate the degree of kidney failure so i am giving you the example this is a very common scenario that patients having a serum clean of 1.2 milligrams to be taken for surgery or for yes to prescribe certain drugs and you feel so happy that because the never values are key one is normal value of say point eight to one point two or one point three by that particular laboratories then obviously you feel safe or secure but these are the examples given for a male patient with a weight of 55 kg if a patient has a weight of 55 kg and his age is 30 the serum creatinine of persons with age 30 at 55 kg weight in the egfr comes to 70 but the same person if he is 50 years old and the crate is 1.2 his egfr now drops to below 60 57. more than that if the person's age is 70 weight of 55 creatine of 1.2 egfr is 45 grade 3 right and at the age 80 the same serum creatine of 1.2 the egfr is 38 right so never ever be correct by only serum creatinine of course there are many variations as we said the serum creatine might be different in the male and female and persons with the skeletal mass but in general you have to go by the egfr and what is important is the stable egfr in a patients having volume depletions or patients and diuretics on or patients with heart failure all the values may change if you see over a period of few days what is important is what is the stable creatinine values and stable egfr and that is why the cutoff value of egfr for three months persistent three months is very very important we know creatine has few of the drawbacks that it is partly secreted in the proximal tubules and it does depends on the muscle mass so a new parameter or a marker has come that is called systos cysteine c with a value of 0.62 to 1.1 milligram per liter of course this is not available or routinely used and cystasine is also a protein which is secreted by the all nucleated cells in the body it has no effect of the diet or the muscles so that is why theoretically it is definitely a better molecule or a better parameter or marker for the egfr unfortunately that has not turned out to be the case and there are many factors like patients being high bmr or male gender or high lean mass or fat mass definitely the cystacin level has also been higher so practically we do not use the cysteine in a routine practice nephrons do use it when they have to take the critical decisions about whether the patient should be shifted to the dialysis or he should be prepared for the fistula for the maintenance dialysis otherwise not routinely use another very important parameter of calcium phosphorus and parathyroid hormone these are very very important especially in the setting of chronic kidney disease we know the normal serum is anything between nine and 10.5 or to be exact 8.6 to 10.3 when we say serum calcium it measures the total calcium and the ionized calcium portion also so serum concentration of calcium is generally remaining between 8.6 to 10.3 the kinase calcium part is almost about 50 percent of the serum calcium levels the phosphorus is between 2.5 to 4.5 milligram cylinder is slightly on the higher side and the parasite levels are anything between 11 to 51 picogram per milliliters it is better to use the parathyroid hormones for the indications of the bone health for the patient with ckt because that is the first to get affected than the calcium and phosphorus and the calcium and phosphorus levels are maintained till very late time the degree of ionized calcium and is affected because of the alkalosis and the hyperphosphatemia which tend to decrease the ionized calcium and that is why in alkalosis we set it any right because the ions calcium is reduced and persons having hyperparathyroidism or hypoalbanemia ah definitely uh have more ionized calcium what is important is as i said more important thing is the parasite levels rather than this these are may be important when the patient has symptoms or when the patients are dialysis and we have to attend the calcium levels because of the factors right but what is important is parathyroid levels and because it starts rising even when the patient's gfr is just below 60 i mean that is you can say that mild impaired renal function right so even at that level the calcium and phosphorus levels phosphate levels may be normal range but the parathyroid level will start rising and this is very very important because the calcium and phosphate levels may start showing the different values when the egfr is more less than 40 ml per minute we can we do see hypocalcemia as well as hypercalcemia in patients with chronic kidney disease more often hypocalcemia and that is the one which is a stimulus for the parathyroid hormone secretions and the earlier part it is the phosphate when the phosphate start rising that is what increases decreases the ionized calcium one of the stimulus for the parasite hormone so parasite hormone maintains the calcium at the expense of the excretion of the phosphorus as well as also the resumption of the bone so parathyroid hormone maintains the calcium but once the calcium is higher maybe that calcium supplement salt patient is taking adiabatic inadvertently and bone resorption is out of control we might get hypercalcimia when the patient has hypercalcimia and hyperphosphatemia when the product of calcium phosphate is higher than 40 we get the extra skeletal calcifications which can include the calcifications in the blood vessels also and which is important adverse output for