I’ve observed that students will frequently become paralyzed when they see 2CK surg vignettes that have many answer choices, generally including: cardiac tamponade, hemothorax, pneumothorax (spontaneous vs tension vs open), pulmonary vs myocardial contusion, flail chest, ruptured bronchus, ruptured esophagus.
Student says, “Yep that’s me.”
Someone posted in our WhatsApp group today about this topic which is why I randomly decided to improvise a response to it. The following notes are casual/quick and cut to the chase:
Cardiac tamponade
- Tamponade = pericardial effusion + hemodynamic decompensation (i.e., low BP).
- Will present in vignettes as Beck triad (hypotension, JVD, muffled heart sounds) +/- pulsus paradoxus (drop of systolic BP >10 mmHg with inspiration).
- Usually due to stab wound / trauma to chest or LV free-wall rupture post-MI.
- Do echo to confirm then pericardiocentesis or pericardial window (latter NBME 8 for 2CK).
- Most important point about tamponade is that it is the rate of fluid accumulation around the heart that is most important. That is, a stab wound to the chest + fast accumulation of 100 mL of blood could cause tamponade, whereas malignancy + 400 mL chylous accumulation over 6 months might not.
Hemothorax
- Vignette will give uni- or bilateral dullness to percussion + decreased breath sounds.
- Neck veins will be flattened due to hypotension, rather than JVD, as with tamponade.
- Malignant pleural effusion can be a cause of hemothorax, not just trauma.
Spontaneous pneumothorax
- Usually due to “ruptured subapical bleb” in young, tall, lanky patient (vignette will often give basketball/volleyball player).
- I’ve seen cocaine use sometimes mentioned as well –> 22M + plays basketball + uses cocaine + sharp chest pain on one side.
- Hyperresonance over one lung + ipsilateral tracheal deviation.
- Small ones can be observed in theory, but USMLE will want “needle decompression followed by chest tube” for 2CK management.
Tension pneumothorax
- Tension pneumothorax = pneumothorax + hemodynamic decompensation (i.e., decreased blood pressure).
- Usually due to trauma or iatrogenic injury.
- Patient will have contralateral tracheal deviation and hyperresonance of a lung. I’ve seen one Q where BP was technically normal, but the HR was somewhere around 120 (which means patient was imminently decompensating).
- As with spontaneous pneumothorax, do needle decompression followed by chest tube. I’ve also just seen straight-up “tube thoracostomy” as an answer without mentioning the needle first.
Open pneumothorax
- Due to penetrating trauma.
- Distractor on USMLE. Don’t think I’ve ever seen this as a correct answer anywhere on NBMEs.
- Open pneumothorax in theory could cause a tension pneumothorax, so if the USMLE assessed this in theory, they’d probably just have the student select tension pneumothorax.
Pulmonary contusion
- Pulmonary contusion, to my observation, is a diagnosis of exclusion across USMLE vignettes because the presentations are so multifarious – i.e., you’ll often get a vague vignette + be forced to eliminate the other answer choices in order to converge back on pulmonary contusion as the correct answer.
- Classic textbook presentation is: “white-out” of the lung + the patient is fluid-sensitive (i.e., giving IV fluids can cause decreased O2 sats) because contused lung can’t handle preload well.
- But Qs practically never present that way, and USMLE won’t say “white-out. I’ve also seen myocardial contusion present with sensitivity to fluids.
- Pulmonary contusion vignette tends to be trauma +/- rib fractures, where there are vague “infiltrates” in an area of lung (or beneath the rib fractures if they are there).
- USMLE loves to contrast this one with myocardial contusion, where they will always mention bruising/pain over the sternum.
- Trauma +/- rib fractures +/- decreased O2 sats with fluid –> is there pain/bruising over the sternum? Yes? –> myocardial contusion; No? –> did you rule out other causes like tamponade? –> Ok, then pulmonary contusion.
Flail chest
- Will present as paradoxical breathing (i.e., chest moves out with expiration and in with inspiration).
- Due to trauma.
Ruptured bronchus/airway
- Should be mentioned tangentially that “ruptured bronchus” or “ruptured airway” will be a USMLE answer if they say a patient has a “persistent air leak” despite presence of a chest tube.
Ruptured esophagus
- Can be Boerhaave syndrome (spontaneous rupture due to severe straining/vomiting) or iatrogenic.
- Q will give unstable patient (i.e., low BP, high HR, high RR) in patient who just had endoscopy (iatrogenic).
- Subcutaneous emphysema (i.e., crunching/crackling of air under the skin) is a HY finding, but I’ve seen Qs where they don’t mention this.
