Introduction

Understanding empty Sella syndrome (ESS) is crucial in demonstrating how subtle anatomical changes in the brain can have significant clinical consequences. Distinguishing between the primary and secondary types allows for timely diagnosis and ensures it is correctly managed.

ESS is a rare condition in which the Sella turcica which surrounds and protects the pituitary gland becomes filled with cerebrospinal fluid (CSF), resulting in flattening or shrinking of the pituitary gland. This syndrome can present itself with headaches, visual disturbances, or endocrine dysfunction and can be diagnosed through radiological findings. 

ESS can be classified into two groups: primary and secondary: 

• Primary empty Sella (PES) occurs in the absence of a prior pituitary disease and can be linked to congenital (present at birth) defects of the Sellar diaphragm
• Secondary empty Sellar syndrome (SES) can develop from damage to the pituitary such as surgery, radiation or a tumour. Secondary ESS is more likely to present itself with significant hormonal or visual complications

Distinguishing these two types is essential as management techniques will differ between the two.

What is the pathophysiology?¹

To understand ESS, it is necessary to understand the normal anatomy of the Sella turcica and pituitary gland. The Sella turcica houses the pituitary gland, with the diaphragm sellae acting as a barrier to prevent cerebrospinal fluid (CSF) from entering the Sella.

However, in ESS, this barrier is compromised, allowing CSF to enter the Sella turcica and thus, will compress the pituitary tissue. This is why an empty appearance is seen in the imaging. The underlying mechanisms will differ depending on whether the condition is primary or secondary:

• PES arises from a congenital defect or incomplete formation of the diaphragm sellae, thus allowing CSF to gradually enter. Over time, the Sellar space gradually enlarges, and the pituitary will become thinner
• SES is caused by a condition which changes the anatomy of the pituitary gland such as through a tumour, radiation, brain surgery and head trauma. As the gland volume decreases, CSF will flow into the vacant space

What are the clinical features and diagnosis of PES?

PES can be worsened by chronically raised intracranial pressure, such as in idiopathic (having no known cause) intracranial hypertension, which is strongly associated with obesity (commonly seen in middle-aged women), and is less likely to occur in children.

It is frequently an incidental finding on brain imaging, with many people remaining asymptomatic (not showing symptoms) and may present with non-specific headaches, visual disturbances or even mild endocrine changes such as reduced growth hormone levels. On an MRI, the diagnostic feature is a CSF-filled Sella showing a flattened pituitary tissue and is often diagnosed once every other aetiology has been excluded.² 

What are the clinical features and diagnosis of SES?

Unlike PES, SES usually presents itself with symptoms such as hypopituitarism, with the destruction of the pituitary tissue leading to the deficiency of important hormones such as ACTH, TSH, and other growth hormones. Some patients may also experience visual disturbances due to prior effects from tumours or even scarring around the optic (eye) structure.

On imaging, SES can appear very similar to PES. However, the clinical history of previous pituitary disease is key in this differentiation.²

For both, CT scans and MRI are used to detect complications and show detailed images of the structure, thus ensuring an accurate diagnosis. However, sometimes tests to check for elevated pressure in the brain may also be undertaken such as through a lumbar puncture or even examination of the retina.

What are other symptoms of this syndrome?

Further symptoms may include:

• Headaches
• Erectile dysfunction
• Irregular menstrual periods
• Early puberty in children
• Low libido
• Fatigue
• Hormonal imbalances

In rare cases, some patients may also have:

• Increased pressure within the skull
• Increased cranial pressure causing swelling of the optic disc
• Vision changes

However, symptoms tend to vary between individuals, with other factors also contributing such as age and what caused this syndrome. The symptoms may also be presented to other similar health problems; thus, further testing is required to ensure it is accurately diagnosed.

How is ESS managed?

The management of ESS will largely depend on whether the condition is primary or secondary.

For PES, symptomatic patients that are experiencing headaches or visual disturbances may need targeted therapy such as the management of intracranial hypertension.

For SES, as it is a result of prior pituitary damage and associated with hormone deficiencies, an endocrine assessment is carried out, with a replacement therapy or medications needed for deficiencies in adrenal, thyroid or even growth hormones.³ Addressing the underlying causes is essential, with multidisciplinary care needed to improve the patient’s quality of life.

Summary

Empty Sella Syndrome (ESS) is a rare condition in which the Sella turcica is filled with CSF, with the pituitary gland presenting itself as flattened. It can be classified as primary or secondary, with distinct causes and management techniques. 

PES may be a result of a prior pituitary disease such as a congenital defect of the diaphragm or due to chronically elevated intracranial pressure. It is often asymptomatic with some patients experiencing minor headaches and visual changes. 

SES results from pituitary damage such as surgery, radiation or tumour regression and is more likely to cause hypopituitarism and other complications. Managing this syndrome will depend on symptoms and their underlying causes;PES will require observation, whereas SES will require endocrine evaluation and hormone replacement. Distinguishing this is crucial in ensuring an accurate diagnosis, appropriate management and prevention of long term complications. 

FAQs

What is the prognosis of this syndrome?

It is generally considered as good, with medications treating hormonal imbalances.

What is the difficulty healthcare professionals have with PES?

The exact cause of PES is currently unknown and requires further research.

How is it typically diagnosed?

Diagnosis is made through an MRI, which shows a CSF-filled Sella, with a thin structure of pituitary tissue. Clinical history would also be needed to differentiate between primary and secondary.

Is ESS dangerous?

PES is generally considered to be benign. However, SES can have serious consequences if hormonal imbalances are left untreated. Thus, highlighting the importance of early detection.