Case Report: A case of recurrent thrombosis in pediatric antiphospholipid syndrome associated with pediatric onset systemic lupus

Antiphospholipid syndrome presenting as isolated renal vein thrombosis: a case report and review of the literature

BACKGROUND

Pediatric antiphospholipid syndrome is a rare systemic autoimmune disorder characterized by recurrent thrombotic events in the presence of antiphospholipid antibodies. Isolated right renal vein thrombosis resulting in a nonfunctional kidney is an uncommon manifestation of antiphospholipid syndrome. Here, we present our experience with antiphospholipid syndrome secondary to systemic lupus erythematosus.

CASE PRESENTATION

A 10 year-old girl from a Hindu family in Sindh, Pakistan, who had previously been healthy, presented in 2020 with a 1-week history of abdominal pain, gross hematuria, vomiting, and fever. On examination, she was anxious, febrile, hypertensive, and had an enlarged, tender right kidney. Other systemic examinations, including skin, locomotor, respiratory, cardiovascular, and nervous systems, were unremarkable. Initial investigations for ureteric colic and acute pyelonephritis were negative, but revealed thrombocytopenia on complete blood count, mild proteinuria, hematuria on urinalysis, and normal kidney and liver function tests, along with normal prothrombin and activated partial thromboplastin times. An abdominal ultrasound showed a diffusely enlarged, echogenic right kidney with a loss of corticomedullary distinction and cortical hypoechoic areas, while the left kidney appeared normal. Color Doppler ultrasound identified a large thrombus in the right renal vein, completely obstructing its lumen and showing no blood flow. The thrombus extended into the inferior vena cava. Computed tomography angiography confirmed an organized thrombus completely blocking the right renal vein and extending into the infrahepatic portion of the inferior vena cava. No prothrombotic risk factors were identified during clinical evaluation, and thrombophilia screening was negative. However, lupus serology and antiphospholipid antibodies were positive, confirming a diagnosis of secondary antiphospholipid syndrome.

MANAGEMENT AND OUTCOME

The patient was treated with enoxaparin anticoagulation, later transitioned to warfarin sodium, and her hypertension was managed with captopril and amlodipine. She showed gradual improvement over 10-12 days and was discharged on anticoagulants, antihypertensive medications, antiplatelet agents, and hydroxychloroquine. A follow-up Doppler ultrasound revealed persistent blockage of the right renal vein by the thrombus, with no thrombus in the inferior vena cava. A dimercaptosuccinic acid scan indicated a nonfunctioning right kidney. While nephrectomy was recommended, her parents declined the procedure. Anticoagulation therapy was switched to rivaroxaban to avoid frequent international normalized ratio monitoring. Her captopril was replaced after control of blood pressure with losartan. Over the next 4 years, her follow-up was uneventful. She demonstrated normal growth, stable blood pressure (off antihypertensive), and normal kidney function without proteinuria. There were no lupus flares or thrombotic recurrences. Her most recent urinalysis was normal, with a serum creatinine level of 0.6 mg/dL and an estimated glomerular filtration rate > 170 mL/min/1.73 m2.

CONCLUSION

Isolated renal vein thrombosis is a rare presentation of antiphospholipid syndrome and poses a diagnostic challenge in the absence of preexisting prothrombotic risk factors. Early diagnosis and timely management are crucial to prevent organ damage. In this case, the patient retained a solitary functioning kidney. Long-term follow-up is essential to monitor for lupus flares, thrombus recurrence, hypertension, proteinuria, and progression to chronic kidney disease, as well as to ensure continued thromboprophylaxis.

Pediatric antiphospholipid syndrome: is it the same as an adult?

IMPORTANCE

Antiphospholipid syndrome in neonates and children is a rare, but in some cases life-threatening condition with arterial and/or venous thrombosis and/or non-thrombotic neurological, skin, ophthalmological and other manifestations.

OBSERVATIONS

This review highlights the available information about the features of pediatric APS, including the rare catastrophic form, the differences between pediatric and adult APS, and the role of genetic thrombophilia in APS manifestation.

