What are the causes of secondary dysmenorrhoea?

Causes of Secondary Dysmenorrhoea

Secondary dysmenorrhoea is menstrual pain caused by underlying pelvic pathology, with endometriosis being the most common cause, followed by adenomyosis, uterine fibroids, pelvic inflammatory disease, and structural abnormalities. 1, 2

Primary Pathological Causes

Endometriosis

• Endometriosis is the most common cause of secondary dysmenorrhoea, characterized by pain that typically begins before menstruation onset (not just during menses), deep dyspareunia exaggerated during menses, and sacral backache with menses. 1, 2
• The depth of endometriosis lesions correlates with pain severity more than the visual appearance or extent of lesions seen at laparoscopy. 1
• Painful lesions involve peritoneal surfaces innervated by peripheral spinal nerves rather than those innervated by the autonomic nervous system. 1

Adenomyosis

• Adenomyosis presents with dysmenorrhoea, menorrhagia, and a uniformly enlarged uterus on examination. 2
• This condition represents invasion of endometrial tissue into the myometrium and is a significant cause of secondary dysmenorrhoea, particularly in older reproductive-age women. 3, 2

Uterine Fibroids (Leiomyomas)

• Fibroids cause acute pelvic pain through torsion of pedunculated fibroids, prolapse of submucosal fibroids, or acute infarction/hemorrhage in degenerating fibroids. 1
• Fibroids are the second most common cause of acute pelvic pain in perimenopausal and postmenopausal women and represent a more common cause than in premenopausal populations. 1

Pelvic Inflammatory Disease (PID)

• PID accounts for approximately 20% of pelvic pain cases and includes tubo-ovarian abscess, oophoritis, salpingitis, endometritis, cervicitis, or peritonitis of gynecologic origin. 1
• The majority of PID cases relate to sexual activity, though recent instrumentation and surgery are common iatrogenic causes. 1
• Isolated endometritis can occur with cervical stenosis. 1

Structural and Mechanical Causes

Structural Abnormalities (PALM-COEIN Classification)

• Polyps, adenomyosis, leiomyomas, and endometrial malignancy or hyperplasia are recognized structural abnormalities that can lead to dysmenorrhoea according to the PALM-COEIN classification system. 4

Ovarian Pathology

• Ovarian cysts account for one-third of pain cases attributed to gynecologic origin in perimenopausal and postmenopausal women. 1
• Ovarian neoplasms represent the etiology in 8% of acute pelvic pain cases. 1
• Ovarian torsion has been reported as a cause of acute pain, though it is considered rare in the postmenopausal period. 1

Other Structural Causes

• Retained intrauterine device can cause secondary dysmenorrhoea. 1

Key Diagnostic Distinctions

When evaluating dysmenorrhoea, abnormal uterine bleeding, dyspareunia, noncyclic pain, changes in intensity and duration of pain, and abnormal pelvic examination findings all suggest secondary dysmenorrhoea requiring further investigation. 2

Clinical Red Flags for Secondary Causes

• Pain commencing before menstrual onset rather than with flow onset. 1
• Deep dyspareunia exaggerated during menses. 1
• Sacral backache specifically associated with menses. 1
• Uniformly enlarged uterus on examination (suggests adenomyosis). 2
• Abnormal pelvic examination findings. 2

Diagnostic Approach

• Transvaginal ultrasonography should be performed if secondary dysmenorrhoea is suspected based on history or physical examination findings. 2
• A pelvic examination is indicated in patients who have had vaginal intercourse to assess for structural abnormalities and pelvic pathology. 2

Pathophysiology Context

While primary dysmenorrhoea results from increased prostaglandin production causing myometrial contraction and vasoconstriction without underlying pathology 3, 5, 6, secondary dysmenorrhoea involves identifiable structural or inflammatory pelvic disease that mechanically or biochemically generates pain through distinct mechanisms specific to each underlying condition.