Let's move to another clinical case.
We have a 22-year-old woman who presents to her primary care provider
with new-onset tea-colored urine that developed during an upper respiratory infection.
She has no medical problems and only takes oral contraceptive pills.
Her physical exam is relatively unremarkable and her creatinine is normal at 0.73 mg/dL,
and her urinalysis shows numerous red blood cells,
at least 50% of them on microscopic review have dysmorphic features.
She also has a spot urinary albumin-to-creatinine ratio that estimates about 1.5 g of protein.
She has no serum complement abnormalities so she has a normal C3 and C4 complement in her blood.
She otherwise feels relatively well.
So, what is the most likely etiology of her renal presentation?
Let's go through it and take a look, and see if we can answer that question.
So, some of the important things to really note is that she notes tea-colored urine.
When a patient talks about either tea-colored urine or cola-colored urine,
that's very suggestive of gross hematuria, meaning that you can see blood in urine with a naked eye.
She also mentioned that this occurred during an upper respiratory infection.
That's a term that we call synpharyngitic hematuria
and it's almost pathognomonic for something like IgA nephropathy.
Now, let's look at our labs.
She's got numerous RBCs and 50% of them have dysmorphic features.
Again, along with that proteinuria, that subnephrotic range,
that really makes us think about nephritic syndrome.
So, very suspect for some kind of glomerulonephritis.
Taken together, her most likely etiology is IgA nephropathy.