investigations

Last reviewed 01/2018

• basal levels of T4, T3, TSH, prolactin, gonadotrophins, testosterone, cortisol,U+Es (dilutional hyponatraemia), FBC(normochromic normocytic anaemia). Note in hypopituitarism thyroxine is reduced and TSH is reduced or normal
• assessment of visual fields
• skull radiology
• CXR may show signs of a primary tumour that has produced metastases, sarcoidosis or tuberculosis

Undertaken after specialist advice:

• combined pituitary test may reveal an absence of the normal rises in gonadotrophins, TSH and cortisol after GnRH, TRH and insulin injection. A basal cortisol measurement MUST be made before undertaking a combined pituitary test in patients suspected of hypopituitarism. If cortisol is already low, insulin could be dangerous and ACTH should be measured to differentiate between primary and secondary hypocortisolaemia. Insulin stress test is contraindicated in patients with a history of ischaemic heart disease, ischaemic changes in the ECG or a history of seizures; alternatives testing agents include metyrapone, glucagon or depot synacthen
• CT/MRI scan