“…It is stated that rigidity is not seen in 20% of acceptable cases (Britt and Kalow, 1970) and even fever may be lacking (Bernardt and Horder, 1978). If a child develops masseter rigidity at the start of general anesthesia and then there is no fever because cooling measures are promptly instituted (Carballo, 1975;Caseby, 1975;Davis, 1977, Donlon et al, 1978Dodd et al, 1981;Inoue et al, 1977;Jago and Payne, 1977;Schmitt et al, 1975), was this an aborted attack of MH or some other kind of reaction to succinylocholine? It is clearthat fullblown attacks of MH may start with masseter spasm and there have been cases of masseter spasm alone or with myoglobinuria but no other manifestations of MH; not all of these patients have "positive" tests for MH-susceptibility (Flewellen and Nelson, 1982).…”