Acute Kidney Injury

SPEAKER_01 0:11

Hello everyone and welcome to an exciting new episode of Home of Medicine Podcast. My name is Ben Lovell. I'm an acute physician working in London in the UK, and I'm joined by my ever faithful and very intelligent co-host.

SPEAKER_00 0:24

I am sorry, I'm laughing because I've never been described as very intelligent before. Thank you very much, Ben. I'm Dr. Amy Burbridge. I'm an acute physician as well.

SPEAKER_01 0:33

So time for me to present a case to you. Lovely. And of course, once more, we're on the medical take, our favourite place to be. And I would like to present to you a case which has been Clarked and you're going to see on the post-take wardround. This is a 72-year-old male who's been referred from ED with an AKI, acute kidney injury. This is a very simple story. A few days of lethargy, reduced oral intake, and a bit of vomiting, which is unusual for him, culminating in a hospital admission where he's been found to have an AKI. So referred to Medics, please for ongoing management. So far, so easy. Any initial thoughts or what do you think whilst walking to the bed space or what questions do you ask next?

SPEAKER_00 1:18

So 72-year-old gentleman who's AKI. I want to know what the level of AKI is, what is urea creatinine, or what is potassium. I'm thinking lethargy vomiting. I'm thinking, okay, has he had gastroenteritis? Has he vomited? Has he been on some medication? I'm thinking, is this prerenal, renal, or post-renal AKI? Probably the vomiting. It's probably pre-renal. Is he on lots of diuretics that he's still being taken when he's not very well? The lethargy, is that because of the AKI or was that pre-existing lethargy? Um, I want to know what his blood pressure is he hypotensive, what's his urine output? Lots of things going on in my head. But I guess the first question I always ask was AKI. Is it pre-renal, renal, or post-renal?

SPEAKER_01 2:10

Yeah. In in life, in our work, what is it mostly out of those three options? Prerenal. It's always prerenal. It is. No, I agree with you. Um, and if someone says to me, hi, this patient's got a few days of vomiting or diarrhea or decreased oral intake and has now got um an AKI, you think, well, this will be the easiest post take I'll do all day. Fantastic. Off home early for tea. But it's quite straightforward, and you think a bit of fluids, and they'll be right as rave. But you're right. We should always think about the renal and the post-renal causes as well. But this is normally a very, very common scenario we see on the medical take. So let's go and meet our man. He confirms he's been all he's all right usually, but at the last few days, under the weather, a bit of malaise, no diarrhea, because I asked, but he had a little bit of vomiting, not much, but a bit, and he's been off his food, no appetite, couldn't really eat, and a bit of a tummy ache. Um, and that was it. And then he thought he'd come in today to get checked out. He thought he'd be discharged, but they did some bloods here in AE, and they've told him that his kidney test is unusual. And you can see from the clerking his creatinine is 220. No previous creatinine to base, you know, to compare that to. But the assumption is this is an acute kidney injury. Uh and that's his presentation, really. Anything else you'd like to know from uh history presenting complaint that I haven't mentioned?

SPEAKER_00 3:32

Uh any recent viral illness or bacterial illness?

SPEAKER_01 3:36

Well, he's not sure, but he says he hasn't had any dysuria um or urino frequency that would point towards a lower urinary tract infection, no cough or cold or sputin reduction indicating a chest infection, just an upset stomach, a bit of stomach pain, off his food, no appetite, just for a few days, and then he's vomited once or twice.

SPEAKER_00 3:57

Okay. Any uh widespread body aches?

SPEAKER_01 4:01

Uh denies widespread body aches. You mean just a general sort of myalgic?

SPEAKER_00 4:05

Yeah.

SPEAKER_01 4:05

No, no, not myalgic, no.

SPEAKER_00 4:07

Okay, is he jaundice?

SPEAKER_01 4:09

No, not from the bedside, nope.

SPEAKER_00 4:12

Okay. Um, has anybody else been unwell at home?

SPEAKER_01 4:15

Good question. No. Is that is this part of your uh gastroenteritis questions? Yeah, I asked that one as well. Yeah. Because they tend to eat the same food and that the bug tends to go from one person to another. What else do you ask in your gastroenteritis questions out of curiosity?

SPEAKER_00 4:30

Um, so has anybody else been unwell at home? Have you eaten anything differently or drank anything differently? I asked that. Have you been to a restaurant that you don't normally go to? Yeah, I ask that. Um I always ask about any dodgy take or any undercooked chicken.

SPEAKER_01 4:46

Yeah, you need eating any food unusually food recently.

