Empty saddle syndrome

Introduction to empty saddle syndrome Empty saddle syndrome (emptysellasyndrome) refers to a group of syndromes caused by the subarachnoid space invading the pituitary fossa, causing compression and deformation of the pituitary and enlargement of the sella. The term saddle syndrome was first used in 1949 by Sheehan and Summers to describe postpartum pituitary necrosis. In the past, some people also called the saddle defect, the arachnoid cyst in the saddle or the diverticulum. By 1950, Busch investigated the autopsy data of 788 known pituitary diseases, and found that 40 of them were absent, and the saddle was subarachnoid. Cavity filling, at this point, the saddle syndrome is commonly used as an independent disease. basic knowledge Sickness ratio: 0.0002%-0.0006% Susceptible people: no specific population Mode of infection: non-infectious Complications: pituitary tumor

Cause of empty saddle syndrome

(1) Causes of the disease

Primary empty saddle

Primary empty saddle refers to non-saddle surgery, radiation therapy or pituitary infarction, but because the saddle hole (ie funnel hole) becomes larger and cannot be filled by the pituitary stalk, causing the subarachnoid space of the saddle to pass through the pore. Into the saddle nest, according to autopsy data, the incidence of primary empty saddle is 5.5% to 23.5%. The cause of this disease has not been fully clarified and may be related to the following factors:

(1) Congenital saddle developmental defects: On the basis of the developmental defects of the saddle, the pulsatile pressure of the cerebrospinal fluid into the saddle increases, and under the continuous action of this pressure, the arachnoid is squeezed into the saddle fossa (Fig. 1). However, according to many data, normal people have more than 20% of saddle defects or dysplasia. However, the saddle syndrome is not necessarily present, so the defect of saddleback development is not the only factor causing the vacuolar saddle.

(2) An empty saddle occurs after the enlarged pituitary gland is reduced: for example, women often have a 2 to 3 times increase in pituitary gland during pregnancy, which may cause saddle hole and pituitary support, and postpartum (especially multiple pregnancy) pituitary recovery And shrinking, sputum can cause empty saddle, primary hypothyroidism due to negative feedback inhibition, can increase the pituitary, after thyroid hormone replacement therapy, due to negative feedback inhibition, the pituitary shrink, may also cause empty saddle, then According to the literature, it is rare to see the situation. It should be noted that prolactinoma is a relatively common tumor. Occasionally, it is reduced by adenomas (generally large adenomas) after the application of dopamine agonists. It leads to empty saddle and even pituitary apoplexy. It has also been reported in the literature that spontaneous degeneration of prolactin giant adenoma can cause the third ventricle to break into the enlarged saddle fossa, leading to empty saddle, sudden intracranial hypertension symptoms, and cerebrospinal fluid examination showing sterility. Meningitis-like abnormalities are worthy of caution.

(3) increased intracranial pressure: obesity syndrome, chronic congestive heart failure, benign intracranial hypertension (also known as pseudo-brain tumor), hypertension, hydrocephalus and other intracranial diseases, can cause increased pressure on cerebrospinal fluid, And the third ventricle can be enlarged, and the subarachnoid space is compressed, especially on the basis of the defect of the saddle and the enlargement of the saddle hole, and the subarachnoid space is more likely to be pushed into the saddle socket.

(4) Arachnoid adhesions in the sellar region and arachnoid cysts on the saddle: Such arachnoid lesions can cause local drainage of cerebrospinal fluid, even if the normal cerebrospinal fluid pressure can be depressed by the continuous impact of the saddle, and then the defect is open. After a certain degree of sputum, the subarachnoid space and the anterior lower part of the third ventricle can be inserted into the saddle fossa.

(5) Hypothalamic-pituitary disease: In the past, it was thought that rare lesions with pituitary blood supply and autoimmune pituitary insufficiency caused by pituitary atrophy may occur in the saddle syndrome, but in recent years, attention has been paid to hypothalamic-pituitary in adolescents. It is not uncommon for people to develop empty saddles. Cacciari et al observed 339 children with growth hormone deficiency, diabetes insipidus, secondary gonadal insufficiency, delayed puberty, precocious puberty or multiple pituitary hormone deficiency. Adolescent patients, 10.9% of patients confirmed by magnetic resonance examination that there is a saddle, sputum should pay attention to avoid the diagnosis and treatment of the saddle syndrome, resulting in hypothalamic-pituitary hypofunction and visual impairment, late, Bianconicini et al. In the case of the empty saddle syndrome, 57 cases (80.2%) were found.