the cardiac cardiovascular disease so hypocalcemia hyper calcium both are important and whenever the calcium in phosphates are very high always look for the the product and which means that is the calcification extra calcium sms vitamin dsa is generally not advised in the setting of the kidney diseases but very often we go for the vitamin d assay very importantly remember the values are different whether you use the nanogram per milliliter or nanomole per liter normally most of the laboratories here we see nanogram per milliliter and the values are generally accepted as more than 30 is normal less than 30 but less than more than 20 is continuous insufficient and less than 20 is the deficiency levels when we measure vitamin d some of the laboratories measure the total vitamin d levels while some of the laboratories mentioned vitamin d2 and vitamin d3 it's not important what is important is the total vitamin d levels the total vitamin d level is measured by the metabolites called 25 hydroxy vitamin d or lc diode the calcium levels are measured and that gives the idea of whether the patient has a deficient in vitamin d having a sufficient vitamin d levels or vitamin d in excess we know these days vitamin d is prescribed so much right in any patients with any pains ah we keep prescribing and patients also on their own keep taking vitamin d in higher dose like 50 or 60 000 units and the levels might go beyond 100 or 150 nanogram per liter which is a vitamin d intoxications so it's very important that we measure vitamin d a total vitamin d theoretically the active vitamin d that is called the calcium trial or 125 dihydroxy colical sepheral or biological active form of vitamin d is theoretically the most right indicator of the renal functions but that is not the case the reason is the values of 125 dihydrox vitamin d or what is called calcitriol is very very minuscule compared to the total vitamin d it is almost 1000 for less than the vitamin d so the values may not reflect plus the half life the half life of vitamin d is about two to three weeks as compared to the half life of values of vitamin the activity in d so next time your ass always go for the total vitamin d and do not mention vitamin d2 d3 just write total vitamin d and that should be sufficient uric acid is another important test that uh routinely ask but honestly it's not very very important unless the patient is already having the hyperuricemia or having a gout or uric acid stones that is nephrolithiasis utic acid is the end product of the purine metabolism and many times we find very high or very low uric acid levels as a single reading which doesn't make much sense because we have to see the underlying conditions uric acid may go up if the patient is uh having an acute breakdown of the tissues or hemorrhage or hemolysis or if there is and the patient is receiving the chemotherapy and there is a tumor necrosis or tumor lysis so that's called tumor lysis syndrome so even whenever the patient's uric acid level is very high right and there are none of such factors like the reasons for the uric acid to go up better that we repeat the uric acid levels after a week and even if it is high or more than eight milligram even after a week and there are no reasons for you level to go up then it's better we repeat it after six months if the patient does not have acute cow this is mainly applicable to the hyperuricemia in a patient suspected to be cow if there are no flares you do not require to start a uricosauric drugs if the patient's uric acid is not higher by 8 milligram percentage the uric acid whenever is very high hyperuricemia definitely is related to the metabolic syndrome chronic kidney disease cardiovascular diseases and insulin resistance so definitely it's an important factor but we have to keep in mind that uric acid levels have to interpret along with the patient's profile and it has to be on the higher side many patients are receiving the either the allopyrinol or fabric acid just because one of the values was high which is not correct because the idea of giving urichosteric drugs is to prevent the attack of gout and which doesn't occur just by a single reading of this so it's very very important that we see low uric acid is also sometimes useful and especially when we are looking at the patients with hyponatremia or primary polydipsia or siadh the low uric acid level definitely goes in favor of siads or syndrome of adh yeah uric acid stones we have not been talking about the stones we already talked about the urine analysis and the eric stones last time when we talked about the radiologist of uric acid we i take correctly so important other tests which we do go in setting of acute or chronic kidney diseases are the electrolytes that potassium is very very important and definitely a patients having a hyperkalemia we have got to be very aggressive in the treatment part because this is one electrolyte which can have a negative outcome in a matter of seconds so potassium is something that we have to measure and whenever the position are on the higher side we have what to make sure that the patient is not on drugs like the ac inhibitors or the potassium sparing diuretics so potassium is something that we need to go likewise the nephrologists routinely order venous bicarbonation in the creatine on the higher side the complete blood count is for the anemia because we know that anemia one of the important cause of persistent anemia could be a chronic