Idiosyncratic reaction after injection of polyacrylate - polyalcohol copolymer

ABSTRACT Context: Polyacrylate-polyalcohol copolymer is a synthetic product, non-biodegradable, with low rate of therapeutic failure and lower incidence of reactions at the site of injection, when compared to biodegradable agents. We report an unprecedent, exuberant and persistent inflammatory reaction following injection of that substance. Patient: a 17 years-old patient with vesico-ureteral reflux and complete pyelocaliceal right duplication was submitted to treatment with polyacrylate-polyalcohol copolymer (STING technique). In the seventh day of post-operatory, she presented intense dysuria and hypogastric pain, without laboratory exams alterations; a symptomatic treatment was started. After two months, the symptoms persisted and an ultrasound detected thickening of bladder wall close to the uretero-vesical junction. After that exam, a cystostopic biopsy showed epithelial hyperplasia with increased edema of lamina propria, suggesting an adverse reaction to the polymer. After four months, there was complete remission, but the reflux persisted with the same grade. Hypothesis: This is an unprecedent reaction following injection of this copolymer. The presence of characteristics such as absence of infection, temporal relation between treatment and beginning of symptoms, and detection of epithelial hyperplasia at the local of injection reinforce the hypothesis of association of the substance and adverse reaction. In that patient, important complains motivated early investigation of urinary tract, that confirmed those aspects. Maybe if that reaction had occurred in patients with lower capacity of expression (such as in infants) it would be unnoticed.

摘要
背景：聚丙烯酸酯-聚醇共聚物（polyacrylate-polyalcohol copolymer）是一种合成产物，不可生物降解，与可生物降解制剂相比，其治疗失败率更低，注射部位不良反应的发生率亦更低。本文报道1例注射该物质后出现前所未有的剧烈且持续性炎症反应。
病例资料：患者为17岁，患有膀胱输尿管反流（vesico-ureteral reflux）及右侧完全性肾盂肾盏重复畸形，接受聚丙烯酸酯-聚醇共聚物注射治疗，采用STING技术（STING technique）。术后第7天，患者出现剧烈排尿困难及下腹痛，实验室检查无异常，遂予以对症治疗。2个月后，患者症状仍未缓解，超声检查提示膀胱输尿管连接部附近膀胱壁增厚。针对该检查结果，行膀胱镜活检，结果显示上皮增生伴固有层水肿加重，提示该聚合物引发了不良反应。术后4个月，患者症状完全缓解，但膀胱输尿管反流仍维持原分级。
假说：本例为注射该共聚物后出现的前所未有的不良反应。无感染证据、治疗与症状发作存在明确时间相关性，以及注射部位上皮增生的检出结果，均进一步支持该物质与不良反应存在关联的假说。该患者存在明确的临床主诉，促使医护人员早期开展泌尿系统检查，证实了上述特征。若该不良反应发生在表达能力较弱的患者（如婴幼儿）中，可能会因无法被及时察觉而漏诊。