View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Elsevier - Publisher Connector Kidney International, Vol. 23 (1983), pp. 387—392 Altered anion handling by choroid plexus in renal insufficiency JULIO V. RIVERA, RAFAEL RAMIREZ-GONZALEZ, and JULIO MORALES The Nuclear Medicine and Nephrology Services, Veterans Administration Medical and Regional Office Center, San Juan, Puerto Rico Altered anion handling by choroid plexus in renal insufficiency. Abnor- drugs were administered within 15 mm of each other. Imaging mal localization of 99mTc pertechnetate was detected in the choroidwas accomplished with a dual probe nuclear rectilinear scanner plexus of patients with renal insufficiency despite the administration of potassium perchiorate. This was found in 8 of 21 studies on patients on (Model 084 Ohio, Technicare Corporation, Cleveland, Ohio). conservative medical treatment, in 35 of 41 studies in patients on Eighty-four brain scans were performed in 70 patients with hemodialysis, in 12 of 22 studies in renal transplant recipients, and in 1 chronic renal insufficiency, which included 21 studies of pa- of 5 with acute renal insufficiency, but not in any of 33 persons free of tients receiving conservative medical treatment, 41 of patients renal disease. Abnormal retention of pertechnetate was also observed on chronic hemodialysis, and 22 of renal transplant recipients. in the salivary glands of 21 renal patients. The increased localization of 99mTc pertechnetate could not be related to high blood levels ofFor comparison, we also reviewed brain scans performed on 33 radioactivity, altered protein binding, increased erythrocyte labeling or patients referred for various neurological problems. Each one to impaired gastrointestinal absorption of potassium perchlorate. It is of these patients immediately followed or preceded a chronic proposed that this finding represents a manifestation of choroid plexus renal patient on the day's schedule and formed the "control" dysfunction resulting in altered handling of anions by this organ. A possible relation to neurological disease in chronic renal insufficiency is group. During a later period, brain scans were performed on suggested. five persons with acute renal insufficiency. Scans were reviewed by two observers, one of whom was Conservation des anions par les plexus choroldes modifiée lors deunaware of the patient's clinical condition. The presence of l'insuffisance rénale. Une localisation anormale de pertechnetate devisualization of the choroid plexus was noted and classified as a été détectée dans les plexus choroides de malades ayant une insuffisance rénale malgré l'administration de perchlorate de potassium. slight (+), moderate (+ +), or marked (+ + +). Notation was Cela a été trouvé dans 8 sur 21 etudes de malades sous traitementalso made as to whether or not the parotid glands, which may conservateur medical dans 35 sur 41 etudes de malades en hémodialyse, also concentrate this material, were clearly visible in these dans 12 sur 22 etudes de receveurs de transplant renal, et dans 1 étude studies. sur 5 malades atteint d'insuffisance rénale aigue, mais non chez 33 personnes indemnes de maladie rénale. Une retention anormale du In five renal patients in whom the choroid plexus was pertechnetate a egalement été observée dans les glandes salivaires de 21 visualized despite medication with perchiorate, the study was parmi les malades rénaux. L'augmentation de Ia localisation du pertech- repeated following oral administration of strong iodine solution, netate de 99"Tc ne pouvait pas être reliée aux concentrations sanguines 0.5 ml, US Pharmacopeia, Rockville, Maryland. Iodide is also de radioactivité élevées, a une alteration de Ia liaison protéique, a une augmentation du marquage érythrocytaire, ni a un trouble de l'absorp- usually effective in blocking the uptake of pertechnetate by the tion gastrointestinale de perchlorate de potassium. II est propose que ce choroid plexus. Eight renal patients with elevated serum creati- résultat représente une manifestation de dysfonctionnement des plexusnine had brain scans following the administration of s9mTc choroIdes, resultant d'une alteration de Ia conservation des anions par diethylenetriaminepenta-acetic acid (DTPA). This complex is cet organe. Une relation possible avec l'atteinte neurologique decommonly used for brain scanning to avoid localization of l'insuffisance rénale chronique est suggeree. radioactive technetium in the choroid plexus. To determine if labelling of erythrocytes or altered plasma protein binding with mTc could play a role in the visualization The choroid plexus, site of cerebrospinal fluid production,of the choroid plexus we performed the following experiments: actively concentrates