Primary hypothyroidism in chronic renal failure

Serum thyroid hormone concentrations have been measured in 8 patients with chronic renal failure (CRF) who are currently enrolled on a chronic hemodialysis program. Three of these patients were diagnosed to be suffering from coexistent primary hypothyroidism whereas the other 5 were considered euthyroid. There was a variable decline in serum thyroid hormone levels in both groups. However, the serum TSH response to TRH was normal or blunted in the euthyroid group but was characteristically brisk in subjects with CRF and coexistent primary hypothyroidism. The TRH test may be useful in the diagnosis of primary hypothyroidism coexistent with CRF.