A 62-year-old male with chest pain who says it began one hour ago. You auscultate crackles, blood pressure 142/82, SpO2 94% RA. After aspirin, en route he sweats and wheezes and BP drops to 106/82. You should suspect:

• A. Pneumonia
• B. Anaphylactic reaction
• C. Cardiac asthma
• D. Right-sided heart failure

Answer: (B)

The main idea is recognizing an anaphylactic reaction to a drug, shown by bronchospasm and systemic shock after exposure. In this scenario, the patient develops wheezing and a drop in blood pressure after receiving aspirin. Wheezing signals bronchoconstriction, not fluid in the airways (which would cause crackles). The sudden hypotension reflects distributive shock from widespread vasodilation and increased vascular permeability that can occur in anaphylaxis. Sweating also fits the sympathetic surge seen with anaphylactic reactions.

Pneumonia wouldn’t suddenly cause new wheezes and hypotension right after giving aspirin, and its crackles come from fluid in the lungs due to infection, not an acute allergic trigger. Cardiac asthma involves wheezes from pulmonary edema due to heart failure and wouldn’t typically present with an abrupt BP drop after a drug exposure. Right-sided heart failure would show signs like peripheral edema and JVD rather than an acute bronchospastic event following a medication.

So, the combination of new wheeze, diaphoresis, and a fall in blood pressure after aspirin points to an anaphylactic reaction.