In this lecture, we’re going to review hematuria and also glomerulonephritis.
So let’s start with hematuria.
Hematuria can be either gross or microscopic.
Gross means you can simply see the blood
and microscopic hematuria is when we see it under the microscope.
Generally, more than 5 cells per high-powered filed tells you that there is hematuria.
About 0.5-2% of school age children will, at one point, get hematuria,
so this is not an uncommon problem.
But we have to remember when we’re checking for hematuria
that not everything that's red in pee is blood.
Rhabdomyolysis or breakdown of muscle can look like blood,
also hemoglobinuria from hemolysis.
Patients on certain drugs such as pyridium or rifampin
can have dark or almost bloody-looking urine.
Likewise, dyes; if a patient were to say, eat something with a lot of red dye,
they may have urine that looks like blood.
Certain metabolites may look like blood
though those are often abnormal if you find them.
So things like porphyria or high bilirubin levels or patients with tyrosinimia.
Likewise, some foods if eaten in large quantities
such as beets or blackberries can cause a bloody-looking urine.
And in infants, this is common,
there can be a little red spot in the front of the diaper
that parents may think is blood in the urine,
but is in fact urate crystals and those are common in infants and found in the diaper.
Also there maybe blood but is not coming from the urine.
In older girls, menses may come out in the urine sample
and appear to be blood or blood maybe from the stool as well.
So when you see a patient with hematuria, there’s a few questions you want to ask.
You need to ask if there was a recent sore throat or recent skin infection
because this patient may have post-strep glomerulonephritis.
You should ask about fever, dysuria or flank pain,
that maybe a sign of pyelonephritis or kidney infection.
A patient with nephritic syndrome or significant renal involvement
may have high blood pressure.
So asking about blood pressure is important.
It’s important to ask about a family history of deafness or renal disease.
Remember, Alport syndrome which is which is X-linked can happen in these patients
and can be familial, resulting in renal disease and deafness.
It’s important to ask about other chronic medical problems.
For example, patients with sickle cell or lupus may present with blood in their urine.
Also ask about any history of a purpuric rash,
palpable purpura over the legs or buttocks area could be Henoch-Schonlein purpura
which absolutely presents with blood in the urine
and that is in fact the symptom we worry about.
Lastly, of course, a history of trauma.
If there is trauma to anywhere on the urinary tract,
one can have bleeding that comes out in the urine.
So hematuria is really a multisystem potential.
It could be from multisystem disease
or it could be from somewhere localized in the renal tract.
Let’s go through what your differential would be for all of these various problems.
So multisystem diseases that can cause hematuria include lupus,
Henoch-Schonlein purpura,
either Wegener’s or Goodpasture syndrome,
hemolytic uremic syndrome,
sickle cell disease
or HIV nephropathy after the patient has been sick for a period of time.
Patients may have tubular disease in their kidneys, in the tubules,
and that can include pyelonephritis, interstitial nephritis,
acute tubular necrosis, say after someone took some ibuprofen,
or papillary necrosis.
Patients may also have vascular disease in the kidneys
which could include arterial or venous thrombi or an aneurysm
or perhaps a hemangioma in a patient with significant hemangiomas.
There can be anatomic disease that’s causing abnormalities in the kidney
which can then be damaged and have some hematuria.
Examples would be hydronephrosis or polycystic kidney disease.
Patient may have multicystic dysplasia or tumors or some sort of renal trauma.
Lower down in the urinary tract,
patients may have stones, cystitis, urethritis, trauma or bladder tumor.
Sometimes, a simple virus can cause a cystitis
which causes blood in the urine and this resolves of its own.
Occasionally, patients have isolated renal disease that can cause hematuria.
The most common is IgA nephropathy.
We already mentioned Alport syndrome and post-strep glomerulonephritis,
but there are other glumerulo diseases that can happen.
These include focal segmental glumerulosclerosis,
rapidly progressive glomerulonephritis,
membranous nephropathy
or patients may get benign familial hematuria
which is a thin membrane disease that persists in families.
When we think of the glomeruli as causing disease,
we like to break things down into either a primary protein spilling disease
or a primary blood spilling disease.
What we’ll do is we’ll check patients for their urine and we will do urine dipstick.
That urine dipstick will tell us whether there is protein, blood or both.
Classically, we are taught that there are certain diseases that are nephrotic
such as focal segmented glomerulonephritis
and other diseases that are nephritic such as post-strep glomerulonephritis.
And that these will present with either protein spilling or blood spilling.
But the reality is more like this slide, there is some overlap.
Oftentimes, patients can spill both but one issue is more predominant than the other.
So if we see a patient with hematuria,
there are some urine studies we need to do.
First, we need to look for signs of urinary tract infection such as
white blood cells in the urine or nitrites or leukocyte esterase.
Remember, nitrite is 99% specific.
So if you see blood in the urine and nitrites,
this is almost definitely urinary tract infection.
Less specific are those other findings.
The urine electrolytes may be helpful in patients where you suspect kidney stones
especially if you were to get a calcium to creatinine ratio
which can tip you off that this patient has hypercalciuria resulting in stones.
We usually will get a Chem 7 on these patients and for a variety of reason.
The Chem 7 is important to check for renal failure and ongoing renal problems
with renal damage and so, a BUN and creatinine will be key.
Also in end-stage renal disease, you can see other problems such as hyperkalemia.
The CBC is important to check for blood loss if this is an ongoing problem
and again, that high white count may be indicative of a pyelonephritis.
In patients with post-strep glomerulonephritis or
MPGN or lupus or other disease that are systemic,
you may see low complement levels and that can be a clue that something is going on.
The renal ultrasound is first line for most renal imaging.
So if we have a patient where we suspect there is renal involvement,
the ultrasound is usually where we start.
We really limit the CT for things like renal stones,
although renal stones can absolutely be imaged on ultrasound as well.
Occasionally, we will use a voiding cystourethrogram
that’s really for use in diagnosing hydronephrosis
and in particular, for diagnosing what type of hydronephrosis is going on.
The VCUG is a little bit of radiation and is fairly painful,
so we want to limit its use.
Cystoscopy is important for when we suspect a bladder bleed,
especially a bladder bleed of undetermined etiology.
We might want to look for what the source is.