What is the differential diagnosis for a female of reproductive age with a 10-day history of left lower quadrant (LLQ) pain, intensity 8/10, constant when untreated but relieved with ibuprofen (nonsteroidal anti-inflammatory drug (NSAID)) every 8 hours, associated with intermenstrual spotting, heavy menstrual bleeding, anemia, and hair loss?

Differential Diagnosis for Left Lower Quadrant Pain in Reproductive-Age Female

The most likely diagnoses in this clinical presentation are uterine fibroids with possible degeneration, endometriosis, or pelvic congestion syndrome, given the constellation of left-sided pain responsive to NSAIDs, intermenstrual spotting, heavy menstrual bleeding, anemia, and hair loss in a reproductive-age woman.

Primary Gynecologic Considerations

Uterine Fibroids (Leiomyomas)

• Fibroids are a leading consideration given the chronic left lower abdominal pain (10 days), heavy menstrual bleeding lasting 5 days, anemia, and complete pain relief with ibuprofen every 8 hours 1
• Fibroids cause several distinct pain presentations including chronic pelvic pain and pressure, dysmenorrhea, and acute severe pain from fibroid degeneration, infarction, or hemorrhage 1
• The positional relief (lying on side with knees bent) and constant nature when untreated are consistent with fibroid-related pressure symptoms 1
• Heavy menstrual bleeding from fibroids commonly leads to iron-deficiency anemia, which can cause hair loss 1
• NSAIDs are effective for fibroid-related pain because they reduce prostaglandin levels, which are elevated in women with excessive menstrual bleeding 2, 3

Endometriosis

• Endometriosis affects 5-10% of reproductive-age women and presents with severely painful symptoms involving neuroinflammatory processes 4
• The condition causes peripheral and central sensitization, explaining the high pain intensity (8/10) and requirement for regular NSAID dosing 4
• Intermenstrual spotting is a recognized feature of endometriosis 4
• Heavy menstrual bleeding and dysmenorrhea are common manifestations 4
• The chronic nature (10 days) and response to NSAIDs align with endometriosis pathophysiology 4

Pelvic Congestion Syndrome

• Pelvic congestion syndrome presents as chronic pelvic pain caused by engorged and refluxing pelvic veins, with dilated periuterine and periovarian veins (≥8 mm) 5
• Estrogen overstimulation contributes to this condition, making it relevant in reproductive-age women 5
• The positional relief obtained by lying on the side may reduce venous pooling 5
• Many women with pelvic congestion have morphologic findings of polycystic ovarian syndrome, which can be associated with heavy menstrual bleeding 5
• Pain characteristics include chronic, dull, aching quality that may be lateralized 5

Important Non-Gynecologic Differential

Sigmoid Diverticulitis

• Acute diverticulitis of the sigmoid or descending colon is the most common cause of adult left lower quadrant pain overall 1
• However, the 10-day duration, complete relief with NSAIDs, absence of fever, and lack of gastrointestinal symptoms (no nausea, vomiting, constipation, or diarrhea) make this less likely 6
• Diverticulitis typically presents with fever, leukocytosis, and gastrointestinal symptoms 6

Recommended Diagnostic Approach

Initial Imaging Study

• Transvaginal ultrasound combined with transabdominal approach is the initial imaging study of choice for women of reproductive age with left lower quadrant pain where gynecologic pathology is suspected 6, 1
• This approach provides both anatomic overview (transabdominal) and superior spatial resolution (transvaginal) 6
• Ultrasound with Doppler should be included to evaluate for pelvic congestion syndrome, assessing for engorged periuterine and periovarian veins, low-velocity flow, and altered flow with Valsalva maneuver 5

Alternative or Additional Imaging

• CT abdomen and pelvis with IV contrast is the most useful examination if ultrasound is equivocal, if complications are suspected, or if a non-gynecologic etiology needs evaluation 6, 1
• Contrast-enhanced CT demonstrates the best diagnostic performance for fibroid complications, with contrast enhancement showing 86% sensitivity 1
• MRI pelvis may be considered if ultrasound is inconclusive and provides excellent soft tissue characterization for fibroids and endometriosis 6

Critical Clinical Pitfalls

Anemia and Hair Loss

• The combination of anemia and hair loss strongly suggests chronic iron-deficiency anemia from heavy menstrual bleeding rather than acute blood loss 1
• This supports a chronic gynecologic process (fibroids or endometriosis) over acute diverticulitis 1

NSAID Response Pattern

• Complete pain relief with ibuprofen every 8 hours is highly characteristic of prostaglandin-mediated pain from gynecologic sources 2, 3
• NSAIDs reduce prostaglandin levels, which are elevated in women with excessive menstrual bleeding and dysmenorrhea 3
• This response pattern is less typical for diverticulitis, which usually requires antibiotics for resolution 6

Intermenstrual Spotting

• New intermenstrual spotting since pain onset is a red flag for gynecologic pathology, particularly fibroids (especially submucosal), endometriosis, or hormonal dysfunction 1, 4
• This symptom is not explained by diverticulitis 6

Age-Specific Considerations

• In reproductive-age women, gynecologic causes must be prioritized before assuming gastrointestinal pathology 6
• Beta-hCG should be obtained to exclude ectopic pregnancy before any imaging with ionizing radiation 6