kidney disease because of the low adipotene release likewise if the patient has suggestion of collagen diseases we may go for the anti nuclear acid a antigen test as well as the ana profile full profile different types of ds dna and all ribonuclear proteins and many other requires or maybe we go for the complement level so all these important tests are required in the setting of patients having collagen diseases and he has the altered renal functions likewise if the patient is acute kidney injury or he is in metabolic acidosis we might go for the rtl blood gas analysis we have already had a full session on the idea blood analysis by other speakers previously so obviously we will not be discussing it then there are few newer markers for acute kidney jury of course they haven't come in the practice and they are more theoretical but just to complete the list of the biomarkers for acute kidney injury one important marker is the urinary neutrophil gelatinous associated lipo kelly or in short called n-gal we know that creatinine is a very late marker and by the time the creatines come to two we know that the egfr has gone to almost 40 as we discussed earlier so that is why we need the markers for acute kidney injury so that we can prevent the further damage to the kidney whenever there is a kidney injury we are worried about not only the pre renal cause for acute injury but many times the persistent prerenal cause can lead to establish acute tubular necrosis and the long term could be failure so that is why we need the markers but unfortunately these markers are still in the experimental stage or available at a very few places uh in even in the western countries the another marker is b type network peptide that we use for the heart failure so in a series of patients who had undergone bypass surgery right they use angle and bnp and found that it's very well correlated to the acute kidney injury more than even the creatinine levels then urinary protein markers biomarkers like kidney injury molecules km1 and interleukin 18 are also used but there is a very useful test which is going to be my last slide and that is called the proximoid stress test this is a very very important test right for knowing whether the patient has acute kidney injury which is likely to be because of the prerenal cause or patient has established acute tubular necrosis so you know freezomite is a diuretic which is a very powerful diuretic which works even in the setting of the significant reduction in the gfr and whenever the patient has only good and acute kidney injury what you need to see is whether it is just pre-renal or there is an element of acutabular necrosis so what we do the moment patient comes with the higher creatine values or oliguria we try to make sure that the patient becomes euvolemic if the patient is clinically dehydrated and hypovolemic and hypotensive we give fluids and make him uvolumi and at that stage if the urine output is not x on expected lines as we discussed in the rifle criteria then we administered one milligram per kilogram of furosemide right if the patient is not the cellular patient is not regularly receiving the prosemite but if the patient is already on frozen mind even if the small dose then it is better we give 1.5 milligram per kilogram of furosemide intravenously bolus those after that we measure the urine out for the next two hours because the effect of frozen mite will be there in two hours and the two hours frozemide response if it is more than 200 ml of urine then we can say that this is a pre-renal cause and the kidneys are very very likely to recover if we continue the conservative treatment but if the patient does not respond to the furosemide bolus dose and the urine occurs is less than 200 ml in two hours that means patient has ongoing renal dysfunction and is these patients may require dialysis so always in acute kidney injury at least before uh or before we think of the dialysis at least give a furosemide stress test and it has been shown to be equivalent or better than the newer markers for the acute kidney injury so always go for the furosemide stress test and mind you we have to use only phrasal mite not the other diuretic which works on the loop of endless that is nice possibility it is only the furosemite which has been tested and found to be that useful so with this i stop here and will take up any questions we have not discussed many because it's already 50 minutes and i'm sure there will be many questions and comments and suggestions i see many learned physicians and critical care specialists i get more comments than the questions from them and this primarily was assassin for the beginners and those who are not used to the details of the egfr and the calcium phosphorus and all so thank you all for listening and being with us for a large number till the end and all questions definitely are welcome yes thank you so much it was so wonderful and meticulous as always uh just stopping the ppt so we want to take the question yeah yes your doctor is giving you a moment to put your questions in the comment box also you could come on stage using the ray's hand feature so i see we have a couple of raise hands uh dr nandani and dr srinivasan i'm accepting your raise hand request uh dr nandani have accepted it if you wish to come on stage and ask your query here you could do so by turning on your audio and video ma'am okay in the meanwhile dr srinivas i have accepted your request as well you