Overview
A series of clinical manifestations caused by insufficient secretion of anterior pituitary hormones of any cause is called anterior pituitary hypopituitarism, which is divided into two categories: primary and secondary, the former due to the destruction of pituitary secretory cells, and the latter due to the lack of stimulation of the pituitary gland due to hypothalamic lesions, and clinically, the former is the most common. Pituitary crisis refers to the lack of adrenocorticotropic hormone and thyroid hormone when the anterior pituitary gland is hypopituitarized, the body’s stress capacity decreases, and the crisis is induced by infections, vomiting, diarrhea, dehydration, cold, and starvation, and by the application of sleeping pills or anesthetics.
Etiology
1. Pituitary gland and its nearby tumor compression or infiltration.
Including pituitary tumor, pars plana or suprasellar tumor or malignant tumor metastasis or infiltration.
2. Ischemic necrosis of pituitary gland
The most common is postpartum hemorrhage (Sheehan syndrome). Others include diabetic vasculopathy, atherosclerosis, eclampsia, temporal arteritis, and so on.
3. Pituitary surgery, trauma, radiation damage or pituitary stroke
4. Pituitary destruction caused by various intracranial infections or inflammatory diseases
Such as viral encephalitis, tuberculous meningitis, purulent meningitis, autoimmune pituitary inflammation, fungal infection, etc.
5. Vacuolar pterygoid
6.Hypothalamic lesions causing pituitary hormone releasing hormone secretion disorders
7. Others
Including metabolic disorders (chronic renal failure may present with low secretion of GnRH and TSH), tuberculosis, sarcoidosis and so on.
Symptoms
(I) Anterior pituitary hypopituitarism manifestations
1. Insufficient secretion of anterior pituitary hormones
The severity of hypopituitarism is related to the degree of hormone deficiency, which causes a series of symptoms and signs of hypopituitarism in the corresponding target gland. It is generally believed that anterior pituitary hormone insufficiency is often preceded by GH and GnRH deficiencies, while TSH and ACTH deficiencies appear later.
(1) Growth hormone secretion insufficiency Adults have no obvious manifestations; some patients may have low fasting blood glucose and slow fracture repair, while children with GH deficiency have growth retardation or stagnation.
(2) Insufficient secretion of gonadotropins Decreased libido. Female patients have scanty menstruation or amenorrhea, scanty or disappearing pubic hair and axillary hair, atrophy of breast and external genitalia; male patients have scanty beard, loss of pubic hair and axillary hair, impotence, small and soft testicles, muscle weakness, and atrophy of genitalia. In children, there are sexual development disorders.
(3) Insufficient secretion of thyroid-stimulating hormone Fear of cold, hypothermia, poor appetite, abdominal distension, constipation, slow movement, slow reaction, swollen face, dry skin, mute voice, sparse hair, eyebrow loss, slow heart rate, and in severe cases, mucous edema, apathy, stiffness, and even coma may occur. Hyperlipidemia and carotenemia may occur in some patients, but they are not as obvious as primary hypothyroidism. In children, growth retardation, backward bone age and mental retardation may occur.
(4) Inadequate secretion of adrenocorticotropic hormone (ADH) Decreased appetite, weight loss, generalized weakness, poor resistance and susceptibility to infection. Symptoms of hypotension, hypoglycemia, and hyponatremia often occur, and in severe cases, nausea, vomiting, high fever, shock, and other critical manifestations may occur.
(5) Others: Pituitary hormone deficiency, lactogen deficiency, postpartum lactation.
2. Pituitary tumor
In addition to the above manifestations, there are also symptoms and signs of compression of the pituitary tumor and clinical manifestations of the pituitary tumor itself. Tumor compression may cause headache, visual loss, visual field defect, diplopia, blindness, etc. Some patients may also have cerebrospinal fluid leakage, uremia, etc. GH tumor may have a series of manifestations of acromegaly.
(II) Pituitary crisis
1. Hypoglycemic coma
It is the most common, and most of the time develops when eating too little, starving or fasting, or after injecting insulin. It is characterized by hypoglycemic symptoms, syncope (epileptic seizures or even coma) and hypotension. A history of hypopituitarism and a test for hypoglycemia can confirm the diagnosis.
2. Infection-induced coma
The symptoms are high fever, post-infectious coma and low blood pressure.
3. Central nervous system depressant-induced coma
Sedatives and anesthetics can cause patients to fall into a prolonged sleep or even coma with a normal dose.
4. Hypothermic coma
Cold induced in winter, characterized by hypothermia and coma.
5. Sodium loss coma
Sodium loss and dehydration caused by surgery or gastrointestinal dysfunction, leading to peripheral circulatory failure.
6. Water intoxication coma
Because of the original drainage obstacle of this disease, excessive water intake can cause water intoxication. The main manifestations are low blood sodium and decreased hematocrit.
Examination
1. Low level of hormone secretion from pituitary gland
Including GH, PRL, FSH, LH, TSH, ACTH and so on.
2. Low level of target gland hormones
Including thyroid hormone, sex hormone and adrenocorticotropic hormone.