There are mental disorders, such as anxiety or depression with behavioral disorders, and several patients with hypothalamic diseases, which are characterized by mental disorders and obesity. To this end, the authors put forward a hypothesis that the empty saddle syndrome may be a new Hypothalamic syndrome may be caused by a series of abnormalities in the secretion of hormones and neurotransmitters due to subarachnoid compression or pulling of the pituitary gland and/or pituitary stalk, such as leptin, neuropeptide Y (NPY), Orexins, Opioid melanocyte corticosteroid (POMC)-derived peptides and the like.

(6) Others: Mucopolysaccharide storage disease, masculinization, gonadal dysplasia, renal tubular acidosis, some chromosomal abnormalities, and pointed-to-finger (toe) malformation (Carpenter syndrome) have been reported in the literature. Occasionally, it can coexist with the empty saddle, but its causal relationship is still unclear. Kalman syndrome (Kallmann syndrome) may be complicated by empty saddle syndrome. It may be due to the disease of the midline of the brain. It is the pathological basis of the empty saddle.

2. Secondary empty saddle

Secondary empty saddle generally refers to the tumor caused by surgery or radiotherapy in the saddle, especially when accompanied by increased intracranial pressure, whether accompanied by hydrocephalus, can cause secondary saddle syndrome, in addition, Intra-saddle tumors, especially degeneration and necrosis of pituitary giant adenoma, cause voids in the saddle, and the subarachnoid space is pulled due to local adhesion of the saddle to the area of the saddle, and the cystic or saddle cyst in the saddle expands and destroys. The saddle, which communicates with the subarachnoid space, can also cause an empty saddle. The secondary empty saddle is more likely to be complicated with pituitary insufficiency, and it is easy to cause visual field defect or visual disturbance after the surgery is pulled into the pituitary fossa by scar contraction. Be careful not to mistake the tumor for recurrence and erroneously perform radiotherapy. Imaging should be performed. If it is confirmed that the saddle syndrome can avoid inappropriate treatment.

(two) pathogenesis

The normal saddle hole (funnel hole) only accommodates the passage of the pituitary stalk. For example, the saddle hole is larger, and there is a gap around the pituitary stalk. Due to the certain continuity of the pituitary capsule and the intracranial arachnoid, under the pulsating pressure of the cerebrospinal fluid, The cerebrospinal fluid can enter the saddle through the arachnoid channel, so that the saddle is filled with cerebrospinal fluid, forming a so-called arachnoid cyst. The arachnoid cyst is mostly located in front of the pituitary, pressing the pituitary to the rear and being squashed, and finally clinging to the saddle back. The sella becomes an anatomical cavity and promotes the expansion of the sella.

In the case of increased intracranial pressure, such as hydrocephalus, brain tumor, benign intracranial hypertension, hypertension, obesity, chronic heart failure, it is more conducive to cerebrospinal fluid into the saddle.

The role of the cavity in the saddle: when the volume of the pituitary is reduced, it is easy to promote the formation of the empty sella, such as: 1 after the multiple pituitary volume expansion of the mother; 2 after the spontaneous necrosis of the pituitary adenoma; 3 Sheehan syndrome caused by vasogenic pituitary atrophy ; 4 primary pituitary atrophy such as children with insufficient pituitary function; 5 hypothyroidism leads to pituitary hyperplasia after thyroid hormone treatment and pituitary reduction.

Prevention of empty saddle syndrome

Take a proper rest and avoid strenuous exercise. However, when the condition is stable, pay attention to proper exercise. Increase the ability to resist disease, avoid cold, reduce the chance of infection. Once various infections occur, apply strong antibiotics and control infections in time. The diet is mainly light, and it is advisable to eat more fruits, vegetables and high-quality high-protein foods. It is banned from spicy, fatty and savory, as well as mildewed products, preserved foods, and alcohol.

