From the Guidelines
Laboratory evaluation for hypopituitarism should include both basal hormone measurements and stimulation tests to assess pituitary function, with initial testing measuring morning cortisol, free T4, TSH, prolactin, IGF-1, LH, FSH, testosterone (in men), and estradiol (in women) as recommended by the most recent guidelines 1. When evaluating patients for hypopituitarism, it is essential to consider the clinical presentation, including symptoms such as headache, fatigue, and visual changes, as well as biochemical evidence of hormonal deficiencies.
- The initial laboratory evaluation should include:
- Morning cortisol
- Free T4
- TSH
- Prolactin
- IGF-1
- LH
- FSH
- Testosterone (in men)
- Estradiol (in women) Stimulation tests, such as the insulin tolerance test or glucagon stimulation test for ACTH/cortisol assessment, GHRH-arginine or insulin tolerance test for growth hormone, and GnRH stimulation test for gonadotropins, are also crucial for definitive diagnosis 1.
- For suspected adrenal insufficiency, an ACTH stimulation test is recommended, with a cortisol level below 18 μg/dL at 30 or 60 minutes indicating adrenal insufficiency.
- Central hypothyroidism is diagnosed with low free T4 and normal or low TSH.
- Hypogonadism is indicated by low testosterone in men with normal or low LH/FSH, or amenorrhea in women with low estradiol and normal or low gonadotropins.
- Growth hormone deficiency is suggested by low IGF-1 levels and confirmed with stimulation testing. These tests help determine which hormonal axes are affected and guide appropriate hormone replacement therapy, which must be tailored to each patient's specific deficiencies, as outlined in the management guidelines for hypophysitis 1.
From the FDA Drug Label
According to current standards, confirmation of the diagnosis of adult GHD in both groups involves an appropriate GH provocative test with two exceptions: (1) patients with multiple pituitary hormone deficiencies due to organic disease; and (2) patients with congenital/genetic GHD.
The diagnosis of hypopituitarism involves laboratory tests, including GH provocative tests.
- Key points for diagnosis include:
- GH provocative test for confirmation of adult Growth Hormone Deficiency (GHD)
- Exceptions to GH provocative testing include patients with:
- Multiple pituitary hormone deficiencies due to organic disease
- Congenital or genetic GHD 2
From the Research
Hypopituitarism Labs
To diagnose hypopituitarism, several laboratory tests are used, including:
- Baseline blood sampling for thyroid stimulating hormone, gonadotropin, and prolactin deficiencies 3
- Dynamic stimulation tests for adrenocorticotropic hormone (ACTH), growth hormone, and antidiuretic hormone deficiency 3, 4
- Measurement of basal pituitary and target hormone levels, except for growth hormone (GH) and adrenocorticotropic hormone (ACTH) deficiency 4
- Hormonal testing to identify specific hormonal deficiencies, which is essential for effective treatment 5
Diagnosis and Treatment
The diagnosis of hypopituitarism is based on:
- Clinical evaluation and hormonal testing 5
- Detailed investigation of symptoms of target endocrine gland function relative to the corresponding pituitary hormone deficiency 6
- A thorough and longitudinal history and physical examination, including visual field testing 6 Treatment involves:
- Hormone replacement therapy, which is the mainstay of treatment 3, 4, 6, 5
- Physiologic replacement of the individual end-organ hormone deficiencies, requiring close lifelong monitoring 7
- Prompt pharmacotherapy, surgery, and/or radiotherapy to restore normal endocrine function and quality of life 6