A 16-year-old girl is brought to the office due to dark brown urine and fatigue for a week. Temperature is 37.2 C (99 F), blood pressure is 140/94 mm Hg, pulse is 80/min, and respirations are 16/min. Physical examination shows no abnormalities. Laboratory results are as follows:
| Serum chemistry | |
| Blood urea nitrogen | 24 mg/dL |
| Creatinine | 1.7 mg/dL |
| Urinalysis | |
| Specific gravity | 1.016 |
| Protein | +2 |
| Blood | moderate |
| Leukocyte esterase | negative |
| Nitrites | negative |
| White blood cells | 1-2/hpf |
| Red blood cells | 20-30/hpf |
Which of the following is the most appropriate next step in management?
Show Explanatory Sources
Hematuria can be due to a nonglomerular or glomerular source. The most common cause of gross hematuria in children is nonglomerular (eg, urinary tract infection, perineal/meatal irritation, trauma). However, glomerular disease should be suspected with any of the following:
Therefore, this patient with dark brown urine, in addition to 2+ proteinuria, hypertension, and elevated creatinine, likely has a glomerular source of bleeding.
Initial evaluation of glomerulonephritis includes serum complement (C3, C4) levels, as well as a complete blood count and albumin level. Low C3 is suggestive of poststreptococcal glomerulonephritis (PSGN), the most common glomerulonephritis in children, or lupus nephritis. Antistreptolysin O (seen in PSGN) and antinuclear antibody (seen in systemic lupus erythematosus) testing can help differentiate these conditions. If laboratory evaluation is unrevealing and symptoms persist, renal biopsy may be indicated for diagnosis (eg, IgA nephropathy, membranoproliferative glomerulonephritis).
(Choices A, B, and C) Bladder imaging may be indicated for painless hematuria to evaluate for a tumor; because of radiation exposure, ultrasound, not CT scan, is typically preferred as the initial imaging study in children. Visualization/tissue sampling via cystoscopy is diagnostic. However, bladder tumors are extremely rare in children, cause pink/red (not brown) urine, and are not typically associated with proteinuria, hypertension, or elevated creatinine.
(Choice D) Hemoglobin electrophoresis is diagnostic of sickle cell trait, which can cause papillary necrosis from sickling within capillaries of the renal medulla. The classic presentation is isolated, painless, gross hematuria; hypertension, proteinuria, and elevated creatinine are atypical. Moreover, in children, PSGN is far more common than renal papillary necrosis.
(Choices E and G) Management of patients with hematuria and other symptoms of a urinary tract infection (eg, dysuria, urgency, frequency) includes empiric antibiotics, urine culture, and repeat urinalysis in 2 weeks to confirm resolution of hematuria. Urine is typically pink or red, not brown, and urinalysis classically shows pyuria (white blood cells ≥5/hpf), leukocyte esterase, and/or nitrites, none of which is seen here. In addition, asymptomatic microscopic hematuria may also be followed by serial urinalyses, but this patient has symptomatic gross hematuria that warrants further evaluation.
Educational objective:
Glomerular sources of gross hematuria should be considered in a patient with brown urine, red blood cell casts, proteinuria, hypertension, and/or edema. Initial evaluation includes serum complement (C3, C4) levels.