Sieving coefficient inaccuracies during hemodiafiltration in patients with hyperbilirubinemia

Hemodiafiltration has assumed an important role in the supportive therapy of critically ill patients. The viability of the filter used for hemodiafiltration can be monitored by estimating the sieving coefficient of small molecules such as creatinine and/or urea. We report on three patients with severe hyperbilirubinemia whose creatinine sieving coefficient was spuriously elevated as a result of discordance in the accuracy of creatinine measurement in plasma and ultrafiltrate respectively. This discordance was a consequence of lack of bilirubin clearance during hemodiafiltration. As a result, while the plasma creatinine determination by the kinetic Jaffe method was negatively influenced by the hyperbilirubinemia, the ultrafiltrate creatinine was not. This report is the first to document the lack of bilirubin clearance during hemodiafiltration and its impact on the calculation of sieving coefficient based on creatinine. The use of urea as the solute for determining the sieving coefficient allows for an accurate estimate and provides a valid means of monitoring this parameter in the setting of hyperbilirubinemia. Received: 18 April 2000 / Revised: 16 June 2000 / Accepted: 20 June 2000     

Idiopathic hypercalciuria of childhood: 4- to 11-year outcome

Apart from a minority with urolithiasis, the majority of children diagnosed with idiopathic hypercalciuria present with macro- or microhematuria, abdominal or back pain, or voiding symptoms. With dietary and pharmacological interventions, most such children become asymptomatic and are lost to follow-up, hence their long-term outcome is unclear. In the present study, we evaluated the status of 14 males and 19 females aged 8-17 years (mean 11.9 years, median 11.2 years) 4-11 years (mean 6.9 years, median 6.5 years) after the initial diagnosis of idiopathic hypercalciuria not associated with urolithiasis. A questionnaire was answered and two random urine samples provided 3-4 weeks apart were analyzed for calcium (Ca), sodium (Na), potassium (K), and creatinine (Cr). Urine Ca/Cr ratio > or =20.21 (mg/mg) was defined as hypercalciuria. At the time of the study none were under follow-up, although 7 children were still exhibiting voiding symptoms. No child developed clinical urolithiasis. Based on the first urine specimen, 16 of the 33 (48.4%) were hypercalciuric. Their 2nd urinalysis showed persistent hypercalciuria in 8 and normocalciuria in 8. Urine Na/K ratio (mEq/mEq) decreased in the latter 8 from 5.08+/-2.67 to 3.03+/-2.23 (P<0.05). Of the 17 initially normocalciuric children, 5 did not submit a 2nd specimen, 11 remained normocalciuric, and 1 became hypercalciuric with an increase in urine Na/K ratio. Twenty-three children (all 8 persistently and 9 intermittently hypercalciuric plus 6 normocalciuric) were studied by ultrasonography. Only in 1 asymptomatic persistently hypercalciuric child was a single small renal calcification noted. Introduction of a low-Na/high-K diet in 7 persistently hypercalciuric children resulted in a decrease in UNa/K ratio from 7.34+/-2.15 to 4.14+/-3.09 (P<0.01) and UCa/Cr ratio from 0.25+/-0.04 to 0.13+/-0.03 (P<0.01). We conclude that even though over time most hypercalciuric children become asymptomatic, many remain hypercalciuric. Further follow-up is required to ascertain whether these children are at risk of developing kidney stones. If they are at risk then long-term compliance with a low-Na/high-K diet might be beneficial, as it can normalize calciuria in the majority of these children.     

玻璃体内注射曲安奈德治疗视网膜中央静脉阻塞引起的黄斑水肿

目的：探讨玻璃体内注射丙酮化曲安奈德用于治疗视网膜中央静脉阻塞（CRVO）引起黄斑水肿的安全性和有效性。方法：在Wisconsin大学和Bascom Palmer眼科研究所．对13例（13只眼）连续的CRVO引起黄斑水肿的患者应用玻璃体内注射丙酮化曲安奈德（4mg）治疗．回顾研究其病历记录。每次玻璃体内注射时应用27G或30G针头通过睫状体平坦部注射。主要结果测量：Snellen视力的变化、黄斑水肿的临床表现、应用光学相干断层扫描仪（OCT）测量中心凹的增厚以及并发症的出现频率。结果：13例患者的平均年龄为67岁（四分位数间距为57—77岁）．注射前症状的平均持续时间为8个月（四分位数间距为4—9个月）。患眼在初诊时的平均视力为20／500．在6个月随诊检查时的平均视力为20／1踟。所有13例患者都完成了6个月的随诊检查。非缺血型CRVO患眼（n=5）的视力有显著的提高．而缺血型CRVO患眼（n=8）没有显著的视力提高。患者没有出现视力下降。初诊时OCT测量的平均中心凹厚度为590μm（视网膜增厚=416μm）。12例患者在1个月随诊检查时OCT测量的平均中心凹厚度为212pm（视网膜增厚=38μm）。13例患者在3个月随诊检查时OCT测量的平均中心凹厚度为193μm（视网膜增厚=19μm）。在3和6个月随诊检查之间．4例患者的黄斑水肿复发．其中3例患者再次接受了曲安奈德的注射。这3例患者中的2例经过再次治疗视力提高。在6个月随诊检查时．13例患者OCT测量的平均中心凹厚度为281μm（视网膜增厚=107μm）。没有发生视网膜脱离或眼内炎等并发症。1例患者出现了眼压的升高．应用2种房水生成抑制剂治疗得以控制。结论：在部分CRVO引起黄斑水肿的患者中．玻璃体内注射曲安奈德可能是一种有效的治疗方法。与缺血型CRVO患者相比．非缺血型CRVO患者可以获得更令人满意的效果。部分患者可能需要重复治疗。在本组患者中未发现严重的并发症。     

Using imaging to identify psychogenic parkinsonism before deep brain stimulation surgery. Report of 2 cases

The frequency with which patients with atypical parkinsonism and advanced motor symptoms undergo deep brain stimulation (DBS) procedures is unknown. However, the potential exposure of these patients to unnecessary surgical risks makes their identification critical. As many as 15% of patients enrolled in recent early Parkinson disease (PD) trials have been found to lack evidence of a dopaminergic deficit following PET or SPECT imaging. This suggests that a number of patients with parkinsonism who are referred for DBS may not have idiopathic PD. The authors report on 2 patients with probable psychogenic parkinsonism who presented for DBS surgery. They found that both patients had normal caudate and putamen [(18)F]-fluorodopa uptake on PET imaging, along with normal expression of specific disease-related metabolic networks for PD and multiple system atrophy, a common form of atypical neurodegenerative parkinsonism. The clinical and PET findings in these patients highlight the role of functional imaging in assisting clinical decision making when the diagnosis is uncertain.