Cardiogenic and obstructive shock: Viva

Branch 1: Classification and recognition

The candidate should recognise that this boy is in cardiogenic shock. The cold, mottled peripheries, the capillary refill of 5 seconds, the gallop rhythm and the hepatomegaly are the signature of a cold, low-output state from pump failure, not the warm, vasodilated shock of early sepsis or the fluid-responsive hypovolaemia. A strong candidate states the problem representation clearly: a 10-year-old with a three-day viral prodrome and a cold low-output shock with a gallop and hepatomegaly, consistent with myocarditis until proven otherwise. ^[1]

If the examiner presses on the classification, the candidate should explain the four shock types (hypovolaemic, distributive, cardiogenic, obstructive) and the warm versus cold split. Cardiogenic and obstructive shock share the cold phenotype and are the two types where aggressive fluid resuscitation can harm. The candidate should distinguish cardiogenic shock (gallop, hepatomegaly, bilateral crackles) from obstructive shock (distended neck veins, muffled heart sounds or unilateral absent breath sounds) and explain that point-of-care ultrasound confirms the mechanism within minutes. ^[1][15]