will receive a prompt on the screen saying turn on your audio and video and that's how you could uh come on stage to ask the question uh so earlier on we had a comment uh from dr ashok so uh he was asking your opinion on the mat uh dr srinivasan has raised i'll continue the question sir opinion on the matter a for calculating gfr ckd epi would be considering the indian population ckd epi would that be a more accurate method as i said that i put the values in the right all the different equations and the difference was of one milliliter only or maximum two milliliters between ckd mdrd and uh c cg that the cockpit called so practically whatever you use it a person but national kidney foundation definitely go for the ckd but they also add the value of cysteine for that right but the difference is in the equation for a very small part but what we find that if we put into the weight part and the age and the gender probably it is a more reliable right for an individual patient so maybe i would go for the opera of golf or mdrd but people who use security practically the values are difference of hardly one or two millimeters so shouldn't make much difference whatever you are familiar with you can continue using it yes sir so it cannot be a matter of verses both are good options absolutely absolutely absolutely yeah dr srinivasan i had accepted your request accepted your request yes good evening good evening yeah sir uh with the just the urea creatine values uh however it is accurate to differentiate the ckd with architecture injury without any ultrasonographic features no we need obviously we need ultrasonography not only ckd and aki but there can be ak on top of ckd we also need to go for the other parameters what is the calcium phosphate levels and pph levels there is bone mineral disease we have not touched about this inner osteodystrophy what we now call it uh cpd mineral and bone disease mbd nice but that's a separate topic by itself but definitely whenever in doubt you seriously follow the patients hydrate the patients remove the acne cause objective injury and in a couple of cases secretly we say only when there is a persistent egfr right for more than three months and with there is an evidence of damage right so sonography definitely would be required for labeling somebody where we might find either the polycystic kidney disease or chronically contracted [Music] the idea is to say that the urea is something which is reabsorbed right whenever there is a hypo whenever there is a decrease in the gfr acutely like hypovolemic there is a renal perfusion because urea with sodium is also re-absorbed area sodium water is react so while creating a secret at the same rate so creatine will not rise but the urea is high so the urea is high and the creative is not high very high enough we can say there is an element of breathing and try to correct it and see that you would never find a very high area with a low creatine on the conditions the patient is having some issue breakdown and their production is high our patient is on very high protein diet okay thank you i hope that that clears your dog [Music] thank you yeah thank you dr moving on yeah uh yeah yes moving on to the other question there is a question on how can we uh once again how can we diagnose uh syndrome of inappropriate secretion of adhere s-i-a-d-s right say that i did touch about it only when there was mention of the uric acid on the lower side syndrome of a inappropriate adh is whenever the ad secretion is generally related to the osmolality right but if the hospital it is inappropriately high that means whenever the patient has suppose the adhd secreted from the extra pituitary site or because of the cns infections or trauma or commonly it's the paraneoplastic tumor in the form of some bronchogenic malignancy all these factors the adh is very high the anteriority hormone what does it does it increases the it does not allow the urine i mean to pass right so there is a hypovolemia and this is a hyponatremic uh there is a euvalemia with hyponatremia there is a dimensional hyponatremia in that circumstances we have to establish that there is no renal failure there is no thyroid other causes of hyponatremia has to be allowed clinically when the patient is you volume right psn does not have renal failure hypothyroidism kidney failure or liver failure and in that setting if you measure the urinary osmolarity if it is more than expected when the patient has so much of high momentum we expect the urine osmoly to be on the lower side but if it is more than 100 typically more than 300 urinary osmolarity right in that case we can say this is an adh and we give a trial of the drugs which are against adh that is what we use these this is the weapons right or webton is a drug that we use and see and it will have the sid yes so it's not one test that will pick up the sidh we need to rule out the other causes for the hyponatremia right and clinically patient has to be you olamic this and is not dehydrated or patient is not hypervolume in the edema like ccm or cerosis all situations okay so we have a question on why torso might stress test can't be done because torsima is metabolized and it doesn't work in the setting of uh for the test because what we need is that two hour station that is what the studies have proven beyond doubt that it is the prosemite which has there are so many papers about the test the validity of the furosemide uh stress test which is not