Acute Kidney Injury
Summary
This on-demand teaching session will cover acute kidney injury (AKI), one of the most common presentations seen in acute medical wards. Led by Dr. Jagdish Genius, a ST1 in medicine, participants will explore the causes of AKI, such as GI losses, systemic illness, outflow obstruction, malignancy, and medications, and learn how to assess the hydration status, including BP, pulse, capillary refill time, skin turgor, and JVP, among others. Additionally, Dr. Genius will provide an interactive discussion about a case presentation to help participants understand how to interpret blood tests and diagnose AKI.
Learning objectives
Learning Objectives:
- Recognize and define the symptoms of acute kidney injury (AKI).
- Explain the importance of evaluating patient history, clinical presentation, and laboratory values in the diagnosis of AKI.
- List the potential causes of AKI.
- Demonstrate an understanding of how to effectively manage an AKI patient on the wards.
- Utilize a range of assessments to determine a patient’s hydration status.
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Computer generated transcript
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The following transcript was generated automatically from the content and has not been checked or corrected manually.
um, doctor Jag undies. Can you try and just say a few words just so that we can hear you, please? Hello? Hi. Can you hear me? Hello? Hello? Hi. Lydia, can you hear me? Yes. You can hear you. Thank you. Yeah, OK, just share your slides, and then we'll just waiting for a few more. Uh, yeah. Can you see my slides now? Yeah, we can see. Thank you. All right. Okay. Thank you. Uh huh. Yeah. Um hi. Everyone will start in about two minutes, if that's OK. Thank you. Yeah. Yes. Yeah. Um, Dr Jack, please, can you see the chat box as well? I can't either. Chen Hong? Yes. Um, can you just send in a message just to see, make sure that we're on the same page and no, it's fine, I think. Okay. Uh, okay. I think we're gonna start now, So Good evening, everyone. My name's Debbie. Um, one of the teaching fellows at Wigan. Um, today we have Doctor Jagdish genius in one of the ST ones in medicine. Um, we'll be talking us to acute kidney injury, some of the causes of acute kidney injury and how we usually manage it as a junior doctor on the wards. Um, in my experience, this is one of the most common presentation that we get being referred from emergency medicine to acute medicine. You know, when we get our patient's who have really poor kidney functions or just some AKI. So I think, um, I'll not speak much. And, uh, Doctor, check this. You can take the stage, please. Thank you. Thank you. Thank you for the interruption. Um, good evening, everyone. Hope everyone is. Well, um, so I'm just gonna talk about acute kidney injury. Um, so when when we see acute kidney injury, that's probably one of the most commonest condition being referred as an F one or an F two or an s U one. As a junior doctor, you'll come across a lot of acute kidney injury, so it's quite a big topic. I've tried to summarize it so that, um, can fit in within an hour. And just to summarize and make it easy today, um, so we'll start off with the introduction. So acute kidney injury. As we all know, it's a rapid and, uh, reversible decline in renal function. Uh, so that's probably an important key word when you compared to a chronic, it's reversible and evident by a rapid decline in G f R over a period of hours, two days. So anyone when you work in the hospital, usually you have if you have a computer system, uh, when you order for an renal function, there will be a G f r uh, alongside with the U. N s. So this is usually you get an E g f r like an estimated glomerular filtration rate. But sometimes this can be might not be correct as well, because this is an estimated reading. So usually, for example, if the, uh, they will do an estimation reading for a patient, uh, for example, 80 kg, Uh, but the patient might be not be 80 kg at all so that there might be some discrepancy in value. So sometimes it's good to use a creatinine clearance as well. Uh, if you go into like creatinine clearance calculator, then you'll get a proper reading. And so it can occur with a patient with usually, uh, with a normal renal function or any patient with chronic kidney disease so they can have acute on chronic kidney disease. or they can have purely acute kidney injury. And, uh, it's one of a significant problems in the acute medical on a daily basis. So, uh, this is this statistic. I got it from my trust. So at least 30% of an acute medical patient admitted to medical assessment unit Uh, they have an evidence of AKI to varying degrees of