Differential Diagnosis for Left Sided Pelvic Pain with Normal Pelvic Ultrasound
Single Most Likely Diagnosis
- Ovarian Cyst: Even though the pelvic ultrasound is normal, small ovarian cysts or those that are not easily visualized might still cause pain. Ovarian cysts are common in women of reproductive age and can sometimes rupture or cause torsion, leading to acute pain.
Other Likely Diagnoses
- Endometriosis: This condition, where tissue similar to the lining inside the uterus grows outside of it, can cause chronic pelvic pain, especially if the endometrial implants are on the left side. Ultrasound might not detect endometriosis, especially if the implants are small or not near the ovaries.
- Irritable Bowel Syndrome (IBS): IBS can cause abdominal and pelvic pain, and its symptoms can sometimes be confused with gynecological issues. The pain can be localized to one side, depending on the bowel segment involved.
- Constipation: Severe constipation can cause significant pelvic pain, especially if there is a large fecal impaction in the rectum or sigmoid colon on the left side.
Do Not Miss Diagnoses
- Ectopic Pregnancy: Although less likely if the patient is not pregnant or if a pregnancy test is negative, an early ectopic pregnancy can present with pelvic pain before a visible pregnancy on ultrasound. This is a medical emergency.
- Appendicitis: If the appendix is located in the pelvic area (which can happen if it's retrocecal), appendicitis can cause left-sided pelvic pain. This condition requires prompt surgical intervention.
- Diverticulitis: Inflammation of a diverticulum in the sigmoid colon, which is often on the left side, can cause severe pelvic pain and is a serious condition that may require hospitalization.
Rare Diagnoses
- Lymphoma or Other Pelvic Tumors: Although rare, lymphomas or other tumors in the pelvic area can cause pain. These would typically be visible on imaging studies, but sometimes small tumors might not be easily detected.
- Pelvic Inflammatory Disease (PID): While PID usually causes more diffuse pelvic pain, it can sometimes be localized to one side, especially if the infection is primarily in one fallopian tube.
- Nerve Entrapment or Neuropathy: Conditions like ilioinguinal neuralgia or pudendal neuralgia can cause chronic pelvic pain that might be localized to one side. These are less common causes of pelvic pain but should be considered in the differential diagnosis.