Pulmonary embolism as the initial manifestation of steroid-sensitive nephrotic syndrome in an adolescent: a case report

Pulmonary embolism (PE) is uncommon in adolescents and often presents with non-specific symptoms, which may delay diagnosis. Nephrotic syndrome (NS) is a recognized risk factor for venous thromboembolism; however, thromboembolic events may occasionally precede overt renal manifestations, creating additional diagnostic challenges. We report a case of a 17-year-old male adolescent with steroid-responsive NS initially presenting with PE. The patient initially developed fever, cough, and abdominal pain, leading to a preliminary diagnosis of pneumonia and cholecystitis before PE was identified. Computed tomography pulmonary angiography revealed bilateral multiple pulmonary emboli. Laboratory evaluation showed hypoalbuminemia, but initial repeated urinalyses were negative for proteinuria and renal function was preserved. During hospitalization, the patient developed edema, acute kidney injury, and nephrotic-range proteinuria. No definite evidence of secondary NS was identified. Renal biopsy was not performed due to concurrent anticoagulation therapy and refusal from the patient’s family. His symptoms improved after anticoagulation and glucocorticoid therapy, and there was no recurrence during a two-year follow-up. This case highlights two important diagnostic challenges: PE should be considered even in adolescents with non-specific symptoms, and NS may remain clinically silent when thromboembolic events occur, particularly in patients with unexplained PE accompanied by hypoalbuminemia.