PEDIATRICS

Karina Luise Glaser, MD

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Hematuria

Microscopic hematuria: more than 5 red blood cells per high power field in the sediment from 10 mL of centrifuged freshly voided urine.

Gross hematuria (visible to the naked eye): may originate from the kidney (may contain red blood cell casts, and is usually brown) or from the bladder and urethra (pink urine, may contain clots).

Recurrent gross hematuria

Recurrent episodes which usually develop 1-2 days after the onset of a viral upper respiratory tract infection. It resolves over 1-2 weeks, but microscopic hematuria may persist. Biopsy is recommended after the second episode.

Berger nephropathy: IgA is the predominant immunoglobulin in mesangial deposits. It affects most commonly males than females (2:1); patients present with gross or microscopic hematuria. Progressive disease develops in 30% of patients. The development of hypertension, diminished renal function or proteinuria > 1 g/ 24 h indicate a poor prognosis.

Idiopathic hematuria: the diagnosis is established by normal findings on biopsy. Long term follow up is necessary to exclude Alport syndrome. The development of diminished renal function, proteinuria or hypertension demands a second biopsy.

Alport syndrome: most common hereditary nephritis. It can be associated with sensorineural hearing loss and eye abnormalities (cataracts, anterior lenticonus, macular lesions). The complications include hypertension, urinary tract infections and chronic renal failure. Genetic counseling is necessary for prevention. Males develop end stage renal disease in the 2nd- 3rd decades of life, and hearing loss(X-linked dominant disorder).

Idiopathic hypercalciuria: excessive gastrointestinal absorption of normal dietary calcium intake or a defect in renal calcium reabsorption. The diagnosis is established by a 24 h urinary calcium >4 mg/ kg of body weight or a urine calcium to creatinine ratio . 0.2 (mg/mg). The differential diagnosis is hypercalcemic hypercalciuria due to hyperparathyroidism and vitamin D intoxication. The main complication is nephrolithiasis. Oral thiazide diuretics may be used (increase calcium reabsorption).

Gross or microscopic hematuria

Acute poststreptococcal glomerulonephritis: classic example of the acute nephritic syndrome (sudden onset of gross hematuria, edema, hypertension and renal insufficiency). It follows infection of throat or skin with nephritogenic strains of group A b-hemolytic Sreptococcus. It is rare under the age of 3.

Membranous glomerulopathy: uncommon in childhood. Usually associated with systemic lupus erythematosus, cancer, gold or penicillamine therapy, syphilis, hepatitis B.

Systemic lupus erythematosus: fever, weight loss, rash, hematologic abnormalities, arthritis, involvement of heart, lungs, central nervous system, kidneys. It affects most commonly adolescent girls. The clinical manifestations are mediated by immune complexes.

Membranoproliferative (mesangiocapillary) glomerulonephritis: most common cause of chronic glomerulonephritis (continuing injury leading to end stage renal failure.

Glomerulonephritis of chronic infection: Subacute bacterial endocarditis (Streptococcus viridans), infected ventriculoatrial shunts for hydrocephalus (Staphylococcus epidermidis), syphilis, hepatitis B or C, candidiasis, malaria. The eradication of infection leads to resolution.

Rapidly progressive glomerulonephritis: rapid progression to end stage renal failure.

Goodpasture disease: pulmonary hemorrhage associated with glomerulonephritis. It is rare in childhood.

Hemolytic uremic syndrome: most common cause of acute renal failure in young children. Most common in children under 3; it follows an acute episode of gastroenteritis (bloody diarrhea) or upper respiratory tract infection. The clinical manifestations include microangiopathic hemolytic anemia, thrombocytopenia and acute renal failure.

Infection as a cause of hematuria: bacterial, mycobacterial or viral infections of the urinary tract (inflammatory reaction).

Hematologic diseases causing hematuria

Coagulopathies and thrombocytopenia: hemophilias, disseminated intravascular coagulation, thrombocytopenia.

Sickle cell nephropathy: ischemia.

Renal vein thrombosis: hematuria associated with flank masses, microangiopathic hemolytic anemia and thrombocyopenia. In newborns and infants it is associated with asphyxia. dehydration, shock, sepsis and diabetes of the mother; in children it is associated with nephrotic syndrome, cyanotic heart disease and use of angiographic contrast agents.

Anatomic abnormalities associated with hematuria

Congenital anomalies: cystic kidneys, uteropelvic junction obstruction.

Trauma: blunt or penetrating, foreign object, crushing type.

Autosomal recessive polycystic kidney disease.

Autosomal dominant polycystic kidney disease (rare in childhood).

Vascular abnormalities: hemangiomas, arteriovenous malformations.

Miscellaneous etiologies of hematuria

Nephrolithiasis

Renal tumors

Exercise hematuria: resolves within 48 hours

Drugs: heparin, warfarin, aspirin, penicillins, sulfonamides, cyclophosphamide.

Evaluation of the child with hematuria

History and physical examination.