113 Hematuria
Key Points• Hematuria can be a transient and incidental finding, or it can be caused by underlying and otherwise silent life-threatening disease.
• Infection is the most common cause of symptomatic hematuria in all age groups. Crystalluria and glomerulonephritis are more common in children; malignancy and nephrolithiasis are more common in adults.
• Patients with microscopic hematuria should have urinalysis repeated with their primary care provider about 1 week after discharge from the emergency department.
• All patients with gross hematuria warrant careful evaluation to ensure adequate urinary drainage. Those with difficulty passing clots, evidence of retention, or poor mobility should have a three-way Foley catheter placed in the emergency department.
• Although hematuria alone is rarely grounds for admission, emergency associated disease processes should be considered and excluded. Such processes include urosepsis, obstructing ureteral stone, renal parenchymal disease, coagulopathy, symptomatic anemia, intraabdominal injury in the setting of trauma, renal vein thrombosis, and aortic abdominal aneurysm.
Scope and Definitions
Gross (macroscopic) hematuria, visualized as red-colored urine, is disconcerting to most patients, but it does not always imply significant blood loss: as little as 1 mL of blood may turn 1 L of urine red. Dysuria is common in patients with gross hematuria, and urinary retention may develop if high-volume bleeding leads to clots that obstruct urethral outflow.1
Microscopic hematuria refers to the detection of more than three RBCs per high-power field (HPF) in a spun sample of urine sediment not visible to the naked eye.1,2 Screening of asymptomatic individuals suggests that up to 10% of adults and 6% of children may have some degree of microscopic hematuria at any given time.2–4 Typically an incidental and transient discovery, it can be associated with dysuria or pain. Because microscopic hematuria may be the only clue to previously undiagnosed structural, neoplastic, or inflammatory conditions, follow-up is essential.2–5
Pigmenturia (pseudohematuria) refers to urine that appears red or dark without RBCs detected by urine microscopy. A urine dipstick may register a positive test result for blood if hemoglobin, myoglobin, or bilirubin is present in the urine, as in the case of hemolysis, rhabdomyolysis, or jaundice. Pigmented urine with a negative dipstick test result may be caused by certain foods or medications (Table 113.1).
Table 113.1 Differential Diagnosis of Hematuria
| DIAGNOSTIC CLUES | POSSIBLE DIAGNOSIS (NONGLOMULAR CAUSES) | POSSIBLE DIAGNOSIS (GLOMULAR CAUSES) |
|---|---|---|
| Hematuria in the Adult and Pediatric Patient | ||
| Trauma (blunt or penetrating) | Renal or bladder injury, at risk for other intraabdominal injuries | |
| Suprapubic pain or lower tract symptoms (dysuria, urgency, frequency, suprapubic pain) | UTI | |
| Flank pain | Stones, pyelonephritis, renal vein thrombosis, renal cyst, renal arteriovenous malformation | IgA nephropathy, glomerulonephritis |
| Hypercoagulable state and acute-onset flank pain | Renal vein thrombosis | |
| Elevated blood pressure | Glomerulonephritis | |
| Risk factors for muscle injury; viremia, exertion, crush injury, sympathomimetic drug use | Rhabdomyolysis | |
| Cough, hemoptysis | Vasculitis | |
| Sickle cell disease | Papillary necrosis | Glomerulonephritis |
| Cancer treatment | Radiation- or cyclophosphamide-associated cystitis | |
| Travel history | Schistosomiasis, tuberculosis | |
| Coagulopathy (hemophilia, idiopathic thrombocytopenic purpura) or anticoagulation | Bleeding diathesis | |
| Pregnancy | Preeclampsia | |
| Diet: beets, berries, rhubarb Medications: quinine sulfate, phenazopyridine, rifampin, phenytoin | Pseudohematuria (pigmenturia) | |
| Nail or patellar abnormalities | Nail-patella syndrome | |
| Hematuria in the Pediatric Patient | ||
| Recent illness (pharyngitis, impetigo, viral illness) | Postinfectious glomerulonephritis | |
| Abdominal pain | UTI, hypercalciuria, stone | HSP |
| Concurrent illness | IgA nephropathy | |
| Arthralgias | HSP, SLE | |
| Diarrhea (± bloody) | HUS | |
| Hearing loss | Alport syndrome | |
| Family history of hematuria or kidney disease | Polycystic kidney disease, hypercalciuria | Benign familial hematuria, thin basement disease, Alport syndrome |
| Rash (purpura, petechiae) | Bleeding dyscrasia, abuse | HSP, SLE, HUS |
| Edema | Glomerulonephritis, nephrotic syndrome | |
| Abdominal mass | Wilms tumor, hydronephrosis, polycystic kidney disease | |
| Conjunctivitis, pharyngitis | Adenovirus (hemorrhagic cystitis) | |
| Meatal erythema or stenosis | Masturbation, infection, trauma | |
| Hematuria in the Adult Patient | ||
| Age > 40, smoking history, analgesic abuse, Schistosoma exposure, pelvic irradiation, exposure to chemicals | Urogenital tract cancer | |
| Flank pain | Angiomyolipoma, AAA | |
| Pulsatile abdominal mass | AAA | |
| Atrial fibrillation | ||
