Hypopituitarism

Hypopituitarism or adenohypophyseal insufficiency is the set of alterations that affect the synthesis of hormones in the adenohypophysis.

How is it produced?

In hypopituitarism there will be a lack of production of one or more of the hormones manufactured by the anterior pituitary. The anterior pituitary gland manufactures the following hormones: growth hormone, prolactin, thyroid stimulating hormone, adrenal gland stimulating hormone, and ovarian cycle stimulating hormones. These hormones are stimulated by other hormones made by the hypothalamus, except prolactin, which is inhibited by the hypothalamus. Hypopituitarism has varied origins and appears whenever there is a destruction of at least 75% of the anterior lobe. It is rarely hypothalamic in origin.

The causes of hypopituitarism can be differentiated between those of a genetic type, related to the development of the pituitary, and those that are acquired throughout life by different causes. The latter are the most frequent. In the case of being of genetic cause and therefore hereditary, the defects may lie in disorders in the embryonic development of the pituitary gland, which ultimately lead to a deficit of the hormones that it secretes. There are numerous causes and syndromes that can occur with these alterations, such as pituitary dysplasia, septo-optic dysplasia, Kallmann syndrome, Lawrence-Moon-Bardet-Bield syndrome, Frölich syndrome and Prader-Willi syndrome. , among others.

Acquired causes include pituitary tumors (adenomas and craniopharyngiomas), infarcts or ischemic necrosis of the pituitary gland (Sheehan's syndrome, infarcts in diabetes mellitus, and in vascular aneurysms or thromboses the internal carotid artery), and hemorrhagic infarcts or stroke. pituitary. It can also appear in inflammatory processes such as sarcoidosis and meningitis and of iatrogenic cause due to surgical removal or radiation of the pituitary.

Rarely, the acquired causes of hypopituitarism are due to hypothalamic alterations, as in the case of hypothalamic tumors (pinealomas, meningiomas, metastases, etc.), head injuries, and inflammatory and infectious processes of the hypothalamus.

Symptoms

The symptoms and signs of hypopituitarism are related to its cause and the specific hormones that are missing. The onset of the disease is usually slow and insidious and may not initially be identified by the patient as abnormal. In this way, the signs and symptoms will depend on the extent of the injury, how quickly it is established, the age of the patient and the altered hormones. In children, the most common is impaired growth and pubertal development.

In adults, the hormones that control the ovarian and testicular cycles are lost first, giving rise to hypogonadism, which in women causes loss of menstruation (amenorrhea), infertility and regression of secondary sexual characteristics (pubic hair, fat distribution, etc. .). Impotence, testicular atrophy, regression of secondary sexual characteristics, and infertility appear in males. The growth hormone is then lost, causing growth retardation in children and an alteration of the body's composition in adults. Then the thyroid stimulating hormone is lost, giving one the symptoms of hypothyroidism. Finally, the last one that is usually altered is usually the hormone that stimulates the adrenal glands, causing adrenal insufficiency that includes different symptoms such as weakness, lethargy, fatigue, nausea and vomiting, muscle and joint pain, as well as low blood pressure.

Diagnosis

The diagnosis is based on the hormonal study to detect the hormones that fail. Imaging techniques, especially magnetic resonance imaging, will be the next step to reveal the presence of tumors, infections or bleeding.

Treatment

The treatment will consist of the replacement of the missing hormones. This treatment will be for life. The lack of the hormone that stimulates the adrenal glands is treated with glucocorticoids. The lack of the hormone that stimulates the thyroid is treated with thyroxine. The lack of hormones that regulate the ovarian and testicular cycle will be treated with the relevant sex hormones (testosterone in men and conjugated estrogens + progesterone in women). Gonadotropin will be given for fertility. In adults, growth hormone deficiency and prolactin deficiency are not usually treated. But in children somatotropin will be given.

Surgical treatment is mainly aimed at the surgical removal of tumors or the drainage of a cerebral hemorrhage (when this is the cause). It is mandatory to establish periodic controls (clinical, analytical, radiological) in all these patients to evaluate their status and efficacy of the treatment.

Precautionary measures

There are no measures to prevent hypopituitarism. But in the event of suspicion (for example, menstruation and fertility alterations in women or impotence in the male, to which growth alterations or symptoms of hypothyroidism can be added) it is essential to consult a doctor for a study and a treatment as early as possible.