Acute Oxalate Nephropathy (急性草酸腎病變)

January 2, 2018

Acute Oxalate Nephropathy

http://renalfellow.blogspot.tw/2018/01/acute-oxalate-nephropathy.html?utm_source=feedburner&utm_medium=email&utm_campaign=Feed:+blogspot/yKDtf+(Renal+Fellow+Network)

義大利這個月的病例很有趣，喚起考腎專的回憶...

年輕人，呈現AKI, high anion gap metabolic acidosis, high osmolal gap, oliguria, seizure，否認服用毒物或是藥物等，重要的是：驗血、驗尿也沒有毒藥物反應（包含ethylene glycol 也是測不到）。後來做了kidney biopsy：
the presence of several calcium oxalate monohydrate crystals mainly within tubular lumens consistent with acute oxalate nephropathy (Figure above).

最後患者承認喝了一點汽車的抗凍劑。

乙二醇 (ethylene glycol)

乙二醇，又名甘醇。化學式HOCH₂—CH₂OH。屬於最簡單的二元醇。無色無臭、有甜味液體，能與水以任意比例混合。用作溶劑、防凍劑以及PETE等的原料。 乙二醇對動物有毒性，人類致死劑量估計為1.6 g/kg，不過成人服食30毫升已有可能引致死亡。 維基百科

根據文獻回顧，ethylene glycol可以被誤食、用來下毒、自殺或是他殺之用。輕則神經或是腎臟受損，重則死亡。

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要診斷ethylene glycol病例，除了以上這些實驗室檢查結果和症狀外，病史也很重要，但就如同作者說的，患者常會隱瞞或是來診時血、尿已經測不到ethylene glycol了。這時候，腎臟切片就很重要了，如同這個病例呈現的。
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造成體內草酸過多的原因：including with orlistat therapy, Roux-en-Y gastric bypass surgery, celiac disease, and Crohn's disease. ethylene glycol ingestion, and less commonly ascorbic acid. Oxalate nephropathy has also been seen in association with large quantities of iced tea consumption ( sixteen 8-oz glasses (約240 cc/杯) of iced tea daily) and most recently with "green smoothy cleanse (果菜汁冰沙)".

5種新的糖尿病分類

過往的糖尿病粗略的分為1, 2型，在臨床上似乎無法精確分類患者。現在有這5種分類，讓我們照顧起患者，更加了解背後的致病機轉和所應配合的治療方針。

http://www.thelancet.com/journals/landia/article/PIIS2213-8587(18)30051-2/fulltext?elsca1=tlpr

Scandinavian patients with newly diagnosed diabetes had the following elements collected at baseline: age at diagnosis, BMI, glutamate decarboxylase antibodies (GADA), hemoglobin A1c (HbA1c) levels, and homeostatic model assessment 2 to estimate beta-cell function (HOMA2-B) and insulin resistance (HOMA2-IR) using C-peptide concentrations. Based on these factors, patients were classified into one of the following clusters:

1) Severe autoimmune diabetes (就是過往認為的type 1 DM): affected 6% of patients in the derivation cohort; characteristics include early-onset disease, relatively low BMI, and GADA-positive
2) Severe insulin-deficient diabetes: 18% of patients; GADA-negative but similar to cluster 1; lowest HOMA2-B scores
3) Severe insulin-resistant diabetes: 15%; higher HOMA2-IR scores
4) Mild obesity-related diabetes: 22%; obese, but not insulin resistant
5) Mild age-related diabetes: 39%; older than other clusters, but largely similar to cluster 4

重點是這研究發現：
Patients with severe insulin-deficient diabetes had the highest rates of retinopathy, while those with severe insulin-resistant diabetes had higher rates of end-stage renal disease and coronary events.
作者提醒以上這insulin-deficient和insulin-resistant患者常被當作type 2 DM治療，也許是insulin用得晚。因此，要特別加強這2種分類的患者糖尿病治療，來減少以上的併發症。

維他命B12(Hydroxocobalamin)和透析失敗

在洗腎患者的貧血，維他命B12不論是口服或注射都是常用藥物。這篇文章提到一位年輕患者，神智不清，急性腎損傷，低體溫，代謝性酸中毒，疑似Cyanide中毒，因此給予注射Hydroxocobalamin 解毒（FDA 2006）。後來患者要透析時，透析機Fresenius 2008K，一直出現“blood leak alarm”, 更換人工腎臟也是一樣的警告，後來只好改CVVH 。

原因呢？

Hydroxocobalamin causes an orange/red discoloration of bodily fluids and can permeate dialysate. This can lead to dialysis failure due to defraction of light from discolored dialysate, resulting in triggering of the blood leak sensor in certain hemodialysis machines. The case highlights the need for an awareness of hydroxocobalamin effects in hemodialysis and its potential to delay initiation of emergent dialysis in critically-ill patients.

原文：
Proc (Bayl Univ Med Cent). 2017 Apr;30(2):167-168.
Hemodialysis failure due to Hydroxocobalamin