SPEAKER_00 4:50

Yeah, I asked those questions as well. Yeah. Um, any travel as well, I guess. Uh for gastroenteritis. Good point. Um I'm a little lump. What else? Any dizziness? Dizziness. No, no dizziness. Any itchy skin from uremia? Uh that's a bit of a stretch, isn't it? Um I want to know his past medical history, what medication he takes.

SPEAKER_01 5:15

Let's move on. So moving down the history, past medical history is hypertension, for which he takes amylodipine and low sartan. He also um has um some osteoarthritis, some aches and pains, for which he takes intermitted ibuprofen.

SPEAKER_00 5:30

Mm. Okay.

SPEAKER_01 5:32

And that's I've sort of done drug history there as well, really. Amlodopene, low sartan, and PRNN say.

SPEAKER_00 5:38

So I'm thinking with an on steroidal and with a uh low sarcan, I'm thinking, is this going to be uh acute tubular necrosis? Is this going to be renal renal failure, sort of renal kidney injury? Because we know that if you're on a an ACE or an ARP plus brufen, you can get afferent and efferent constriction of the blood phone to the kidneys, which can lead to acute tubular necrosis, which can lead to acute kidney injury.

SPEAKER_01 6:09

Yes, I'm holding vigorously. You're exactly right. So again, the AKI, you screen for nephrotoxics and the drugs, drug history. Um NSAIDs as you mentioned, they they um they change the tone of the afferent arterial so the kidneys, they they can certainly precipitate an AKI, and that's got to go, unfortunately. And low saratam, we can probably hold that whilst he's whilst his kidneys are recovering as well.

SPEAKER_00 6:32

Yeah, I probably wouldn't carry on with the amylodopene because if he's got an acute kidney injury, um, I'd be worried about blood pressure control actually. And I often find that if they're underfilled, if it's prerenal, they're hypotensive. So they may not actually need the blood pressure control because they may be hypotensive. So I'd just be cautious there as well.

SPEAKER_01 6:52

Okay. Should we move on? Yeah, uh social history. Social history. Non-smoker, retired, married, lives with his wife, drinks four pints a night. Ooh, four pints of what? Four pints of lager. Okay.

SPEAKER_00 7:09

Okay, that's quite a lot. So that's 28 pints a week. So that's around that's 50 plus units per week. That's too high.

SPEAKER_01 7:19

Do you counsel on the post-tate award round about quality?

SPEAKER_00 7:23

Absolutely.

SPEAKER_01 7:23

I do. Do you? I think if not every time. I think sometimes it's very minimal in this case of oof, you know, that's a bit too much. You've really got to keep an eye on that. But uh that's the my light touch, but sometimes I will dig into a bit more. How how do you what do you do it? What do you say?

SPEAKER_00 7:40

Uh, I mean, it depends how well the patient is. If the patient was unwell, you know, I'm not gonna start chatting about alcohol. Moribundan, yeah, exactly. But if the patient is is well and able to converse, um, I'd I'd say so that's quite a lot. Do you drink anything else? Is it just lager or do you drink side? Do you drink, do you drink shorts as well? Do you drink in the home? Do you drink out? Is this every week? Yeah. Um, do you drink in the evenings or is it throughout the day? Do you binge drink? And I'd probably go into it a little bit. You know, my wardrounds take two hours per patient. So um, yeah, I would mention that certainly. Um, I tend to do it particularly in the STEC setting, actually. Um, when it's a bit more clinical. Uh, sorry, a bit more like a clinic, and I have a little bit more time sometimes.

SPEAKER_01 8:30

Okay. Uh and that's about it for social history, really. So that's the that's the history in its entirety.

SPEAKER_00 8:37

What was he retired or from?

SPEAKER_01 8:40

Oh gosh, he did something to do with um something in factories to do with like moving part like engineering, but like a hands on thing.

SPEAKER_00 8:48

Sorry, I just not aniline dyes or anything. I'm thinking no. No, okay. I'm just thinking bladder cancer, hydro nephrosis. I'm overthinking. Okay. Okay, so okay. I guess I'm really non-the-wiser. I'm gonna I'm gonna examine him. Okay.

SPEAKER_01 9:06

Um, on examination, he's slim, probably a little bit dry. Um, his uh heart rate is 98 and regular. His BP is 141 over 89. His saturations are 97% on air.

SPEAKER_00 9:21

On air, yeah.

SPEAKER_01 9:22

On air, yeah. He's ephebrile at 36.7.

SPEAKER_00 9:26

Yeah.

SPEAKER_01 9:26

And his respiratory rate is 18. Um, his chest is clear, and his abdomen is soft and not no organomegaly. Um, no peripheral edema, uh, no big DVT that you can see in the legs.

