The writer remembers the case of a young patient who presented herself to our
observation with a very subtle clinical picture: she showed signs of severe
dehydration with hypernatremia. The young man was a worker and for hours he
worked in the sun. At first we thought it was a trivial dehydration, but then,
when we tried to correct the hydro-electrolyte balance, it was evident that
we were filling the well with a bucket! Each rehydrating therapy was in vain: the
patient always urinated abundant light urine (polyuria) and there was no way to
keep water. An encephalic CT scan with contrast media (these are the first
diagnostic tools at our disposal) allowed us to clarify the clinical picture and
to make a diagnosis
For hypopituitarism, in medicine, we mean the reduced secretion of one or more
of the nine hormones normally produced by the pituitary gland (also called
hypophysis) which is found in the base of the brain. If there is a decrease in
the secretion of all pituitary hormones, the term panipopituitarism is often
used. On the other hand, the signs and symptoms of hypopituitarism vary
according to the hormones in which production is lacking. The first description
of the condition was made in 1914 by the German physician Morris Simmonds who
demonstrated in a young woman of 46 years the deficit of the pituitary gland in
the anterior portion: this woman had accused puerperale fever 11 years before
the death and to following weakness, lack of the cycle (amenorrhea), aging and
anemia. These signs were referred to as "Simmonds syndrome". However, it had to
be later, in 1950, when the diagnosis of "empty sella" was put, as documented by
a radiological investigation (pneumoencephalography and X-ray tomography) and
later with the discovery of the radioimmunoassay method developed by Rosalyn
Yalow and Solomon Berson in the late 1950s it was possible to dose the pituitary
hormones.
The causes are:
-Tumors: hypophyseal adenomas that compress the normal tissue in the gland and
rarely from other brain tumors present outside the gland, such as
craniopharyngioma, meningioma, chordoma, ependymoma, glioma or metastasis of
tumors present in other parts of the body.
- Infections, inflammation and infiltrations: encephalitis, brain infections (brain
abscess, meningitis, encephalitis) or the gland itself or can be infiltrated by
abnormal cells (neurosarcoidosis, histiocytosis) or a quantity of excessive iron
(hemochromatosis). The empty saddle syndrome is the unexplained disappearance of
the pituitary tissue, probably due to external pressures. Autoimmune (or
lymphocytic) hypophysitis occurs when the immune system directly attacks the
hypophysis.
-Vascular: pregnancy comes to an end, the pituitary gland that becomes
hypertrophied, becomes vulnerable to low blood pressure, for example, it can
result from hemorrhages, such as for example. in postpartum hemorrhage, (Sheehan's
syndrome) also called post-partum hypophyseal necrosis.
- Radiation
-Other physical causes, traumatic brain injury, subarachnoid hemorrhage,
neurosurgery and ionizing radiation
The incidence of pituitary pathology stands at 45.5 out of 100,000, generally for 61% hypopituitarism depends on the finding of tumors of the pituitary gland, 9% on other types of lesions and 19% on other causes. It may be a previous traumatic brain injury, with a spontaneous subarachnoid hemorrhage or brain radiotherapy.
The hormones of the pituitary gland perform different actions on the organism
and the symptoms of hypopituitarism therefore depend on which hormone is lacking.
The pituitary gland is divided into an anterior part that produces 7 hormones,
and an intermediate and a posterior part, called neurohypophysis.
We will have the following hormonal deficits:
• Somatotropic, GH, independent of the activity of the other endocrine glands;
stimulates the deposition of calcium in the bone tissue and the proliferation of
cartilaginous cells, increases the mass of skeletal muscles and stimulates
protein synthesis. It is also called growth hormone and its lack causes the
arrest of the individual's statural and weighted development.
• Folliculotropic, FSH, for the phase of the sexual cycle that leads to the
production of the follicle, stimulates the ovaries ie to form the follicles and
the secretion of their hormones, estrogens.
• Luteotropic, LH or luteinizing, of the second phase of the cycle responsible
for the production of progesterone. In humans, these hormones regulate
spermatogenesis
• Tireotrope, TSH, the one that stimulates the production of thyroid hormones
• Corticotropic, ACTH, which leads to the production of adrenal hormones.
The posterior part of the pituitary or neurohypophysis is a secretory appendix
that produces:
• ADH or vasopressin, which controls the excretion of urine by the kidney and
thus regulates the water and electrolyte exchange of organic liquids;
• Oxytocin acting on the uterus, stimulating contractions during childbirth
• The prolactin, the hormone of lactation and of sexuality and excitement.
Finally there is the hormone MSH, produced by the intermediate part, called
intermediary, with action on the melanocytes,
Symptoms can be subtle and are often initially attributed to other causes. In
most cases, there is a deficiency of three or more hormones. The most common
problem is the deficiency of follicle-stimulating hormone (FSH) and / or
luteinizing hormone (LH) that involves abnormalities of sex hormones. Growth
hormone deficiency is more common in people with underlying cancer than those
with other causes.
