Growth in Children with Steroid Sensitive Nephrotic Syndrome

Growth in children with nephrotic syndrome: a post hoc analysis of the NEPTUNE study

BACKGROUND

Steroids, the mainstay of treatment for nephrotic syndrome in children, have multiple adverse effects including growth suppression.

METHODS

Anthropometric measurements in children < 18 years enrolled in the Nephrotic Syndrome Study Network (NEPTUNE) were collected. The longitudinal association of medication exposure and nephrotic syndrome characteristics with height z-score and growth velocity was determined using adjusted Generalized Estimating Equation regression and linear regression.

RESULTS

A total of 318 children (57.2% males) with a baseline age of 7.64 ± 5.04 years were analyzed. The cumulative steroid dose was 216.4 (IQR 61.5, 652.7) mg/kg (N = 233). Overall, height z-scores were not significantly different at the last follow-up compared to baseline (- 0.13 ± 1.21 vs. - 0.23 ± 1.71, p = 0.21). In models adjusted for age, sex, and eGFR, greater cumulative steroid exposure (β - 7.5 × 10-6, CI - 1.2 × 10-5, - 3 × 10-6, p = 0.001) and incident cases of NS (vs. prevalent) (β - 1.1, CI - 2.22, - 0.11, p = 0.03) were significantly associated with lower height z-scores over time. Rituximab exposure was associated with higher height z-scores (β 0.16, CI 0.04, 0.29, p = 0.01) over time.

CONCLUSION

Steroid dose was associated with lower height z-score, while rituximab use was associated with higher height z-score.

Overt Hypothyroidism and Severe Growth Retardation in a Preschool Girl with Poorly Controlled Nephrotic Syndrome: Case Report and Literature Review

Background

Nephrotic children may develop thyroid hormone dysfunction due to urinary excretion of thyroid hormones. In contrast to the subclinical hypothyroidism that affects around 30% of children with nephrotic syndrome (NS), the patient in this case had overt hypothyroidism and severe growth retardation.

Clinical case

A 5 years and 8 months old girl with steroid-dependent NS was referred from another center due to persistent edema and decreased diuresis, being treated with mycophenolate mofetil (MMF) 250 mg once a day and L-thyroxine 50 mcg daily since 4 months of NS onset because of hypothyroidism. Her albumin was 12.64 g/l, cholesterol 25.64 mmol/l and proteinuria 5 g/l. Severe growth retardation was observed: patient's height was 93.5 cm (-13 cm <3 percentile), weighted 17.2 kg (15-25 percentile). Her disease vintage was over 3 years. Girl's growth velocity has slowed down from 3.5 months. The patient received a high cumulative dose of prednisolone (approx. 7800 mg in 1 year and 8 months). Thyroid-stimulating hormone was higher (18.04 mU/L) with reduced FT4 11.43 pmol/l and IGF-1 < 15 µg/L. Kidney biopsy revealed minimal change disease, and genetic testing was negative. Intensive NS treatment with methylprednisolone pulse therapy, enlarged doses of MMF and albumin infusion were started and L-thyroxine dose was increased to 75 mcg. TPOAb was in normal range (12.65 IU/ml). After 3 weeks she was discharged with no edema and after stopping methylprednisolone treatment thyroid function normalized and L-thyroxin was discontinued. Two weeks later standard growth hormone stimulation test with clonidine showed partially insufficient growth hormone secretion. During NS remission with normalization of thyroid function (TSH 6.680 mU/l, FT4 13.85 pmol/l) and normalization of IGF-1 level (132 mcg/l) partial catch-up growth was observed (height velocity increased from 3.5 cm/year to 7.3 cm/year, based on 4-month calculation period).

Conclusions

Clinicians should be aware of a risk of developing hypothyroidism and consider thyroid function testing during the treatment of children with NS, as well as actively treat hypothyroidism and evaluate growth.