Renal Case: 63-year-old Man with Microscopic Hematuria

00:01 Okay, let's start with a clinical case. We have a 63-year-old gentleman.

00:05 He's noted to have microscopic hematuria and proteinuria on his recent laboratory data.

00:11 He has a history of hepatitis C, genotype 1a, and he's planned by his hepatologist for direct-acting antiviral therapy.

00:21 On physical exam, his blood pressure is elevated to 150/88 mmHg, he has trace, maybe 1+ lower extremity edema, otherwise, his exam his fairly unremarkable.

00:32 On laboratory data, his serum creatinine is slightly elevated at 1.3 mg/dL and his urine analysis is positive for blood on the dipstick.

00:41 When you look at the urine sediment underneath the microscope, it shows dysmorphic red blood cells, so those funny-shaped red blood cells that we were talking about.

00:49 A few red blood cell casts and that spot urinary albumin-to-creatinine ratio is high at 1.2 g, meaning that it estimates about 1.2 g in a 24-hour period of time.

01:02 When the blood studies, the serological studies, show a low complement C3 and C4.

01:09 So, the question is, what is the most likely etiology of this man's renal presentation.

01:14 Let's take a look through our history and our exam, and see if we can come to some clinical clues here.

01:20 So, I think importantly, our gentleman has microscopic hematuria and proteinuria in the setting of hepatitis C.

01:28 That's important because there are only certain diseases that are going to manifest with certain viral infections.

01:34 So, something like hepatitis C-associated MPGN might be coming to mind.

01:40 His exam definitely manifest with some of the features of nephritic syndrome that we talked about.

01:45 He has an elevated blood pressure, he's got some edema, proteinuria, and hematuria.

01:50 His laboratory data is also interesting.

01:53 We see an increase in his creatinine, we also see these dysmorphic red blood cells, and red blood cell cast.

02:00 That's a giveaway that there's something going on.

02:02 This is what we call an active sediment.

02:04 So, this is hematuria of glomerular origin and he also has subnephrotic range proteinuria.

02:11 The clincher in this case is that he has a low C3 and C4, so complement is being activated through that classical pathway of activation.

02:20 Taken together with hepatitis C, this really is membranoproliferative glomerulonephritis in association with hepatitis C.

02:29 We'll go over that so you'll understand that process.