there for the torso mite so that is what of course people do use diet or there is a car semi in the clinical practice but the literature is for furosemide only understood yes uh so coming to the next question okay so dr himani asks us so uric acid are always on higher side in patients who already are diagnosed with ckd but not on dialysis so can we start them on allopurinol once they go on dialysis yes definitely if there is a patience is not on dialysis you need to because uric acid itself is also a top nephrotoxic substance so we generally they do start the either allocalenol or fabric so state right but the in here the indication is not to reduce the uric acid levels for the ground but it is for the prevent nephrotoxicity of the high leakage levels okay it is being used yes so we have a question so i'm just combining two questions here sir so dr pranji asks uh what test can we recommend normally on an annual basis to check the status of kidneys also uh what about exercise role of exercise in renal health see role of exercise is very important that we the patient has been doing the exercise we have to evaluate because the creatine is going to be on the higher side and the patient muscle mass is more present those who exercise also take more protein so we have to evaluate this created in in listen to that part number one the intake part but the earlier question was what is the test then test is serum creating based on any of the equations that you are comfortable with so you don't need other trees unless the creating is on the egfr is lower creations are or there are reasons to go for urea because every test is expensive blood urea bloody nitrogen has so many other reasons for it to rise or reduce so that creating something which is fairly constant and that is why for renal health it is the serum creatinine that is suggested with egfr of course not only isolated serum creatine yeah and so on an annual basis we can recommend these simple two tests that is created yes and egfr yeah and unless there's any indication or no there's no requirement for all the complicated tests at that moment now only when it is high serum creates eye you have to evaluate for security then you go for the calcium phosphorus parathyroid sonography for anemia and the cause for that cause also we might go for the collagen profile and all yes i understood coming to the next question sir sir fgf23 and clotho factors at the markers though not commercially available are these the earliest ones so these are the earliest ones to rise in ckd and predict cvd outcomes and your thoughts on the same ah that is true but unfortunately as it is not available and the parathyroid hormone is practically doing the same job practically right the fgf 23 as the cloth occlude is a protein which modulates these the changes right so fine but it's not it's still in the experimental stage and not routinely perform fgf3a and paratherma is practically same they do the same functions right they control the ionized calcium but it is the parathyroid hormone which is the most important hormone for minute to main minute variation of ionized calcium right but yes point well taken that they are the other taste in the markers right newer markers yes also a question on any extra precautions to take while recommending rfts or egfr tests to pregnant in patients who are currently pregnant in pregnancy the values have to be interpreted right particularly serum uric acid when you are talking definitely because there is at what gestation of the pregnancy we are going for the test serum create any uric acid levels generally much lower on that side because of the plasma expansion we know that the blood volume is much more the plasma volume is much more in the pregnancy than the normal person's normal woman and especially towards the end of the second trimester right the plasma volume is maximum so that is the time when we expect the creatinine and uric acid to be much lower even in the same person right so it has to be seen with the gestation or we have to equate with the justices yes and when we say that what precautions we take when we go for the renal function test we have to know whether the patient is on diuretic number one whether the patient is well hydrated and not taking extra water right generally tendency that you take a lot of water you don't need to take extra water it's just this normal patient should be a normal diet no high protein diet or low protein diet or not on diuretic or we keep that factor when we and go for the test analysis or interpretations got it noted uh so we have a question from dr narayanan till what level of creatinine ace inhibitors can be given for hypertension in adp autosomal dominant polycystic kidney disease right this these days the creatinine is not very very important as far as the continuation the treatment is concerned as long as the patient is stable hemodynamically stable and if there is no other indication for dialysis then probably you don't have to stop the but what is important is that you measure a creatine level you start the ac inhibitors or arvs and see we expect the rise in the system creating initially about 30 percent right whenever we start ac individuals or arvs but if the creatine is double that is the time you stop right then it's better that the involved nephrologist maybe that is the time that we have to initiate the dialysis and do not be on the ac inhibitors or arvs but otherwise say the value just value is not