From the Guidelines
A workup for a suspected pituitary issue should begin with a comprehensive blood test panel to assess hormone levels, including TSH, ACTH, prolactin, growth hormone, FSH, LH, and IGF-1, followed by an MRI of the pituitary gland with and without IV contrast, as recommended by the most recent guidelines 1. The blood tests should be conducted in the morning when hormone levels are most reliable.
- Imaging studies are essential, with MRI being the gold standard due to its superior visualization of the pituitary gland and surrounding structures.
- Dynamic testing may be necessary to evaluate pituitary function, such as the insulin tolerance test for ACTH/cortisol assessment, TRH stimulation test for TSH, or GHRH stimulation test for growth hormone.
- Visual field testing is important if the pituitary lesion is near the optic chiasm.
- A complete medical history and physical examination focusing on symptoms of hormone excess or deficiency should precede these tests. The workup should be coordinated by an endocrinologist who can interpret results and develop an appropriate treatment plan, as suggested by recent consensus guidelines 1. This systematic approach is necessary because the pituitary gland controls multiple hormonal systems, and dysfunction can manifest in various ways depending on which hormones are affected, highlighting the importance of a thorough diagnostic workup 1. Early diagnosis is crucial as some pituitary conditions can lead to serious complications if left untreated, emphasizing the need for prompt and accurate diagnosis 1.
From the Research
Diagnostic Approach
The workup for a suspected pituitary issue involves a combination of clinical evaluation, hormone level assessments, and neuroimaging studies 2. The diagnostic process can be challenging due to the variable clinical manifestations of hypopituitarism, which depend on the severity of hormone deficiency 3.
Hormone Level Assessments
Baseline blood sampling is used to diagnose deficiencies in thyroid stimulating hormone, gonadotropin, and prolactin, whereas dynamic stimulation tests are usually needed to diagnose adrenocorticotropic hormone (ACTH), growth hormone, and antidiuretic hormone deficiency 4.
Additional Tests
In children with suspected pituitary dwarfism, screening for insulin-like growth factor 1 (IGF-1) and insulin-like growth factor binding protein 3 (IGFBP-3) can be useful, but IGF-1 testing should not be performed alone and should be combined with other tests due to its relatively poor sensitivity 5.
Key Considerations
- Repeated pituitary function assessment at regular intervals is needed for diagnosis of the predictable but slowly evolving forms of hypopituitarism 4.
- An experienced team approach is necessary to optimize results in the management of pituitary lesions, such as thyroid-stimulating hormone (TSH)-secreting pituitary adenomas 6.
- Treatment aims to replace deficient hormones and address the underlying cause and related complications when possible 2.
Common Causes and Complications
- The most common cause of hypopituitarism in adulthood is a pituitary adenoma, or treatment with pituitary surgery or radiotherapy 4.
- Patients with hypopituitarism are at risk of excess mortality, with cortisol deficiency due to adrenocorticotropic hormone (ACTH) deficiency being a key risk factor 4.
- Thyroid-stimulating hormone-secreting pituitary lesions are often delayed in diagnosis and can be difficult to treat 6.