ssmTc pertechnetate, a material often In ten patients including six of the chronic renal group and used in the performance of brain scintigraphy [1]. To avoid thefour controls, blood samples were secured 30 mm after the interference of pertechnetate localization with the interpreta-administration of pertechnetate (99mTc) for determination of in tion of brain scans, potassium perchlorate is given routinely tovivo labelling of erythrocytes. Erythrocytes were separated by persons undergoing this examination. centrifugation and washed with normal saline. The proportion Following the casual observation of visualization of theof activity per unit of volume of whole blood, erythrocytes, and choroid plexus on pertechnetate brain scans in several patientsplasma was determined. with endstage renal disease, we undertook a systematic study to determine the frequency of this finding and its possible causes. Methods Received for publication June 18, 1981 Brain scans were performed 1 to 2 hr following the adminis- and in revised form July 16, 1982 tration of 20 to 30 mCi of 9smTc pertechnetate by the intrave- 0085—2538/83/0023—0387 $01.20 nous route and 300 mg of potassium perchlorate orally. The two © 1983 by the International Society of Nephrology 387 388 Rivera et a! Dialysis Control Ca C 25 C, 0 Transplant Medical C .0a, E 45% .0 z 0 .0a, E 23% z IltIM'ihjI IsMtl Fig. 1. Frequency and degree of choroid plexus visualization on brain scan in patients with chronic renal insufficiency according to treatment modality, acute renal failure, and nonrenal. Symbols relating to cho- roid plexus visualization are: LI, none; ,small;ll, moderate to marked. <2 2to2.9 3to 5.9 6toQ.9 >10 Serum creatinine, mg/dI In nine renal patients on maintenance hemodialysis and ten normal persons, the in vitro association of ssmTc pertechnetate Fig. 2. Frequency and degree (LII, none; ii, small; 1111, moderate to marked) of choroid plexus visualization on brain scan in patients with with serum proteins was examined by the equilibrium dialysischronic renal disease. The majority (38 of 48) of those whose serum method described by Hays and Green [21. creatinine was >3 mg/dl showed abnormal concentration. Twelve A possible role of blood radioactivity levels in choroid plexus patients with abnormal localization and serum creatinine <2 were visualization was tested in the following two observations: recipients of renal transplants. In this group the finding could not be In 20 unselected subjects, including patients with acute and related to the level of creatinine (Table 1). chronic renal insufficiency and nonrenal patients, the whole blood concentration of ssmTc radioactivity was determined at the time of starting the brain scan, and it was related to the degree of visualization of the choroid plexus. sample (cpm/mlIM2 of body surface corrected to 0 time) was In three patients with chronic renal insufficiency requiringdetermined in duplicate in a well scintillation counter. hemodialysis the level of blood radioactivity was determined 1 hr after injection, immediately preceding brain scanning. He- Results modialysis was then carried out for 4 hr at the end of which Figure I summarizes the results of brain scans in each group. blood radioactivity determination and brain imaging wereFifty-six brain scans in renal patients including subjects in each repeated. treatment category showed a concentration of pertechnetate in To view the distribution of activity in the salivary and thyroid the choroid plexus, although this was not seen in any of the glands and the large vessels at the base of the neck, scintillationcontrol group. The finding was by far most pronounced and camera views were taken 30 to 180 mm after the injection offrequent in patients on hemodialysis. 99mTc pertechnetate in six renal patients and seven controls. The frequency of visualization of the choroid plexus correlat- Potassium perchlorate was taken by these patients immediatelyed with the level of serum creatinine which may be considered after the 30-mm scintiphoto had been obtained. One of theman index of severity or duration of disease (Fig. 2). Patients was given lemon and later a full meal, and viewing was repeatedwhose serum creatinine was above 3 mg/dl (38 of 48) usually after 5hr. concentrated pertechnetate in the choroid plexus, but the To test the possibility that impaired absorption of perchloratemajority of those with serum creatinine below that level did not. might explain the results observed, the gastrointestinal absorp-The exception was 12 transplant recipients whose creatinine tion of sodium s9mTc pertechnetate, a very similar ion, waslevel was normal or slightly elevated at the time of examination. studied. Five normal adults and five patients with chronic renalIn