Concept and etiology

Hypothalamic-pituitary or central cause amenorrhea may be the first symptom of very serious pathologies. Central amenorrheas are characterized by low estradiol levels, and normal or low gonadotropin levels depending on the stratum that is affected, subdividing for this reason into central amenorrheas of hypothalamic and pituitary origin and secondary to hyperprolactinemia, distinguishing in the first two cases between organic and functional causes due to their different diagnostic and therapeutic implications. Las amenorreas centrales se caracterizan por presentar niveles bajos de estradiol, y normales o bajos de gonadotrofinas en función del estrato que se vea afectado, subdividiéndose por ello en amenorreas centrales de causa hipotalámica, hipofisaria y secundarias a hiperprolactinemias, distinguiendo en los dos primeros casos entre causas orgánicas y funcionales por sus distintas implicaciones diagnósticas y terapéuticas.

Although conceptually it may be a hypothalamic or pituitary entity, the hyperprolactinemia group has been considered independently due to its clinical importance and the characteristic elevation of prolactin levels.

Clínic

• Absence of menstrual bleeding.
• Symptoms secondary to hypoestrogenism typical of the picture and the moment in which it has been established. Thus, if the pathology occurs shortly after menarche, the amenorrhea will also be accompanied by the absence or inadequate development of secondary sexual characteristics.

Diagnosis

To arrive at a diagnosis of central amenorrhea, it is essential to perform a global assessment of amenorrhea. The differentiation between primary and secondary amenorrhea is essential to adequately guide the patient’s history and clinical examination, which should always include assessment of nutritional status, examination of secondary sexual characteristics, and examination of the external and internal genitalia, without forgetting other signs and symptoms such as galactorrhea, androgenization or symptoms suggestive of thyroid pathology.

The basic complementary tests include general analysis and hormonal analysis.

Genital ultrasound is especially useful in cases of primary amenorrhea, as it allows confirmation of the presence or absence of internal genitalia.

Other specific diagnostic tests such as nuclear magnetic resonance, genetic studies, and campimetry, among others, will be necessary only in certain cases, to confirm or rule out certain diagnostic suspicions.

Evaluation of the patient with functional CA

Weight loss, intense physical exercise or stress can alter the pulsatile secretion of GnRH (gonadotropin-releasing hormone). The most common is associated with weight loss, especially when it is rapid or when the BMI falls below 19. It affects adolescents and young women, with a prevalence of 0.5-1%. It is the ratio of body fat to total weight that most influences the dysfunction. 22% body fat mass is necessary to maintain menstrual function. The drastic restriction of fats in the diet even without weight loss can also trigger menstrual disturbances. Weight loss leads to an alteration in the pulses of GnRH and consequently of FSH (follicle-stimulating hormone) and LH (luteostimulating hormone).

The most serious situation is constituted by eating disorders -anorexia nervosa, restrictive, bulimia-, mental disorders that cause amenorrhea due to weight loss and that are accompanied by other symptoms secondary to starvation: malnutrition, hypotension, hypothermia, bradycardia, constipation, abdominal pain, and decreased bone mineral density.

Central amenorrhea due to intense physical exercise affects 5 to 25% of highly competitive athletes, especially in pre-competition training, when there is low weight or when the diet is incorrect. It can coexist with stress and be accompanied by eating disorders to varying degrees: «Female athlete triad»: Amenorrhea + Anorexia + Athlete.