Empty Sella Syndrome (ESS)
What is empty sella syndrome?
The pituitary gland sits in the sella turcica, a bony box at the base of the brain, which protects it. On magnetic resonance imaging (MRI) scans of a normal brain, the pituitary gland would normally almost fill the sella turcica.
Empty sella syndrome is a condition where the pituitary gland appears flattened or shrunken within the sella turcica on a MRI scan. Alternatively, the sella turcica can enlarge with the pituitary gland size remaining relatively normal, giving the appearance of an ‘empty sella’. The pituitary gland usually continues to function normally, but in a minority of cases can become underactive (hypopituitarism).
What causes empty sella syndrome?
Empty sella syndrome can be due to primary or secondary causes. Primary empty sella syndrome occurs in people who have a weakness in the membrane (diaphragma sellae) that normally covers the pituitary gland. Cerebrospinal fluid is the fluid that flows around the brain. As a result of the weakened membrane, this fluid can leak into the sella turcica and apply pressure on the gland. This can lead to either a flattening of the pituitary gland or expansion of the sella turcica, giving the appearance of an empty sella.
In secondary empty sella syndrome, the pituitary fossa becomes empty because the pituitary gland has been removed through surgery or damaged through radiation treatment or pituitary apoplexy. In some cases, there has been a pituitary tumour that has shrunk without treatment.
What are the signs and symptoms of empty sella syndrome?
Most people with empty sella syndrome do not have symptoms and it is often only detected when brain scans are undertaken for other reasons. A minority of people may experience headaches or disturbed vision. Deficiency in the production of one or more pituitary hormones (hypopituitarism) is present in less than 10% of people with primary empty sella syndrome. See the article on hypopituitarism for further information.
How common is empty sella syndrome?
It is difficult to estimate how common empty sella syndrome is. Evidence from brain imaging techniques suggests that some degree of primary empty sella is common in the normal population and it is more frequently seen in women than men. Pituitary hormone deficiency (hypopituitarism), however, is only present in a small minority of such individuals.
Secondary empty sella syndrome only affects people who have already had treatment for a pituitary disorder. It affects both genders equally. Empty sella syndrome is not inherited.
How is empty sella syndrome diagnosed?
Empty sella syndrome is diagnosed on computerised tomography (CT) or MRI scans of the pituitary area or brain. It is often identified coincidentally whilst carrying out investigations for other reasons. The patient is investigated as an outpatient. Blood tests are also carried out to make sure the pituitary gland is functioning properly and to check for hormonal deficiencies.
How is empty sella syndrome treated?
Patients with empty sella syndrome who have no symptoms, and with no hormonal dysfunction, do not require any specific treatment. If the patient is deficient in one or more hormones, hormone replacement treatment may be required. Normal pituitary hormone replacement treatment is not usually associated with any side-effects.
What are the longer-term implications of empty sella syndrome?
Individuals with normal pituitary function require occasional long-term follow-up. Patients needing pituitary hormone replacement treatment require the same management as other patients with hypopituitarism.
Ref: From Your hormones, Society for Endocrinology