Transient synovitis associated with leuprolide depot (Lupron).

A 6.6-year-old female presented to endocrinology with precocious puberty for evaluation and management. Workup was initiated, and a diagnosis of central precocious puberty was confirmed. A decision was made to initiate pubertal blockade using gonadotropin-releasing hormone agonist (GnRHa) therapy with depot leuprolide acetate injections every 3 months. The patient received the first depot leuprolide acetate injection in the right ventrogluteal area. Six hours following the injection, the patient was reported to be inconsolable in pain, which was localized to the right hip site of the earlier injection and associated with a refusal to ambulate. The pain and discomfort continued to progress over the next 24 h despite an alternating regimen of Tylenol and ibuprofen prompting admission to the emergency department. Vital signs demonstrated a low-grade fever and elevated C-reactive protein. An ultrasound of the right hip demonstrated fluid accumulation within the joint. Over the next week, the patient was unable to walk independently and required assistance for activities of daily living. By 2 weeks after the injection, the pain began to remit, and the patient resumed activities of daily living. Following consultation with allergy, a decision was made to continue GnRHa suppressive therapy with an alternative analog (Triptodur). The patient tolerated subsequent treatment without reaction. Although gonadotropin-releasing hormone agonists (GnRHa) have a generally good safety profile, there is a history of both local and systemic hypersensitivity reactions associated with their use. Despite the long-acting formulation of depot leuprolide acetate, the systemic reaction in this case appears to be self-limited. Discontinuation of therapy or a change to an alternative formulation of GnRHa analog should be considered based on the need for therapy versus the potential risk of rechallenge.