00:01 Let's move on to our next clinical case. 00:03 A 28-year-old man presents to his primary care provider for new onset cola-colored urine. 00:09 In questioning him further, he recalls a terrible sore throat a few weeks ago that resolved with some antibiotics he was given at the urgent care center. 00:19 On physical exam, he's noted to have an elevated blood pressure at 147/90 mmHg which is new for him. 00:25 He was lower-extremity edema and periorbital edema. 00:28 His serum creatinine is high at 1.9 mg/dL and his urine analysis shows numerous red blood cells and he also has white blood cells in there as well. 00:39 Nearly all of those red blood cells, when looking underneath the microscope, showed dysmorphic features and he actually has 2-3 red blood cell cast per high power field. 00:48 On a urinary spot albumin-to-creatinine ratio, it estimates about 2 g per gram of albumin. 00:54 So, estimating about 2 g of protein excretion with a 24-hour period of time. 00:59 He has a low serum complement C3 but he has a normal serum complement C4. 01:05 So, what is the etiology of this patient's renal presentation? Let's see if we can find some clues in our case. 01:13 So, one of the things that is important to note, he has cola-colored urine. 01:17 When people describe tea or cola-colored urine, remember, that really is a symptom or sign of gross hematuria. 01:26 Hematuria or blood cell seen with a naked eye. 01:29 The other thing that's really important is he's describing an infection, an upper respiratory infection, in particular, a sore throat. 01:38 But that happened weeks ago before the onset of the tea-colored urine. 01:42 So, that temporal correlation is important. 01:44 It's not synpharyngitic like it was with our IgA nephropathy. 01:48 He had the sore throat first, treated with antibiotics, and now, he's manifesting with a tea-colored urine. 01:56 That's more indicative of a post-infectious glomerulonephritis. 02:01 The other thing which is important, he's got some signs of nephritic syndrome with his elevated blood pressure. 02:07 Again, those dysmorphic RBCs. He is volume overloaded or hypertensive. 02:13 Again, he's got that periorbital edema. And his laboratory values. 02:19 So, he's got an elevated creatinine, he's got those dysmorphic-looking red blood cells, and I think the clincher here is we have a low C3 complement and a normal C4. 02:30 That is an alert to us telling us that the alternative pathway of complement activation is being turned on and there's only a couple of things that we need to think about with that. 02:38 We're either thinking about complement mediated MPGN or something like infection-associated GN and in fact, that's what this gentleman has, post-infectious or infection-associated GN.
The lecture Renal Case: 28-year-old Man with Cola-colored Urine by Amy Sussman, MD is from the course Nephritic Syndrome.
Which of the following differentiates postinfectious glomerulonephritis from IgA nephropathy?
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