Differential Diagnosis for 35-year-old Female with Chest Pain and Exertional SOB

• Single most likely diagnosis:

  • A. PE (Pulmonary Embolism): The patient's recent history of normal vaginal delivery 2 weeks back increases her risk for pulmonary embolism due to the hypercoagulable state associated with pregnancy and the postpartum period. Her symptoms of chest pain and exertional shortness of breath (SOB), along with low oxygen saturation (88%) and a significantly low DLCO (40%), are highly suggestive of a pulmonary embolism. The normal PFTs (FEV1, FVC, TLC) but low DLCO further support this diagnosis, as DLCO measures the ability of the lungs to transfer gas from inhaled air to the bloodstream, which can be impaired in conditions affecting the pulmonary vasculature like PE.

• Other Likely diagnoses:

  • None are as strongly supported as PE given the clinical context and laboratory findings. However, other conditions could potentially cause similar symptoms and should be considered in the differential diagnosis based on further evaluation and additional symptoms.

• Do Not Miss (ddxs that may not be likely, but would be deadly if missed.):

  • Cardiac conditions leading to heart failure or acute coronary syndrome: Although the patient's vital signs are stable and there's no mention of orthopnea, PND, or significant past medical history, cardiac causes of chest pain and SOB should always be considered due to their potential severity. The recent postpartum state also poses a risk for peripartum cardiomyopathy, though this would more likely present with signs of heart failure.
  • Amniotic fluid embolism or other postpartum complications: Though less likely given the timing (2 weeks postpartum) and presentation, these conditions can be catastrophic and should be considered in the differential diagnosis of a postpartum patient with acute symptoms.

• Rare diagnoses:

  • Pulmonary veno-occlusive disease (PVOD): A rare condition characterized by obstruction of the small pulmonary veins, which could explain the low DLCO and symptoms of SOB. However, this diagnosis is much less common and would require further evaluation.
  • Other thromboembolic diseases or vasculitides: Conditions such as antiphospholipid syndrome could potentially cause similar symptoms but are less likely and would require specific diagnostic testing for confirmation.