Complications of empty saddle syndrome Complications pituitary tumors

1. Patients with endocrine dysfunction can correct it (such as hypoplasia of the pituitary gland with target gland hormone replacement, high PRL can be inhibited by bromocriptine), pay attention to regular review, so that the dose of supplement or replacement therapy is at an appropriate level To prevent over or under,

2. Concurrent pituitary tumors should pay special attention to choose the appropriate treatment plan according to the size and nature of the tumor.

3. If there is vision, visual field changes or cerebrospinal fluid rhinorrhea require surgical exploration or sphenoid sinus surgery, the postoperative complications of transsphenoidal surgery have been reported as 7%, can also be treated with nasal endoscopy, pay attention to surgical contraindications And appropriate surgical selection, postoperative hormone testing should be carried out, and postoperative treatment should be done.

Symptoms of saddle syndrome common symptoms pituitary dysfunction edema amenorrhea cystic disturbance disorder nausea hypertension visual field defect optic nerve atrophy visual impairment

More common in female patients, accounting for 80% to 90%, common in women, with an average of 4 children, mostly obese, the average age of onset is about 40 years old, from the age of 20 to 70 years old, children are rare, there are Among the endocrine symptoms, 43% of the women were women.

1. Headache: Most common, seen in 50% of patients, 1/3 of patients come to seek treatment because of headache, so the incidence is higher than that of pituitary adenoma patients. Most of the headaches are located in the frontal sac, without timing, often appear alone, probably due to The dura mater is involved, without nausea and vomiting.

2. Obesity: Common, especially in women, accounting for 40% to 78%. In men, only 10% of patients, usually with impaired glucose tolerance, obesity may be related to labor, dietary factors and menopause.

3. Visual impairment: seen in 38% of patients, including 30% of patients with visual loss, 12% of visual field defects, 10% of optic disc edema, and 10% of optic atrophy. The cause of visual field defect is different from the expansion of optic vertebrae on the saddle. However, the optic chiasm is pushed down into the saddle, and sometimes the anterior portion of the third ventricle breaks into the saddle, causing the optic nerve to be distorted. The cross-hatch is caused by irregular visual field defects on the saddleback, mainly involving On the nasal side or the double nasal side, or on the single nose side, etc., bilateral hemianopia may also occur, in short, asymmetrical and variable.

4. Other symptoms: the incidence rate is 15% to 30% of hypertension, 10% of cerebrospinal fluid rhinorrhea, 11% of benign intracranial hypertension, and other rare symptoms include epilepsy and disturbance of consciousness.

5. Endocrine function: The pituitary gland is squeezed by the arachnoid cyst and sticks to the saddle wall. However, most patients in the clinic have no pituitary dysfunction. Only a few patients have pituitary hyperfunction such as amenorrhea - lactation, high prolactin blood. Symptoms, acromegaly or symptoms of hypopituitarism.

Secondary empty sella syndrome: secondary empty saddle sign can occur after radiotherapy (external irradiation or radionuclide gold-198 or sputum-90 intra-saddle implantation) or pituitary surgery Patients with spondylolisthesis, vision loss, visual field defects, etc., are easily mistaken for pituitary tumor recurrence, and cerebral angiography or CT can confirm the empty saddle sign to avoid unnecessary surgery.

Examination of empty saddle syndrome

Endocrine function test: The blood concentration of pituitary hormone in patients with primary empty saddle is mostly normal. Even for the stimulation test of pituitary hormone, most patients are basically normal, but recently Bianconcini et al have made comprehensive and 71 cases of primary empty saddle syndrome. Detailed pituitary hormone assays, including excitatory and inhibitory tests of pituitary reserve function, showed that 50.7% of patients had one or more endocrine abnormalities, of which prolactin increased by 14%, pituitary hypofunction accounted for 10.4%, and gonadal function Decreased 7%, diabetes insipidus 2.8%, ACTH increased by 1.4%, growth hormone decreased by 15.4%, pituitary adenoma 8.4%, the author had 10 pituitary-target gland dynamics test for severe primary empty saddle, including pituitary gland The function of the leaves decreased, the prolactin increased (the CT scan showed no signs of microadenomas), the growth hormone deficiency, the decrease of gonadotropin and the decrease of ACTH were in 1 case, and 5 cases showed normal function of pituitary storage. One of the gonads of postmenopausal women Hormone is still high; 1 case of insulin-hypoglycemia excitatory test shows that growth hormone is weakly reactive, but this case is obviously obese, while normal human obesity growth hormone can also be weakly reactive. Therefore, the empty saddle syndrome should still be followed regularly for endocrine function.

