A 7-year-old boy was brought to his pediatrician because he had developed hematuria, which required hospitalization. Approximately 6 weeks before his admission, he had a severe sore throat but received no treatment for it. Subsequently, he did well except for complaints of mild lethargy and decreased appetite. Approximately 3 weeks before admission, he had a temperature of 101° F daily for 7 days. He complained of minimal bilateral back pain. Physical examination revealed a well-developed young boy with moderate bilateral costovertebral angle (CVA) tenderness. The remainder of the physical examination results were negative. His blood pressure was 140/100 mm Hg in both arms and legs. Studies Results Urinalysis, p. 956 Blood +4 (normal: negative) Protein +1 (normal: negative) Red blood cell casts Positive (normal: negative) Specific gravity 1.025 (normal: 1.010-1.025) Color Red-tinged (normal: amber-yellow) Urine culture and sensitivity (C&S), p. 973 No growth after 48 hours Blood urea nitrogen (BUN), p. 511 42 mg/dL (normal: 7-20 mg/dL) Creatinine, p. 190 1.8 mg/dL (normal: 0.7-1.5 mg/dL) Creatinine clearance test, p. 193 64 mL/min (normal: approximately 120 mL/min) Renal ultrasound, p. 866 No tumor; kidneys diffusely enlarged and edematous Intravenous pyelogram (IVP), p. 1057 Delayed visualization bilaterally; enlarged kidneys, no tumor; no obstruction seen Renal biopsy, p. 751 Swelling of glomerular tuft, along with polymorphonuclear leukocyte infiltrates in Bowman’s capsule (findings compatible with glomerulonephritis); immunofluorescent staining, positive for IgG Anti-DNase-B (ADB) titer, p. 79 200 units (normal: ≤170 units) Total complement assay, p. 172 33 units/mL (normal: 75-160 units/mL) Diagnostic Analysis The blood, protein, and RBC casts in the boy’s urine indicated a primary renal disorder. The elevated creatinine and BUN levels indicated that the problem was severe and markedly affecting his renal function. Both kidneys were probably equally impaired. Intravenous pyelogram (IVP) was helpful only in ruling out Wilms tumor or congenital abnormality. Normally an IVP would not be performed in light of this patient’s impaired renal function. It is presented here for demonstration of the information it can provide. Renal ultrasound is a much safer test to visualize the kidney to exclude neoplasm. The ultrasound findings were compatible with an inflammatory process involving both kidneys. Renal biopsy was most helpful in suggesting glomerulonephritis. The history of recent pharyngitis, fever, the positive ASO titer, the positive ADB titer, and the finding of immunoglobulin IgG antibodies on the immunofluorescent stain all suggested poststreptococcal glomerulonephritis. The patient was placed on a 10-day course of penicillin. He was given antihypertensive medication, and his fluid and electrolyte balance was closely monitored. At no time did his creatinine or BUN level rise to a point requiring dialysis. After 6 weeks, his renal function returned to normal (creatinine, 0.7 mg/dL; BUN, 7 mg/dL). His antihypertensive medications were discontinued, and he remained normotensive and returned to normal activity. Critical Thinking Questions (the ones that needs to be answered) 1. At what point would the BUN and creatinine have signified the need for dialysis? 2. What was the cause of the patient’s hypertension? 3. What would you do if this patient had developed a swollen mouth and neck after the IVP?