From the Guidelines
Testing for suspected hypopituitarism or pituitary gland disorders should begin with a comprehensive hormonal evaluation, including morning cortisol, ACTH, TSH, free T4, and electrolytes, as well as consideration of LH, FSH, and testosterone levels in males or estrogen in premenopausal females with fatigue, loss of libido, and mood changes, as recommended by the most recent guidelines 1. The initial testing should aim to identify which pituitary axes are affected, and dynamic testing may be necessary to assess ACTH-cortisol reserve, growth hormone reserve, and gonadotropin function.
- Key initial tests include:
- Morning cortisol and ACTH levels
- TSH and free T4 levels
- Electrolyte panel
- LH, FSH, and testosterone (in men) or estrogen (in premenopausal women) if symptoms suggest gonadal axis involvement
- Imaging studies, particularly MRI of the pituitary with contrast, are essential to visualize the gland and identify tumors, empty sella syndrome, or other structural abnormalities, as supported by recent recommendations 1. Additional testing may include visual field examination if a pituitary mass is compressing the optic chiasm, water deprivation test for diabetes insipidus, and serum sodium and osmolality measurements.
- The timing of these tests is crucial, with basal hormone levels typically collected in the morning when hormone secretion is at its peak.
- It is also important to consider the potential for false-negative results in certain tests, such as ACTH stimulation, and to be aware of the need to start corticosteroids first when planning hormone replacement therapy for multiple deficiencies, as highlighted in recent guidelines 1. Testing should be conducted before initiating hormone replacement therapy, as replacement hormones can interfere with accurate assessment of pituitary function.
- A comprehensive approach, including hormonal evaluation and imaging studies, allows for precise diagnosis of the type and extent of pituitary dysfunction, guiding appropriate treatment strategies, as emphasized by recent studies 1.
From the Research
Testing for Hypopituitarism
To diagnose hypopituitarism or a pituitary gland disorder, the following tests are recommended:
- Baseline blood sampling for thyroid stimulating hormone, gonadotropin, and prolactin deficiencies 2
- Dynamic stimulation tests for adrenocorticotropic hormone (ACTH), growth hormone, and antidiuretic hormone deficiency 2
- Visual field testing to assess for any visual disturbances 3
- Longitudinal history and physical examination to monitor symptoms and hormone levels 3, 4
- Hormonal testing to identify specific hormonal deficiencies 5, 4
Diagnostic Considerations
Diagnosis of hypopituitarism is based on:
- Clinical evaluation of symptoms and signs of target endocrine gland function relative to the corresponding pituitary hormone deficiency 3
- Laboratory tests, including basal hormone levels and dynamic function tests 6
- Identification of the specific hormonal deficiencies essential for effective treatment 5
Ongoing Monitoring
Patients with hypopituitarism require: