Amenorrhoea (primary and secondary).pdf

Definition: Absence of menstrual period. Primary amenorrhea is defined as the absence of menstruation in a female by the age of 15, or by age 16 if there are otherwise normal secondary sexual characteristics, such as breast development and pubic hair. Secondary amenorrhoea (more common) is when pe...

Definition: Absence of menstrual period. Primary amenorrhea is defined as the absence of menstruation in a female by the age of 15, or by age 16 if there are otherwise normal secondary sexual characteristics, such as breast development and pubic hair. Secondary amenorrhoea (more common) is when periods stop for 3 months or more in a row after you've previously had regular periods. Primary Causes: Lifestyle Low body fat can decrease oestrogen levels, preventing menstruation. Excessive physical activity can lead to functional hypothalamic amenorrhea, decreasing secretion of GnRH, subsequently lowering FSH and LH production. Psychological stress can also decrease GnRH production. Pituitary Prolactinomas are benign pituitary adenomas that produce prolactin, inhibiting the secretion of GnRH. Other pituitary adenomas can also disrupt normal FSH and LH secretion PCOS PCOS, high testosterone, insulin resistance, and often elevated LH levels with low FSH, leads to anovulation and amenorrhea. Genetic Kallmann Syndrome: Primary amenorrhea + Anosmia (absent sense of smell) + Hypodontia (some teeth not developing) Turners Syndrome 45XO: MOST common cause of primary amenorrhea. Primary amenorrhea + webbed neck, short stature, coarctation of the aorta, bicuspid aortic valve, streak gonads on US Androgen Insensitivity Syndrome: absent uterus + 46XY + male testosterone levels + female phenotype Mullerian Agenesis: Primary Amenorrhea + Absent uterus & upper vagina Thyroid Both hyper and hypothyroidism may lead to amenorrhea due to disruption of the hypothalamic-pituitary-gonadal axis. They are much more commonly associated with secondary amenorrhea. Medications Antidepressants, birth control (secondary amenorrhea), antihypertensives etc. Secondary Causes: See primary causes + Pregnancy! Most common cause of secondary amenorrhea. Breast Feeding Elevated prolactin levels during lactation suppress ovulation, leading to amenorrhea. Menopause Hypergonadotropic amenorrhea is seen in menopause and results from the ovaries' diminished response to gonadotropins (FSH and LH) due to follicular depletion. This leads to persistently elevated gonadotropin levels but insufficient oestrogen production, which disrupts the endometrial cycle, ultimately causing amenorrhea. Cushings Elevated cortisol levels can inhibit the HPG axis, leading to decreased LH and FSH and resulting in amenorrhea. Investigations: Target investigations to ddx. bHCG, BSL Bloods: Serum FSH/LH, TFT, PCOS screen, prolactin, androgens + oestrogen, cortisol Pelvic U/S