Differential Diagnosis for Recurrent Lower Abdominal Pain in a 16-Year-Old Girl
- Single Most Likely Diagnosis
- Dysmenorrhea: This condition is characterized by recurrent, crampy lower abdominal pain associated with menstruation, often accompanied by symptoms like nausea, diarrhea, and sometimes vomiting. The pain typically starts just before or at the onset of menses and lasts for 1-3 days, which aligns with the patient's symptoms. The recent increase in symptoms could be due to the regularization of her menstrual cycle, which can sometimes exacerbate dysmenorrhea.
- Other Likely Diagnoses
- Mittelschmerz: This condition refers to mid-cycle pain, often associated with ovulation. However, given the timing of the patient's pain in relation to her menstrual cycle, this seems less likely. Mittelschmerz typically occurs around the time of ovulation, which is roughly halfway through a 28-day menstrual cycle.
- Endometriosis: Although less common in adolescents, endometriosis can cause cyclical pelvic pain that worsens over time. The presence of increased clear vaginal discharge and the fact that she has become sexually active could be considered, but the absence of pain during intercourse and the normal pelvic exam findings make this less likely at this stage.
- Do Not Miss Diagnoses
- Ectopic Pregnancy: Despite the negative urine pregnancy test, it's crucial to consider ectopic pregnancy in any female patient of childbearing age presenting with lower abdominal pain, especially given her recent sexual activity. The risk, although low, necessitates careful consideration and possibly further evaluation if symptoms persist or worsen.
- Pelvic Inflammatory Disease (PID): This condition can cause lower abdominal pain and is a significant concern in sexually active adolescents. However, the absence of fever, abnormal vaginal discharge, or cervical motion tenderness makes this less likely. Nonetheless, PID is a critical diagnosis not to miss due to its potential long-term consequences.
- Rare Diagnoses
- Ovarian Cysts or Torsion: These conditions can cause acute or intermittent lower abdominal pain but are less likely given the cyclical nature of the patient's symptoms and the absence of a palpable mass on examination.
- Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease or ulcerative colitis can cause chronic abdominal pain, diarrhea, and sometimes correlate with menstrual cycles due to hormonal influences. However, the primary symptoms and normal findings on wet mount microscopy and speculum examination make this a less likely consideration at this point.