Clinical and hormonal characteristics of central hypothyroidism at diagnosis and during follow-up in adult patients

OBJECTIVE: We studied the clinical and hormonal profiles of patients with central hypothyroidism (CH), the adequacy of levothyroxine (L-T4) treatment and the influence of other pituitary hormone replacement therapies. METHODS: We reviewed medical records of 108 adult patients with child-onset (CO; n=26) or adult-onset (AO; n=82) CH. RESULTS: At diagnosis, the most frequently reported symptoms were fatigue and headaches in AO patients, and growth retardation in CO patients. Serum TSH was normal in a majority of CH patients, low in 8% and elevated in 8%. Serum free thyroxine (fT(4)) was usually reduced, but remained within the low normal range in 28% of the study population (mostly CO patients). Similarly, serum total T(4) (tT(4)), total triiodothyronine (tT(3)) and free T(3) (fT(3)) were found to be within the normal range in significant subsets of patients. Interestingly, the clinical and biochemical characteristics of CH patients with normal f/t T(4) levels were not different from those of the patients with low fT(4) values. The thyroid hormonal profile was not influenced by gender, etiology or by the number of hormone deficiencies. At last evaluation, the mean dose of L-T(4) was 1.6+/-0.5 microg/kg/day and was negatively correlated to current age (P