Differential Diagnosis for Recurrent Pelvic Pain

The patient's symptoms of intermittent severe episodes of right lower quadrant and suprapubic pelvic pain, elevated CRP during episodes, and normal diagnostic tests, suggest a complex condition. Here's a categorized differential diagnosis:

• Single Most Likely Diagnosis

  • Endometriosis: This condition is a strong candidate given the patient's history of pelvic pain since adolescence, the cyclical nature of the pain (implying a possible link to menstrual cycles), and the fact that the pain resolved during pregnancy (a known phenomenon in some cases of endometriosis). The elevated CRP during episodes may indicate inflammation associated with endometriosis.

• Other Likely Diagnoses

  • Interstitial Cystitis: This condition could cause suprapubic pain and may not be fully ruled out by normal urine tests and cystoscopy, as findings can be subtle and intermittent.
  • Irritable Bowel Syndrome (IBS): Although stool testing was normal, IBS can cause significant abdominal pain and could potentially contribute to the patient's symptoms, especially if the pain is related to bowel movements or food intake.
  • Adenomyosis: Similar to endometriosis, adenomyosis can cause pelvic pain and is more likely to be considered given the patient's gender and age.

• Do Not Miss Diagnoses

  • Ovarian Torsion: Although less likely given the intermittent and long-standing nature of the pain, ovarian torsion can cause severe pelvic pain and is a surgical emergency.
  • Appendicitis: Despite the normal abdominal CT, recurrent appendicitis or a chronic appendiceal condition could cause intermittent right lower quadrant pain.
  • Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause abdominal pain, elevated CRP, and may have normal stool tests if the disease is not actively causing gastrointestinal symptoms.

• Rare Diagnoses

  • Ehlers-Danlos Syndrome: This genetic disorder can cause hypermobile joints and may be associated with chronic pain syndromes, including pelvic pain, due to ligamentous laxity or other mechanisms.
  • Tarlov Cysts: These are rare nerve root cysts that can cause pelvic pain, although they are less commonly considered as a primary cause of the symptoms described.
  • Obturator Neuralgia: Compression or irritation of the obturator nerve can cause pelvic pain, but this is a less common condition and might not fully explain all the patient's symptoms.