Yeah, took me a while to figure that one out. The bulging septum in constrictive pericarditis reflects blood returning to the RV against fixed filling pressures (as with tamponade). But why Kussmaul's? Simply put, in constrictive pericarditis, the blood returning from the IVC displaces blood returning from the SVC. Whereas inspiration reduces intrathoracic pressure, it increases intra-abdominal pressure. In this manner, Kussmaul's behaves similar to hepatojugular reflux. In tamponade, if you will, the bulging septum permits (accommodates) RV filling from both the SVC and IVC. I know it is confusing. The sentinel paper on Kussmaul's comes from a cardiologist on UMass staff (Theo Meyer). The paper is entitled 'Mechanism underlying Kussmaul's sign in chronic constrictive pericarditis' was published in the AJC in Nov 1989. The distinction between tamonade and constriction continues to be defined in the Q-banks but this subtle distinction. Not so sure the NBME harps on this fact but it is worth hanging onto. Thank you for the note. HS

Good question: it would need to distinguish itself from look alikes. Here are the characteristics I've seen: Juvenile idiopathic arthritis (JRA): sounds like Kawasaki disease (fever, rash, adenopathy) but liver/spleen ↑ and often presents with (joint, fever, rash); negative serologies (↑ WBC, anemia of chronic disease). It is surely pretty ill-descript but the composite presentation will exclude other answer options. Remember, I view the answer options as your differential diagnosis. It just won't line up with the other options. It is a tough one...HS

@@HowardSachs12DaysinMarch Got it. Thanks!

Thank you! Such kind words sustain the effort. Best of luck with your studies. HS

Yes, the day job does interfere with production!

@@HowardSachs12DaysinMarch I imagine the whole being a doctor thing can be challenging. I have two more years of being a medical student, so you know living the dream everyday.

Much appreciated. Best of luck with the studies...HS

Well, it's not missing (Part 1). You are inquiring about another presentation?

And my best regards back to India and your lovely cat! HS

Thank you so much! Much appreciated. HS

Not sure what the question is/was but most assuredly is the visceral surface...

That is a fabulous point! You'll have to think in terms of a 'leathery' heart/pericardium in constrictive disease compared to tamponade, where the heart is in a fluid filled. Although there is entrapped, the septum is still 'expansile (or rubbery)' Again, fabulous point in the sense that constrictive pericarditis is a disease of the pericardium, not the heart per se. Yet, if you consider external beam radiation as the prototype, you can envision that leathery septum. Finally, and in fairness, I've discussed this with cardiologists who have a tough time reconciling Kussmaul's in constrictive pericarditis v tamponade so it is okay to use your imagination a little bit (and appreciate that the NBME likes this little nugget). Thank you so much for the consideration...HS