Hematuria Differential Diagnosis:
Hematuria is blood in the urine. There are two types of blood in the urine exist. It may be grossly visible (macroscopic) or detectable only on urine examination (called microscopic). In many patients, particularly young adult patients, the hematuria is transient and of no consequence. However there is an appreciable risk of malignancy in patients over age 35 years with hematuria, even if transient.
The following mnemonic lists the most common causes of hematuria that you should memorize for both the wards and your USMLE Step 2 CS examination.
Physical Examination for Hematuria:
NOTE: Make sure to wash your hands or wear gloves before you start physical examination. Make sure to ask for permission before you start each physical exam. Make sure to use proper draping (don’t forget to tie back patient’s gown). Make sure to explain each physical examination in layman’s term to your patient. Do NOT repeat painful maneuvers.
- Cardiovascular exam: Auscultation
- Pulmonary exam: Auscultation
- Abdominal exam: Auscultation, Palpation, Percussion, Check for CVA tenderness.
- Genital Exam (not required for actual USMLE Step 2 CS exam)
Other Differential Diagnosis for Hematuria:
- Bladder cancer
- Coagulation disorder
- Prostate Cancer
- Polycystic kidney disease
- Renal Cell Carcinoma
- IgA nephropathy (Berger Disease)
- Pyelonephritis (Acute / Chronic)
- Urinary Tract Infection (UTI)
Urine dipstick: the urine sediment (or direct counting of RBC per mL of uncentrifuged urine) is the gold standard for the detection of microscopic hematuria. A positive dipstick test must always be confirmed with microscopic examination of the urine to differentiate true blood in the urine from myoglobinuria (muscle breakdown in the urine).
Urine culture: all patients should have a urine culture to exclude infection prior to evaluation of hematuria. Patients who have a positive urine culture should be treated for infection with close follow-up.
Imaging study of kidney and collecting system should be obtained for all patients with gross or microscopic hematuria who have no evidence of glomerular bleeding, or infection or other known cause for hematuria. Multidetector CT urography (CTU) is the preferred initial imaging modality in most patients with unexplained gross or microscopic hematuria. Multidetector CTU should not be used in pregnant woman; ultrasonography may be used in the evaluation of pregnant women.
Renal biopsy in patients with glomerular hematuria (defined by the presence of dysmorphic red cells and/or red cell casts) is the presence of risk factors for progressive disease such as proteinuria and/or an elevation in the serum creatinine concentration.
Cystoscopy should be performed on all patients with gross hematuria who have no evidence of glomerular bleeding, nephrolithiasis, or infection. Patients who have blood clots should have cystoscopy even if they have evidence of a glomerular lesion since blood clots are virtually never associated with glomerular bleeding and would suggest the presence of two separate lesions in the glomerulus and in the upper or lower collecting system. Cystoscopy should be performed on all patients over 35 years with microscopic hematuria after ruling out benign causes, such as infection, menstruation, vigorous exercise, medical renal disease, kidney stones, viral illness, trauma, or recent urological procedures. Cystoscopy should also be performed in those patients with microscopic hematuria who are at increased risk for malignancy, regardless of age.
Other Diagnostic Work up:
- Genital exam
- Rectal exam (check for BPH or Prostate cancer)
- CBC, PT/PTT
- Kidney ultrasound
- CT of abdomen / pelvis
- Intravenous pyelogram (IVP)
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