Comment & Response May 14, 2019
Acute Kidney Injury Related to Sepsis—Reply
Matthieu Legrand, John A. Kellum
JAMA. 2019;321(18):1828-1829. doi:10.1001/jama.2019.2072
In Reply 回答
Dr Seres comments on the effect of low muscle mass on serum creatinine level. We agree that muscle mass and cachexia can decrease sensitivity of serum creatinine to detect a drop in GFR and AKI. Recently, Yoo and colleagues1 reported overestimation of GFR in patients with cirrhosis and with low muscle mass detected by abdominal computed tomography.2 This point was addressed in our article1 when considering the overestimation of GFR using serum creatinine at discharge from the intensive care unit due to muscle mass loss during the stay. Estimation of GFR based on creatinine clearance may be more accurate in this setting. Short-term (2-4 hours) urine collection may overcome some of the limits of creatinine clearance measurements to detect acute changes in GFR.3
Seres医生就有关低肌肉量对于血清肌酐水平的影响进行了评论。肌肉量与恶液质能够降低血清肌酐发现GFR下降和AKI的敏感性，我们对此表示赞同。近期，Yoo及其同事报告，对于肝硬化患者及腹部CT检查发现肌肉量低的患者，GFR往往被高估。我们的文章中也谈到了这一点，即由于住ICU期间肌肉量丢失，因此根据转出ICU时的血清肌酐可能高估GFR。这种情况下，根据肌酐清除率估计GFR可能更加准确。收集短期（2-4小时）尿液可能克服通过肌酐清除率发现GFR急性改变的某些局限性。
Dr Perazella mentions the use of urine sediment as a biomarker of kidney disease. However, data on the use of urine sediment in septic AKI are scarce. In a 2-center prospective study, urine sediment was analyzed in 73 patients and showed a higher urine microscopy score (based on renal tubular epithelial cells and granular cast observation) in patients with septic vs nonseptic AKI.4 Urine microscopy was specific but poorly sensitive to detect worsening AKI (urine microscopy score ≥3 had a sensitivity of 0.67 [95% CI, 0.39-0.86] and specificity of 0.95 [95% CI, 0.84-0.99]). Urine sediment may help establish the cause of AKI and provide prognostic information but has poor sensitivity to detect AKI and worsening of AKI. Furthermore, it is not an indicator of GFR.
Perazella医生提到，尿沉渣可以作为肾脏疾病的生物标志物。然而，全身性感染引起的AKI中，有关尿沉渣的数据非常少。在一项2个中心参加的前瞻性研究中，共对73名患者的尿沉渣进行了分析。结果表明，与非全身性感染AKI相比，全身性感染AKI患者尿显微镜评分（基于尿液中小管上皮细胞及颗粒管型）更高。尿显微镜检用于发现AKI恶化具有较好的特异性，但敏感性不佳（尿显微镜评分≥ 3的敏感性0.67 [95% CI, 0.39-0.86]，特异性0.95 [95% CI, 0.84-0.99]）。尿沉渣可能有助于明确AKI的原因，并提供预后信息，但是对于检测AKI及AKI恶化的敏感性较低。 而且，尿沉渣并不能反映GFR。
Perazella also challenges the renal toxicity of vancomycin. While renal toxicity of vancomycin has been controversial, current evidence establishes the drug as a nephrotoxin.5 We agree that appropriate antibiotic treatment of sepsis is crucial and should not be delayed. However, safe and effective alternatives to vancomycin are often available to treat patients with proven or suspected infection with methicillin-resistant Staphylococcus aureus (eg, linezolid in a patient with pneumonia such as in our case) with a decreased risk of renal toxicity. Limiting additional factors that contribute to kidney injury is expected to limit the duration of AKI and promote recovery.
Perazella还对万古霉素的肾毒性提出了质疑。尽管万古霉素的肾毒性存在争议，但现有证据表明，这种药物具有肾毒性。我们同意针对全身性感染的正确抗生素治疗非常重要且不应延迟。然而，我们可以选择安全及有效的抗生素替代万古霉素，治疗确诊或疑似的MRSA感染（如我们的病例为肺炎患者接受利奈唑胺的治疗），从而降低肾毒性风险。限制造成肾损伤的其他因素有可能缩短AKI病程并促进肾脏恢复。
