Differential Diagnosis for the 28-year-old Woman with a Positive Home Pregnancy Test
- Single most likely diagnosis: + Ectopic pregnancy: The patient's presentation with a positive pregnancy test, absence of an intrauterine gestation on transvaginal ultrasound, and a slow rise in β-hCG levels (<50% increase over 48 hours) are highly suggestive of an ectopic pregnancy. The failure of β-hCG to decrease after a diagnostic dilation and curettage (D&C) further supports this diagnosis, as it indicates the presence of a persistent pregnancy outside the uterus.
- Other Likely diagnoses: + Miscarriage: Although the patient does not report vaginal bleeding or cramping, a miscarriage could still be considered, especially given the slow rise in β-hCG levels. However, the absence of an intrauterine gestation on ultrasound and the failure of β-hCG to decrease after D&C make this less likely. + Pituitary or ectopic source of β-hCG: In some cases, β-hCG can be produced by pituitary tumors or other ectopic sources, leading to false-positive pregnancy tests. However, the patient's symptoms and ultrasound findings make this less likely.
- Do Not Miss diagnoses: + Molar pregnancy: Although rare, a molar pregnancy can present with a positive pregnancy test and elevated β-hCG levels. It is crucial to rule out this diagnosis, as it can have serious complications if left untreated. + Ovarian torsion: This is a rare but potentially life-threatening condition that can occur in pregnancy. Although the patient does not report severe pain, ovarian torsion can sometimes present with mild or intermittent symptoms.
- Rare diagnoses: + Heterotopic pregnancy: This is a rare condition where there is both an intrauterine and an ectopic pregnancy. Although the patient's ultrasound did not show an intrauterine gestation, it is essential to consider this diagnosis, especially in patients undergoing fertility treatments. + Phantom pregnancy (pseudocyesis): This is a rare condition where a woman believes she is pregnant, despite the absence of a true pregnancy. However, the patient's positive pregnancy test and elevated β-hCG levels make this diagnosis unlikely.