severity. And in a reason audit, which was done last year, it shows a mortality rate of 50%. Uh, so any patient who comes in with a K, I have to be very careful about it and managed it accordingly. So I'll start off my presentation with a case presentation. Uh, so if anyone, I'll just go through like a discussion so you can just use the chat box in between, Uh, so that can be like an interactive session. So we got a 36 years old, fit and healthy. Gentleman, let's say you see this patient in a any who came with who comes with a five days history of diarrhea and warm eating, and, uh, we generalized pathology and abdominal crime. He has a history of travelling one week ago, and, uh, what would be your further history. Like what? Do you want to ask this patient? If someone could just post in the comment box and and we can just go through it. So 36 years old, Quite quite a young gentleman. Uh, probably There's no past medical history. Just came in at a short history of diarrhea and warm eating. Um, as a history of travelling one week ago. Anything else you guys want to ask him? Fever. Stool content? Yeah. Uh, yeah. So you probably want to ask more history on the diarrhea and warm eating. You know that it started five days ago. So you want to know, uh, what is the consistency? Is there any blood in the diarrhea? And, uh, is it getting better over the five days? Because, you know, that's been going on for five days, and then obviously you come to warm eating. How? I mean, how many episodes are they and any is it Only food particles any blood contain. And, uh, fever is very important. And also, you want to probe a bit more on the abdominal crime. How bad is how severe is? It will probably use your sockets. Um, for to explain further on the history taking and, uh, fever is obviously very important. Uh, just to see if there is any ongoing infection. Uh, you probably want to ask a bit more on the travel history as well. Where the patient when? Uh, because likely might be having some Castro and society. So with that travel history, you will probably, um, narrow down your history to what likely the infection to be. And, uh, has he warm? It'd urine output. Yes. So any patient who comes in with, uh, GI losses like diarrhea, warm eating, it's in your history taking. It's good to include some questions so that you know what houses hydration status like, um, so how much of fluids is he drinking? How much of you? How good is urine output? Um, and, uh, whether there is any signs of symptoms of dehydration. So all this it's important to be included in the history. So So that's probably the vague history for anyone who comes to diarrhea and warm eating. But let's say if you're suspecting that this patient is a kidney injury, uh, there's some other histories that you want to ask is, um obviously alongside with the systemic illness like any other systemic illness. And, uh, any symptoms of outlaw outflow obstruction? Because later on, we'll be looking at the causes of the acute kidney injury. Then you know that these symptoms of outflow obstruction is important to rule out the post renal acute kidney injury History of malignancy. Probably not so important in this case, uh, because of the young age and, uh, very short history. But it's good to have it in mind that if anyone with an elderly age group with prolonged symptoms and obviously you want to ask history of malignancy um, medication. This is important as well, because there's a lot of medications out there over the counter. Medication can affect your renal function. So always remember to ask the patient if they have been recently started on a new medication or as they've been taking any over the counter medication history or family history of renal disease. Obviously, this is very important as well, and, uh, past medical history. But in this patient is negative. So clinically, this patient seems to be dehydrated, with coated tongue and lips. Uh, blood pressure's fine, slightly tachycardic at 96 f febrile saturations are normal. Um, examinations. Pretty normal. So So, like, uh, I mean, like I explained earlier, Like, um, any patient who comes to diarrhea and more meeting it's always important to assess the hydration status. And, uh, do you guys anyone wants to just utilize the comment box just to say, uh, what are the symptoms and signs you see in, um, how do you assess fluid status in a patient? Nice. Auscult it by vessel Crabs pitting edema. BP Pulse. Yes. So anyone who comes, uh, with an acute kidney injury, or generally, when you want to assess the fluid status, it's good to establish whether the patient is hypoallergenic or you're anemic or hyperkalemic or fluid overload. Because this is very important in terms of your