Pseudocholinesterase hyperactivity with succinylcholine resistance: an unusual cause of difficult intubation.

We describe a case of difficult intubation, possibly due to marked pseudocholinesterase hyperactivity that caused rapid inactivation of succinycholine. Possible causes of difficult intubation and pseudocholinesterase hyperactivity are discussed. Literature on genetic variants associated with markedly increased pseudocholinesterase activity are reviewed. It is concluded that pseudocholinesterase hyperactivity may be a rare cause of difficult intubation. We recommend that pseudocholinesterase activity should be determined in all patients who appear to be resistant to the action of normal doses of succinylcholine or mivacurium.