Nephrology Dialysis Transplantation 2005 20(5):1005-1006; doi:10.1093/ndt/gfh651
© The Author [2005]. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved. For Permissions, please email: journals.permissions@oupjournals.org
Nephroquiz
(Section Editor: M. G. Zeier)
A glowing report on dialysis
Christine Stabroth and
Friedrich C. Luft
Medical Faculty of the Charité
Franz Volhard Clinic, Wiltberg Strasse 50
D-13125 Berlin, Germany
Email: luft{at}fvk-berlin.de
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Introduction
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Dialysis is suitable for the removal of low molecular weight
toxins with a small volume of distribution. Examples are methanol,
ethanol and salicylate. Heavily protein-bound, large molecular
weight compounds or those with very large volumes of distribution
cannot be removed effectively by haemodialysis. This fact is
sometimes difficult to explain to impatient colleagues who are
convinced that ‘machines can do everything’. We
recently were confronted with an unusual removal indication.
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Case
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A 36-year-old woman who had been a dialysis patient since young
adulthood was referred from an ambulatory dialysis practice
to our surgical department for parathyroidectomy. She had a
past history of failed renal transplantation and had no residual
renal function. The patient had high parathyroid hormone (PTH)
values, bone disease, and had not responded to phosphate binders
and vitamin D therapy. The patient was dialysed in our unit
and duly operated upon. In addition to severely hyperplastic
parathyroid glands, the pathologist noted the presence of a
papillary carcinoma of the thyroid gland. Consultation with
the nuclear medicine department took place and since the prospects
for the tumour were clearly most opportune with a high dose
of radioactive iodine (
131I), the patient was given, on a Friday
morning, 2952 MBq of
131I, a therapeutic dose for a malignant
tumour. The material is generally excreted within 52 h in patients
with normal renal function. However, at 48 h, she still exhibited
80% of the full radioactive dose. Since the thyroid cells avidly
take up the material, the full therapeutic benefit had been
accrued; however, the patient had no means of excreting the
residual radioactive material. In the nuclear medicine service,
in a separate building termed the ‘bunker’ by non-experts
in nuclear medicine, all excreta are collected from such patients
and undergo disposal. However, our patient had no urinary excreta
to offer and, thus, the point was mute. We were called on Sunday
afternoon with the comment that, ‘the patient is still
glowing’ (nuclear medicine jargon for highly radioactive).
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Questions
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- Can radioactive materials be ‘dialysed off’?
- Is there any danger to the nursing or medical personnel?
- What about the equipment and disposal problems?
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Answers to the quiz on the preceding page
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None of us had ever been confronted by such a problem before.
German law is very detailed and explicit on the disposal of
radioactive waste. Subsequently, even patients being treated
with radioactive iodine for non-malignant conditions (hyperthyroidism)
are hospitalized and all biological materials are collected
and undergo disposal. Sodium iodide, radioactive or not, is
a salt that dissociates 100%. The ions are obviously not protein
bound. The iodide space should be only a little different or
not different from the chloride space. Disposal of the dialysate,
albeit a larger volume, should not be very different from the
disposal of other items. The same would be true for tubing and
dialyser. The machinery should be unencumbered. We arranged
for large tanks to be available for the spent dialysate and
brought the machine and a water purification reverse osmosis
device to the nuclear medicine department.
The patient underwent three dialysis treatments (Figure 1). The detection of the total dose decreased from 80 to 
40% after the first dialysis. Two days later, a second dialysis was done and the total dose detected decreased further to 11%. After a final treatment, the radioactive counts were at sufficiently low levels that the patient could be discharged. She did well, her tumour responded appropriately to the treatment and her bone disease got better.
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Fig. 1. The percentage total 131I dose exhibited by the patient is shown. She was dialysed at 44, 76 and 120 h (arrows). The prompt decline in radioactivity is evident.
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According to the German radiation safety law, patients can be
discharged when their continuously generated radioactivity is
<3.5 µS/h. Our dialysis nurses were rightly concerned.
However, their cumulative dose was estimated at 50, 40 and 10
µS, respectively. The allowed yearly maximum for personnel
in the medical professions is 1000 µS. The disposal containers
for the dialysate proved to be no problem and our equipment
was not radioactive.
We thought that we were unique in our experience, but we are not. Recently, Sinsakul and Ali reported two dialysis patients with thyroid cancer that presented a similar dilemma [1]. As they point out, therapeutic doses of 131I can be administered to dialysis patients without hazard to patients or staff. French colleagues recently reported a similar experience [2].
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Teaching point
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Iodine is a halide; why should it not be dialysable like any
other? Radioactivity is not mysterious, it can be handled like
any other confounding variable.
Conflict of interest statement. None declared.
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References
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- Sinsakul M, Ali A. Radioactive 131I use in end-stage renal disease: nightmare or nuisance? Semin Dial 2004; 17: 53–56[Medline]
- Magne N, Magne J, Bracco J, Bussiere F. Disposition of radioiodine (131)I therapy for thyroid carcinoma in a patient with severely impaired renal function on chronic dialysis: a case report. Jpn J Clin Oncol 2002; 32: 202–205[Abstract/Free Full Text]
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