management. Um, whether this you you you want to give more fluids for this patient or you think that this patient is you. Olymic doesn't need any fluids. Or you feel that this patient is overloaded and you want to give some diuretics. So to assess the fluid status, obviously you start from your regular BP pulse. Um, the rate the character capillary refill time. Usually it's less than two second If you dehydrated, probably maybe prolonged uh, simple mucus membrane examination. And, uh, just to see if your tongues are quoted and, uh, you can check for the skin turgor as well JVP and then JVP maybe raised in a case of, like, fluid overload. So that's one of the signs that you know that this patient is overloaded heart sound in terms of If you're suspecting a heart failure, then, um, you can listen to some gallop rhythm or some other murmurs bread sound just to see if, um, there is any fluids in the lung, so you might get some crackers and pitting edema. Also, to suggest that the patient is overloaded, Uh, do check at the sacral and peripheral. Um, G C s sometimes, um even when the patient's are dehydrated, they can They can be confused, especially in the elderly age group. So it's good to assess the G. C. S and, uh, obviously the urine output. So back to our patient, uh, he had the routine blood tests. Um, so anyone just want to interpret the blood test for me today? So hemoglobin is 134. White cell is 7.2 platelet is 288. Urea is 19.6. Creatinine is 380. Potassium, 4.9 sodium. 131 CRP of 2. 70. Yes, normal. Fbc. I agree with that. Normal fbc Um, so you can see the blood gas has been given as well. The pH is 7.29 and bicarbonate is 15.8. Uh, any comment about the renal function? Hi, Curtin in, um, reduce renal function. Renal function quite bad. We need to compare Based. Um, yes. Okay. So you can see I mean, some quite obviously know that the renal function is not normal. Um, ideally, in a in a usual situation, you have to compare with the patient's baseline, but given that we don't have the history of, I mean the baseline of this patient, But bear in mind that, um, this patient is quite young without any past medical history generally fit and healthy. So you assume that this patient might have a normal baseline and, um, came up with a deranged kidney function. So you're suspecting that might be an A k I, uh, crp of 2. 70. obviously, that's not normal. So that's ongoing infection pH of 7.29 bicarbonate of 15.8. So that's a bit of S E doses there as well. So what's the differential with this patient? And how would you manage anyone? Just a wild guess. What do you think going on with this patient? Yeah. Previously K I do to gastroenteritis. Yeah, that's right. So, possibly, like this patient, um, came into the five days history of diarrhea and warm eating. So you might be having some gastroenteritis. Had a history of food intake. Five days. I mean, one week ago, when he was traveling, so he might be prerenal AKI due to the gastroenteritis. Um, so yeah, that's good. So how would you manage this patient? So whenever you see this patient a any, um, alongside with the clinical history and examination. Uh, a two e approach is obviously very essential, because with a two e, obviously you can rule out the cause of the AKI and logistics. Be careful when you prescribe the energetics because this patient having an 80 I so make sure you check with your trust guideline or the pharmacies just to make sure that your your energetic doesn't interfere with the renal function IV fluids. So that's that's why it's important to do a fluid status assessment. So, um, you know that this patient is dehydrated. His technique Ardeche. He has a coated tongue, dry skin. Um, so you know that he will need a lot of fluids. So catheterized because you want to monitor the urine output a streak input output charting is important. Husband all nephrotoxic six. So any patient's with an A. K. I, uh, you will need to do what we call us. Medication review, review all the medication, um, to see that if this medication needs to be suspended or needs any dose adjustment if you're not too sure, you can always check with the pharmacies. Antibiotics were indicated, so make sure when you're prescribing antibiotics. I would say that most of the antibiotics, um, has his own renal adjusted dose. So do check with the B N f or with the pharmacies. If you want, you're in deep and analysis. Um, usually any case of AKI, especially AKI. Stage three will come back to it later on. Uh, you would need to do a urine dip and analysis ultrasound, K U B mostly for the post renal AKI. Uh, if the patient is not responding for the treatment. So that's the first scenario, like patient with a pre renal AKI. So come to our definition