Genu varum deformity due to premature epiphyseal closure after treatment with isotretinoin for neuroblastoma: A case report

Analysis of the effects of isotretinoin on the premature epiphyseal closure in pediatric populations: a literature review

CONTEXT

Oral isotretinoin, a systemic retinoid and a vitamin A derivative, has been widely utilized to treat acne in both adult and pediatric populations. Additionally, systemic retinoids have also been utilized to treat neuroblastoma in pediatric patients. Common side effects associated with oral isotretinoin include dry eyes, dry mouth, elevated liver enzymes, depression, and arthralgia. Less common side effects of isotretinoin include hearing loss, pseudotumor cerebri, anaphylaxis, and skeletal abnormalities including growth arrest. The U.S. Food and Drug Administration (FDA) has received reports of premature epiphyseal closure in patients treated with isotretinoin retinoids, which are commonly prescribed by primary care providers as a treatment for acne. It is important to raise awareness of the potential side effects of isotretinoin to enable informed treatment decisions before beginning an isotretinoin regimen.

OBJECTIVES

This chapter aims to elucidate that isotretinoin, given at various doses and durations, has been associated with growth plate abnormalities, which can lead to premature epiphyseal closure.

METHODS

Two databases were utilized for the literature review and were conducted at different time periods. Our literature review was conducted between December 2020 and June 2021, utilizing PubMed with the following search terms: "isotretinoin" and "isotretinoin and premature epiphyseal closure." In April 2021, we searched the FDA's "Drug Data and Adverse Event Report System" utilizing the terms "isotretinoin" and "epiphysis premature fusion." We included in our query reports of patients worldwide under 18 years of age with premature epiphyseal closure or growth plate damage secondary to isotretinoin. Studies published in English between 1980 and 2020 were also included, as well as background sources relating to an isotretinoin profile with side effects and dosing. We narrowed our search to exclude patients with a history of growth plate disorders due to trauma, malignancy, or other pathological processes, as well as patients with growth arrest due to endocrine factors. Growth plate abnormalities associated with retinoid derivatives other than isotretinoin were also excluded.

RESULTS

A total of 28 items were selected for our literature review including: one FDA drug label, one FDA website of adverse reactions, 19 supplemental articles, six case reports, and one case series of premature epiphyseal closure secondary to isotretinoin. The FDA received 41 reports worldwide of premature epiphyseal closure related to isotretinoin in patients under 18 years of age. Additionally, premature epiphyseal closure and growth plate abnormalities occurred in nine patients with various durations and doses of isotretinoin ranging from the lowest dose of 0.5 mg/kg/day for a few months to 3.5 mg/kg/day for years.

CONCLUSIONS

Isotretinoin-induced premature epiphyseal closure and growth plate deformities seem to be linked to higher doses of isotretinoin for the duration of months to years. There have been reported cases of premature epiphyseal closure in individuals receiving therapeutic doses of isotretinoin for acne treatment, which are much lower compared to the high doses utilized for neuroblastoma. Based on this study, isotretinoin appears to impact the growth plates of proximal tibia and distal femur. A cause-and-effect relationship between isotretinoin and premature epiphyseal closure cannot be concluded.

Update on premature physeal closure. Diagnosis and treatment

PURPOSE OF REVIEW

Premature Physeal Closure (PPC) is the most common consequence of a mostly posttraumatic, physeal injury. They are of utmost importance because they can significantly alter physeal function and lead to disorders such as limb length discrepancies and angular deformities.

RECENT FINDINGS

The type of physeal fracture has not demonstrated a solid predictive value in the formation of PPC, especially in the knee where almost any type of fracture can produce it. The detection of physeal damage with imaging tests (simple radiology and MRI) is very accurate; however, their predictive capacity to foretell which injury will generate a physeal bridge is still poor. For this reason, it is not advisable to make surgical decisions at the first medical assessment. Direct surgical management of PPC's (resection-interposition technique) has generally shown high unpredictability. Nevertheless, the latest interposition materials (chondrocytes and mesenchymal stem cells) showed promising results.

SUMMARY

PPC is an often devastating consequence of physeal injury and as such deserves further research. To date little is known about etiopathogenesis, risk factors and natural history among other aspects. Until direct surgery offers more consistent results, acute osteotomies and bone distraction for progressive correction continue to be the most widespread treatments for PPCs.