During needle manipulation for a supraclavicular brachial plexus block, a patient develops chest pain and dyspnea. The most likely diagnosis is:

During needle manipulation for a supraclavicular brachial plexus block, a patient develops chest pain and dyspnea. The most likely diagnosis is:

• A. Angina
• B. Pneumothorax
• C. Phrenic nerve irritation
• D. Intravascular injection

Answer: (B)

The key idea is that in a supraclavicular block, the pleura and lung apex lie very close to the needle path. If the needle punctures the pleura, air leaks into the pleural space and a pneumothorax can develop. The hallmark is sudden chest pain and shortness of breath that begin during needle manipulation, reflecting direct injury to the lung surface rather than a cardiac or nerve-related event. Angina is driven by myocardial blood flow and activity, so its onset isn’t typically tied to a needle track in this region. Phrenic nerve irritation could cause diaphragm-related symptoms, but it’s less likely to produce abrupt chest pain with dyspnea exactly at the moment of needle entry. Intravascular injection would more often cause systemic signs of local anesthetic toxicity rather than focal chest pain and dyspnea. Therefore, pneumothorax best explains the scenario.

The key idea is that in a supraclavicular block, the pleura and lung apex lie very close to the needle path. If the needle punctures the pleura, air leaks into the pleural space and a pneumothorax can develop. The hallmark is sudden chest pain and shortness of breath that begin during needle manipulation, reflecting direct injury to the lung surface rather than a cardiac or nerve-related event. Angina is driven by myocardial blood flow and activity, so its onset isn’t typically tied to a needle track in this region. Phrenic nerve irritation could cause diaphragm-related symptoms, but it’s less likely to produce abrupt chest pain with dyspnea exactly at the moment of needle entry. Intravascular injection would more often cause systemic signs of local anesthetic toxicity rather than focal chest pain and dyspnea. Therefore, pneumothorax best explains the scenario.