Signs of MH

Q: What usually precedes first in Malignant Hyperthermia (MH)? (select one)

A) hypercarbia

B) tachycardia

C) muscle rigidity

D) peaked T waves

Answer: A

While in OR or ICU, if a patient is intubated, an unexplained increase in end-tidal carbon dioxide (ETCO2) associated tachypnea (breathing over the ventilator) is the first sign, followed by tachycardia. Core body hyperthermia follows. These are considered hallmarks or 'first three signs' of MH.

Masseter or generalized muscle rigidity may occur or persist despite paralysis with a neuromuscular blocker, and EKG changes of hyperkalemia usually occur last. Isolated rhabdomyolysis may also occur.

#pharmacology

#muscles

References:

1. Larach MG, Gronert GA, Allen GC, et al. Clinical presentation, treatment, and complications of malignant hyperthermia in North America from 1987 to 2006. Anesth Analg 2010; 110:498.

2. Larach MG, Localio AR, Allen GC, et al. A clinical grading scale to predict malignant hyperthermia susceptibility. Anesthesiology 1994; 80:771.