3. Hypothalamic hormone excitation test
Used to determine whether the lesion is in the hypothalamus or in the pituitary gland itself, such as GnRH (LHRH) excitation test, TRH excitation test, CRH excitation test. Generally speaking, hypothalamic lesions may have a delayed response to the above tests.
4. Insulin tolerance (insulin hypoglycemic excitation) test
To understand the reserve function of pituitary hormones such as GH, PRL, ACTH, etc. However, this test is dangerous and should be used with caution for those who have been clearly diagnosed.
5. Pituitary hormone excitation test
To determine the target gland’s ability to respond to pituitary hormones, such as ACTH excitability test, mostly showing delayed response.
6. Corresponding changes caused by hypoplasia of target gland.
For example, the level of erythrocyte and hemoglobin will be lowered, hypoglycemia, hyponatremia, hyperlipidemia and so on.
7. Imaging examination
For adenopituitary-hypothalamic lesions, CT and MRI can be used to identify the lesions, which are more accurate than X-ray and tomography of the pterygoid, and as far as possible, non-invasive examination can be done to understand the lesion site, size, nature and its degree of invasion of neighboring tissues.
8. Fundoscopy
In patients with intracranial hypertension, optic papillae edema may appear, and in patients with tumor compression of optic nerve or optic cross, optic nerve atrophy may appear.
Diagnosis
The diagnosis of the disease can be established on the basis of history, symptoms, signs and hormonal measurements of the pituitary gland and target glands, as well as the selection of appropriate functional tests. The disease needs to be differentiated from primary gonadal, thyroid, and adrenocortical hypoplasia, anorexia nervosa, and malnutrition. Diagnosis of the disease should seek to identify the cause.
Differential diagnosis
1. Primary single target gland hypogonadism
Clinical manifestations of single target organ hypogonadism, decreased hormone level of single target gland, elevated level of corresponding pituitary prohormone, and normal hormone level and prohormone level of other target glands are present in laboratory tests.
2. Multiple Glandular Failure Syndrome
Multiple target gland failure syndrome occurs in the clinic, often combined with other autoimmune diseases such as diabetes mellitus, hypoparathyroidism, etc. The main point of differentiation is that the pituitary prohormone level is increased in this syndrome and there is no evidence of pituitary space-occupying lesions.
3. Chronic wasting disease
Such as tumors, liver disease, tuberculosis, severe malnutrition, these diseases can affect the hypothalamus to release hormone secretion, resulting in different degrees of endocrine hypocrine function, but generally lighter, pubic hair, axillary hair does not fall off, and there are the manifestations of the respective primary disease, according to the corresponding medical history, physical signs, laboratory tests to be identified.
4. Anorexia nervosa
A series of endocrine dysfunction can occur, but the disease is mostly in young women, with incorrect concept of eating and aesthetic concepts, mostly with mental triggers, significant weight loss, elevated plasma cortisol levels, identification is not difficult.
Treatment
After removing the cause of hypopituitarism, long-term replacement therapy of target gland hormones is performed.
1. Adrenocorticotropic hormone
Adrenocorticotropic hormone (AChE) is the first treatment for total anterior pituitary hypopituitarism and is preceded by thyroid hormone and sex hormone replacement. Hydrocortisone (cortisol) or cortisone (corticosteroid) or prednisone (prednisone) is preferred, and is taken on the basis of the principle of minimum effective replacement dose. Hydrocortisone can be given intravenously in case of severe infections, major surgery and other severe stresses to avoid crises.
2. Thyroid hormone
Start with a small dose and gradually increase the dose to the minimum effective replacement dose. After 1~2 weeks of adrenocorticotropic hormone supplementation, thyroxine (L-T4) can be supplemented, or dry thyroid tablets can be used, and the dose can be gradually increased to the maintenance amount. When the dose is large, it can be taken in divided doses. For patients with coronary artery disease, myocardial ischemia, or elderly patients, more attention should be paid to the slow increase of the dose starting from a small dose.
3. Sex hormone
(1) Fertile women should establish artificial cycles to restore secondary sexual characteristics and sexual function and prevent osteoporosis.
(2) Men should use androgen replacement therapy to maintain secondary sexual characteristics and libido.
4. Principles of treatment of pituitary crisis
(1) Rapid correction of hypoglycemia: first, inject 50% glucose 40-100 ml, then 10% glucose 500-1000 ml for maintenance;
(2) Hormone replacement therapy Depending on the severity of the disease to give drugs, generally every 8 hours intravenous administration of hydrocortisone 100mg, the situation is critical, can be used to succinyl hydrocortisone 100mg into 60ml of 50% glucose and then slowly pushed. After the crisis, the appropriate amount of target gland hormone long-term replacement therapy should be given.
(3) Maintain water, electrolyte and acid-base balance, especially for low sodium and water intoxication.
(4) Remove causative factors: Use vasoactive drugs for treatment of shock, active and effective anti-infective treatment for infection, and use sedative and analgesic anesthesia drugs that may induce crisis with caution.
(5) Treatment of primary pituitary disease