SPEAKER_00 9:43

Do you do one of your famous fluid status assessments?

SPEAKER_01 9:47

What do you mean, famous?

SPEAKER_00 9:48

Well, we've talked about it a few times on the podcast.

SPEAKER_01 9:51

Uh I'm really fascinated by fluid status because I know you are. That we all know the inter um observer variability is but crazy high. Uh, and unless someone is crispy or a bag of fluid, physicians are not great about determining. And that's why you get someone who can't say slightly underfilled, and the next person says uvolemic, and the third person says slightly overfilled. Um, but but of course I do. I'm a physician. Of course I look for look at fluid status. So I always hold my patients' hands, I feel the warmth of their hands and their feet. Um, I feel for pulse volume, I feel for skin turger, I look at their tongue, their mucous membranes, um, a JVP check that's useful for overfilling, i.e., you know it's waggling their ears. But I've got to say, I'm not one for saying, oh, they've got a very sunken JVP in keeping with the low volume state, because I don't think I can make that call. Um, what else? And that's probably what I do for fluid state is some people are very keen on doing lying standing blood pressures, but in my experience, you've got to be really underfilled to develop a positive drop, um, especially in younger patients. I just I think they they auto-regulate too well until they're at the point where they're about to decompensate. So I don't routinely do line standing. And then I look for pitting edema at the sacrum and at the links as well to look for overfilling. Have I missed anything out? Do you do anything differently?

SPEAKER_00 11:15

I mean, you could ultrasound the IVC.

SPEAKER_01 11:19

I thought that wasn't very evidence-based.

SPEAKER_00 11:22

Well, I mean, I don't do it, but I'm just wanted to bring a little bit of poker sin, because you know that's my new favourite skill.

SPEAKER_01 11:28

Because I actually know how to do that, because I can cut.

SPEAKER_00 11:31

You can.

SPEAKER_01 11:32

So I know how to look at the IVC. Um, so two centimetre IV. The IVC be one and two centimetres in diameter. And if it um if it's less than one centimetre or there's a big collapse when they do a sniff in, that could underfill. But I'm certain intensivists have told me very recently it's a load of baloney and doesn't actually correlate with anything because you're not taking into account cardiac status. Of course, absolutely throws everything into a spin. If someone's got a bit of heart failure, you can't measure.

SPEAKER_00 12:00

No, there's too many moving parts, aren't there, to have that? Okay. Uh what am I gonna do?

SPEAKER_01 12:08

Oh, yes, what are you gonna do? Would you like um any more examination findings or would you like the blood results?

SPEAKER_00 12:16

GCS 15?

SPEAKER_01 12:17

Oh, yes.

SPEAKER_00 12:18

Yeah, glucose?

SPEAKER_01 12:20

Glucose was completely normal. I don't know the exact value, but it was normal.

SPEAKER_00 12:23

Lactate.

SPEAKER_01 12:24

Lactate wasn't done as point of routine in this.

SPEAKER_00 12:28

Okay, I was just wondering about um uh gas, because I want to know what his pH is and his base excess and bicarb thinking about the acute kidney injury.

SPEAKER_01 12:35

Oh, I see. Now, sadly lacking. I don't have information uh because he came to ED via um GP who'd done bloods in the community, and that's the bloods we were using this morning. They were same-day bloods, but a point of care DPG wasn't felt to be necessary because he looked well and uh they thought we have information we needed. So I went to potassium. Yes, okay. So potassium is 4.0.

SPEAKER_00 12:59

Okay, so I'm happy with that. Urea and creatinine. You've told me his creatinine was 220. So what was his urea?

SPEAKER_01 13:11

Now, interesting, we don't know because we don't routinely measure urea, in my trust. Um, it's felt to be a non-useful test except in GI Blees, where you can bring up biochemistry and add it on. So I didn't have that, but if you'd like, I shall ring biochemistry and ask him to add on a urea.

SPEAKER_00 13:25

Uh, I mean, have you got his EGFR?

SPEAKER_01 13:28

Uh yes, which is low in the two in the 220s, it was calculated as something like 37.

SPEAKER_00 13:33

Okay, so not too bad.

SPEAKER_01 13:35

Sodium 132.

SPEAKER_00 13:38

So a little bit low. Okay. Uh full blood count?

SPEAKER_01 13:43

Okay, HB 101, MCV 92, white cells 8.8, cells 5.1.

SPEAKER_00 13:53

LFTs?

SPEAKER_01 13:54

LFTs were completely normal.

SPEAKER_00 13:57

Bone profile.

SPEAKER_01 13:58

Uh not done.

