An empty sella is a condition where the bony pocket at the base of your skull that normally houses the pituitary gland appears empty or partially empty on imaging. The pituitary gland isn’t actually missing. Instead, it has been flattened or compressed, usually by cerebrospinal fluid (the fluid that surrounds your brain) pushing down into the space. Prevalence estimates range from 2% to 20% of the general population, and many people never know they have it.
What Happens Inside the Skull
The sella turcica is a small, saddle-shaped depression in the bone at the base of your brain. It cradles the pituitary gland, a pea-sized structure that produces hormones controlling everything from your thyroid to your reproductive system. A thin membrane called the diaphragma sellae normally covers the top of this pocket, keeping the pituitary snugly in place.
In an empty sella, that membrane has a gap or weakness. Cerebrospinal fluid seeps through and fills the space, gradually pressing the pituitary gland flat against the floor of the bony pocket. On an MRI, the sella appears to be filled with fluid rather than gland tissue, giving the impression it’s “empty.” The pituitary is still there, just compressed. In many cases, the compressed gland continues to function normally.
Primary vs. Secondary Empty Sella
Doctors classify empty sella into two types based on what caused it. The distinction matters because the underlying cause determines whether you need monitoring or treatment.
Primary empty sella develops without an obvious trigger. It’s the more common form and is thought to result from a combination of a naturally weak or incomplete membrane over the sella and subtle, long-term increases in the pressure of cerebrospinal fluid. Most people with primary empty sella are female and often have obesity, high blood pressure, or chronic headaches. Many are diagnosed incidentally when brain imaging is done for an unrelated reason.
Secondary empty sella has a clear cause. It can develop after surgery on the pituitary gland, radiation therapy to the area, or treatment of a pituitary tumor. It can also follow pituitary apoplexy, a rare event where a tumor in the gland suddenly bleeds or loses its blood supply. In secondary cases, the gland has been physically reduced in size, and fluid fills the space left behind.
The Link to Elevated Brain Pressure
One of the strongest associations with empty sella is idiopathic intracranial hypertension (IIH), a condition where pressure inside the skull is chronically elevated without a tumor or other structural cause. The relationship works like this: persistently high cerebrospinal fluid pressure pushes down through the membrane covering the sella, slowly remodeling the bony cavity. Over time, the sella widens and the pituitary flattens, producing the characteristic appearance on imaging.
Studies of patients with IIH find partially or completely empty sellas at remarkably high rates, ranging from 2.5% for a totally empty sella to as high as 94% when partial emptying is included. The typical patient profile overlaps heavily with IIH: obese, middle-aged women. Finding an empty sella on a scan can sometimes be the first clue that intracranial pressure is elevated, even before other symptoms develop.
Symptoms You Might Notice
Most people with an empty sella have no symptoms at all. The finding is often discovered by accident during an MRI or CT scan ordered for headaches, dizziness, or something entirely unrelated.
When symptoms do occur, headache is the most common complaint, followed by visual disturbances like double vision or decreased sharpness. Other possible symptoms include dizziness, fainting episodes, irregular or absent menstrual periods, unexpected nipple discharge, erectile dysfunction, low sex drive, and excessive thirst with frequent urination. These symptoms don’t come from the empty sella itself but from the pituitary gland not producing enough of one or more hormones, or from the elevated intracranial pressure that caused the empty sella in the first place.
In rare cases, cerebrospinal fluid can leak through the base of the skull and drip from the nose, a condition called CSF rhinorrhea. One study of patients surgically treated for spontaneous cerebrospinal fluid leaks found that 100% of them had a completely or partially empty sella on imaging. The spontaneous leak group consisted primarily of obese, middle-aged women, reinforcing the connection between elevated brain pressure, empty sella, and CSF leaks.
How It Affects Hormone Levels
The pituitary gland produces hormones that regulate your thyroid, adrenal glands, growth, reproductive system, and water balance. When the gland is compressed, it may still function perfectly well. But in some people, one or more hormone levels drop below normal.
Thyroid-stimulating hormone is one that can be affected. If your pituitary doesn’t release enough of it, your thyroid slows down, which can cause fatigue, weight gain, feeling cold, and sluggish metabolism. Hormones involved in reproduction (the ones that trigger ovulation and testosterone production) can also be disrupted, leading to irregular periods, fertility issues, or low libido. Growth hormone and the hormone that controls water retention in the kidneys are other potential casualties, the latter explaining the excessive thirst and urination some patients experience.
Risk factors for developing hormone problems with an empty sella include being female, being overweight, and having cardiovascular risk factors like high blood pressure. Not everyone with an empty sella will have hormonal deficiencies, but blood work to check pituitary function is a standard part of the workup once the finding is identified.
How It’s Diagnosed
Empty sella is diagnosed through imaging, almost always an MRI of the brain. On the scan, the sella turcica appears filled with cerebrospinal fluid instead of gland tissue. Radiologists classify it as partially empty when some pituitary tissue is still visible but the gland’s height is reduced, or completely empty when the gland is so flattened it’s barely detectable. The sella itself may appear widened or enlarged, particularly in cases associated with chronically elevated intracranial pressure.
After the imaging finding, the next step is blood tests to measure the full range of pituitary hormones. This determines whether the compressed gland is still doing its job or whether specific hormones have fallen below normal levels. If there’s concern about elevated brain pressure, additional testing may be warranted.
Treatment and What to Expect
If your pituitary function is normal and you have no symptoms, an empty sella typically requires no treatment at all. It becomes a noted finding in your medical record, and your doctor may recommend periodic blood tests to check hormone levels over time, but many people live their entire lives with an empty sella and never have a problem.
When hormone deficiencies are present, the treatment is hormone replacement tailored to whichever hormones are low. If your thyroid hormone is insufficient, you take thyroid medication. If reproductive hormones are affected, hormone therapy can restore menstrual cycles or testosterone levels. The goal is to replace what the compressed pituitary can no longer produce in adequate amounts.
If the empty sella is linked to elevated intracranial pressure, treating that underlying condition becomes the priority. Weight loss can significantly reduce intracranial pressure in people who are overweight. Medications that decrease cerebrospinal fluid production are another option. For the rare complication of a cerebrospinal fluid leak through the nose, surgical repair is typically necessary, and these patients may need more aggressive management to prevent the leak from recurring.