Simmons Sierra C, Smith Maxwell L, Chang-Miller April, Keddis Mira T
Department of Internal Medicine, Mayo Clinic, Phoenix, Arizona, USA.
Am J Nephrol. 2015;42(6):451-9. doi: 10.1159/000443747. Epub 2016 Jan 27.
Lupus nephritis (LN) is a serious and common complication of systemic lupus erythematosus (SLE) that predisposes to significant morbidity and mortality. Studies show that prompt diagnosis and treatment improves patient survival. We present a case of a 49-year-old female with an atypical presentation of LN who initially presented with new-onset hypertension, edema, arthritis, serositis and recently diagnosed leukocytoclastic vasculitis who later developed acute kidney injury, hematuria and nephrotic syndrome. Laboratory testing showed mixed cryoglobulinemia and elevated perinuclear anti-neutrophil cytoplasmic (p-ANCA) and myeloperoxidase (MPO) antibodies. SLE-related serologies were negative. Kidney biopsy showed diffuse proliferative global glomerulonephritis with a full-house nephropathy pattern on immunofluorescence suggestive of LN. Due to high clinical suspicion and renal biopsy findings, she was treated for LN with prompt renal response to immunosuppression. Cryoglobulins, p-ANCA and MPO titers normalized and the negative SLE serologies remained negative. Literature review on antinuclear antibody (ANA)-negative and seronegative LN revealed the following patient presentations: (1) renal-limited or renal and extra-renal manifestations of SLE with negative serologies and (2) renal and extra-renal manifestations of SLE with negative serologies at presentation who develop positive serologies later in follow-up. Both groups represent a unique and challenging cohort of patients who may require longer follow-up and further testing to rule out other glomerular diseases that may mimic LN on renal biopsy. The absence of SLE-related serologies should be weighed against a high pre-test probability of ANA-negative or seronegative LN. If highly suspected, the patient should be treated promptly with close monitoring.
狼疮性肾炎（LN）是系统性红斑狼疮（SLE）一种严重且常见的并发症，易导致显著的发病率和死亡率。研究表明，及时诊断和治疗可提高患者生存率。我们报告一例49岁女性，其LN表现不典型，最初表现为新发高血压、水肿、关节炎、浆膜炎，近期诊断为白细胞破碎性血管炎，随后发展为急性肾损伤、血尿和肾病综合征。实验室检查显示混合性冷球蛋白血症以及核周抗中性粒细胞胞浆抗体（p-ANCA）和髓过氧化物酶（MPO）抗体升高。SLE相关血清学检查为阴性。肾脏活检显示弥漫性增殖性全小球性肾小球肾炎，免疫荧光呈满堂亮肾病模式，提示为LN。由于临床高度怀疑且肾脏活检结果明确，她接受了LN治疗，免疫抑制治疗后肾脏反应迅速。冷球蛋白、p-ANCA和MPO滴度恢复正常，SLE血清学检查仍为阴性。关于抗核抗体（ANA）阴性和血清阴性的LN的文献综述显示了以下患者表现：（1）SLE的肾脏局限性或肾脏及肾外表现，血清学检查阴性；（2）SLE的肾脏及肾外表现，初诊时血清学检查阴性，随访后期血清学检查转为阳性。这两组患者均代表了独特且具有挑战性的群体，可能需要更长时间的随访和进一步检查，以排除肾脏活检时可能类似LN的其他肾小球疾病。ANA阴性或血清阴性LN的高预测概率应与SLE相关血清学检查阴性相权衡。如果高度怀疑，应立即对患者进行治疗并密切监测。
