Can Patients with Hypothyroidism Have Empty or Partially Empty Sella?
Yes, patients with hypothyroidism can absolutely have empty or partially empty sella, and this association occurs through multiple distinct mechanisms—most commonly as part of hypopituitarism causing central hypothyroidism, but also paradoxically in primary hypothyroidism where chronic pituitary hyperplasia from elevated TSH can lead to subsequent pituitary compression and empty sella formation. 1
Understanding the Bidirectional Relationship
Primary Hypothyroidism Leading to Empty Sella
Chronic primary hypothyroidism can cause pituitary hyperplasia that eventually results in empty sella formation. In a study of 41 cases of partial empty sella, 75.6% were associated with adenohypophyseal hyperfunction including primary hypothyroidism, where chronic TSH elevation causes pituitary enlargement followed by compression and empty sella development 1
Primary hypothyroidism with empty sella is well-documented but represents a rare finding, with case reports demonstrating patients who develop complete hypopituitarism alongside primary hypothyroidism, confirmed by elevated TSH with low thyroid hormones and positive anti-TPO and anti-Tg antibodies 2
The mechanism involves long-standing thyroid hormone deficiency causing compensatory pituitary hyperplasia, which over time can lead to herniation of the subarachnoid space into the sella 3
Central Hypothyroidism as Part of Empty Sella Syndrome
Approximately 30% of patients with empty sella demonstrate some degree of hypopituitarism, with thyroid axis deficiency occurring in 8-81% of cases. 4, 5, 6 This represents central hypothyroidism where the pituitary fails to produce adequate TSH
Central hypothyroidism in empty sella presents with low free T4 accompanied by low or inappropriately normal TSH, distinguishing it from primary hypothyroidism where TSH is elevated 6
In a study of patients with primary empty sella, hypothyroidism was found in 50% of cases, making it one of the most common endocrine abnormalities alongside hypocortisolemia (62.5%) 7
Clinical Implications and Diagnostic Approach
Mandatory Hormonal Screening
- All patients with partially empty sella require comprehensive hormonal screening regardless of symptoms, as hormonal deficiencies may reach 50%. 5 This must include:
- Thyroid function tests (TSH and free T4) to differentiate central from primary hypothyroidism 4, 6
- Morning cortisol and ACTH to assess adrenal axis 4, 6
- Sex hormones (testosterone, estradiol, FSH, LH) 4, 6
- Prolactin levels (elevated in approximately 28% of cases) 4
- IGF-1 for growth hormone axis assessment 6
Imaging Confirmation
MRI using high-resolution pituitary protocols is the preferred diagnostic modality and can confirm empty sella even without IV contrast 8, 4, 5
No additional urgent imaging is needed if MRI already demonstrates partially empty sella without other concerning features 4, 5
Critical Treatment Considerations
Hormone Replacement Sequencing
When both adrenal insufficiency and hypothyroidism coexist in empty sella syndrome, glucocorticoid replacement must always precede thyroid hormone replacement to avoid precipitating adrenal crisis. 6, 9
A case report demonstrated that physiologic doses of glucocorticoid (cortisone acetate 25 mg/day) can lead to normalization of thyroid function in patients with empty sella and partial hypopituitarism, suggesting glucocorticoid is necessary to maintain remaining pituitary functions 9
Special Clinical Scenarios
- In thyroid cancer survivors with ablation-induced hypothyroidism, normalization of levothyroxine treatment after long-standing inaccurate management has been associated with development of empty sella syndrome, requiring hydrocortisone and hypogonadism treatment alongside appropriate hypothyroidism management 3
Common Pitfalls to Avoid
Do not assume all hypothyroidism in empty sella is central—primary hypothyroidism can coexist or even precede the development of empty sella. 2, 1 Check TSH levels: elevated TSH indicates primary hypothyroidism, while low/normal TSH with low free T4 indicates central hypothyroidism 6
Do not overlook the need for complete pituitary axis evaluation even when hypothyroidism is the presenting feature, as panhypopituitarism occurs in 6-29% of patients with pituitary disorders 6
Do not start thyroid hormone replacement before ensuring adequate cortisol replacement in patients with suspected hypopituitarism, as this can precipitate life-threatening adrenal crisis 6, 9
Do not attribute the empty sella finding to a single cause—the diagnosis should specify the relationship, such as "hypothyroidism with partial empty sella turcica" rather than assuming causation 1