Classification and levels of lesion
To determine treatment tactics, amenorrhea is classified according to the level of dysfunction in the reproductive system. At each "tier," the problem can be functional, anatomical (organic), or congenital.
| Level | Examples of pathologies |
|---|---|
| Central | Nervous anorexia, hyperprolactinemia, pituitary adenoma, Sheehan's syndrome |
| Ovarian | Polycystic ovary syndrome, premature ovarian failure, gonadal dysgenesis |
| Adrenal | Tumors, adrenogenital syndrome, ACTH excess |
| Uterine | Asherman's syndrome, tuberculosis, curettage of the basal layer of the endometrium |
A separate distinction is made for cryptomenorrhea, in which the ovaries function normally, but blood fails to escape due to developmental anomalies or cervical atresia. There is also iatrogenic amenorrhea, caused by surgical intervention (hysterectomy) or medication intake (gonadotropin agonists).
Pathogenesis and systemic consequences
The neurohumoral regulation of the cycle functions as a unified mechanism from the cerebral cortex to the uterus. A breakdown in one link disrupts the entire system.
With the exception of the uterine form, amenorrhea always leads to hypoestrogenism and anovulation. Estrogen deficiency entails hyperandrogenism, the severity of which depends on the level of the lesion. Hormonal imbalance triggers the process of virilization (masculinization):
- skeletal structure changes;
- hirsutism (male-pattern hair growth) and hypertrichosis appear;
- the voice deepens, the clitoris hypertrophies;
- secondary sexual characteristics remain underdevelopment.
The skin also suffers: it becomes dry, atrophic, with a marbled pattern and acne. Purple striae may appear on the abdomen, thighs, and chest.
Hyperprolactinemia as a cause of amenorrhea
A frequent companion of central amenorrhea is an excess of prolactin. Normally, the hypothalamus constantly suppresses its production via dopamine. If this control weakens, prolactin levels rise sharply, leading to prolactrotroph hyperplasia and adenoma formation.
Causes of elevated prolactin:
- Physiological: sleep, stress, physical activity, pregnancy, and lactation.
- Medication-induced: combined oral contraceptives, antipsychotics (haloperidol), antiemetics (metoclopramide), opioids, and antidepressants.
- Pathological: trauma to intrauterine receptors (frequent curettage), hypothyroidism.
Mechanism of action: prolactin excess inhibits the synthesis of gonadotropin-releasing hormone in the hypothalamus. As a result, LH and FSH levels drop, the ovaries cease steroid synthesis and lose sensitivity to stimulation. The outcome is infertility, cycle disorders up to amenorrhea, and galactorrhea (milk secretion).
Interesting fact: in 30–40% of female patients, adrenal androgens are elevated in parallel. This is due to the shared regulation of prolactin and ACTH, as well as the presence of prolactin receptors in the adrenal cortex.
Diagnosis and treatment of hyperprolactinemia
To confirm the diagnosis, prolactin levels are studied dynamically, the hormonal profile is assessed, and functional tests with dopamine agonists (bromocriptine) or antagonists (metoclopramide) are performed. CT or MRI is prescribed to rule out pituitary tumors.
Prolactin levels help suspect the type of tumor: in microadenomas, it ranges from 2500 to 10,000 mIU/L; in macroadenomas, it exceeds 5000 mIU/L.
Treatment tactics:
- Functional form: dopamine agonists (bromocriptine, cabergoline) are prescribed. They restore fertility in 75–90% of cases. In case of luteal phase deficiency, ovulation stimulants (clomifene) are added.
- Pituitary microadenoma: treated conservatively. Long-term medication causes tumor dystrophy and regression. Pregnancy during treatment proceeds safely under the supervision of a neurologist and ophthalmologist.
- Pituitary macroadenoma: requires neurosurgical intervention or radiation therapy.
To easily recall the levels of lesions in amenorrhea, use the acronym ЦЯМНЩ: Central, Ovarian, Uterine, Adrenal, Thyroid gland.
Class and exam questions
How does false amenorrhea differ from true amenorrhea?
In cryptomenorrhea, the ovaries function normally, but menstrual blood cannot escape due to anatomical barriers (e.g., atresia of the cervical canal).
Why does ovulation stop in hyperprolactinemia?
High prolactin levels suppress the production of gonadotropin-releasing hormone in the hypothalamus. This leads to a decrease in FSH and LH, without which follicular maturation is impossible.
Can a pituitary microadenoma be cured without surgery?
Yes, the main method is conservative therapy with dopamine agonists. Long-term medication leads to the reduction and even complete disappearance of the tumor.
What else to study on this topic
- Sheehan's syndrome: clinical presentation of total and partial pituitary hypofunction
- Gigantism and adiposogenital dystrophy: etiology and pathogenesis
- Ovarian amenorrhea: premature ovarian failure and resistant ovary syndromes
- Uterine amenorrhea: Asherman's syndrome and genital tuberculosis
- Functional tests in the differential diagnosis of amenorrhea
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