What is the differential diagnosis for abdominal distension in a young female?
(1) Pregnancy: The most frequent cause of abdominal distension in a young female, this is not viable in her case owing to her regular menstruation and lack of elevated ß-HCG or AFP. Molar pregnancy or gestational trophoblastic moles occur frequently in women under 29 years of age, but can also be ruled out in this case by the low ß-HCG . (2) Small bowel obstruction: Massively dilated loops of small bowel can distend the abdomen secondary to obstruction. However, in this case, no GI symptoms are reported and the pain is not periumbilical as one would expect from midgut pathology. Although acute appendicitis is associated with RLQ pain and can cause SBO, this diagnosis is not consistent with the chronology of her history (distension preceding pain). (3) Hepatosplenomegaly: Enlarged liver and/or spleen may increase abdominal girth and can result from a variety of disease processes. Although liver pathology would be more likely to evoke RUQ than RLQ pain, it should remain on the differenti