important the obvious reason is the advantage of containing ac meters in arvs which has the best anti-proteinating drugs the one factor is gfr and another is albino protein urea so protein anti proteinatic effect of the arbs and ace inhibitors is something that is why nowadays the nephrologists continue using these drugs till very late right okay thank you sir uh so dr sunny asks us sir could you please talk about the role of secondary hyperphosphatemia in ckb see secondary hyperphosphatemia is something that not routinely encounter but hyperphosphatemia is something that is going to have the effect on the parathyroid hormones and the calcium as i said if there is hyperphosphatemia and hypercalcemia it's going to produce extra skeletal calcification so that has to be prevented by the use of the phosphate binders or preventing the phos phosphate diets right and the maybe you require dialysis but beyond that i am not sure how far the secondary hyperphosphatemia is to be managed maybe we will involve the nephrologist at that point of time yes um yes i'll come to the next one so we have a question uh at which egfr we should withhold contrast study see at any contrast study is going to aggravate the renal functions abnormally so best thing is to make sure that the generally at the grade 4 and grade 5 you do not know the contrast studies or petrol you have to do it for a specific reasons use a water soluble dyes and use as minimum as possible but you sometimes if suppose the patient requires the angiography for the interventions then what we do we just go for the first dialysis right then do the contrast study and then we may require another dialysis after twenty fourths of auditor so it's not that we cannot do it but we have to weigh the risk versus benefit and most of the patients end up on dialysis if the egfr is very low may be less than 30 but if it is required we do dialysis right improve the gfr and go for it okay is no longer used as a preventive or therapeutic for the patients having a higher creatinine undergoing any of the contrast studies that is now called out of favor okay uh so we still do have a couple of more questions would it be all right yeah sure definitely i'm happy to answer to the best of my ability jesus next one subtle how long can a trial of lasix infusion be can be given in a case of acute or chronic disease before initiating dialysis see plastics or fusamoid is not for as a trial except one single bolas it is no longer used as a trial right that the use of plastics is decided only for to see whether there is a reversibility of the acute kidney injury in the form whether there is an element of regional or established accutabular necrosis that's it otherwise it's not that a particular level of lasiks or you keep on giving it and you look at it that's not the case you give only once as a stress test or it's just one of those tests before right if the patient does not respond if patient does not have more than 200 ml of urine intake when two hours then you don't keep on doing the trials right you treat it that is different if the patient is you olamic you may give the diuretics either the torsometer or freezemite but that is not something that we keep on doing it ultimately we have to call the nephrologist and consider the dialysis even in acute kidney injury we might need few dialysis not that they will be on a chronic dialysis and in ckd i'm sure that it's not something that is decided by the urine output it is decided by the patient's hydration status if the patient is individuals we may need to give it right if the patient is not on removing or we have the hemodialysis then we have the doing it negative right when we do hemodialysis we decide how much volume is to be removed so not that we have to be on diuretics for a long most of the ck patients are not on diuretics whenever is very small those okay so so coming to the next one role of rfts in the diagnosis of renal artery stenosis i don't think that we need to go further in renal functions for the renal artists what we do is the one is the first sonography and if there is a difference in the size of the kidneys or otherwise we go for the renal doctor straight away and nowadays we can also go for the ct abdomen right with the contrast rather than going for the renal functions but there can be differential renal functions and the difference in ranil estimations and the but that is more at the experimental level we have got a simple test of renal doppler right and this it is current so we do not go for the differential renal function test yes uh perhaps prefer imaging techniques for that uh criminal right absolutely yeah so we have a question on urine cretinine please brief about urine threatening test uh says dr rk sony i did not get the questions the urine creatinine is measured as a part of the creatine clearance test right either it is a 24 hours or a spot we can do the spot also it is a spot what we do is we see the urine algae creating ratio right acr right and that is what we go for it right otherwise it is not something that is useful it again it's we have got a better parameter but when we do it the urine creatine is more for the albuminuria part reading of the albumin apart rather than for the creatinine right so we measure the protein amount of protein 24 hours or the spot protein and amount of creatinine at the same time during the creatine and measuring so that is why we mentioned it is so much so of milligram per gram