1 What is the definition of gross and microscopic hematuria?

2 What else, besides RBCs, can cause urine to appear red or brown?

Reddish or brownish discoloration of the urine from some compound other than blood is common. Myoglobinuria and porphyrinuria present with red or tea-colored urine. Several ingestions also discolor the urine. Infants may have precipitation of urate crystals that make their urine appear red or orange in the diaper.

3 What can cause a “false-positive” urine dipstick?

You may encounter a positive urine dipstick, but upon microscopic examination no RBCs are seen. The dipstick is sensitive to any heme compound and will be positive for intact red blood cells as well as hemoglobin from hemolyzed RBCs and myoglobin from rhabdomyolysis. Several other oxidizing compounds, such as bleach or microbial peroxidase, can also turn the dipstick spuriously positive.

Goldsmith DI, Novello AC: Clinical and laboratory evaluation of renal function. In Edelmann CM (ed): Pediatric Kidney Disease, 2nd ed. Boston, Little, Brown and Company, 1992, pp 461–465.

Liao JC, Churchill BM: Pediatric urine testing. Pediatr Clin North Am 48:1425–1436, 2001.

Liebelt EA: Hematuria. In Fleisher GR, Ludwig S, Henretig FM (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 345–349.

4 What is the most likely diagnosis of a child presenting to the emergency department (ED) with “red urine”?

The majority of children who visit an ED for red urine are diagnosed with urinary tract infections (UTIs) (26% with documented infections and 23% with suspected UTI or viral cystitis). Perineal irritation accounts for 11% of cases, and meatal stenosis with ulcer is found in another 7%. Hematuria is from traumatic injuries in 7% of cases; acute glomerulonephritis is diagnosed in 4%, and a rare patient may have a Wilms’ tumor or other oncologic process involving the genitourinary tract.

Even though parents or patients may assume that blood in the diaper or toilet is from urine, it may actually be from several other sources: vaginal bleeding (menses, foreign body, infection, trauma), rectal bleeding (fissure, hemorrhoid, trauma), or urethral prolapse.

Ingelfinger JR, Davis AE, Grupe WE: Frequency and etiology of gross hematuria in a general pediatric setting. Pediatrics 59:557–561, 1977.

5 Is there a way to determine glomerular versus nonglomerular blood in the urine?

See Table 16-1.

Table 16-1 Glomerular Versus Nonglomerular Blood in the Urine

RBC = red blood cell.

Adapted from Kalia A, Travis LB: Hematuria, leukocyturia, and cylindruria. In Edelmann CM (ed): Pediatric Kidney Disease, 2nd ed. Boston, Little, Brown and Company, 1992, pp 553–563.

6 What is the differential diagnosis of hematuria in a child?

See Table 16-2.

Table 16-2 Differential Diagnosis of Hematuria in Children

Adapted from Kalia A, Travis LB: Hematuria, leukocyturia, and cylindruria. In Edelmann CM (ed): Pediatric Kidney Disease, 2nd ed. Boston, Little, Brown and Company, 1992, pp 553–563.

7 How would you evaluate a child with blunt abdominal trauma for renal injury?

See Fig. 16-1.

Figure 16-1 Algorithm for evaluation of renal injury in a child with blunt abdominal trauma. CT = computed tomography, IVP = intravenous pyelography.

From Buckley JC, McAninch JW: Pediatric renal injuries: Management guidelines from a 25-year experience. J Urol 172:687–690, 2004; Perez-Brayfield MR, Gatti JM, Smith EA, et al: Blunt traumatic hematuria in children. Is a simplified algorithm justified? J Urol 167:2543–2547, 2002; and Santucci RA, Langenburg SE, Zachareas MJ: Traumatic hematuria in children can be evaluated as in adults. J Urol 171:822–825, 2004.

8 Why are children at more risk than adults for renal injury after blunt trauma?

Kidneys in children are proportionally larger and have less protective perirenal fat and musculature than adult kidneys.

