Shah Neal, Rosales Ivy, Smith Rex Neal, Berchuck Jacob E, Yee Andrew J, Tolkoff-Rubin Nina
Clin Nephrol. 2019 May;91(5):311-316. doi: 10.5414/CN109693.
This case highlights the importance of getting a thorough workup for acute kidney injury before assigning a diagnosis.
A 68-year-old male was referred to our clinic after a recent outside hospitalization for septic knee arthritis and acute kidney injury requiring hemodialysis. He had chronic kidney disease presumed secondary to diabetes with baseline GFR 50 mL/min. He complained of fatigue and weight loss. Vital signs were within normal limits. Exam was notable for trace ankle edema, healed right knee scar, and right internal jugular hemodialysis catheter. Medications included amlodipine, aspirin, atorvastatin, furosemide, sevelamer, and cephalexin. Calculated creatinine clearance was 6 mL/min with urine output 2 L/day. Urinalysis showed 1+ protein, 2+ glucose, and fine granular casts. Clinical impression was ischemic acute tubular necrosis in recovery phase. However, when he did not improve and continued requiring dialysis, further workup showed elevated serum κ free light chains and urine Bence-Jones protein. Renal biopsy showed κ light chain crystalline tubulopathy, interstitial inflammation, and extensive fibrosis. Subsequent bone marrow biopsy showed 15% κ-restricted plasma cells. Multiple myeloma was diagnosed, and chemotherapy initiated. With decrease in κ light chain burden, kidney function improved, and patient was able to come off dialysis.
CONCLUSION: This case describes a rare presentation of κ light chain crystalline tubulopathy and illustrates the value of a comprehensive evaluation for acute kidney injury to enable prompt diagnosis and therapy. .
该病例强调了在做出诊断前对急性肾损伤进行全面检查的重要性。
一名68岁男性在因脓毒性膝关节炎和急性肾损伤在外院住院治疗后被转诊至我们的诊所，其急性肾损伤需要进行血液透析。他患有推测继发于糖尿病的慢性肾脏病，基线肾小球滤过率为50 mL/分钟。他主诉疲劳和体重减轻。生命体征在正常范围内。体格检查发现有微量踝部水肿、右膝愈合瘢痕以及右颈内静脉血液透析导管。用药包括氨氯地平、阿司匹林、阿托伐他汀、呋塞米、司维拉姆和头孢氨苄。计算得出的肌酐清除率为6 mL/分钟，尿量为2升/天。尿液分析显示尿蛋白1+、尿糖2+以及细颗粒管型。临床诊断为恢复期缺血性急性肾小管坏死。然而，当他病情未改善且仍需要透析时，进一步检查发现血清κ游离轻链升高以及尿本周氏蛋白阳性。肾活检显示κ轻链结晶性肾小管病、间质炎症和广泛纤维化。随后的骨髓活检显示15%的κ限制性浆细胞。诊断为多发性骨髓瘤，并开始化疗。随着κ轻链负荷的降低，肾功能改善，患者能够停止透析。
本病例描述了κ轻链结晶性肾小管病的罕见表现，并说明了对急性肾损伤进行综合评估以实现及时诊断和治疗的价值。
