Empty sella syndrome is a condition where the pituitary gland, a pea-sized hormone-producing gland at the base of your brain, becomes flattened or shrunken inside its bony compartment. On an MRI, the space looks “empty,” but it’s actually filled with cerebrospinal fluid that has leaked in and compressed the gland. Estimates suggest that 8% to 35% of people have some degree of empty sella on imaging, but fewer than 1% of them ever develop symptoms.
What Happens Inside the Skull
The pituitary gland sits in a small saddle-shaped pocket of bone at the skull’s base called the sella turcica. Normally, a thin membrane called the diaphragma sellae acts like a roof over this pocket, keeping the brain’s fluid-filled spaces separate from the gland below.
In empty sella syndrome, that membrane is either weak or incomplete. The brain’s outer lining bulges downward through the gap, carrying cerebrospinal fluid with it. That fluid presses on the pituitary, gradually flattening it against the floor of its bony compartment. The gland may still function, but on imaging it can be so compressed that it’s barely visible, making the sella appear hollow.
Primary vs. Secondary Types
The distinction matters because the two forms have different causes and different rates of hormone problems.
Primary empty sella develops without any prior surgery, injury, or tumor. The most common explanation is a congenital weakness in the diaphragma sellae, sometimes combined with changes in intracranial pressure or shifts in pituitary volume that occur during pregnancy. It’s far more common in women, who are four times more likely than men to have it. Most cases appear between the ages of 30 and 40, and full-term pregnancy raises the likelihood further. A condition called pseudotumor cerebri (idiopathic intracranial hypertension), which raises cerebrospinal fluid pressure and predominantly affects young, overweight women, is also closely linked.
Secondary empty sella results from something that physically damages or shrinks the pituitary: brain surgery, radiation, a head injury, pituitary apoplexy (sudden bleeding into the gland), or a tumor that later regresses. Because the gland has already been injured, hormone deficiencies are significantly more common in this form.
Symptoms Most People Experience
The majority of people with an empty sella on imaging have no symptoms at all. The finding often shows up incidentally when an MRI is done for an unrelated reason, like headaches or dizziness. That incidental finding alone does not mean you have empty sella syndrome. The term “syndrome” applies only when the structural change causes problems.
When symptoms do occur, they can include persistent headaches, visual changes (particularly loss of peripheral vision, since the optic nerves run just above the sella), and signs of hormone imbalance such as fatigue, irregular periods, low libido, or sensitivity to cold. In rare cases, cerebrospinal fluid can leak through a weak spot in the skull base and drain from the nose, a condition called CSF rhinorrhea. This tends to happen when intracranial pressure is elevated, though it can occasionally occur at normal pressure if there’s a congenital defect in the thin bone separating the sinuses from the brain.
Hormonal Effects
A compressed pituitary can still produce hormones normally, but in a meaningful minority of cases it cannot. A study published in Frontiers in Endocrinology found that about 34% of people with primary empty sella had at least one hormone deficiency, compared with nearly 64% of those with the secondary form.
In primary empty sella, the most commonly affected hormones involve reproductive function (low sex hormones, seen in about 26% of patients), followed closely by thyroid-stimulating hormone deficiency (about 25%) and growth hormone deficiency (about 23%). Adrenal insufficiency, meaning the pituitary fails to adequately stimulate the adrenal glands, appeared in roughly 22%.
In secondary empty sella, the pattern shifts. Adrenal insufficiency is the leading problem, affecting about 55% of patients. Low sex hormones and growth hormone deficiency each affected around 45%, and thyroid hormone deficiency about 36%. The higher rates across the board reflect the additional damage the pituitary sustained from whatever caused the secondary form in the first place.
These deficiencies can be subtle. Fatigue, weight gain, feeling cold, or losing interest in sex are easy to attribute to stress or aging. Blood tests measuring pituitary hormone levels are the only reliable way to detect them.
How It’s Diagnosed
MRI is the primary diagnostic tool. Radiologists look at the pituitary on a side-view image and assess how much the gland has been compressed. A widely used grading system classifies findings on a scale from normal (no compression) through mild, moderate, and severe concavity of the gland’s upper surface, all the way to no visible pituitary tissue at all. A “partially empty sella” means the gland is compressed but still visible. A “totally empty sella” means no gland tissue can be identified on imaging, though a thin rim of pituitary tissue is almost always present along the floor.
After the imaging finding is established, the next step is a full panel of hormone blood tests to check whether the pituitary is still doing its job. Visual field testing may also be ordered if there’s any concern about the optic nerves being affected.
Treatment and Management
If you have an empty sella on imaging but no symptoms and normal hormone levels, no treatment is needed. Periodic monitoring with blood work is reasonable, since hormone function can change over time, but many people go their entire lives without any problems.
When hormone deficiencies are detected, treatment involves replacing the specific hormones the pituitary is no longer producing in adequate amounts: thyroid hormone, cortisol replacement, sex hormones, or growth hormone, depending on what’s low. This is managed by an endocrinologist and typically involves daily or regular medication.
For people with visual field loss caused by the optic structures sagging into the sella, or for those with CSF leaking from the nose, surgical intervention may be necessary. CSF rhinorrhea in particular requires repair because persistent leaks carry a risk of meningitis. These procedures are performed through the nose in most cases and are relatively well tolerated.
Who Is Most at Risk
Primary empty sella is overwhelmingly more common in women, particularly those who have been pregnant and those with obesity or elevated intracranial pressure. The typical age range is 30 to 40, though it can appear earlier in women. People with a history of pituitary surgery, radiation to the head, or significant head trauma are at risk for the secondary form. If you’ve been told you have an empty sella on a scan, the most useful next step is confirming whether your pituitary hormones are functioning normally, since that determines whether the finding is clinically meaningful or simply an anatomical variation.