Rationale: Chronic thromboembolic pulmonary hypertension (CTEPH) is rare in children and determining the underlying etiologies is essential for treatment. Venous thromboembolism, a well-known complication in nephrotic syndrome (NS), always occurrs during the treatment in course of the disease. However, CTEPH as the first manifestation of NS has not been reported till now.
Patient concerns: A 12-year-old boy initially complained of hemoptysis, cough and shortness of breath with exertion, any symptoms regarding NS such as edema were not presented. Due to the identification of P2 enhancement, liver enlargement (2 cm below the rib) and jugular vein distension, pulmonary hypertension (PH) was firstly suspected and ultimately confirmed by detection of enlargement of right atrium (RA) and right ventricle (RV) enlargement (RA = 45mm, RV = 30mm), mild tricuspid valve regurgitation (TR) and elevation of pulmonary arterial pressure (63 mmHg) on echocardiogram. In order to search the underlying causes of PH, series of targeted laboratory evaluation and imaging were conducted, and pulmonary arterial embolism (PE) in inferior lobes of double lungs was found on chest contrast-enhanced computed tomography.
Diagnosis: NS was unexpectedly discovered by detection of lower serum albumin level (24.4 g/L), severe proteinuria (+++, 4.62 g/24 h) when we were searching for the predisposing factors causing thromboembolism.
Interventions and outcomes: After treatment of NS, the symptom regarding shortness of breath with exertion gradually became less apparent and was relieved one month later. Proteinuria and microscopic hematuria also disappeared. Encouragingly, RA and RV dilation, and the pulmonary arterial pressure almost returned to a normal range half a year later, with alleviation of MR.
Lessons: CTEPH can occur rarely in children and NS is an important predisposing factor. PE could be the first manifestation of NS. When pediatricians encounter children with PE or CTEPH, NS as the underlying etiology should be considered. Except for renal venous thrombosis, the possibility of PE needs to be paid more attention in children with NS.