Differential Diagnosis for a 20-week Pregnant Woman with Shortness of Breath, Rapid Heart Rate, and Respirations with 87% Oxygen Saturation on Room Air

• Single Most Likely Diagnosis
  • Pulmonary embolism is less likely but still a consideration, however, the most likely diagnosis in this context could be anemia of pregnancy. This condition is common due to increased blood volume and demand for iron, leading to decreased oxygen-carrying capacity, which can cause shortness of breath and increased heart rate.
• Other Likely Diagnoses
  • Asthma exacerbation: Pregnancy can affect asthma control, and an exacerbation could present with shortness of breath and increased respiratory rate.
  • Pregnancy-induced hypertension: Although more commonly associated with high blood pressure, it can lead to cardiac issues that might cause shortness of breath.
  • Gestational cardiomyopathy: A rare condition but can occur, leading to heart failure symptoms such as shortness of breath.
• Do Not Miss Diagnoses
  • Pulmonary embolism (PE): Although less common, PE is a critical diagnosis to consider due to its high mortality rate. Pregnancy increases the risk of PE due to hypercoagulability.
  • Amniotic fluid embolism: A rare but potentially fatal condition that can cause sudden onset of shortness of breath and cardiovascular collapse.
  • Placenta previa or abruption: While these conditions more commonly present with bleeding, they can also lead to significant maternal distress and potentially affect respiratory status indirectly.
• Rare Diagnoses
  • Peripartum cardiomyopathy: A rare condition where the heart muscle becomes weakened, occurring during the last month of pregnancy or within 5 months after delivery.
  • Pneumonia: Although not exclusive to pregnancy, pneumonia can present with similar symptoms and should be considered, especially if there's a history of exposure or other suggestive symptoms.
  • Thyroid storm: In pregnant women with untreated or undertreated hyperthyroidism, a thyroid storm can occur, leading to severe symptoms including shortness of breath and tachycardia.