Shock

Rationale

Shock is inadequate tissue perfusion. It is a frequently encountered life-threatening emergency. Regardless of the underlying cause, certain general measures are usually indicated that can be lifesaving. Although hypotension is commonly present, shock can exist in its absence.

Causal Conditions

(list not exhaustive)

1. Cardiogenic
   1. Myocardial dysfunction
      1. Myopathy (e.g., congenital, acquired)
      2. Ischemia
      3. Inflammation (i.e., infectious or inflammatory myocarditis)
      4. Mechanical (e.g., valvular disease, congenital heart disease)
   2. Rhythm abnormalities
2. Hypovolemic
   1. Fluid loss (e.g., dehydration)
   2. Hemorrhage
   3. Third space loss
3. Distributive (diminished systemic vascular resistance)
   1. Sepsis
   2. Anaphylaxis
   3. Neurogenic
   4. Drugs or toxins
   5. Endocrinologic (e.g., addisonian crisis)
4. Obstructive
   1. Pulmonary embolus
   2. Pulmonary hypertension
   3. Tension pneumothorax
   4. Pericardial disease
   5. Aortic dissection/obstruction
   6. Vena caval obstruction

Key Objectives

Given a patient with shock, the candidate will diagnose the cause and recognize the urgency, paying particular attention to whether the shock is compensated or uncompensated. The candidate will initiate appropriate and timely management.

Enabling Objectives

Given a patient with shock, the candidate will

1. list and interpret critical findings, including those based on symptoms and signs of shock and information necessary to diagnose the underlying cause;
2. list critical clinical investigations and interpret the results of the investigations, including tests to confirm the presence of shock as well as the underlying cause;
3. construct an effective initial management plan, including
   1. restoring tissue perfusion depending on the underlying cause, and
   2. initiating specific therapeutic interventions for the underlying cause of shock.