Primary Dysmenorrhea

Primary Dysmenorrhea - Period Pain Primer

• Definition: Recurrent, crampy menstrual pain; no underlying pelvic pathology.
• Prevalence: Very common, especially in adolescents and young women; affects up to 50-90%.
• Onset: Typically 6-24 months after menarche, once ovulatory cycles are established.
• Risk Factors: Early menarche (<12 yrs), nulliparity, heavy/prolonged menses, smoking, family history, BMI extremes.

⭐ Key mechanism: Excess endometrial prostaglandins (PGF2α, PGE2) lead to uterine hypercontractility and ischemia.

Primary Dysmenorrhea - Cramp Culprits

• Pathogenesis: Excess prostaglandins (PGF2α, PGE2) from shedding endometrium.
  • Action: ↑ myometrial contractility → uterine ischemia → pain.
  • Sensitizes nerve endings to pain.
• Leukotrienes: May contribute to inflammation and pain.
• Vasopressin: Potential role in uterine hypercontractility and ischemia.
• Key: Absence of underlying structural pelvic pathology.

⭐ Prostaglandin levels are 2-10 times higher in women with primary dysmenorrhea compared to asymptomatic women during menstruation. This directly correlates with pain severity.

Primary Dysmenorrhea - Symptom Spotlight

• Pain Characteristics:
  • Crampy, spasmodic, colicky uterine pain.
• Location:
  • Suprapubic, midline lower abdomen.
  • May radiate to lower back and inner thighs.
• Timing:
  • Begins hours before or just with menstrual onset.
  • Peaks within 24 hours of menstrual flow.
  • Typically lasts 48-72 hours.
• Associated Systemic Symptoms:
  • Nausea, vomiting, diarrhea.
  • Fatigue, headache, dizziness, irritability.
  • Severity can vary significantly.

⭐ Primary dysmenorrhea often improves after childbirth or with increasing age due to uterine nerve changes or reduced prostaglandin levels after pregnancy-induced uterine denervation or stretching of uterine nerve fibers during childbirth, and decreased prostaglandin synthesis with age related hormonal changes and uterine maturation..

Primary Dysmenorrhea - Spotting Signs

• Diagnosis: Primarily by characteristic history (crampy, midline, lower abdominal pain; starts with or just before menses, lasts 1-3 days).
• Pelvic examination: Typically normal. Key to diagnosis: exclusion of secondary causes.
• Red flags for secondary dysmenorrhea:
  • Onset after age 25
  • Abnormal uterine bleeding (AUB)
  • Dyspareunia, infertility
  • Pelvic abnormality on exam
  • Lack of response to NSAIDs/OCPs
• Investigations: Usually not required for typical cases. Consider pelvic ultrasound if atypical features or unresponsive to initial therapy.

⭐ Onset of primary dysmenorrhea is typically within 6-12 months of menarche, coinciding with the establishment of ovulatory cycles.

Primary Dysmenorrhea - Taming Torment

• Pathophysiology: Excess endometrial prostaglandins (esp. $PGF_{2\alpha}$) → uterine hypercontractility, ischemia.
• Stepwise Management:
  • Non-pharmacological: Reassurance, local heat, exercise, TENS, dietary changes (low fat, Vit B1, E, Mg, Omega-3).
  • Pharmacological (1st line): NSAIDs. Start 1-2 days pre-menses or at pain onset; continue 2-3 days.
    • Mefenamic acid 500mg TDS
    • Ibuprofen 400-600mg TDS-QID
    • Naproxen 250-500mg BD
  • Hormonal (2nd line/contraception): Combined OCPs, progestins (LNG-IUS, DMPA).
  • Surgical (LUNA, PSN): NOT indicated.

⭐ Pain typically starts with menses, lasting 48-72h; pelvic exam is normal.

High‑Yield Points - ⚡ Biggest Takeaways

• Primary dysmenorrhea is painful menstruation without underlying pelvic pathology.
• Onset is typically 6-12 months after menarche, coinciding with ovulatory cycles.
• Caused by excess endometrial prostaglandins (PGF2α, PGE2), leading to uterine hypercontractility and ischemia.
• Presents as crampy, colicky lower abdominal pain starting with menses, lasting 48-72 hours.
• Diagnosis is clinical; pelvic examination is characteristically normal.
• NSAIDs are first-line treatment; COCs are effective second-line options.