Steroid-Dependent Nephrotic Syndrome With Growth Faltering
A 6-year-old boy with steroid-sensitive nephrotic syndrome has had four relapses in 14 months. Each relapse remits within 10 days of prednisolone 60 mg/m2/day, but he relapses within 3 weeks of tapering below 0.5 mg/kg every other day. He now has a round face, height velocity falling from the 50th to the 15th percentile, BMI 22 kg/m2, BP 118/74 mmHg (99th percentile 117/76), and cushingoid features. Serum albumin is 32 g/L, creatinine 0.35 mg/dL, and urine protein-to-creatinine ratio 1.8 mg/mg. His parents are distressed by steroid effects and ask whether stronger treatment can be avoided. He has no hematuria, his hypertension is new, and complement is normal.
1. Classify his relapsing course and identify which findings argue against continuing the same steroid strategy without a steroid-sparing plan.
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Classification. He is a frequent relapser (four relapses in 14 months) and steroid-dependent, because he relapses during tapering and after reaching a low alternate-day dose. He is not steroid-resistant: each episode remits within 10 days of full-dose prednisolone.
Findings against unchanged strategy. The cumulative steroid burden is already producing cushingoid features, a fall in height velocity across two percentiles, and new systolic hypertension (118 mmHg exceeds his 99th percentile of 117). BMI 22 kg/m2 adds to cardiometabolic risk. Although steroids commonly cause hypertension and cushingoid change, persistent or severe hypertension, hematuria, or renal dysfunction should prompt reconsideration of the diagnosis and possibly biopsy; this boy currently has no hematuria and normal creatinine.
Judgement. Continuing repeated high-dose steroid courses without a steroid-sparing plan risks further growth suppression and hypertension. The goal is to maintain remission with the lowest effective steroid exposure while adding a steroid-sparing agent and monitoring for steroid toxicity.
2. Choose a steroid-sparing agent for this boy and justify it against the alternatives, including monitoring and the main risks.
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Preferred options. For a steroid-dependent frequent relapser with steroid toxicity, a calcineurin inhibitor (tacrolimus or cyclosporine) or mycophenolate mofetil are reasonable first steroid-sparing agents. Levamisole is an alternative for frequent relapsers but is less useful for steroid dependence. Cyclophosphamide can induce sustained remission but carries cumulative gonadal and oncogenic risk, especially in a boy, so I would reserve it.
Choosing for this child. Because he already has new hypertension and obesity, cyclosporine is less attractive: it causes hypertension, hypertrichosis, gingival hyperplasia, and nephrotoxicity. Tacrolimus has less cosmetic effect but can also raise blood pressure and cause tremor, hyperglycemia, and hypomagnesemia. Mycophenolate avoids nephrotoxicity and hypertension but is less potent and depends on reliable dosing. If adherence is good and hypertension is controlled, I would use mycophenolate first and reserve tacrolimus for relapse; if relapses are frequent despite mycophenolate, switch to tacrolimus.
Monitoring. Check trough levels if a calcineurin inhibitor is used, creatinine, electrolytes, magnesium, glucose, blood pressure, urine protein, and infection/vaccine status. Counsel about live vaccines and teratogenicity for mycophenolate.
3. What monitoring and supportive measures would you use to protect his growth and blood pressure while treatment is adjusted?
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Growth. Plot height velocity, not just height, every 3 months; document cumulative prednisolone dose and aim for the lowest effective exposure. Ensure adequate protein, calcium, and vitamin D intake; check 25-OH vitamin D and consider bone density if multiple courses. Refer to pediatric endocrinology if height velocity remains below the 25th percentile or if growth deceleration persists after steroid reduction.
Blood pressure. Home BP monitoring with a validated cuff, salt restriction, and weight management. Treat persistent hypertension; an ACE inhibitor may be useful if proteinuria persists, but only after resolving the acute steroid effect and confirming renal function. Monitor creatinine and potassium after starting.
Disease control. Track urine protein-to-creatinine ratio, albumin, and relapse frequency; do not taper too quickly. A steroid-sparing agent should be continued long enough to demonstrate a reduction in relapse rate. Educate the family that the aim is not zero medication but the lowest cumulative steroid dose with normal growth and BP.