Differential Diagnosis for A-V Mismatch
- Single Most Likely Diagnosis
- Pulmonary Embolism: This is often the first consideration in A-V mismatch due to its potential for high morbidity and mortality. It occurs when a blood clot blocks an artery in the lung, leading to a mismatch between ventilation and perfusion.
- Other Likely Diagnoses
- Pneumonia: Especially if it's lobar pneumonia, it can cause areas of the lung to be poorly ventilated while still being perfused, leading to A-V mismatch.
- Chronic Obstructive Pulmonary Disease (COPD): COPD can lead to areas of the lung being under-ventilated relative to perfusion, especially during exacerbations.
- Asthma: Similar to COPD, asthma can cause under-ventilation of certain lung areas due to bronchoconstriction.
- Do Not Miss Diagnoses
- Pulmonary Arteriovenous Malformation: Although rare, this condition can lead to significant A-V mismatch and can be life-threatening if not diagnosed and treated properly.
- Severe Pneumothorax: A large pneumothorax can collapse a lung, leading to a significant area of lung tissue being ventilated but not perfused, or vice versa, depending on the extent and nature of the injury.
- Cardiac Shunt (e.g., Patent Foramen Ovale): Right-to-left shunts can lead to deoxygenated blood bypassing the lungs and entering the systemic circulation, causing an A-V mismatch.
- Rare Diagnoses
- Goodpasture Syndrome: An autoimmune disease that can cause pulmonary hemorrhage, leading to areas of lung being poorly ventilated but well-perfused.
- Mitral Stenosis: Can lead to pulmonary congestion and edema, potentially causing A-V mismatch due to impaired gas exchange.
- Neurogenic Pulmonary Edema: Can occur after severe neurological insults and leads to non-cardiogenic pulmonary edema, causing A-V mismatch.