Pseudocholinesterase Deficiency: Pathophysiology and Anesthetic Considerations
Drugs (anticholinesterases)
Break down or inhibit the pseudocholinesterase enzymeà↓ pseudo- cholinesterase activity
Note:
Pseudocholinesterase has many synonymous
names including butyrylcholinesterase, BChE, BuChE, plasma esterase, plasma cholinesterase, and serum cholinesterase
Malignancy Abnormal gene
expressionà↓ protein synthesis
Acquired
Liver disease
↓ liver’s ability to synthesize proteins
Malnutrition
↓ molecular precursors for protein production
Renal Disease
Mechanism unclear
Fluid Overload
Hemodilution of circulating proteins
Hereditary
BChE (Butyrylcholinesterase) gene mutation
↓ production or production of non-functional pseudo- cholinesterase by the liver
↓ synthesis of pseudocholinesterase by the liver
Pseudocholinesterase Deficiency: reduced levels of functional pseudocholinesterase in plasma and tissues
Impaired ability to hydrolyze ester linkages of substrates like neuromuscular blocking agents (e.g. succinylcholine, mivacurium, diamorphine, acetylsalicylic acid, methylprednisolone, cocaine, heroin )
Prolonged
binding of neuromuscular blocking agent to nicotinic cholinergic receptors in neuromuscular junctions
↑ patient’s susceptibility to side effects from drugs with ester linkages
Mivacurium administered to produce muscle paralysis
Succinylcholine administered
to produce muscle paralysis
Competitively binds to acetylcholine nicotinic receptor
Irreversibly binds to acetylcholine nicotinic receptor
Active site of post-synaptic acetylcholine receptor is blocked
Continuous depolarization
of skeletal muscle
Acetylcholine cannot act on receptor = skeletal muscle can’t depolarize
Skeletal muscle unable to repolarize
Skeletal muscle paralysis
Acetylcholine released cannot trigger an action potential
↑ duration of muscle fiber paralysis
Since respiratory muscles are affectedà Apnea requiring sedation and respiratory assistance for up to several hours
Extended paralysis and/or anesthesia
Authors: Evan Allarie Yan Yu* Reviewers: Stephen Chrusch Brooke Fallis Melinda Davis* * MD at time of publication
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published December 4, 2021 on www.thecalgaryguide.com