Commonest cause of primary amenorrhea is:
A. Genital tuberculosis
B. mullerian anomalis
C. Ovarian dysgenesis
D. hypothyroidism
Correct Answer: B. mullerian anomalis
Explanation
The commonest cause of primary amenorrhea is Turner syndrome (gonadal dysgenesis / ovarian dysgenesis).
Here’s a detailed explanation:
Primary amenorrhea is defined as the absence of menarche by:
- Age 13 in girls with no secondary sexual characteristics
- Age 15 in girls with normal secondary sexual characteristics
Causes of primary amenorrhea can be broadly divided into:
- Hypogonadism (Gonadal failure) – Most common cause
- Turner syndrome (45,XO) → ovarian dysgenesis → streak ovaries → lack of estrogen → no secondary sexual characteristics
- Pure gonadal dysgenesis in 46,XX females (rare)
- Hypothalamic–pituitary disorders
- Kallmann syndrome (anosmia + hypogonadotropic hypogonadism)
- Functional hypothalamic amenorrhea
- Outflow tract abnormalities
- Mullerian agenesis (Mayer-Rokitansky-Küster-Hauser syndrome) → normal secondary sexual characteristics but absent uterus and vagina
- Imperforate hymen
- Endocrine disorders
- Hypothyroidism, hyperprolactinemia, congenital adrenal hyperplasia (less common)
Summary Table: Cause Key Feature Frequency Gonadal dysgenesis (Turner) No secondary sexual characteristics Most common Mullerian agenesis Normal secondary sexual characters 2nd most common Hypothalamic/pituitary causes Delayed puberty, low FSH/LH Less common Endocrine disorders Other systemic symptoms Rare
✅ Answer: Ovarian dysgenesis (Turner syndrome) is the most common cause of primary amenorrhea.
Other Options Details
Here’s a detailed description of the options you provided:
A. Genital Tuberculosis (GTB):
- Definition: Infection of the female genital tract by Mycobacterium tuberculosis.
- Common sites: Fallopian tubes (most common), endometrium, ovaries, cervix, and rarely the vulva or vagina.
- Symptoms: Infertility, menstrual irregularities (oligomenorrhea, amenorrhea), chronic pelvic pain, and sometimes pelvic mass.
- Diagnosis: Endometrial biopsy, PCR, laparoscopy, hysterosalpingography.
- Management: Anti-tubercular therapy (ATT) for several months; sometimes surgical intervention if there’s severe damage.
B. Mullerian Anomalies:
- Definition: Congenital malformations of the female reproductive tract due to abnormal development of the Mullerian ducts.
- Types: Septate uterus, bicornuate uterus, unicornuate uterus, agenesis of uterus/vagina (Mayer-Rokitansky-Küster-Hauser syndrome).
- Symptoms: Primary amenorrhea, recurrent pregnancy loss, infertility, dysmenorrhea.
- Diagnosis: Ultrasound, MRI, hysterosalpingography.
- Management: Surgical correction in some cases, assisted reproductive techniques if fertility is affected.
C. Ovarian Dysgenesis:
- Definition: Abnormal development of the ovaries, often leading to streak ovaries (nonfunctional).
- Causes: Genetic disorders, e.g., Turner syndrome (45,X), Swyer syndrome (46,XY with gonadal dysgenesis).
- Symptoms: Primary amenorrhea, lack of secondary sexual characteristics, infertility.
- Diagnosis: Karyotyping, hormone profile (low estrogen, high FSH/LH).
- Management: Hormone replacement therapy (HRT) for puberty and bone health; fertility options are limited.
D. Hypothyroidism:
- Definition: Deficiency of thyroid hormone (T3, T4) causing slowed metabolism.
- Causes: Autoimmune (Hashimoto thyroiditis), iodine deficiency, drugs, thyroid surgery.
- Symptoms: Fatigue, weight gain, cold intolerance, constipation, dry skin, hair loss, menstrual irregularities (menorrhagia, oligomenorrhea).
- Diagnosis: Serum TSH and free T4 levels.
- Management: Lifelong thyroid hormone replacement (levothyroxine).
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Writer: Vandita Singh, Lucknow (GS India Nursing Group