Question 97

Question:

A 44 year-old obese woman who has been recovering from a knee sprain develops sudden shortness of breath and left-sided chest pain with inspiration. On exam, HR is 110, RR is 24, Temp is 37 C, the pulmonic portion of the second heart sound is accentuated, 3 cm of JVD is appreciated, and the right leg is slightly swollen and tender. Trachea is midline and lung sounds are equal bilaterally without wheezes, rales, or rhonchi. The remainder of physical exam is unremarkable. If pathological examination was performed, what would be seen in the affected lung tissue?

Correct Answer: C.  Hemorrhagic wedge-shaped infarct

This patient has a pulmonary embolus (PE). This patient is at known risk due to her obesity and immobility (suggested by recent knee sprain). The sudden onset, pleuritic chest pain, and findings on exam are consistent with PE. Since both pulmonary arteries and bronchial arteries supply the lungs, a hemorrhagic (red) infarct would be seen with occlusion of a pulmonary arterial branch. The wedge shape represents the area of lung tissue normally supplied by that branch. Sudden onset and lack of fever make tuberculosis (caseating necrosis with acid-fast bacilli) or bacterial pneumonia (exudative consolidation with Gram-positive cocci) far less likely. Loss of alveolar septa is seen in emphysema.