Differential Diagnosis for Intermittently Severe Pelvic Pain
Single Most Likely Diagnosis
- Primary Dysmenorrhea: This condition is characterized by recurrent, crampy lower abdominal or pelvic pain associated with menstruation, often described as feeling like contractions. Given the patient's age and symptom description, this is a plausible diagnosis, especially since she has not been pregnant before and her colonoscopy and TVUS (transvaginal ultrasound) are either normal or pending, which does not immediately suggest another cause.
Other Likely Diagnoses
- Ovarian Cysts: These can cause intermittent severe pelvic pain, especially if they rupture or torsion occurs. The pain can be sharp and may feel like contractions.
- Irritable Bowel Syndrome (IBS): Although the colonoscopy was normal, IBS can cause significant abdominal pain that might be perceived as pelvic, and the pain can sometimes be severe and intermittent.
- Endometriosis: This condition can cause chronic pelvic pain, dysmenorrhea, and dyspareunia. The pain can be intermittent and severe, sometimes feeling like contractions, although a definitive diagnosis usually requires laparoscopy.
Do Not Miss Diagnoses
- Ectopic Pregnancy: Although the patient reports not having been pregnant before, it's crucial to rule out pregnancy, including ectopic pregnancy, due to its potentially life-threatening nature. A pregnancy test should be performed.
- Appendicitis: This condition can present with severe, intermittent abdominal pain that may initially be diffuse or around the navel before localizing to the right lower quadrant. It's a surgical emergency if suspected.
- Ovarian Torsion: This is a gynecologic emergency that can cause severe, sudden pelvic pain. It requires immediate surgical intervention to preserve ovarian function.
Rare Diagnoses
- Adenomyosis: A condition where tissue similar to the lining inside the uterus grows into the muscular walls of the uterus, leading to painful, heavy periods. It's less common and might not be the first consideration but could be a cause of severe pelvic pain.
- Interstitial Cystitis: A condition causing bladder pressure, bladder pain, and sometimes pelvic pain. The symptoms can be intermittent and severe, but it's less likely to cause contraction-like pain.
- Pelvic Inflammatory Disease (PID): An infection of the female reproductive organs that can cause severe pelvic pain. It's less likely if the patient does not report any risk factors such as multiple sexual partners or previous STDs, but it should be considered, especially if other symptoms like fever or abnormal vaginal discharge are present.