Empty saddle syndrome – symptoms and causes of the disease, research, treatment

Proven content

Defects in the field of vision, headaches of varying severity – these are the most common symptoms of a condition called empty saddle syndrome.

Before we present the disease itself, it is worth explaining what a saddle is, or more precisely, a Turkish saddle. It is a bone cavity inside the skull where the pituitary gland is located, closely cooperating with another part of the brain – the hypothalamus. The Turkish saddle is located near the optic junction at the base of the skull. The pituitary gland is the most important endocrine gland (weighing only 0,7 g), whose task is to produce hormones that control the work of other endocrine glands.

A good couple

The pituitary and hypothalamus are two endocrine glands in the brain that control how the other glands work – the thyroid gland, adrenal glands, ovaries, and testes.

The pituitary gland is located in the center of the head and rests in the Turkish saddle. It is part of the sphenoid bone and has a cavity on its surface, in which the pituitary gland is located. The diaphragm of the saddle runs above the pituitary gland. It’s part of the dura mater of the brain. The pituitary gland communicates with the hypothalamus via a funnel, a narrow structure containing vessels and nerve fibers. The funnel pierces the diaphragm of the saddle and connects to the hypothalamus. In the vicinity of the pituitary gland there are optic nerves that cross with each other.

The pituitary gland consists of anterior, middle and posterior parts.

The front part produces:

– adrenocorticotropin (ACTH), which affects the work of the adrenal glands and regulates the secretion of cortisol by them,

– thyrotropin (TSH), which is responsible for the functioning of the thyroid gland and regulates the secretion of thyroxine (T4) and triiodothyronine (T3),

– follicle stimulating hormone (FSH) and luteinotropin (LH) – hormones that determine the work of the ovaries and testes, regulate the secretion of sex hormones and the maturation of the ovum and the production of sperm,

– prolactin (PRL) – responsible for the production of milk in breastfeeding women,

– growth hormone (GH) regulates the metabolism of proteins, sugars and fats and is responsible for the proper growth of the body.

The middle part of the pituitary gland produces:

– melanotropin (MSH), which stimulates the synthesis of melanin, i.e. the pigment contained in the skin.

The posterior part of the pituitary gland does not produce its own hormones, but here the hormones produced by the hypothalamus accumulate, which are transported through a funnel and the nerve fibers in it to the pituitary gland. These hormones include oxytocin (it causes the uterus to contract during labor and allows milk to be secreted when suckling the breast), vasopressin (ADH), and antidiuretic hormone (it inhibits the removal of water from the body because it limits the volume of urine excreted).

The hypothalamus produces substances that stimulate (liberins) or inhibit (statins) the secretion of certain hormones by the pituitary gland.

Empty saddle syndrome

The Turkish saddle is equipped with a diaphragm. If it is damaged or deformed, it leads to a condition called empty saddle syndrome. It happens when the spider mite (spider mite), whose task is to protect the brain, presses (convexes) into the area of ​​the Turkish saddle. The pituitary gland and funnel are then pinched, which can lead to an impairment of the production and secretion of pituitary gland hormones.

Symptoms

Professionals distinguish two types of empty saddle assembly.

Primary empty saddle syndrome is usually asymptomatic and is diagnosed on head imaging for a different reason.

Secondary empty saddle syndrome has a variety of symptoms. The most common hormone secretion is abnormal. The increase in prolactin concentration (hyperprolactinaemia) results from the pressure on the funnel. As a result, the transport of dopamine (a substance produced in the hypothalamus that inhibits the secretion of prolactin in the anterior pituitary gland) is impaired. Excess prolactin leads to menstrual disorders, difficulty getting pregnant (no ovulation), galactorrhea, decreased libido, loss of sexual hair and facial hair, reduced bone mineral density, inhibition of sperm production and gynecomastia in men.

Antidiuretic hormone (ADH) deficiency may result in diabetes insipidus, which will be associated with compression of the funnel or compression of the posterior pituitary gland. The symptom of this will be passing large amounts of very diluted urine, accompanied by increased thirst.

With empty saddle syndrome, although this is rare, visual field defects can occur depending on where the optic nerves are compressed. Headaches of varying intensity are neurological symptoms of the disease.

The causes of the disease

Primary empty saddle syndrome is usually the result of a developmental disorder. During the formation of individual elements of the brain, the diaphragm of the saddle does not develop or its structure is incorrect.

Secondary empty saddle syndrome is the result of damage to a properly formed saddle diaphragm. Damage can occur during operations performed in the brain, especially around the pituitary and hypothalamus. Another cause of damage may be radiation to the head (radiation therapy) due to brain tumors. Yet another cause is arachnoiditis in the optic junction. The inflammatory process can lead to the destruction of the saddle diaphragm structure.

What research?

Diagnosing empty saddle syndrome begins with collecting a very detailed medical history and careful examination of the patient. If the doctor suspects this condition, he or she will refer the patient to a head X-ray which reveals an enlargement of the Turkish saddle. To confirm the diagnosis, computed tomography or magnetic resonance imaging with contrast is performed.

Another package includes hormonal tests that allow you to assess the concentration of pituitary hormones (ACTH, TSH, GH, FSH, LH and prolactin) and hormones produced in the peripheral glands (thyroxine and triiodothyronine, cortisol, testosterone, estrogens and progesterone).

In order to accurately identify hormonal disorders, stimulation tests are carried out, which involve the administration of hypothalamic hormones, i.e. liberin. If the level of trophic hormones does not rise after stimulation, it is certain that the pituitary gland has been damaged. A hormone test is performed with a blood and urine sample.

An important part of diagnostics is an ophthalmological examination that allows you to establish the field of view. The fundus of the eye should also be examined. In patients at the fundus, a chasis disc is visible, which indicates an abnormal circulation of the cerebrospinal fluid.

What treatment?

In primary empty saddle syndrome cases, no treatment is required. Treatment of the secondary form of the disease depends on the type and severity of symptoms. In the case of hyperprolactinaemia, patients take appropriately selected oral medications.

Anterior pituitary gland insufficiency results in individual peripheral gland insufficiency. This determines the need to take the right hormones, e.g. thyroxine in hypothyroidism, hydrocortisone in hypothyroidism, and finally growth hormone in GH deficiency. When a patient suffers from diabetes insipidus, he takes vasopressin analogues. If retinitis develops around the optic junction, steroids are given.

Surgical treatment of empty saddle syndrome is rarely used. They are performed to restore the proper circulation of the cerebrospinal fluid.

Tekst: Anna Jarosz