SPEAKER_00 14:00

I was just thinking about calcium and phosphate metabolism within the kidneys themselves, but I guess that's something that's more chronic. Um I guess CRP?

SPEAKER_01 14:11

Uh 31.

SPEAKER_00 14:12

Okay. Clotting?

SPEAKER_01 14:16

Normal INR 1.1.

SPEAKER_00 14:21

So we've got uh raised creatinine. CK? Did you do a CK? Not done.

SPEAKER_01 14:26

You can add it on if you'd like.

SPEAKER_00 14:28

Um no. I mean he's a he's anemic, he's got a normacytic anemia. So I'm thinking normacytic anemia, creatinine of 220. Is this an anemia of chronic kidney disease?

SPEAKER_01 14:44

So you're trying to pinpoint is this a man who's got CKD?

SPEAKER_00 14:47

Yes.

SPEAKER_01 14:48

Um, uh, or has this an AKI? Because in the end like creatinin, we have to look for other clues.

SPEAKER_00 14:54

We do.

SPEAKER_01 14:54

Yeah, and one clue you're looking for is the anemia. So some sort of chronic kidney disease, then yes, you do have decreased erythropoetin and you can develop a microcytic, a macrocytic anemic.

SPEAKER_00 15:04

Normacytic, yeah.

SPEAKER_01 15:05

Um yeah, and you mentioned phosphate. So phosphate can creep up a little bit in the plant, which you wouldn't see in an AKI.

SPEAKER_00 15:13

Yeah.

SPEAKER_01 15:14

So I don't know what that is. It takes those two results. Yeah. What would be the cause of the CKD?

SPEAKER_00 15:21

Hypertension.

SPEAKER_01 15:23

I remember when I was um a much uh more junior doctor, I had a consultant who his bug bear was people who would say, past medical history, they've got a diagnosis of CKD. And he'd say, Oh no, they haven't, Sunshine. CKD is a syndrome, it is not a diagnosis. What you mean to tell me is they've got a background of CKD due to X, you haven't completed your statement. That really stuck with me.

SPEAKER_02 15:47

Yeah.

SPEAKER_01 15:48

So it's something I've sort of taken on. So you would say here, CKD likely due to hypertension, because that's the only thing is past natural history. The other big one would be diabetes, wouldn't it?

SPEAKER_00 15:56

Absolutely. Um that's where I am.

SPEAKER_01 16:00

I mean that's where I was.

SPEAKER_00 16:03

I mean, I guess, again, with the newfound famous skills, you can scan for hydronephrosis.

SPEAKER_01 16:09

Okay, so going back to thinking about pre-renal renal uh post-renal. Yeah. So doing a bit of poker looking for hydronephrosis. It'd be unusual as someone who didn't mention also I've had um aneuria, oliguria. Um any other ways you could think of for assessing for post-renal causes at the bedside?

SPEAKER_00 16:31

I could do a bladder scan to identify if there's any urine in his bladder. I could ask examine his prostate to see if he's got prostatomegaly. How do I say is that how you say it? If he's got an enlarged prostate that could be causing um obstruction.

SPEAKER_01 16:47

Um about palpating the bladder.

SPEAKER_00 16:53

Yeah, yeah.

SPEAKER_01 16:54

Do you do that?

SPEAKER_00 16:55

I do, and I and I percuss the bladder. Yeah, and it's often you're like, Oh, you need a weave, and they'll be like, Oh, yes, doctor.

SPEAKER_01 17:03

I do I do that because every now and again you put your hand on, particularly maybe in patients with delirium, yes, delirium, yes, and you go, Blimey, they've got a bladder up to their umbilicus uh yes. Um we can we scan them, please, uh, and catheterizer necessary. And I find that quite useful. Just this morning, when I was putting together this case, I thought, you know what, I'm gonna look up um palpating and percussing for bladder and wonder whether it's a hard sign. I was actually quite surprised. Bladder palpation was found to be a very unreliable sign with a very low sensitivity and specificity in volumes of up to one liter, including 600 to 1 liter, especially people with obesity, with oscites and postpartum women who, of course, still have a slightly um distended uterus, hasn't contracted down yet. Um, and putting the hand on the bladder does not diagnose urine retention. So I thought, I thought maybe you can't rule it in. No, maybe you can't rule it out, but you can still detect it. I thought.

SPEAKER_00 18:02

Yeah.

SPEAKER_01 18:03

I I think you can still put your hand on and feel a great big bladder. But I suppose what I'll take away from that is just because I can't feel it doesn't mean they're not in retention.

