Malignant hyperthermia physiology — FRCA Primary MCQ

Correct answer: C — Right ventricular afterload rises with pulmonary vascular resistance

Abnormal ryanodine receptor calcium release drives the hypermetabolic crisis. Reduced baroreceptor firing increases sympathetic outflow is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Renin rises with reduced afferent arteriolar pressure is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Chronic hypertension shifts cerebral autoregulation right is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. Closing capacity exceeding FRC causes airway closure is less appropriate because it would fit a different clinical clue or a separate anaesthetic problem. In Primary FRCA physiology, the correct answer is usually the variable that best explains the observed change in the anaesthetised patient.

Reference: West's Respiratory Physiology; Ganong Review of Medical Physiology; Primary FRCA textbooks