Response to TRH in suspected hypopituitarism

Area of Science:

• Pediatric Endocrinology
• Neuroendocrinology
• Clinical Chemistry

Background:

• Growth hormone (GH) deficiency diagnosis and therapy in children.
• Thyroid function assessment in pediatric patients.
• Role of thyrotrophin-releasing hormone (TRH) stimulation tests.

Purpose of the Study:

• To analyze TRH stimulation test results in children undergoing GH therapy.
• To investigate abnormal thyroid-stimulating hormone (TSH) responses in euthyroid children.
• To correlate TRH test abnormalities with GH deficiency aetiology.

Main Methods:

• Retrospective analysis of 405 TRH stimulation tests in UK children (1977-1981).
• Categorization of TSH responses based on criteria to minimize assay variation.
• Comparison of TRH test results between hypothyroid, clinically euthyroid, and normal children.

Main Results:

• 93% of hypothyroid children showed abnormal TRH tests.
• 35% of clinically euthyroid children with normal thyroxine had abnormal TSH responses to TRH.
• Abnormal TRH tests were more frequent in euthyroid children with defined GH deficiency aetiology.

Conclusions:

• Abnormal TRH stimulation tests occur in a significant proportion of euthyroid children receiving GH therapy.
• Interpretation of abnormal TRH tests in this group requires further investigation.
• Regular thyroid function monitoring is recommended for these patients pending further clarification.