Secondary to the empty saddle caused by pituitary tumors, not only some patients often measured increased blood prolactin, but also measured the blood concentration of functional adenoma-related hormones increased, but the pituitary hormone in cerebrospinal fluid is very low or not detected, suggesting There is a pituitary-cerebrospinal fluid barrier in the sella. Only when the pituitary tumor spreads to the saddle and destroys the blood-brain barrier, the pituitary hormone can be directly released into the subarachnoid space. In addition, the pituitary of the pregnant woman is significantly enlarged, and the prolactin cells are obvious. Proliferation, prolactin secretion is also significantly increased, may allow prolactin directly through the blood-brain barrier, progesterone diurnal secretion rhythm changes also help the identification of empty saddle and pituitary adenoma: normal people and empty saddle patients blood prolactin The level of the prime, the ratio of 1 to 3 o'clock at midnight and 10 o'clock in the morning is greater than 1.5, while the above ratio of patients with pituitary tumors is often less than 1.5.

X-ray inspection

Sella plain and tomography: typical morphological changes account for 75%, such as:

(1) Deformation: The lateral position shows that the sella is enlarged, and when the sphenoid sinus is dysplastic, the saddle depth is enlarged and oval, and when the sphenoid sinus is well developed, the saddle is enlarged in a rectangular shape, and the anterior slice shows a uniform symmetrical depression at the bottom of the saddle. It is concave.

(2) Bone quality changes in the saddle floor: On the lateral position, the saddle bottom bone uniformity is thickened in the empty saddle, and the saddle bottom bone is thinner in the pituitary adenoma.

2. Gas brain imaging (PEG)

It shows that there is gas filling in the saddle, and occasionally the pituitary is crescent-shaped and pushed into the lower part of the saddle.

3. Carotid angiography

Failure to show the expansion of the existing saddle tumor to the saddle helps to deny the presence of pituitary adenoma.

4. Isotope brain pool angiography

Only those who have a cerebrospinal fluid rhinorrhea need to perform this test.

5.CT scanning and magnetic resonance imaging

High-resolution CT coronal or magnetic resonance imaging can be quickly and non-invasively diagnosed. Typical images show an enlarged saddle fossa, atrophy of the pituitary gland, and replacement with the same low-density cerebrospinal fluid as in the saddle-upper pool. Intensive direct coronary CT scans were not enhanced. In severe cases, the pituitary gland was severely compressed and moved to the posterior and posterior flaky shape. The pituitary stalk could reach the saddle bottom to form a characteristic "funnel bulge" (infundibulum).

Diagnosis and diagnosis of empty saddle syndrome

Diagnostic criteria

According to the medical history and limited clinical symptoms, it can be diagnosed as ESS, but the diagnosis depends on imaging examination.

The empty sella generally has no effect on vision, but the sputum is so large that different degrees of visual impairment can occur when the fluoroscopy is crossed. The visual field defect, unilateral or bilateral optic disc is pale, and the literature reports the incidence of visual impairment in patients with empty sella. 34.2%, but only 6% in children.

The imaging examination of the sella can reveal:

1 size and shape are normal;

2 spherical symmetry expansion, deep butterfly saddle: deep diameter greater than the front and rear diameter of 4.0mm or more;

3 cup-shaped or quadrilateral, CT examination can be found about 50% of the saddle bone erosion absorption, 84.3% of the size of the saddle is enlarged, and some patients can see a progressive increase in volume, pituitary height <4.0mm, the rest is water The density, the pituitary stalk is extended into the pituitary fossa, and some of the pituitary stalk is offset or moved backward (Fig. 2). Whole brain angiography or contrast agent can enter the saddle through the saddle upper pool.

The MRI examination is similar to the CT effect, but can be examined in the transverse, coronal, and sagittal phases, and the cerebrospinal fluid is longer T1 and T2.

