Dr Stephanie Smith1, Ms Mandish Dhanjal1, Dr Charlotte Frise1, Professor Elizabeth Lightstone1, Dr Maria Atta1
1Imperial College Healthcare NHS Trust, London, United Kingdom
Biography:
Stephanie Smith is an Obstetrics and Gynaecology trainee in Kent, Surrey and Sussex, United Kingdom. She is currently completing a Clinical Fellowship in Obstetrics and Obstetric Medicine at Queen Charlotte’s and Chelsea Hospital, Imperial College Healthcare NHS Trust.
Abstract:
Introduction: Monoclonal Gammopathy of Renal Significance (MGRS) is a pre-neoplastic plasma cell disorder defined by the presence of monoclonal immunoglobulins, which are nephrotoxic and lead to kidney injury. It is rarely seen in women of childbearing age and, like myeloma, is difficult to diagnose in pregnancy.
Case: A 33-year-old nulliparous woman with a history of one early miscarriage, had a booking protein:creatinine ratio (PCR) of >300 mg/mmol with normal blood pressure. She was given antibiotics for a urinary tract infection (UTI); no further investigations were performed. When abroad at 24 weeks she was admitted with threatened preterm labour. Anaemia was treated with transfusion and nephrotic syndrome identified. Later in pregnancy she became more anaemic and breathless, and her PCR continued to increase. Other bloods including calcium and creatinine were normal. Low C3 and kappa light chains were identified and a diagnosis of C3 glomerulonephropathy considered. It was decided to defer renal and bone marrow biopsy until after delivery. Labour was induced at 36 weeks’ due to worsening fluid overload and she had an uncomplicated vaginal birth.
Renal biopsy showed mesangioproliferative glomerulonephritis. Bone marrow biopsy and flow cytometry showed 4.3% plasma cells, of which 88% were abnormal with no high-risk cytogenetics, in keeping with a plasma cell neoplasm. A diagnosis of MGRS was made, and treatment commenced with daratumumab, bortezomib, dexamethasone and thalidomide chemotherapy.
Important learning points from this case include:
– When reviewing the notes from her miscarriage, haematuria and proteinuria were present but did not prompt investigation
– Proteinuria at booking requires investigation and consideration of renal biopsy, particularly if nephrotic-range
– It is unusual for a UTI to cause nephrotic-range proteinuria; if attributed to a UTI ensure resolution after treatment
– Bone marrow aspiration and trephine biopsy can be performed in pregnancy if required
Keywords
Monoclonal Gammopathy of Renal Significance
Nephrotic-range proteinuria
References
Kaseb H, Annamaraju P, Babiker HM. Monoclonal Gammopathy of Undetermined Significance. [Updated 2022 Jul 10]. In: StatPearls [Internet]. Treasure Island (FL): Stat Pearls Publishing; 2024 Jan
Monoclonal Gammopathy of Renal Significance Authors: Nelson Leung, M.D. https://orcid.org/0000-0002-5651-1411, Frank Bridoux, M.D., Ph.D., and Samih H. Nasr, M.D.Author Info & Affiliations. Published May 19, 2021 N Engl J Med 2021;384:1931-1941, DOI: 10.1056/NEJMra1810907, VOL. 384 NO. 2