Severe Hypophosphatemia in a Girl with Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is characterized by various symptoms and multi-organ involvement. Hypophosphatemia has been described in several diseases accompanied with systemic inflammation. However, hypophosphatemia has rarely been described in SLE patients, especially in those without nephritis. We report the case of a 13-year-old girl with SLE who developed hypophosphatemia without renal involvement. Her hypophosphatemia was caused by renal loss of phosphorus and persisted for 7 months. It improved as her complement levels increased. Therefore, hypophosphatemia may be related to disease activity in SLE patients.