welcome to another MedCram lecture we're gonna talk about you nephrotic versus nephritic syndrome now these are both syndrome types that occur in the kidney the question is what's the difference between them and why do they happen in the first place and to understand that we really need to get into the pathophysiology of how these syndromes are different so what we have here is picture of a cross-section of the capillaries in a kidney and what we have here is the endothelium it's the endothelial cell and it completely surrounds the lumen of the vasculature and you notice that there's little slits here that allow things to get through but not the red blood cells typically then this blue line represents the basement membrane which is permeable to a number of things and then finally on the outside is this epithelial cell now the epithelial cell has little foot processes that you see here that look like little triangles around the edge and basically these form a very tight sieve which allows only very small things to get through typically not even proteins are allowed to get through here proteins are too large and these what we call podocytes are helpful for that so if you want to imagine that we've got fluid okay leaving and when that fluid leaves the vasculature lumen and goes through the slits in the endothelium and the basement membrane and comes out even through the podocytes of the epithelial cells in the kidney what we're left with here is basically Bowman's space this is in Bowman's capsule of course and all of this fluid eventually unless it gets reabsorbed it's gonna go down into the toilet okay it flushes down so basically anything that gets outside this area is gonna eventually end up in the urine I think that's a very important thing to remember if you can remember this I'm addict of what a glomerulus looks like you remember that you've got a vasculature that comes in and then leaves and you've got a Bowman's capsule here that picks that up that's what we're looking at here in this picture and that gets picked up goes into the proximal convoluted tubule down the descending loop of Henle up the a sending loop into the distal convoluted tubule and then into the collecting ducts and then out again to the toilet so once again this is a epithelial cell and this is a endothelial cell so what I'd like to do is I'd like to divide this picture if you will into two and on this side we're going to talk about nephrotic syndrome and on this side we'll talk about nephritic syndrome so nephrotic syndrome is fairly straightforward it's a process where for some reason these podocytes which are all connected to the epithelial cell aren't working or they get lost or they recede or they involute something makes them disappear and as a result of that they're not able to keep the protein in and so as a result of that there is loss of protein and it's quite substantial in fact on the order of 3 and 1/2 grams of protein per day can be lost now this tremendous loss of protein has its consequences one of the first symptoms that you'll see is that the urine is very frothy plus frothy urine is caused by protein in the urine now don't get alarmed if your urine is frothy because there's a certain amount of protein that's in there naturally I guess there is some surfactant and the other type of chemicals that will make naturally your urine frothy but if it's especial the frothy think about protein in the urine now as a result of this you're also losing protein so if there's not enough protein in your intravascular space you're not going to be able to keep that fluid in the intravascular space and you're gonna have more leakage of fluid and so this is what we see in patients with loss of protein is they become a de mattes and they'll have edema just about all over their bodies periorbital ewwww even in their legs and sometimes even in their lungs probably the main loss of protein is albumin albumin is the major protein that keeps fluid in the blood vessels now when albumin goes down because of its loss the liver has to compensate and when the liver compensates we get increased lipids in the blood this is another sign of nephrotic syndrome there's also another protein that's lost called anti thrombin 3 now antithrombin 3 is a very important anticoagulant in fact it's the same protein that heparin utilizes to exert its effect so the point is is that if antithrombin 3 is also going down in this situation the patient is going to have a hypercoagulable state and since this protein is lost here in nephrotic syndrome because these Poteau sites are not working very well the renal vein this is the blood going back after it's lost is going to be especially poor in antithrombin 3 and that's where we tend to see thrombosis and if there's a thrombosis in the renal vein this could embolize and you could get blood clots to the lung so you should think of DVT s and pulmonary embolisms or Pease in patients with nephrotic syndrome so to review nephrotic syndrome it's basically a problem with the podocytes or even the basement membrane anything that allows protein to sieve through here causing frothy urine decreased albumin increased lipids both in the serum and also in the urine okay you'll see antithrombin 3 being reduced that leading to a hypercoagulable state typically there's about three and a half grams of protein lost per day now there are diseases that are not of the kidney which can cause nephrotic syndrome these are called secondary causes of nephrotic syndrome and there are diseases which specifically affect the kidney which can cause nephrotic syndrome these are called primary nephrotic diseases we'll talk about those in another lecture now on the nephritic side completely different mechanism of action for causing nephritic syndrome whereas before there was a problem with the loss of podocytes in nephritic syndrome what we have is immune complexes so an antibody meeting up with another antigen and complexing this type of an immune complex will lodge itself in the capillary as seen here and it will elicit an immune response against these capillaries and against these antigens now as a result of this a number of white cells are recruited as drawn here there will be many more white cells as a result of this inflammatory response to these immune cells these areas will become inflamed break down and it will allow red blood cells to pour through these openings not only that but also white blood cells to come through and of course since these openings are big enough for whole cells to get through there's also very easily allowed for protein to come through as well and so very often even though the patient may have nephritic syndrome they may also have what we call nephrotic range protein area so the protein may also be high in nephritic syndrome and leading to all the things that we saw over here in nephrotic syndrome but in addition to that there's something that's very very different remember we said all of this stuff on the outside eventually goes into the urine and so what do you think we would expect to see in the urine in addition to protein isn't just mentioned we would also expect to see blood in the urine sediment in the urine because of this breakdown products and also what we call pyuria or white cells in the urine as well and so as a result of this there are a few symptoms that we see in this nephritic syndrome the first thing we see is hematuria that's blood in the urine the next thing that we'll see is oliguria or low urine output and that's because the glomerulus is being damaged and so it can't filter as much because this immune deposition here is not going to allow the free filtration of filtrate it's going to become inflamed and the glomerulus is going to start to shut down that causes a low GFR the other thing that you'll see is high blood pressure because of that lack of filtration so hypertension the last thing you'll see is granular casts so this is the main difference between nephritic and nephrotic usually there's more inflammation on the nephritic side there's less on the nephrotic side typically if you just see an increase in protein in the urine at very high levels like 3 and 1/2 grams a day and nothing else there's no active sediment as what they would say then think of nephrotic syndrome if on the other hand you see a lot of cells debris sediments and inflammatory cells think of nephritic syndrome now just a nephrotic syndrome where there are primary and secondary diseases which can cause nephrotic syndrome there are also primary and secondary diseases that can cause nephritic syndrome and we'll discuss that in upcoming lectures you