now. So when you say AKI, um, it's generally arised in a serum creatinine of 26 micromole per liter or greater within this, uh, 48 hours. So I got this definition from the K legal guideline, uh, so it's either it's either end or or so it doesn't matter if it has only to fulfill one criteria to say that this patient is a K, or 50% or greater rise in serum creatinine known or presumed to have occurred within the past seven days, and a fall in urine output to less than 0.5 ml per kilogram per hour for more than six hours. A staging of AKI has been divided to three stages, Um, depending on the serum creatinine and the urine output. So stage 12 and three, stage one when your serum creatinine is more than 26 small per liter in 48 hours, or 1.5 to 1.9 times the baseline, so It's good that you have the baseline to know that if this patient is in AKI or not, or urine output of less than 0.5 ml per kg power for six hours consecutively. So that's the reason when any patient been admitted with a K I, uh, you would need to insert the catheter so that you can monitor the urine output Stage two when the serum creatinine is, uh, increased by 2 to 2.9 times the baseline or the urine output is less than 0.5 ml per kg power for more than 12 hours. Stage three when you're credited level is, uh, more than three times of your baseline or an increase in serum creatinine to more than 354 or your urine output is less than 0.3 per ml per kg for more than 24 hours, or an area for 12 hours more than 12 hours. So back to our patient now. So let's assume that his bloods five days ago, the urea was five, creating in his 75 I mean and today the urea is 19.6, creating in his 3 80 How would you classify this? His AKI. Which stage do you think he's in now? Some hospital lab results have been made easy to interpret. The AKI grade is generated. Um, yeah, that's right. So depending on the hospital you work in, but usually, um, when you request for a new any, so the egfr will be calculated and generated on the system, so you don't need to do your calculation yourself. But like I said, the EGFR is an estimated global role, a filtration rate. So sometimes it can be over, or an underestimation for someone with a a bigger or a very small size. So in that case, you might need to do a creatinine clearance using the calculator, and you can get a accurate loser. Okay, so anyone which stage of AKI do you think he is in? So let's, um let's assume that his credit. He was 75 5 days ago, and now it's 380. So we'll go back to the our staging. So 75 3 80. That's more than three times, isn't it? So we assume that the 75 was his baseline, and, uh so it's more than three times increase. So is obviously in a stage three a k I. So when we talk about acute kidney injury, uh, this is a very important point. Like you need to know the cause has been divided into three either prerenal. Uh, renal post renal like intrinsic is known as the renal cost. So majority of the patient comes in with an a k i r. Due to prerenal cost. And, uh, about 40% is intrinsic and 5% is post renal to prerenal course. Um usually anything that impair the perfusion of the kidney like dehydration, Subsys, heart failure, blood loss, vascular occlusion. So any causes that's causing some impaired perfusion to the kidney will lead to a prenatal cause. Renal cause, um usually when there is a damage to the kidney itself, damage to the nephron damage to the tubules damage to the glomerular. So this will cost the renal cost like glomerulonephritis vasculitis, acute tubular necrosis do two drugs toxins, interstitial nephritis, and, uh, for post renal. Due to the obstruction like can be due to a benign prosthetic hyperplasia or due to prostate cancer, it's causing outflow obstruction, so that usually causes the post renal AKI can be due to ureteral stricture as well. Nettle stenosis or calculi assess risk factors for AKI. So it's not Definitely this group of patient will get AKI, but, uh, they are usually at a higher risk. So if you encounter any, any patient, more than 65 or a background of diabetes, hypertension reason surgery, uh, drug history nephrotoxic drugs if the patient's are nephrotoxic drugs, sepsis, dehydrated illness, pre existing renal disease. So these are the group of patient's who are highly predisposed to get an A k I. It's always bein mind mint in your history and examination, uh, make sure rule out the causes of the AKI. So when when you encounter a patient in a any like, um so you know that you need to have a baseline in order to know that if this patient is having an a k i or a C K D. But sometimes you do get patient's who's never been to your hospital. Probably. That's the first visit, and you might be having a bit of confusion whether