SPEAKER_00 18:12

Yes, absolutely. So if you can feel it and it's enlarged up to the umbilicus, yes, they're in retention. But if you can't feel it, it doesn't mean they're not in retention.

SPEAKER_01 18:21

That's my takeaway from it. Yeah, so I'm not gonna stop feeling for bladders. I I I still find that quite useful.

SPEAKER_00 18:28

Okay.

SPEAKER_01 18:29

So what's the plan? Post-the ward run plan.

SPEAKER_00 18:31

My plan. Oh god, my plan. He's well.

SPEAKER_01 18:35

Yep.

SPEAKER_00 18:36

Does he even need to come into hospital? Is the question I would ask myself. His heart rate is a little bit fast, though, at 98. 98, yeah. Um, I mean, he is hypertensive, which again would start me to think: is this hypertension-induced chronic kidney disease? And we definitely don't have any pre-blood's from before.

SPEAKER_01 18:59

No, he's not bothered the doctors before, so he don't have any previous renal function to uh so I guess I can't assume because if I assume that this is pre-renal, then I could miss something.

SPEAKER_00 19:13

And because he's never been to the doctors before, I don't have any previous tests. I need to think about the what investigations I'm going to do to identify if this is prerenal, renal, or post-renal. Now, prerenal renal failure is normally due to medications or dehydration or fluid loss. So we've already sort of looked at those at the moment. Renal failure can be due to um vascular insufficiency. So has he got renal arterenosis? It can be due to infection, not really, neoplasm, not really, trauma. Is it medication? So has he got acute tubular necrosis due to the ibuprofen and the ARB? So I want to dip his urine, I want to look for blood, I want to look for protein, I want to do urine creatinine ratio, and I want to do uh urine albumin levels as well to identify actually what is the kidney excreting, I think that'd be quite helpful. You could go down the route of looking for vasculitides. So is this possible that this gentleman has an underlying vasculitis that affects the kidneys? Is this good pasture syndrome? Is this granulomatosis with polyangitis? Is this Shirk Strauss? Probably lower down. Is this renal amyloid? Is this multiple myeloma? Again, I've got nothing to suggest myeloma because the calcium was normal, the albumin was okay. Is this amyloid? Amyloid's rare. Again, something to think about. Um, would I do an ultrasound looking at the blood flow in the renal arteries? Something to think about. I've often seen that when a patient's presented with cardiac overload or fluid on the lungs as well. So listen to the lungs, do a chest x-ray, make sure there's no fluid on the lungs. Post-renal, look for hydronephrosis, could do an ultrasound KUB, could do a bedside ultrasound. I'd want to repeat his bloods in a week's time to see whether they've got worse or better. Would I give him fluid? I'm not sure, Ben. I need some what what I feel like I've done lots of tests and I need to know a little bit more information before I choose the next step. My job is to make sure he's not acutely unwell. He doesn't need dialysis. So he's not hyperkalemic, he's not acidotic, and he's not overloaded. So at the moment, this man does not need dialysis. Um, and he's not acutely unwell. So I I need some investigation results, please.

SPEAKER_01 22:03

So, I mean, uh you've done a way more thinking than I did at at the time, which was so we've got someone here who's been off his food, not eating, drinking much, vomited for a few days, and now is coming with an AKI. This is the, you know, clearly pre-renal, bit of fluids, um, and repeat unit user needs tomorrow, and let's see where we are. I don't think I have enough evidence. I need to do an oxygen KUB. I don't think I need to do that. Um, I did think about ambulating them or not. I guess I was a bit nervous. I don't know if his baseline creatinine is actually 60, in which case it's quadrant. Yes. And that's stage three AKI, which you know I've been taught was a medical emergency. So I wouldn't ambulate him that way. It could be his baseline creatinine is 180, in which case this is barely even an AKI at all. But in the in those unknowns, I said I'll let's bring him in, give him one liter, maybe one and a half, two liters, and then that's out for tomorrow. Let's see. I'm not a fan, I I've got to be honest, I never do a renal screen on all my AKIs.

SPEAKER_00 22:58

No, nor me.

SPEAKER_01 22:59

If I think they're hypovolemic. I don't scan them. There was a vogue a few years ago, I think a policy saying all AKI 3 must have an ultrasound KUB within 12 hours admission to rule out obstruction.

SPEAKER_00 23:12

That was in the guidelines, though, wasn't it?

