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Amenorrhea — a symptom which indicates anatomic, genetic, biochemical, physiological or mental disorders and is characterized by lack of periods more than half a year.
The periods represent spontaneous periodic desquamation of a blanket of the mucous membrane covering a cavity of the uterus. The monthly growth cycle and rejection of a functional layer of an endometria is regulated difficult; mechanisms with participation of rileasing-hormones of a hypothalamus, gonadotrophins of a hypophysis and hormones of ovaries. Various dysfunctions of a hypothalamus, a hypophysis, ovaries, a uterus, a vagina or external genitals can cause anomaly of a menstrual cycle and an amenorrhea.
At an ovulatory menstrual cycle vulval allocations are observed every 24 — 35 days and continue from 2 to 8 days. However after puberty approach, at the peak of genital function and before a menopause anovulatory cycles meet rare periods so often that it is necessary to speak about an amenorrhea only in those. cases when the patient had no periods within 3 months. An amenorrhea throughout 3 and more than terms of a normal cycle, at the woman who menstruated earlier, is called a secondary amenorrhea. The term "primary amenorrhea" never designates lack of periods at the woman who reached 16 years or at the woman, their having.
Though the amenorrhea often happens physiological, for example at pregnancy, absence monthly can indicate any dysfunction of a female genital and therefore demands a careful assessment. By means of systematic inspection it is possible, as a rule, quickly and without special expenses to establish the amenorrhea reason. In most cases for establishment of causes of illness there are enough two-three visits of the doctor, several analyses and diagnostic procedures.
Prevalence of an amenorrhea
The amenorrhea takes the 94th place among diseases which the family doctor most often faces. However this figure not absolutely correctly reflects importance of a problem, lack of periods — an alarming symptom only for limited group of the population, namely for women from 16 to 40 years. Prevalence of a disease is very considerable if to judge by the report from which follows that the main complaint 11% of the students inspected in the university center of health care had an irregularity or absence monthly. According to other research, the secondary amenorrhea occurred for a year at 3,3% of young women.
Exists as far as classifications of an amenorrhea. To provide the most correct approach to treatment of the patient with primary or secondary lack of periods, it is necessary to remember 3 main types of an amenorrhea. First of all it is necessary to exclude the physiological reasons of an amenorrhea. If they are absent, it is necessary to exclude anatomic pathology. And only after it it is necessary to look for the genetic and endocrinological reasons.
Physiological delay. The beginning growth of chest glands and hair on a pubis, the first sign of puberty, as a rule is noted approximately at the age of 11,5, approximately in a year the first periods appear. The beginning forming of mammary glands is combined with growth acceleration, and the maximum addition in growth is in unit of time noted for half a year prior to the beginning of periods. A menarche at girls averages 12,5 — 13 years. After approach monthly growth is considerably slowed down, the subsequent increase in length of a body at most of girls seldom exceeds 10 cm. In spite of the fact that time of emergence of secondary sexual characteristics and approach of periods considerably fluctuates, the admissible limit can be set addition or subtraction of 3 years from middle age. On a delay in sexual. maturing specifies the forming of chest glands which did not begin by 14 years and the lack of hair on a pubis which did not come till 16 flyings of periods or their absence during 3 flyings later began formations of chest glands.
There are convincing proofs that terms of puberty and a menarche are influenced considerably by body weight . By the time of the beginning of periods the body weight of most of young women makes not less than 90% from settlement for their growth and, as a rule, exceeds 40 kg. The full girls who reached this critical body weight at more early age begin to menstruate earlier, than thin. Good food and increase in average body weight can be the cause of earlier average menarche that it is observed in many industrialized countries in the last decade.
Pregnancy and lactation. Pregnancy — the most common cause of a secondary amenorrhea, and sometimes and primary. At most of not lactating women of periods are recovered in 2 months after the delivery, and at 90% from them no later than 3 months after the child's birth. At the same time at women who nurse the amenorrhea often proceeds till 10 months and more. As amenorrhea duration against a lactation can be various, absence monthly at the nursing mother should be considered physiological.
Menopause. Age limits of normal approach of a menopause are much wider, than terms of approach of the first periods. On average the menopause comes approximately in 50 years, but the spontaneous termination of periods can happen on 10 flyings sooner or later. After 40 flyings the amenorrhea is usually considered physiological.
In the absence of genetic or endocrine diseases purely anatomic reasons of an amenorrhea meet seldom. Primary amenorrhea can be caused by fusion of a hymen, an union of vulvar lips, a cross partition of a vagina and an aplasia of a vagina. The secondary amenorrhea can be a consequence of destruction of an endometria as a result of infectious diseases, for example tuberculosis, or, more often, as a result of a uterus scraping after the delivery or for the purpose of abortion. If after that there is no regeneration of an endometria, the amenorrhea develops, in a uterus there can be hems leading to formation of the commissures obliterating a cavity of the uterus (Asherman's syndrome).
