Hypothyroid patients with severe kidney
disease need less thyroxine after renal transplantation
(July 2002)
The background of
the study. The frequency of hypothyroidism may be increased
in patients with severe kidney disease, possibly caused by iodine
excess. This study describes the effect of transplantation on thyroxine
(T4) requirements in patients with hypothyroidism and severe kidney
disease.
Case report. A 55-year-old woman
with severe kidney disease and hypothyroidism had normal serum thyrotropin
(TSH) concentrations while taking 0.15 mg of T4 daily before renal
transplantation. Soon after transplantation, she had the onset of
restlessness, tremor, insomnia, and atrial fibrillation. Her serum
TSH concentration was <0.01 mU/L, with high serum triiodothyronine
and normal serum T4 concentrations. Her dose of T4 was gradually
reduced, with amelioration of her symptoms; six months after transplantation,
while taking 0.025 mg of T4 of daily, her serum TSH concentration
was normal. The patient's transplant functioned well throughout
this interval.
How the study was done. From 1990
to 2000, 456 patients with end-stage renal disease underwent renal
transplantation at the same hospital. Among them, 20 patients (4
percent) also had hypothyroidism and had taken T4 for 1 to 10 years.
The data on T4 doses were obtained by review of the patients' records
before and after transplantation.
The results of the study. The dose
of T4 was reduced in all 20 patients in the first months after transplantation.
At the time of transplantation, while being treated with dialysis,
the patients' mean dose of T4 was 0.137 mg daily (range, 0.05 to
0.2). After transplantation and immunosuppressive drug therapy,
the patients' serum TSH concentrations decreased, and the T4 doses
were reduced. Six months after transplantation, the mean dose was
0.061 mg daily (range, 0.025 to 0.1). The dose of T4 had to be increased
later in three patients who had to resume dialysis therapy.
The conclusions of the study. Patients
with severe kidney disease and hypothyroidism need less T4 after
renal transplantation.
The original article. Thomas MC,
Mathew TH, Russ GR. Changes in thyroxine requirements in patients
with hypothyroidism undergoing renal transplantation. Am J Kidney
Dis 2002;39:354-7.
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