this patient is having an a k i C k D. Uh so there are some other factors that you can look into to know that if this patient is having an a k i c k d like the, uh, an email usually in a CKD patient, they have usually comes with anemia as well, due to the insufficient edit tro pointing, uh, production. So but this is not there in AKI bone disease. Uh, you know that CKD patient usually comes with hypocalcemia with hyper hyper phospho Tamia and, uh, now a few other blood tests that you look at can look into to know that if this patient is an A k I C k D, um, kidney size and neuropathy. I think this is like later stages because CKD due to the chronicity when you do and scan, you can see that it's, uh if there is a the kidney size usually is way smaller than the, um, normal size. So that then you know that this patient might be having something chronic rather than acute. So we go on to the second case today. Um, so 70 years old gentleman came in with two days history of confusion, fever reduce oral intake, uh, past medical history of BPH on long term catheter hypertension. So let's say you see this patient in A and E. And, uh, you saw the blood test done today. If hemoglobin was 120 White cell is 20. Sodium is 148. Potassium is 4.9 urea 60 Creatinine is 200 CRP is 99. And, uh, you're lucky enough to know that this patient actually came into a and E two months ago. So you know that at that time two months ago, his creatinine was 95 his urea is 4.9. Um, so you know that obviously it's in the AKI. So which stages of AKI and what do you think the possible causes are? Anyone Do you want just comment in the chat box? Stage two? Yeah, that's right. Stage two. Yeah, correct. So, first of all, I think, um, when we look back at the definition, I think stage two is about two times 222.9 times the baseline. So we assume that the baseline is 95. So he came into the creatinine of 200. That's probably around stage two of an achy I, uh but be careful when you when you use any mean? Be careful when you get the baseline of the patient. Because so these bloods were done two months ago. And, uh, you need to track back What was the reason for admission two months ago? Because this patient might came in with some infection two months ago and might be having a k I. And when he was discharged, that's probably not his baseline. So just make sure before you establish a baseline, have a look at what's the reason of admission previously? So that, um, you don't underestimate the renal function. So Stage two, a k I. That's right, creatinine increase more than two times the 2 to 2.9 times to reference value. Uh, so the causes. So there can be a lot of, uh, reason here. Um, you know that it's a 70 years old, came in with fever, reduce oral intake. So there's some infection going on, uh, which obviously can affect your kidney. Reduce oral intake, probably hypovolemia, which also can affect your kidneys. It's on a long term care data, so you'll probably need to monitor the urine output as well. You're not too sure if that's been blocked and causing some post renal. So I would say this is a mixture of a prerenal and a post renal AKI. So management, of course, Uh, like we discussed earlier, uh, full history and examination, including a two e assessment fluid status. Um, like we said, just go through the fluid status assessment so that we know this patient is, um, dehydrated or you Olympic or hypokalemic. And the moment if you feel that this patient is hypoallergenic, then you can start giving some fluids. It says risk factors for AKI Think this patient probably has a lot of risk factors for AKI uh, strict input output chart. Optimize the hydration status IV fluids and stop nephrotoxin. I think this sets of management usually is the same for every patient who comes in at AKI and blow it when you monitor the blitz for an A. K. I make sure include your blood gas as well, because they can have some metabolic acidosis due to the kidney injury and, uh, renal amazing. Usually if there is no improvement with the initial management. Uh, you will do a renal imaging like ultrasound kidneys just to see if you're missing out any obstruction. Uh, that could be one of the cause of an achy I send specialized blood tests. So when when you do your history and examination, uh, I mean, obviously, you need to establish the cause of the AKI. And if you're suspecting that, it could be due to due to the intrinsic factor Um, like glomerulonephritis n T g B m disease or acute interstitial nephritis. Then you have to consider sending the specialized blood test or the renal panel, uh, like the complement C three c for a anca, N T, g, B, M and myeloma. But I think this is, uh, not in all cases. You don't usually routinely