SPEAKER_01 23:14

It was, and it's fallen away. Yes. They said if there's suspicion of obstruction. I didn't have a suspicion of obstruction, so so I didn't do that. So and he and he was well. Um, his potassium was fine, so we didn't, you know, does it need uh any RRT whatsoever? So I thought that was pretty straightforward. So my plan was admit fluids, bloods tomorrow, hold nephrotoxic, hold the NSAIDs, hold the Lusartan. He can have his amnodopene because his BP is 141 over 89. Um, and let's see what things are like tomorrow on the ward. And I was quite, I think I spent a total of five minutes on that post-take review, and I was on to the next one, done and dusted.

SPEAKER_00 23:54

Can I, at one point, I need to come and do a ward round with you, Ben?

SPEAKER_01 23:58

I'll get you an honorary observer contract. So you can cut like like we do for our six forms. You can come on, watch me in action. Mistake after mistake after mistake. I say you can bite your bite your tongue and go, oh my words.

SPEAKER_00 24:10

I need to learn from you because I would have probably spent I don't know, 30 minutes. Oh, you're so good.

SPEAKER_01 24:18

Hang on, let's not let's not get speed and you know effectiveness, you know, muddled up. I'm fast, I admit that. Um so that was my plan. Um, yeah, and I I I'd I I would never really think about doing what I would call an aphritic screen. Now, what one thing you might rightly criticize me for is I didn't do a urine dip. Um do you remember the stop AKI? I do. Yeah. Do you remember anything about it?

SPEAKER_00 24:46

Do you know what? I've done very little research, Ben. And I had one paper that I did donkeys years ago when I was an acute trainee with lots of other acute chennies in West Midlands, actually published in Clinical Medicine on this, and I can't remember.

SPEAKER_01 25:04

Oh no.

SPEAKER_00 25:05

Isn't that awful?

SPEAKER_01 25:06

I thought you were gonna say, and that's why I know exactly what it is.

SPEAKER_00 25:09

Oh, and I will just maybe I should just read it now. No, I'm sorry, I can't remember.

SPEAKER_01 25:13

So not worry. It was an acronym, and it was pushed a while ago, sort of nationally, for AKI. Um, and the the the big sort of motto was stop AKI. And S T O P was your acronym, and AKI was AKI. And it's a way of reminding you of the four big potentially um reversible causes of an AKI that present to acute medicine. S stood for sepsis, T stood for toxins, nephrotoxins. O was obstruction, uh, that's your post-renal. And P was a funny one. Do you remember P is uh parenchymal kidney diseases?

SPEAKER_00 25:51

Yeah.

SPEAKER_01 25:52

Kidney, your kidney parenchyma, your your intrinsic renal causes. And it was a way of thinking about the commonest pre-intranal and post-renal causes of AKI. And they said, think stop AKI. S screen for sepsis. T, look at the drug history and stop then for toxins. Oh, consider um catheterization or bladder scanning or an ultrasound KUB. P dip the urine to look for glamorine nephritis. So you're looking for your blood and protein in the urine. I didn't do uh any of that really. No, I did some of that, but I didn't. Yeah. And I I don't. We talk a lot in this podcast about ditch the dip for older people, um, saying it is pretty useless to dip um adults over the age of 65 when you're screening for infection because you have asymptomatic bacteria and we can end up over-treating. But you don't ditch the dip if you're looking for uh intrinsic renal diseases, keep on dipping. So I didn't do that, but I was so satisfied with my post-take diagnosis of uh of prerenal failure, I didn't think I needed to do so. So I admitted him and I saw him the next day on my ward round, and I saw the bloods, and this is bloods after we'd had two litres of fluids. Okay. Uh and the creatinine had gone from 220 to 210. Oh. Oh.

SPEAKER_00 27:09

What do you think of that? Okay. Uh it's not that's not right, is it? What was his urine output like? Had you been measuring that? Had that no. Because sometimes you find when the kidneys have fluids, they suddenly start to kick into action and they have like a polyuria.

SPEAKER_01 27:28

Um, when they have the the eight, when they go into the ATN phase. So if they have a really bad three-week failure and so badly they develop acute tubular necrosis, they then actually start diuresing. Yeah. Um, we weren't measuring it. He didn't seem ill enough to warrant that, to be honest with you.

SPEAKER_00 27:42

Okay, so uh I would have expected it to have got better, quicker, with two litres of fluid in 24 hours, to be honest.

SPEAKER_01 27:52

Me too. I'm glad you said that because normally, even normalized, don't they? Even to give a couple of years.

SPEAKER_00 27:58

Yeah, absolutely. They can go back, but I've maybe not completely normalized, but certainly I've seen them maybe go from 220 to like 120 or something like that.

SPEAKER_01 28:08

And then you send them home and say, keep drinking plenty of fluid.

SPEAKER_00 28:10

So let's check your bloods in a week.