CONCLUSIONS AND RELEVANCE

The clinical manifestations and treatment options for APS in children may differ from those in adults, and prescribing therapy can be challenging due to the unique clinical and morphological characteristics of the pediatric patient. Pediatric APS may be a predictor of the development of certain autoimmune diseases and classic manifestations of APS in adulthood, therefore, a revision of the existing criteria for the diagnosis and treatment of APS in children is necessary.

SARS-CoV-2 spike aggravates lupus nephritis and lung fibrosis in systemic lupus erythematosus

OBJECTIVE

COVID-19 induces the development of autoimmune diseases, including SLE, which are characterised by inflammation, autoantibodies and thrombosis. However, the effects of COVID-19 on SLE remain unclear.

METHODS

We investigated the effects of COVID-19 on SLE development and progression in three animal models. Plasmids encoding SARS-CoV-2 spike protein and ACE2 receptor were injected into R848-induced BALB/C lupus mice, R848-induced IL-1 receptor antagonist knockout (KO) lupus mice and MRL/lpr mice. Serum levels of albumin and autoantibodies, lymphocyte phenotypes and tissue histology were evaluated.

RESULTS

In R848-induced BALB/C lupus mice, the SARS-CoV-2 spike protein increased autoantibody and albumin levels compared with vehicle and mock treatments. These mice also exhibited splenomegaly, which was further exacerbated by the spike protein. Flow cytometric analysis revealed elevated T helper 1 cell counts, and histological analysis indicated increased levels of the fibrosis marker protein α-smooth muscle actin. In KO mice, the spike protein induced splenomegaly, severe kidney damage and pronounced lung fibrosis. In the MRL/lpr group, spike protein increased the serum levels of autoantibodies, albumin and the thrombosis marker chemokine (C-X-C motif) ligand 4.

CONCLUSION

COVID-19 accelerated the development and progression of lupus by inducing autoantibody production, fibrosis and thrombosis.

Case Report: In situ pulmonary artery thrombosis in a 12-year-old girl classified as systemic lupus erythematosus

In situ pulmonary artery thrombosis (ISPAT) is a relatively rare but potentially life-threatening complication of systemic lupus erythematosus (SLE) in children. We report the case of a 12-year-old girl who presented with fever, chest pain, and dyspnea. Immune thrombocytopenia was identified due to purpura and menorrhagia 3 months before presentation with a lowest platelet count of 12 × 109/L. The sudden onset of fever, chest pain, and dyspnea were misdiagnosed as hyperinflammatory responses caused by pneumonia; these symptoms ameliorated with glucocorticoid and antibiotic treatment. The reappearance of symptoms after dose reduction of glucocorticoids and the observation of bloody bronchoalveolar lavage fluid necessitated further evaluation. Pulmonary artery thrombosis/embolism was identified using computed tomography pulmonary angiography and high D-dimer quantitative level of 4,118 μg/L (normal <252 μg/L). Ultrasonography of the deep and superficial veins of both lower limbs and renal veins revealed no thrombosis, suggesting the diagnosis of ISPAT. Further etiological evaluation revealed positive antinuclear antibodies, lupus anticoagulant, and anti-SSA antibodies, confirming SLE. Repeated normal urine analysis indicated that lupus nephritis was unlikely. Further, the negative anticardiolipin and anti-β2 glycoprotein antibodies and temporary positive lupus anticoagulant suggested that antiphospholipid syndrome was unlikely. The patient received anticoagulants, glucocorticoids, hydroxychloroquine, and mycophenolate therapy. Her symptoms gradually improved, and she was discharged. At the 1-month follow-up, the thrombosis had resolved. During the 1-year follow-up, her condition remained well without SLE relapse. Our experience with this case emphasizes searching for SLE in the case of ISPAT and pulmonary hemorrhages. ISPAT can occur in children with SLE and may be caused by hyperinflammatory response during SLE flare.