Sometimes, there are other symptoms that result from the underlying cause.
That there is always a pure hormonal deficit is not always the rule. For example,
in the condition called "acromegaly" if the hypopituitarism is due to a growth
of a tumor producing a hormone, in this specific case, GH, then there may be
symptoms correlated with excess hormonal, e.g. a grotesque facies, big hands and
feet, an elongation of the body, the signs of compression on the optic chiasm,
anatomical structure located behind the bulbs that lies ahead of the pituitary
ghinadola for which there may be visual field defects (hemianopsia). A headache
can also accompany pituitary tumors, as well as pituitary apoplexy (heart attack
or hemorrhage of a pituitary tumor) and lymphocytic hypophysitis (autoimmune
inflammation of the pituitary). Pituitary insufficiency leads to many changes in
the skin, hair and nails, due to the lack of action of the pituitary hormone in
these sites.
In general, in the case of a deficiency of the hormones of the anterior part,
the first signs are correlated with the sexuality of the person (control of
ovary and testis) and with the control of hydro-electrolyte balance and with
thyroid control, which in turn is a function of the TSH. Pituitary hormones
control the function of the adrenal gland, thyroid and gonads (testes and
ovaries). The deficiency of luteinizing hormone (LH) and follicle-stimulating
hormone (FSH), together called gonadotropins, leads in women to oligomenorrhea
or amenorrhea (impaired cycle), resulting in infertility. In the case of man the
loss of secondary sexual characteristics is determined: loss of hair on the
face, on the scrotum and on the trunk as they undergo a decrease in muscle mass
and anemia. Both sexes may experience decreased libido and a loss of sexual
function and an increased risk of osteoporosis (bone fragility). Growth hormone
deficiency (GH) leads to a decrease in muscle mass, central obesity (increase in
body fat around the waist) and impairment of attention and memory. The
adrenocorticotropic hormone deficiency (ACTH) leads to adrenal insufficiency, ie
the lack of production by the adrenal gland of glucocorticoids such as cortisol.
ACTH deficiency is very similar to the disease of primary Addison, which is
characterized by cortisol deficiency as a result of direct damage to the adrenal
glands. The latter form, however, often leads to hyperpigmentation of the skin (bronzyx).
The thyroid-stimulating hormone (TSH) deficiency leads to hypothyroidism (lack
of production of thyroxine (T4) and triiodothyronine (T3) in the thyroid).
Typical symptoms are fatigue, cold intolerance, constipation, weight gain, hair
loss and slowed thinking, as well as a slow heart rate and low blood pressure.
An antidiuretic hormone (ADH) deficiency can lead to the development of diabetes
insipidus, a condition that mimics diabetes mellitus, but in this case does not
depend on whether glucose in urine determines polyuria, but derives from the
inability of the kidney to concentrate. urine with loss of water in the third
compartment and hypernatremia.
The diagnosis of hypopituitarism is formulated based on blood tests. Two types
of blood tests are used to confirm the presence of a hormone deficiency: basal
levels, where blood samples - usually performed in the morning - are performed
without any form of stimulation and dynamic tests, in which the blood is
analyzed after injection of a stimulating substance. Measurement of ACTH and
growth hormone usually requires dynamic testing, while other hormones (LH / FSH,
prolactin, TSH) can typically be determined by examining baseline levels.
LH / FSH levels can be masked by a high level of prolactin and therefore are not
reliable unless the levels of the latter are low or normal. In men, the
combination of low levels of LH and FSH combined with a low testosterone level
confirms the LH / FSH deficiency, while a high level of testosterone would
indicate a problem in another part of the body (for example, a testosterone
secretory tumor). In women, the diagnosis of LH / FSH deficiency depends on
whether it is in menopause or not. Before the menopause, abnormal menstrual
cycles together with low levels of estradiol and LH / FSH confirm a hypophyseal
problem;
If all the pituitary tests are abnormal and the levels of insulin-like growth
factor 1 (IGF-1) appear diminished, it is almost certain to be a deficiency of
growth hormone. If cortisol levels in the morning have values above 500 nmol /
l, ACTH deficiency is unlikely, while a level below 100 is indicative. Levels
between 100-500 require a stimulation test.
Symptoms of insipid diabetes should prompt a formal water deprivation test to
evaluate the body's response to dehydration.
1. removal of the underlying cause;
2. treatment of hormonal deficiencies;
3. management of any other repercussions arising from hormonal deficiencies.
Removal of the underlying cause
Pituitary tumors require treatment when they cause specific symptoms, such as
headaches, visual field defects or excessive hormone secretion. Transsphenoidal
surgery (removal of a tumor thanks to an intervention through the nose and
sphenoid sinuses) can, in addition to solving the symptoms related to the tumor,
improve the pituitary function even if the gland is often damaged further due to
surgery.