As for the CT diagnostic criteria for partial or complete vacuolar sella, there is still controversy. According to 106 women with hypothalamic-pituitary-ovarian axis dysfunction, Krysick measured the pituitary volume and the concave reticle in the saddle by CT. As a result of the sputum, it is proposed that the image change of the pituitary volume of 150 mm3 can be used as a diagnostic criterion for a complete empty sella.

Differential diagnosis

1. CT scan should be differentiated from the following diseases

(1) Arachnoid cyst: Because the cyst contains cerebrospinal fluid, and can compress the ventricle to enlarge it, CT shows low density shadow, and there is no enhancement after injection of contrast agent, so it is easy to be misdiagnosed as empty saddle, which needs to be identified by cerebral angiography. Because the arachnoid cyst does not communicate with the subarachnoid space, there is no contrast agent filling in the cyst.

(2) Epithelioid cysts: CT scans are mostly lobulated, and the upper saddle pool is often deformed, and the density is lower than that of cerebrospinal fluid. There is no enhancement after injection of contrast agent.

(3) Cystic changes of pituitary tumors: After the contrast agent was injected, the tumor showed an increase in the mixed density of high and low.

2. The X-ray diagnosis of the empty saddle must be differentiated from the intra-saddle tumor and chronic intracranial hypertension. The X-ray findings of the saddle tumor vary according to the degree of the lesion. The saddle enlarges and deforms, and is cup-shaped, spherical or flat. The saddle back is raised and elongated; the posterior bed is absorbed and thinned, but the cord-like or flaky image remains; the saddle nodule is moved forward; the saddle bottom is sunken, and if the tumor grows unevenly, a double saddle bottom or Double saddleback phenomenon, X-ray manifestations of intracranial hypertension with the course of disease and condition, mild intracranial pressure and rapid increase of intracranial pressure, X-ray examination mostly negative or only suspected changes, and chronic intracranial Pressure hyperplasia often has signs of sphenoid bone absorption, because the sella is a cancellous bone, when the intracranial pressure is persistently increased, the early manifestation of the posterior bed and the saddle bone is sparsely blurred, and the saddle bottom is gradually atrophied and absorbed. The anterior bed and saddle nodules are dense due to bone, their morphology remains normal, and the long-term intracranial pressure is increased. The sella can be enlarged due to bone resorption. The severe patients have a spherical uniform increase, while the saddle back has no lift. High, can be absorbed or even disappeared.

3. When the diagnosis of the empty saddle and differential diagnosis, the cerebral cerebral angiography can be performed. This is a classic diagnostic method. The angiography should make the patient's head tilt back as much as possible to help the gas enter the saddle area, and there is gas in the saddle. It is a characteristic symptom of the diagnosis of this disease (Fig. 3). The gas-brain film of the mild patient only shows that the soft tissue shadow of the pituitary and the air boundary line are below 3mm below the sacral line (the sacral line refers to the saddle nodule and the saddle-back arc. The connection between the normal and the pituitary is 3mm below the line. If the cerebral angiography combined with the stratified film helps determine whether the gas enters the saddle, the arachnoid adhesion in the saddle area can make the gas of the chiasm difficult. Entering the saddle and being false negative, gas brain imaging is a traumatic examination with certain complications. In recent years, it has been replaced by CT scanning and magnetic resonance imaging.

4. Identification of pituitary tumors, pituitary functional cell tumors have corresponding endocrine hyperthyroidism, the diagnosis requires CT scan or MRI to determine whether the increased sella is caused by tumor or vacuolar saddle, saddle X-ray The examination can only determine whether the saddle is enlarged, but the shape of the saddle can sometimes have a reference meaning. The vacuolar saddle can be enlarged, but the saddle enlargement is not all pituitary tumors, especially for those without endocrine dysfunction. Should be identified with the vacuolar sellar, after the pituitary tumor surgery or radiotherapy, visual impairment once improved and then worsened, not necessarily all tumor recurrence, should first rule out the possibility of vacuolar sellar, and if the lesion in the sellar area is suspected of tumor, surgery Cavitation saddles should also be excluded before or during radiotherapy. In addition, patients with primary vacuolar sella with hyperprolactinemia may have microadenomas in the basal part of the saddle floor.

5. Pay attention to the differentiation of saddle enlargement and bone destruction caused by the increase of chronic intracranial pressure.

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