SPEAKER_01 28:12

Yeah, yeah. That stopped me. Yeah, that that didn't that wasn't right. And it made me think, have I made an assumption that it was pre-renal? Yes. So I went to see the patient and I said, Hello, how are you feeling? He says, Oh, please, can you give me my iproprofen bag? I'm struggling. You stopped it yesterday, and I appreciate it's not good for my kidneys, but the pain is so bad without it. I said, What pain? He said, My back pain. I take it from my back pain and I have for so long, and uh and I can't be without it. And that made me think of something.

SPEAKER_00 28:46

That that makes me think of myeloma.

SPEAKER_01 28:50

Yeah, renal failure, anemia, and back pain. Multiply myeloma until proven otherwise. I thought, whoops, have I missed the myeloma? Yeah. And I said, Did we have a calcium on this chap? And they said, No, not yet. I said, Let's stick it on. I thought we had one. Had it. You hallucinated a calcium. I said we didn't do a brome profile, and then you said later on, oh, his calcium's normal. So you did a little like AI hallucination. I didn't. You didn't correct me! No, I didn't. Ben. Sorry. I'm sorry I didn't. Um, but I did notice that that. So now we've got crab, C R A B, calcium high, renal failure, anemia, bone pain. Crab is myeloma.

SPEAKER_00 29:32

It is. Or well, it's myeloma to prove otherwise, isn't it? Or it could be back pain. And you know, that's caused by musculoskeletal problems, um, and that he's got ATN sync to the briefing.

SPEAKER_01 29:49

You're right, it could be several things. Nicer if it's the one thing, though, isn't it? A bit more diagnostically satisfying. But it's enough for us to do a screen. I said, let's get serum electrophoresis, Bent-Jones proteins. Um, and I think keep giving him a bit of fluid. He's not overloaded and he's got a high calcium, and of course, IV hydration is how we treat hypercalcemia. And and of course, we then eventually received the electrophoresis result, which detected power proteins. And he went on to be diagnosed with myeloma. And he had myeloma, which led to osteolytic lesions in his back, leading to back pain. That probably gave him the slight nausea and stomach pain, which we thought maybe was gastroenteritis. Um, and there's there's his uh his renal failure as well. So thinking about this case altogether, I don't want anyone to listen to this podcast and think I must scream for my eloma every time I meet a patient with AKI. I think that would be the wrong takeover message. Um, what I would like to emphasize is that just like CKD, AKI is a syndrome, not a diagnosis. So the full sentence is AKI due to X, right? So we said AKI due to uh hypovolemia fluid losses due to maybe a bit of a viral infection leading to vomiting. Um, maybe I was guilty of a bit of search satisficing, a term I learned pretty recently from our wonderful colleague Pat Cross Carrie, if he wants to go back and listen to that podcast. Told me that word, um, which is when you find something that um satisfies your curiosity, you stop. Maybe I stopped a bit early at the front door, maybe anchored a bit too early. However, I really don't want to be the doctor that does a phonophritic screen and electrophoresis for all my AKIs. So I think a better learning point from this would be we don't need to over-diagnose or overinvestigate, um, and we don't need to reject a diagnosis, we just need to absorb new information to all of our diagnosis when new information comes to light, and we have to be receptive to new information. So I suppose another way of looking at it was at least I didn't say, gosh, the creatine went 220 to 210, give them another three litres and do it tomorrow. We'll get this sorted out. That would be being closed to any new information and having diagnostic closure. So at least I was able to bring on the new information and then evolve my diagnosis a little bit more. Um, I think it's very unlikely and very unusual that acute physicians do clock a new myeloma at the front door on the post-tech ward round. Um, and it does tend to present in in insidious ways and in different ways and different people. But um, I hope that people can know that having an open mind and changing your diagnosis over time is a sign of a reflective clinician. And sometimes the the ultimate diagnosis is not wave a red flag and say, Here I am at the point of presentation. Sometimes you have to do a bit more uh tests, trial a few more interventions, and then reassess until you're able to put your finger on the cause root that records of the problem. That's my self-assessment.

SPEAKER_00 33:04

Wow, what was the calcium?

SPEAKER_01 33:07

2.82. Yeah. So 2.6 is the upper limit.

SPEAKER_00 33:11

Do you know what? I'm really I'm really cross with you, Ben. Because I also did something there in oh, calcium is normal, and you didn't go, no, Amy, the calcium is 2.82. But why did I say the calcium was normal?

SPEAKER_01 33:28

You tell me. I mean, this is about we talk about cognitive biases all the time. What was the little cognitive flip you did?

SPEAKER_00 33:33

Do you know? I think what I was doing is and I even said protein was normal, but you haven't even told me these things.

