Differential Diagnosis for Sudden Left Lower Chest Pain and Epigastric Pain

Single Most Likely Diagnosis

• Pneumothorax: The sudden onset of left lower chest pain and decreased breath sounds in the left lower chest after forceful vomiting suggests a pneumothorax. The mechanism of injury (forceful vomiting) can lead to rupture of blebs or other lung tissue, resulting in air leaking into the pleural space.

Other Likely Diagnoses

• Esophageal Perforation: Forceful vomiting can also lead to esophageal rupture, which presents with severe chest pain and can mimic pneumothorax symptoms. The epigastric pain component could be related to the perforation affecting the lower esophagus near the stomach.
• Aspiration: Aspiration of gastric contents during forceful vomiting can lead to chemical pneumonitis, which might present with chest pain and decreased breath sounds. However, the acute onset and specific localization of symptoms might make this less likely compared to pneumothorax or esophageal perforation.

Do Not Miss Diagnoses

• Pulmonary Embolism: Although less directly related to the act of vomiting, pulmonary embolism can present with sudden chest pain and decreased breath sounds. It's a critical diagnosis to consider due to its high mortality rate if untreated.
• Cardiac Ischemia: Myocardial infarction can sometimes present with atypical symptoms, including chest pain that might be confused with pulmonary issues, especially in women. The epigastric component could be related to referred pain.

Rare Diagnoses

• Spontaneous Hemopneumothorax: A rare condition where there is both air and blood in the pleural space without an apparent traumatic cause. It could be considered in the differential but is much less likely.
• Gastric Rupture: Although forceful vomiting is more commonly associated with esophageal rupture, gastric rupture is a rare but possible complication that could present with severe epigastric and chest pain.