A 3-year-old boy is brought to the office due to a weeklong history of edema that is gradually worsening. The patient has not been ill recently, and his medical history is unremarkable. He takes no daily medications, and vaccinations are up to date. Temperature is 36.7 C (98.1 F), blood pressure is 104/76 mm Hg, pulse is 85/min, and respirations are 18/min. On examination, there is periorbital edema and 1+ pretibial pitting edema. The remainder of the physical examination is normal. Laboratory results are as follows:
| Sodium | 140 mEq/L |
| Potassium | 3.7 mEq/L |
| Creatinine | 0.5 mg/dL |
| Total cholesterol | 240 mg/dL |
| Albumin | 2.1 g/dL |
| Aspartate aminotransferase (SGOT) | 17 U/L |
| Alanine aminotransferase (SGPT) | 24 U/L |
| Total bilirubin | 0.9 mg/dL |
| Direct bilirubin | 0.3 mg/dL |
Urinalysis shows 4+ proteinuria and no red blood cells. Which of the following is the best next step in management of this patient?
Minimal change disease | |
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*Indicated only for atypical cases. EM = electron microscopy. | |
This patient has acute-onset edema with hypoalbuminemia, hyperlipidemia, and proteinuria, findings consistent with nephrotic syndrome. In this case, the patient most likely has minimal change disease (MCD), which is the most common cause of nephrotic syndrome in young children and which can occur spontaneously or be triggered by infection.
Nephrotic syndrome results in urinary loss of protein (ie, proteinuria), including albumin (ie, hypoalbuminemia). This leads to decreased capillary oncotic pressure, with the resultant shift of fluid from the vasculature to the interstitial spaces causing edema (eg, periorbital, pretibial). Hyperlipidemia is common and appears to be due to increased hepatic lipoprotein production in response to low oncotic pressure. Blood pressure and creatinine are usually normal.
Because nephrotic syndrome due to MCD is caused by T-cell dysregulation and cytokine-mediated podocyte injury (leading to increased glomerular permeability), management is empiric immunosuppressive therapy with corticosteroids. MCD is highly steroid sensitive, and >90% of children achieve remission. However, relapse is common and typically requires repeat corticosteroid courses.
(Choice A) Although albumin can transiently increase oncotic pressure in nephrotic syndrome, this therapy is not recommended for patients with localized edema due to complications of vascular volume overload (eg, hypertension). Albumin with diuretic therapy can be considered in massive edema (eg, anasarca, pleural effusions), which is not seen in this patient.
(Choices B) ACE inhibitors are used in certain nephrotic syndromes (eg, focal segmental glomerulosclerosis [FSGS]) to decrease proteinuria. However, this medication is not indicated in MCD because corticosteroids alone correct the proteinuria in most cases.
(Choice D) Statins may be used in children with prolonged dyslipidemia. However, this patient's hyperlipidemia is likely due to nephrotic syndrome, and treatment of the underlying renal pathology typically improves high cholesterol.
(Choices E and F) Diagnosis of MCD in young children (ie, age 1-10) is usually clinical and does not require biopsy or imaging (eg, kidney ultrasound) in the setting of classic findings. Biopsy is indicated in adults with nephrotic syndrome due to increased likelihood of etiologies other than MCD (eg, FSGS). In contrast, biopsy for young children with nephrotic syndrome is reserved for atypical cases (eg, hypertension, hematuria, elevated creatinine) or steroid-resistant disease, findings not seen in this patient.
Educational objective:
Minimal change disease is the most common cause of nephrotic syndrome in young children and presents with edema secondary to proteinuria and hypoalbuminemia. Diagnosis is clinical in classic cases, and management is empiric corticosteroid therapy.