The two cases presented at Morning Report today were related to hematuria - one case is a patient with Acute Promyelocytic Leukemia (APL), the other was one in which the patient had metastatic Renal Cell Carcinoma. See a prior post for details on APL. Here is some information about workup and other details regarding hematuria
Definition: The Prescence of 3 erythryocytes/hpf on a urinalysis that is centrifuged. Some references say that this should be repeated to confirm the presence of RBCs.
Causes: There are many to know, but here is a semi-exhaustive list of the causes.
Benign Prostatic Hypertrophy
Schistosoma haematobium infection
Renal Cell Carcinoma/Ureteral Malignancy/Bladder Carcinoma/Prostate Cancer
Coagulopathy (and it's various causes)
Injury/Trauma (including Foley placement)
von Hippel-Lindau disease
Polycystic Kidney Disease
Sickle Cell Disease and Trait
IgA Nephropathy and Thin Basement Membrane Disease
Any of the various causes of glomerulonephritis (i.e. SLE, PIGN, MPGN, Goodpasture's Syndrome, Anti-GBM Disease, Hemolytic Uremic Syndrome etc)
Other things to consider: Remember, some medications (such as rifampin, dilantin and chloroquine) can cause a false positive test for blood on the urine dipstick, but there will be no RBCs. Similarly, remember that in rhabdomyolysis, Blood is reported as +, but RBCs are absent. These should be considered in all cases of hematuria. Some foods cause the urine to turn red with a completely normal urinalysis - including beets, berries and food coloring.
All patients with hematuria should have a metabolic panel (to evaluate renal function), CBC and coagulation studies performed.
As far as determining the specific cause, one should first do a Urinalysis with microscopy to determine if there is a glomerular vs nonglomerular cause. Remember that glomerular causes will have RBCs casts and/or dysmorphic Red Blood Cells. If there is indeed a glomerular cause, then workup includes determining the amount and quantity of protein present. Some will then send serum complements (esp C3) to divide the causes into those with normal and those with low Complement levels. Without an evident cause based on the serum workup, renal biopsy may be necessary for the glomerular causes.
If the clinical history is suggestive of infection, then urine culture can be sent. However, some causes of a positive urine culture must be considered in this category besides UTI (i.e. prostatitis, PCKD, and some malignancies!)
If the clinical history is suggestive of nephrolithiasis, one can do a helical CT scan.
If the patient has risk factors for bladder malignancy (i.e. Age>50, smoking history, pelvic irradiation, analgesic abuse) - cystoscopy is warranted as the next step. Urologists actually like three studies done - Urine Cytology, Cystoscopy and CT imaging of the abdomen/pelvis.