9 Hypertension with hematuria is associated with which diseases?

Hypertension found in a patient with hematuria may indicate a renal emergency. Consider glomerulonephritis, obstructive uropathy, polycystic kidney disease, hemolytic uremic syndrome, systemic lupus erythematosus, and Wilms’ tumor.

10 Describe signs and symptoms associated with hematuria that require urgent/emergent evaluation.

Children with hematuria should be evaluated with a full history, family history, and physical examination, which will allow a directed workup of the etiology. Gross hematuria should be evaluated emergently for significant renal trauma, tumor, or bleeding disorder. Hematuria accompanied by edema, proteinuria, oliguria, hypertension, or headache may portend glomerular renal disease that needs emergent evaluation. Signs and symptoms such as fever, dysuria, flank pain, abdominal pain, rash, recent sore throat, or respiratory illness are important factors that will help lead to a diagnosis. Asymptomatic isolated microscopic hematuria is found at one time or another in 1–4% of children and, in most cases, is benign. This is a diagnosis of exclusion, and referral for outpatient evaluation is indicated.

Liebelt EA: Hematuria. In Fleisher GR, Ludwig S, Henretig FM (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 345–349.

11 Which laboratory tests are helpful in the evaluation of hematuria?

All patients with the sign or finding of hematuria should have a urine dipstick and microscopic urinalysis. Depending on the history and physical examination, further blood tests may be indicated. Hematuria with fever, flank pain, urgency, and dysuria usually indicates a urinary tract infection and should be evaluated with a urine Gram stain and culture. Complete blood count, blood urea nitrogen, and serum creatinine may be helpful in all cases except those of isolated microscopic hematuria or obvious urinary tract infection. If the child has sustained or suspected trauma, liver function tests, amylase, and lipase are also recommended. Prothrombin time and partial thromboplastin time will help diagnose any bleeding disorder. If the clinical picture indicates nephritis, then electrolytes, complement levels (C3 and C4), antistreptolysin-O or Streptozyme test, antinuclear antibody titer, hepatitis screen, and erythrocyte sedimentation rate may be helpful.

A patient with a positive dipstick without evidence of RBCs on urine microscopic examination should be evaluated with plasma creatine kinase and urinary myoglobin concentration for rhabdomyolysis, and a bilirubin level for signs of hemolysis.

Feld LG, Meyers KEC, Kaplan BS, Stapleton FB. Limited evaluation of microscopic hematuria in pediatrics. Pediatrics 102:E42, 1998.

Patel HP, Bissler JJ: Hematuria in children. Pediatr Clin North Am 48:1519–1535. 2001.

12 Describe the etiology of nephrolithiasis in children.

Nephrolithiasis is an increasing problem in children in the United States. Stone formation results from environmental and hereditary factors. Hypercalciuria is the most common cause of pediatric urinary stones and has many causes. Genetic syndromes, such as familial idiopathic hypercalciuria, as well as other diseases such as Bartter syndrome and distal renal tubular acidosis, lead to increased urinary calcium excretion and stone formation. Iatrogenic causes include treatment with loop diuretics and prednisone.

Other causes of stone formation include infection with urease-producing organisms (struvite or “staghorn” calculi); cystinuria; hyperoxaluria; medications such as protease inhibitors; and high-protein, low-carbohydrate diets (ketogenic diet).

Gillespie RS, Stapleton FB: Nephrolithiasis in children. Pediatr Rev 25:131–138, 2004.

Hulton SA: Evaluation of urinary tract calculi in children. Arch Dis Child 84:320–323, 2001.

