What are the implications and management of an empty sella (a condition where the sella turcica appears empty) seen on a Magnetic Resonance Imaging (MRI) of the brain?

Empty Sella on Brain MRI: Causes, Implications, and Management

Primary Causes and Pathophysiology

Empty sella results from herniation of the subarachnoid space and cerebrospinal fluid (CSF) into the sella turcica through an absent or deficient diaphragma sellae, causing compression and flattening of the pituitary gland. 1, 2

The condition is classified into two distinct categories:

• Primary empty sella: Occurs without any prior pituitary pathology, representing an idiopathic condition often associated with transient or chronic increases in intracranial pressure. This may be linked to idiopathic intracranial hypertension in some cases. 2, 3

• Secondary empty sella: Develops after pituitary surgery, radiation therapy, medical treatment of pituitary adenomas, spontaneous tumor necrosis (ischemic or hemorrhagic), pituitary infections, autoimmune hypophysitis, or head trauma. 2

Clinical Significance and Prevalence

While empty sella is typically an incidental radiological finding without clinical consequences, approximately 30% of patients demonstrate some degree of hypopituitarism upon formal endocrine testing, though most remain asymptomatic. 1, 4

The prevalence varies by detection method:

• Incidental neuroimaging findings: approximately 12% 3
• Clinical practice settings: up to 35% 3
• Endocrine pituitary disorders (at least one hormone deficit): 19-40% of patients with empty sella 3

When Empty Sella Becomes Empty Sella Syndrome

Empty sella syndrome is defined when the radiological finding is accompanied by:

• Endocrine dysfunction: Hypopituitarism affecting one or more pituitary axes, with thyroid-stimulating hormone, T3, and T4 deficiencies occurring in up to 48% of cases, and elevated prolactin levels in approximately 28% of cases 4

• Neurological symptoms: Headache (often related to coexisting idiopathic intracranial hypertension), non-traumatic CSF rhinorrhea 5, 2

• Ophthalmological manifestations: Visual disturbances, papilledema from increased intracranial pressure, or rarely optic chiasm compression 5, 6

Diagnostic Approach

MRI using high-resolution pituitary protocols is the preferred and gold standard imaging modality for characterizing empty sella, and can confirm the diagnosis even without IV contrast. 1, 4, 3

Recommended Hormonal Screening

All patients with newly identified empty sella should undergo basic hormonal screening to detect subclinical hypopituitarism, regardless of symptoms. 4, 6

The screening panel should include:

• Thyroid function tests (TSH, free T4) 4, 7
• Morning cortisol and ACTH 4, 7
• Sex hormones (LH, FSH, testosterone in males/estradiol in females) 4, 7
• Prolactin levels 4
• Growth hormone/IGF-1 if clinically indicated 7

Ophthalmological Evaluation

Formal ophthalmology assessment for papilledema should be obtained in all patients with empty sella of unknown etiology, particularly if visual symptoms are present or if there are concerns about increased intracranial pressure. 4, 6

Management Algorithm

For Asymptomatic/Incidental Empty Sella:

Urgent workup is not necessary when empty sella is discovered incidentally in patients without history or symptoms of pituitary dysfunction. 4

• Perform baseline hormonal screening as outlined above 4, 6
• Obtain ophthalmology referral for formal papilledema assessment 4, 6
• If no hormonal or visual abnormalities are detected, careful reevaluation at 24-36 months is suggested given the low risk of progression 3

For Symptomatic Empty Sella Syndrome:

Endocrinology referral is indicated if any hormonal abnormalities are detected on screening, or if the patient has symptoms suggestive of pituitary dysfunction such as fatigue, cold intolerance, or sexual dysfunction. 4

Surgical treatment is indicated only for specific complications including non-traumatic CSF rhinorrhea, visual disturbance from mass effect, or severe increased intracranial pressure. 5

Critical Pitfalls to Avoid

• Do not attribute headache symptoms directly to empty sella without considering more common primary headache etiologies. The empty sella finding is likely unrelated to typical headache presentations. 4

• Do not miss rare but important hormonal deficiencies by failing to perform appropriate screening. Even asymptomatic patients warrant baseline endocrine evaluation given the 30% prevalence of hypopituitarism. 4, 6

• Do not order unnecessary urgent imaging or tests that will not change immediate management when the diagnosis is already confirmed on adequate MRI. 4

• Recognize that empty sella can rarely be reversible in cases of CSF pressure changes, particularly after lumbar puncture causing CSF leak and intracranial hypotension. Changes in headache characteristics, especially worsening in orthostatic position, should raise suspicion for this dangerous complication. 8

• Ensure lifelong endocrine surveillance as hormonal deficiencies may develop or progress over time, even in initially asymptomatic patients. 7