of creatine in 24 hours okay sir there was also a question along these lines what advice could we give the patients on how they could reduce it what what to reduce it high creatinine levels how they can uh bring it through this whole time suggesting that creatinine is not a parameter for you see it if the creatine is high but the patient is stable maybe that is nutrition status is good the creatine is low but a patient is symptomatic would better re-evaluate our dietary treatment so all that we need is avoid very high protein diet right i would be more worried about the protesting levels in a patient with chronic kidney disease right that that is why we avoid high potential containing foods and fruits and vegetables right and that is the stage where we use diuretic right to eliminate the excess potassium or excrete potatoes otherwise creatinine is not something to be worried about as the patient is stable we are not worried about the creativity oh except it is very high more than 10 probably that's why we refer to the nephrologist yeah on this note there was also a question if it's if it's too low as well like is there a cause for concern there serum create indian is very low see serum creatine will be low it could be falsely low if the patient has elderly patients the creatinine might be misguiding right patients with a very low muscle mass it's misguiding but for that the creatinine is otherwise not going to be a very low fossil female patient slightly on the lower side okay i hope that answers your question dr himani so coming to the last one here can esr levels indicate a kidney injury or failure esr alone would not suggest but esr very high sr could be a part of the collagen disease or inflammations anywhere or injury so i do not think esr alone esri for that matter is never an isolated test for any particular diagnostic test but very high esr like say more than 100 you always think of a diseases like the [Music] malignancies or collagen diseases or something like multiple myelomas so maybe that is what is in the back of the mind that the patient is having very high esr i would be looking for this causes of very extremely high esr but by itself it will not give you the diagnosis very low here sometimes we worry about we look for something which is like c cultural anemia so okay very low zero one just going through to see if i have not missed anything so a couple of just one i think i would have missed in between dr nisserk asks when to start nephro save and style cysteine or by uh soda bicarb or erythropoietin at what point to start please ask stuff this is the time when we usually these are the drugs usually started by the nephrologists because they are the ones which we usually give when the patient is in the grade four or five or if the patient is protein urea maybe at the grade three b we start it right but not before that right because very expensive drugs and may not be reached to most of the people but definitely it has a role right in the later part of the chronic kidney disease and somebody is again asked the question about why blood urea increase the blood urea increase because the urea is absorbed passively along with sodium and water whenever there is hypoperfusions right if the patient's volume status is normal it's not going to rise right it will be same as creating in this constant rate but if the patient has a hypovolemia hypotension right then the instinctively the kidneys will proximate wheels will retain more sodium and water and along with that the urea is also one of the molecule which gets reabsorbed so urea rice is just a it's a surrogate marker it's not has no its all purpose there's a surrogate marker the urea is rising then the grain is normal and the patient has oliguria so it's a preview thank you sir so there was a question that i saw just running it by you uh making sure we don't miss it so there was a question in um in the scenario of a critically ill patient is there any difference in preference for the method of calculation of gfr would we have any solid preference for one method see as i said the difference will be of one or two three millimeters by milliliters right but if the decision has to be taken about the dialysis or the transplant and definitely it makes several and then we go by the standard recommendation of that is the national kidney foundation is ckd epi for the equations that is one which is the gold standard right if we have to use one formula it is secretly here okay thank you so lastly at what level of ckd should we register for renal transplantation i think all patients in grade 3 four and five are definitely for the to be registered and they start with the hemodialysis and we have to start counseling even great three b and with a very heavy protein area right at any stage we have to counsel for the dialysis and maybe we prepare for the fistula and all for the grade four and five yes thank you so much so we have comments uh from dr arjun thank you so much sir very valuable lessons very informative session and we all agree with the same thank you sir it's always wonderful thank you all of you thank you for very interactive audience and very good questions sam right if you have any questions you can keep writing and we will try to answer it right later on also surely thank you so much thank you all and good night see you again on another topic yeah definitely thank you thank you and good night

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