SPEAKER_01 33:41

Well, I told you LFTs were normal. Normal, you did. Albumin would be included in that. That's true.

SPEAKER_00 33:46

And no, and I think that's quite helpful, isn't it? Protein-albumin ratio with the protein's incredibly high, um, can be in myeloma. Um, I don't know. Maybe I went calcium's normal because myeloma was in my head, and I was like, oh, that's gonna take too much thinking. So I just calcium's normal. I don't know. Isn't that interesting?

SPEAKER_01 34:09

But I think it's interesting because it happens clinically as well.

SPEAKER_00 34:13

Yeah.

SPEAKER_01 34:14

We sort of fill in a few gaps. I filled in a gap and then we rely on our colleagues or our computer systems to say, hang on, stop. That that's not right. Yes, say it. Um, and a lot of the time they do do that, and and we get caught by safety nests, but sometimes not. Sometimes not.

SPEAKER_00 34:33

Yeah. And that's that's um, yeah, it's really interesting actually, because I'd made an assumption there that I'd heard the calcium and I hadn't heard the calcium. I don't know why. Something for me to reflect on, actually, and to think about. Um, because I certainly need to do that. Um, myeloma fascinates me because it presents in such a variety of different ways, doesn't it? And it is like you said, it can be insidious, or it might be their first presentation in an AKI like this gentleman. Sometimes the cow seems normal. It really is a master of disguise, isn't it?

SPEAKER_01 35:09

So um did you enjoy that case?

SPEAKER_00 35:13

I really enjoyed it. Really enjoyed it. I I think these cases are this is what we do in medicine, isn't it? We think, however, I'm just gonna say hickam's dictum. Patients can have as many diseases as they damn well please. So, how do we know he didn't have ATN secondary to brufen and low sartan usage?

SPEAKER_01 35:35

How do we know? Okay, so ATN, you would usually see the polyuric phase after you've lost a whole bunch of. Which we didn't, yeah. ATN and you start diuresing to the high heavens. Yeah. Also, something changes on your urinary sodium. And I don't remember what changes, I would look it up. I remember memorizing this for MRCP memory. Doesn't it go really high? Yeah, I couldn't tell you with any confidence. But uh urinary sodium, you would see some change and urinary uh um and ACR maybe would change as well.

SPEAKER_00 36:12

And you'd have um blood in your dipstick as well, wouldn't you?

SPEAKER_01 36:15

I don't know if you'd have blood in your dipstick. You wouldn't you had glamour nephritis if you had inflamed nephrons.

SPEAKER_00 36:21

Okay.

SPEAKER_01 36:21

Um, but I don't know if you would get a true nephritic picture with ATM.

SPEAKER_00 36:26

Okay. Brilliant.

SPEAKER_01 36:28

Sorry, that's not very educational, nugget, is it? No, I was just thinking that.

SPEAKER_00 36:31

We know I was thinking, what do we need to do now?

SPEAKER_01 36:33

I was thinking that's but you know, I can't be honest when I don't know something. I'm very honest and say, you know, I need to go and look that up.

SPEAKER_00 36:38

Yeah, and actually, I think that yeah, the thought process is there and we're thinking about it, but also I guess we've shown our listeners that we don't know everything.

SPEAKER_01 36:47

And that actually I've just looked it up, urine sodium in ATN is very high. Yes, sorry. Come on, let's all memorize it together, me you and the listeners. ATN high urinary sodium.

SPEAKER_00 36:59

ATN, the N at the end of the ATN can be sodium because it's NA.

SPEAKER_01 37:04

Okay, so let's think of it as ATNA. Acute tubular sodium sodium elevation. That will that will stay in my mind, actually.

unknown 37:14

Yeah.

SPEAKER_01 37:14

N and the ATN stands for sodium because there goes that. Brilliant, we got it. We'll never forget that now.

SPEAKER_00 37:19

Amazing. That can be in our one of our books that we write one day, maybe.

SPEAKER_01 37:24

That's on the long list of things to do, but sure. Great. Amy, thank you so much for playing along with me today.

SPEAKER_00 37:29

Um that was a really good case, thank you.

SPEAKER_01 37:31

Enjoyed that case as well. I quite like these mystery cases where you as you go through. So please um do keep listening to Home of Medicine Podcast out there. We hope it gives you something that you enjoy. Please continue to rate us on whatever app you're listening to us on so we can find new people and tell your friends about us. And I can't wait to uh have you all join us again for our next episode, Home of Medicine Podcast. Thank you so much, and see you later.

SPEAKER_00 37:55

Thanks. Bye.