#1728 New onset proteinuria in two pregnancies: glomerulopathy or preeclampsia?
Authors: Chimenti Giulia , Magli Anna , Njandjo Linda , Fois Antioco , Santagati Giulia , Piccoli Giorgina , Torreggiani Massimo 
Published: May 2024

Abstract

Background and Aims
Distinguishing between preeclampsia in pregnant women and a new onset glomerulonephritis could be challenging.

Method
Here, we present two cases on new onset proteinuria during pregnancy which were diagnosed with primary membranous nephropathy and their treatment.

Results
Case 1. A 27-year-old patient, G6P5A1, was referred to our attention at the 14th week of gestation (wg) for new onset proteinuria of about 5 g/day. She had a personal history of preeclampsia and was already under low-dose Aspirin since the beginning of this pregnancy. She was normotensive, her serum albumin was about 1.8 g/dl (Fig. 1A) and showed no edema. Due to the timing of pregnancy, a glomerular disease was suspected, and she was started on oral prednisolone 20 mg/day. Complementary explorations found a normal SFlT-1 to PlGF ratio as well as normal renal function and positive anti-PLA2R antibodies. A diagnosis of membranous nephropathy diagnosis was, therefore, made. Cyclosporine (CsA) 300 mg twice daily was started, prednisolone was rapidly tapered, and partial remission was rapidly attained. The rest of her pregnancy was uneventful until the 36 wg when hypertension, increase in proteinuria and findings of IUGR developed; on the account of the diagnosis of superimposed preeclampsia, delivery was decided (caesarian section) giving birth to a healthy female baby weighting 1.9 kg (1st Intergrowth centile). After the delivery the patient underwent two injection of Rituximab (Rtx) (1 g 2 weeks apart) and CsA was discontinued. The patient achieved partial remission, and her antibody titer decreased but remained positive. A renal biopsy is scheduled to guide future treatment options.
Case 2. A 44-year-old patient, G3P2A1, without history of previous preeclampsia, was referred to our attention at 32 wg for new onset proteinuria around 5 g/day first discovered at 10 wg. Her blood pressure was normal. She was already under Aspirin treatment, based on a suspicion of preeclampsia, which was however ruled out by the timing of proteinuria onset. At referral additional investigations revealed an increase in proteinuria up to 19 g/l, normal renal function, gestational diabetes, normal SFlT-1 to PlGF ratio and a serum albumin around 1.4 g/dl (Fig. 1B). Anti-PLA2R antibodies were positive, and a membranous nephropathy was diagnosed at 34 wg. Immunosuppression treatment was waived considering the timing of pregnancy and supportive treatment by LMW heparin was started. The patient delivered at 37 wg by urgent cesarian section on the account of onset of hypertension, giving birth to a male baby weighting 2760 g (37th Intergrowth centile). CsA treatment was started 5 days after delivery and Rtx infusion followed 2 weeks after delivery, on the account of her decision to breastfeed. CsA was discontinued 2 months after Rtx first injection with complete sustained remission and undetectable PLA2R antibodies.

Conclusion
Preeclampsia is the most frequent complication of pregnancy. In particular before the 20 wg the distinction between an hypertensive disorder of pregnancy (HDP) and primary glomerular disease is fundamental but may be difficult. In our cases, the early onset of proteinuria was in favor of a primitive disease of the kidney. Complementary explorations allowed diagnosing membranous nephropathy. The treatment of glomerulonephritides, either of new onset or chronic, during pregnancy is challenging. Renal biopsy has a higher risk of complications, especially in mid-pregnancy, and finding positive anti PLA2R antibodies may allow avoiding the histological examination. It is worth noting that preeclampsia developed in both cases towards the end of gestation, stressing the role of chronic kidney disease as a major risk factor for HDP.
The SFlT-1 to PlGF ratio could come in handy both for differential diagnosis and for diagnosis of superimposed preeclampsia.