Genetic and endocrine reasons
Dysfunctions of a hypothalamus. Almost in a quarter of all cases the amenorrhea is combined with decrease in body weight or with reduction of quantity of a fatty tissue. An amenorrhea at which decrease in body weight is observed, explain with hypothalamus dysfunction, however the valid mechanism of this phenomenon is not clear. Usually the amenorrhea arises after a body degrowth, but at patients with the nervous anorexia which developed afterwards cases of the amenorrhea preceding decrease in body weight are described. At the amenorrhea accompanying exercise stresses and chronic diseases loss of body weight is noted too. Gipotalamogipofizarny function can be broken also at excessive obesity. Women with a gross obesity can have no ovulations that conducts to an oligomenorrhea and, sometimes, to an amenorrhea. At some of them periods are recovered when lowering body weight.
Amenored can be called by some other disturbances of a hypothalamus. For example, such general diseases as a sarcoidosis, can influence function of a hypothalamus and lead to an amenorrhea. Besides, the isolated deficit of gonadotrophins, usually owing to absence or a lack of secretion of gonadotrophins-rileasing-hormones of a hypothalamus occasionally meets. Deficit of luteinizing (LG) or follicle-stimulating (FSG) of hormones of a hypophysis or both at the same time is possible. The stress which is also considered as the amenorrhea reason can cause changes of function of a hypothalamus. Believe that many cases of an amenorrhea of not clear etiology are caused by a hypothalamus.
Pituitary frustration. The increased content in blood of prolactin is observed at 15 — 20% of the women suffering from an amenorrhea and can be followed by tumors of a hypophysis of any size. However cases when the tumor did not manage to be found are described. According to various authors, tumors of a hypophysis occur at 25 — 75% of patients with a giperprolaktinemiya and an amenorrhea. Other diseases which cause an amenorrhea due to dysfunction of system a hypothalamus — a hypophysis or direct injury of a hypophysis include a postnatal necrosis of a hypophysis, a cranyopharyngioma and a syndrome of "an empty Turkish saddle".
Dysfunction of ovaries. The amenorrhea can be caused by dysfunction of an ovary both with low, and with the high content of androgens and estrogen. At a dysgenesis of ovaries release of estrogen is so insignificant that secondary sexual characteristics do not form, the mucous membrane of a uterus does not receive sufficient stimulation and the periods do not come.
The aplasia of ovaries often is associated with a karyotype 45X, but meets also at a normal karyotype 46XX, and also at other disturbances of a karyotype, including 45X/46XX; 45X/46Xi (Xq) and 46XY .
Disturbances of a menstrual cycle, including an amenorrhea, are quite often noted at patients with a polycystosis of ovaries (the Matte syndrome — Leventalya). They often observe anovulation which can be caused by impact of estrogen and androgens of ovaries on gipotalamo-pituitary regulation of secretion of gonadotrophins. At 25% of patients with this disease" increase of level of prolactin takes place.
Patients with genetic pathology — testicular feminization, usually see a doctor concerning an amenorrhea. Though on a genotype 46XY and to the content of testosterone such patients are men, phenotypical they certainly are women. Feminization at them is explained by nonsensitivity of fabrics to androgens which is most often caused by deficit of the intracellular receptor proteins specific to testosterone and dihydrotestosterone.
Diseases of adrenal glands. Quite seldom primary and secondary amenorrhea are caused by pathology of adrenal glands. At women with insufficiency of enzyme 17 of a hydroxylase the content of estrogen is lower than norm therefore secondary sexual characteristics do not form and there are no periods. Patients with an inborn hyperplasia of the bark of adrenal glands developing in connection with insufficiency of enzymes 21-or 11-r-hydroxylases can suffer from an amenorrhea and a hirsutism owing to surplus of androgens. The amenorrhea is noted also at patients with a syndrome of Kushinga.
Dysfunction of a thyroid gland. Disturbances of a menstrual cycle can be connected with a hypothyroidism. Chaotic plentiful bleedings, than a long amenorrhea are more characteristic of the persons suffering from primary insufficiency of a thyroid gland. Lack of periods indicates the hypothyroidism connected with insufficiency of a hypophysis more often.
Reception of medicines
Reception of medicines can cause an amenorrhea at the expense of a number of mechanisms. Derivatives of a fenotiazin, tricyclic antidepressants and many hypotensive drugs of the central action, such as Reserpinum and Methyldopa, due to the action on function of a hypothalamus cause an amenorrhea. Chemotherapeutic drugs, such as Cyclophosphanum, can be the cause of insufficiency of ovaries and according to an amenorrhea.
Peroral contraceptive drugs with the low content of estrogen can lead to an amenorrhea owing to inadequate stimulation of an endometria. Many patients at emergence of an amenorrhea change drug or in general stop its use, otherwise the amenorrhea can proceed during howls the term of reception of low-oestrogenic drugs. Numerous cases when the amenorrhea was observed after cancellation of tablets are described. To prove communication of an amenorrhea with the previous reception of contraceptives quite difficult as in the majority of researches control groups were not used, and regarding controlled researches of statistically reliable communication it was not succeeded to reveal.
Value of an amenorrhea
Fortunately, the amenorrhea does not belong to life-threatening states. The reasons of primary amenorrhea are usually more serious, than the reasons of a secondary amenorrhea because lack of periods at 16-year age assumes probability of genetic or endocrine disorders. On the other hand, pregnancy and anovulation are found in patients with a secondary amenorrhea more often. Nevertheless, each woman who saw a doctor has to be very carefully inspected any of the diseases which are giving in to treatment did not remain undetected.