13 How do you diagnose urinary stones in children?

Evaluation and diagnosis should begin with a complete history and physical examination, including a history of urinary infections, current medications, and a detailed family history. A urinalysis and urine culture should be obtained. Microscopic hematuria is present in >90% of children with urinary stones. Infection is commonly seen with stones, so evidence of urinary tract infection does not exclude stones. Renal ultrasonography or nonenhanced helical computed tomography (CT) are the standard methods of diagnosis; they can detect very small stones as well as underlying anatomic abnormalities or alternative diagnoses. Most stones in children are composed of radio-opaque substances and may be seen on plain abdominal radiographs (Fig. 16-2), but the small size of most stones makes this test less sensitive. Intravenous pyelography is another option, although CT has largely replaced it because of increased sensitivity and specificity.

Figure 16-2 CT scan showing kidney stone in the ureter.

Gillespie RS, Stapleton FB: Nephrolithiasis in children. Pediatr Rev 25:131–138, 2004.

Hulton SA: Evaluation of urinary tract calculi in children. Arch Dis Child 84:320–323, 2001.

14 What are the most common causes of dysuria in children?

Dysuria (painful urination) in usually caused by irritation of the bladder or urethra. Common causes of this symptom include cystitis (viral or bacterial), urethritis (infectious, chemical, or traumatic), vaginitis, or balanitis. Children may report or exhibit perineal discomfort and parents may interpret this discomfort as dysuria in the case of pruritus from pinworms (Enterobius vermicularis) or in cases of sexual abuse.

Corboy JB: Pain—dysuria. In Fleisher GR, Ludwig S, Henretig FM (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 499–503.

Kellogg ND, Parra JM, Menard S: Children with anogenital symptoms and signs referred for sexual abuse evaluations. Arch Pediatr Adolesc Med 152:634–641, 1998.

15 Which systemic diseases may present with dysuria?

Urethritis, producing dysuria, is associated with several serious systemic diseases, such as Stevens-Johnson syndrome, Reiter syndrome, and Behçet’s syndrome.

Corboy JB: Pain—dysuria. In Fleisher GR, Ludwig S, Henretig FM (eds): Textbook of Pediatric Emergency Medicine, 5th ed. Philadelphia, Lippincott Williams & Wilkins, 2006, pp 499–503.

16 Name some common causes of urethritis in children.

Infectious urethritis in adolescents is most commonly due to Neisseria gonorrhoeae and Chlamydia trachomatis. Bubble baths, detergents, fabric softeners, and perfumed soaps are often the etiology for cases of chemical urethritis in younger children.

17 A child reports dysuria but is afebrile, with no genital lesions, and has a negative urinalysis for pyuria. What are the most probable diagnoses?

Dysuria in this child may be due to viral cystitis, chemical irritation of the urethra, pinworms, fused labia minora, idiopathic hypercalciuria, urinary tract stone, or bacterial urinary tract infection (a few children will present with negative urinalysis but positive urine cultures).

18 What is “summer penile syndrome?”

Summer penile syndrome is a seasonal acute hypersensitivity reaction to chigger bites on the penis. It is found in endemic areas (Southern and Midwestern United States) during the summer months. This syndrome is always accompanied by significant edema of the penis, and 33% of children present with dysuria. Chiggers are the larval form of the trombiculid mite.

Smith GA, Sharma V, Knapp JF, et al: The summer penile syndrome: Seasonal acute hypersensitivity reaction caused by chigger bites on the penis. Pediatr Emerg Care 14:116–118, 1998.

19 What parasitic infection should be considered in a traveler or recent immigrant presenting with hematuria or dysuria?

Urinary schistosomiasis, caused by Schistosoma haematobium, is a common cause of hematuria and dysuria worldwide. This worm is found mostly in sub-Saharan Africa and enters through the skin after contact with fresh water that harbors the larval form. The worms eventually migrate to the bladder mucosa, where eggs are produced and secreted in the urine. Diagnosis can be made by examination of the urine for eggs. Praziquantel is the mainstay of treatment and is curative in most cases.

Lischer GH, Sweat SD: 16-year-old boy with gross hematuria. Mayo Clin Proc 77:475–478, 2002.

Ross A, Bartley PB, Sleigh AC, et al: Schistosomiasis. N Engl J Med 346:1212–1220, 2002.

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