Priya Sangeetha, Arivazhagan S, Kumar Dilip
Junior Resident, Department of General Medicine, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India, Corresponding Author.
Associate Professor, Department of Nephrology, PSG Institute of Medical Sciences and Research, Coimbatore, Tamil Nadu, India.
J Assoc Physicians India. 2025 May;73(5):81-82. doi: 10.59556/japi.73.0960.
Membranous nephropathy is a type of glomerular disease which results in nephrotic syndrome that can be seen in adults. In most cases of membranous nephropathy, the target antigen has been phospholipase A2 receptor (PLA2R). In recent times, another antigen named neural epidermal growth factor-like 1 (NELL-1) has been labeled. We present a case report of NELL-1-positive membranous nephropathy due to intake of complementary and alternative medication, mercury being the possible content.
A case report-50-year-old female, brought to emergency department with breathing difficulty, bilateral swelling of legs, and reduced urine output for 3 days. Patient had periorbital edema, facial puffiness, and bilateral limb edema on examination. Family members revealed a past history of rheumatoid arthritis for which she is on complementary and alternative medication. Vitals-blood pressure (BP)-70/50 mm Hg, in view of shock, patient was started on inotropes at emergency medical department (EMD). On evaluation, her complete blood count showed anemia, neutrophilic leukocytosis, erythrocyte sedimentation rate (ESR) was high. Serum electrolytes showed hyponatremia. Urine complete showed albuminuria with high urine spot protein-creatinine ratio (PCR). Renal function test showed increase in creatinine level which rapidly worsened on serial monitoring. Liver function test showed severe hypoalbuminemia with albumin-globulin (AG) reversal. Lipid profile showed high cholesterol, triglyceridemia, with increased low-density lipoprotein (LDL). Serum electrophoresis showed hypoalbuminemia with relative increase in alpha 2 fraction, suggestive of nephrotic syndrome. In view of shock and hypotension, adrenal insufficiency was considered and patient was started on steroids. With the clinical presentation and laboratory parameters, the differential diagnoses considered here were membranous nephropathy, minimal change disease, and focal segmental glomerulosclerosis. So, we proceeded with renal biopsy after optimizing her renal parameters, and it was reported as membranous nephropathy and acute interstitial nephritis. Antigen panel for membranous nephropathy was sent and came out to be NELL-1-positive. She was started on IV pulse steroid therapy.
In our case report, we conclude that NELL-1 has been shown to cause a rare form of membranous nephropathy when negative for PLA2R and thrombospondin type 1 domain containing 7A (THSD7A). Our possible explanation is mercury-induced membranous nephropathy.
Our patient was started on pulse steroids and slowly tapered. Her renal parameters gradually improved. Since everything resolved without any active intervention for rheumatoid arthritis, thereby eliminating the inciting agent.
膜性肾病是一种可导致成人肾病综合征的肾小球疾病。在大多数膜性肾病病例中，靶抗原为磷脂酶A2受体（PLA2R）。近来，另一种名为神经表皮生长因子样1（NELL-1）的抗原也已被确定。我们报告一例因摄入补充和替代药物（可能含有汞）导致的NELL-1阳性膜性肾病病例。
病例报告——一名50岁女性，因呼吸困难、双腿双侧肿胀及尿量减少3天被送至急诊科。检查发现患者有眶周水肿、面部浮肿及双侧肢体水肿。家属透露她有类风湿关节炎病史，一直在接受补充和替代药物治疗。生命体征——血压（BP）70/50mmHg，鉴于休克，患者在急诊科开始使用血管活性药物。评估时，她的全血细胞计数显示贫血、中性粒细胞增多，红细胞沉降率（ESR）升高。血清电解质显示低钠血症。尿常规显示蛋白尿，尿蛋白肌酐比值（PCR）高。肾功能检查显示肌酐水平升高，连续监测时迅速恶化。肝功能检查显示严重低白蛋白血症伴白蛋白球蛋白（AG）倒置。血脂谱显示高胆固醇、高甘油三酯血症，低密度脂蛋白（LDL）升高。血清电泳显示低白蛋白血症，α2组分相对增加，提示肾病综合征。鉴于休克和低血压，考虑肾上腺功能不全，患者开始使用类固醇。根据临床表现和实验室参数，这里考虑的鉴别诊断为膜性肾病、微小病变病和局灶节段性肾小球硬化。因此，在优化她的肾脏参数后进行了肾活检，报告为膜性肾病和急性间质性肾炎。送检了膜性肾病的抗原检测，结果显示为NELL-1阳性。她开始接受静脉脉冲类固醇治疗。
在我们的病例报告中，我们得出结论，当PLA2R和含血小板反应蛋白1型结构域7A（THSD7A）为阴性时，NELL-1已被证明可导致一种罕见的膜性肾病形式。我们可能的解释是汞诱导的膜性肾病。
我们的患者开始使用脉冲类固醇并逐渐减量。她的肾脏参数逐渐改善。由于在未对类风湿关节炎进行任何积极干预的情况下一切都得到了解决，从而消除了致病因素。
