From what I understand, the degree of jaw tightness progressively points to MH, although I believe you are correct, simply the incidence of jaw tightness is not completely diagnostic of MH. In the face of MH, a tight jaw will become rigid, then completely rigid. The further you go in the spectrum of jaw tightness -> rigid -> hard as concrete the more the fingers start pointing towards true MH.
Unlike some of my on-line brethern, I am not one to argue with attendings, but I would like for you to clarify this one. I had to treat an MH crisis up in the Trauma ICU the other day and this is still fresh on my mind. MH is an acute loss of control of intracellular calcium ions as a result of exposure to triggering agents, resulting in a release of free, unbound, ionized Ca from normal storage sites. Actions taken by the body in an attempt to maintain CA homeostasis include Ca pumps that require ATP, thus furthering exothermic response. Muscle rigidity happens when unbound Ca approaches contractile threshold. The disease process does not take place at the NMJ, so how would an nondepolarizer treat MH?
We all know the treatment is dantrolene, not because it has NMJ properties, but because is reduces Ca release from the sarcoplasmic retic without changing Ca uptake, a double hit that results in a decreased amount of calcium chilling intracellular and causing havoc. Restoration of intracellular Ca is the goal, not NMJ alteration.
