A 6-year-old girl is brought to the office by her mother due to abdominal pain. The pain is diffuse and began this morning; it waxes and wanes in intensity. The patient has had 2 episodes of nonbilious emesis. She has had no fevers, sore throat, diarrhea, or bloody stools. Two days ago, the patient developed an erythematous, macular rash over her legs and back that has become darker and more confluent today. Blood pressure is 95/60 mm Hg. The abdomen is soft and there is diffuse, mild tenderness on palpation with no rebound, guarding, or appreciable masses. A raised, nonblanching rash is noted over the legs and back. Urinalysis results are as follows: Which of the following renal abnormalities is most likely present in this patient?

Question

A 6-year-old girl is brought to the office by her mother due to abdominal pain.  The pain is diffuse and began this morning; it waxes and wanes in intensity.  The patient has had 2 episodes of nonbilious emesis.  She has had no fevers, sore throat, diarrhea, or bloody stools.  Two days ago, the patient developed an erythematous, macular rash over her legs and back that has become darker and more confluent today.  Blood pressure is 95/60 mm Hg.  The abdomen is soft and there is diffuse, mild tenderness on palpation with no rebound, guarding, or appreciable masses.  A raised, nonblanching rash is noted over the legs and back.  Urinalysis results are as follows:  Which of the following renal abnormalities is most likely present in this patient?

Quizplus · Accepted Answer

11ec160b_3b64_8f28_9249_bfd0187c3a05_MD0001_00 This patient's abdominal pain, purpura, and hematuria are consistent with Henoch-Schönlein purpura (HSP), an IgA-mediated vasculitis of the small vessels. The most common presenting symptom is nonblanching palpable purpura over the back, buttocks, and lower extremities, as seen in this patient. Colicky abdominal pain due to local vasculitis is also common, and other findings can include arthralgia/arthritis affecting the hips, knees, and/or ankles. Renal involvement occurs in over one-third of children with HSP and is due to mesangial deposition of IgA-containing immune complexes, similar to IgA nephropathy. Most patients, especially young children, develop mild nephritis characterized by hematuria, red cell casts, and nonnephrotic-range proteinuria. Serum creatinine is typically normal or slightly elevated. However, more severe complications (eg, acute kidney injury) can occur in a minority of patients. (Choice A) Membranous nephropathy is characterized by thickening of the glomerular basement membrane. It is far more common in adults than children and presents with edema and nephrotic-range proteinuria (≥3+). Moreover, purpura would not be expected. (Choice B) Goodpasture syndrome, which typically affects adolescents and adults, is characterized by glomerulonephritis due to linear deposition of IgG antibodies on the basement membrane. Associated findings include pulmonary hemorrhage, not purpura or abdominal pain. (Choice C) Focal segmental glomerulosclerosis typically presents with edema and proteinuria in adults and is characterized by localized regions of mesangial sclerosis and collapse on light microscopy. This patient's age and purpura make this diagnosis unlikely. (Choice E) Fusion or flattening of podocytes occurs in minimal change disease, the most common form of nephrotic syndrome in children. Patients have proteinuria and edema, not hematuria and rash. (Choice F) Subepithelial immune complex deposition is characteristic of poststreptococcal glomerulonephritis, which can present with hematuria weeks after group A Streptococcus (GAS) pharyngitis or skin infection (eg, impetigo). Although a blanching, erythematous, sandpaper rash can occur with GAS (ie, scarlet fever), palpable purpura is not seen. Educational objective: Henoch-Schönlein purpura is an IgA-mediated small vessel vasculitis that manifests with palpable purpura on the lower extremities, abdominal pain, arthralgia/arthritis, and renal disease (hematuria ± proteinuria). Renal involvement is due to IgA deposition in the mesangium.

A 6-Year-Old Girl Is Brought to the Office by Her