send these bloods only if it's clinically relevant and any patient with an AK Stage two and above uh, consider advice from a kindness or referral to Reno. I think this depends on the trust. So the trust where I work we don't have a renal specialty there. But we do have a AKI nurse, so we, uh, visualize with AKI nurse or, if needed, we usually discuss with self Arenal team, Why are the renal patient pass? So any patient with an AK stage two, we usually get some input from the renal team in Salford. So if you're if you the trust you work in, if they have a renal department, then obviously you can get an input from the renal team. So for AKI, Stage three, Um, just remember that the management is same as stage one and two, but any patient who comes unit AKI three within 24 hours of AKI. Uh, make sure to send the urine dip. Stop the ace and ARB s, I would say Stop the nephrotoxic drugs. If you're not too sure, just go through the medication review with your consultant of pharmacies. I repeat creatinine within 24 hours and ultrasound kidney arenal track. So these sets of investigation and assessment need to be done within 24 hours of an AKI alert. And, uh, take a three. Obviously, you need to discuss with the A k i N s and the renal department, and you would need what we call us the Pharmacies Medication Review within 24 hours of the AKI a lip. This is just to, uh and or reduce the dose of, um, any medication that could alter with the renal function. So review medication so a lot of medication out there, uh, affects the kidney function And, uh, for example, like those nephro toxins like NSAID Ace inhibitor ARB s contrast, amphotericin B or any sort of antifungal. Uh, this group of medics, there's many more out there, but this is a few that have listed these medications we call as nephrotoxin so it can affect your kidney function. Uh, it's good to stop and suspend this medication when the patient is having an AKI and put a note to review again once the patient is out of AKI to see if I need to be restarted. Risk of reduced renal profusion like some anti hypertensive diuretics. Antianginal. So this medication you might need to sort sort of reduce the dose because it might reduce the renal profusion further and, uh, worsens the AK so need to review again risk of urinary retention in anticholinergics. So that could worsen the AKI. And some medication would need adjustment because an exclusion might be affected by renal impairment. So, like for example, metformin, you probably need to reduce the dose depending on the severity of the achy. I, uh, because of the risk of lactic acidosis uh, Digoxin, lithium and opioids. This group of drugs, that dose has to be adjusted as well. Uh, because it's usually excreted through renal. So any patient with a K I the medication can accumulate and cause toxicity, so you need to review the dose again. Another question is when to dialyze a patient with a K I, um So just remember that usually a patient with a K I who comes with uremia like your emmick symptoms confusion your emmick pericarditis, your emmick flab and careful opathy, uh, with severe acidosis, fluid overload, refractory hypochelemia like failure to respond to the medical treatment. And yet, anyway, so this is the five important group of patient's that would probably benefit from dialysis. But obviously, you need to discuss with the renal team as well about this, um, renal referral. Like I said, um, any patient with stage four or five CKD if you if you're not all you encounter CKD patient. Obviously, stage four and five will need a renal referral because, um, they probably just to prep them for the dialysis and all intrinsic cause of a K, like we discussed earlier global rule on arthritis interstitial nephritis. So this group of patient would need a renal referral because, um, the management may vary. They might They might be started on steroids or any other medication. Uh, with an advice from a nephrologist. Inadequate response to treatment. Um, and also, any renal transplant patient comes in with an A k I, uh, or a CKD per se will need a renal referral. And like we saw earlier, like any stage two or three of a K, I will need a renal referral as well, depending on your trust guideline. And that's my references. Thank you so much. Any questions? Yeah. If there is no questions, then I will see you guys in the next session. So do you remember, too? Log in every Wednesday at 6:30 p.m. We do teaching every Wednesday. So I think our next teaching is on pediatric respiratory condition. Next Wednesday at 6:30 p.m. Um, thank you so much, guys. And, uh, please kindly fill up the feedback form. Anything else? Did you Okay, Thank you. Everyone, have a good good evening. Take care. Bye.