Pseudocholinesterase deficiency

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Pseudocholinesterase deficiency
Classification and external resources
ICD-9 289.89
OMIM 177400
DiseasesDB 10829
eMedicine med/1935

Pseudocholinesterase deficiency is an inherited blood plasma enzyme abnormality. People who have this abnormality may be sensitive to certain anesthetic drugs, including the muscle relaxants succinylcholine and mivacurium as well as other ester local anesthetics.[1] An exhaustive list of drugs that are normally metabolized by the pseudocholinesterase enzyme can be found in the following section.

Impacted Groups[edit]

Arya Vysyas[edit]

Multiple studies done both in and outside India have shown an increased prevalence of pseudocholinesterase deficiency in the Hindu Arya Vysya community. A study performed in Coimbatore, India, on 22 men and women from this community showed that 9 of them had pseudocholinesterase deficiency, which translates to a prevalence that is 4000-fold higher than that in European and American populations.[2]

Persian Jews[edit]

Pseudocholinesterase deficiency (anesthesia sensitivity) is an autosomal recessive condition common within the Persian and Iraqi Jewish populations. Approximately one in 10 Persian Jews are known to have a mutation in the gene causing this disorder and thus one in 100 couples will both carry the mutant gene and each of their children will have a 25% chance of having two mutant genes, and thus be affected with this disorder. This means that one out of 400 Persian Jews is affected with this condition.[3]

Effects[edit]

The effects are varied depending on the particular drug given. When anesthetists administer standard doses of these anesthetic drugs to a person with pseudocholinesterase deficiency, the patient experiences prolonged paralysis of the respiratory muscles, requiring an extended period of time during which the patient must be mechanically ventilated. Eventually the muscle-paralyzing effects of these drugs will wear off despite the deficiency of the pseudocholinesterase enzyme. If the patient is maintained on a mechanical respirator until normal breathing function returns, there is little risk of harm to the patient.

However, because it is rare in the general population, it is sometimes overlooked when a patient does not wake-up after surgery. If this happens, there are two major complications that can arise. First, the patient may lie awake and paralyzed, while medical providers try to determine the cause of the patient’s unresponsiveness. Second, the breathing tube may be removed before the patient is strong enough to breathe properly, potentially causing respiratory arrest.

This enzyme abnormality is a benign condition unless a person with pseudocholinesterase deficiency is exposed to the offending pharmacological agents.[4]

Drugs to avoid[edit]

Drugs containing Succinylcholine - e.g. Quelicin & Anectine

These drugs are commonly given as muscle relaxants prior to surgery. That means that victims of this deficiency cannot receive certain anesthetics.

A dose that would paralyze the average individual for 3 to 5 mins can paralyze the enzyme-deficient individual for up to 2 hours. The neuro-muscular paralysis can go on for up to 8 hours.[5]

If this condition is recognized by the anesthesiologist early, then there is rarely a problem. Even if the patient is given succinylcholine, he can be kept intubated and sedated until the muscle relaxation resolves.[5]

Drugs containing Mivacurium - e.g. Mivacron

Mivacron is also a muscle relaxant that is used prior to inserting a tube for breathing.

Drugs containing Pilocarpine - e.g. Salagen

Salagen is used to treat dry mouth. As the name suggests, dry mouth is a medical condition that occurs when saliva production goes down. There are lots of different causes of dry mouth including side effect of various drugs.[5]

Drugs containing Butyrylcholine

Use of butyrylcholine is not common. It can be used to treat exposure to nerve agents, pesticides, toxins, etc.[5]

Drugs containing Huperzine A and Donepezil

These drugs are used to slow the progression of Alzheimer's disease.[5]

Drugs containing Propionylcholine and Acetylcholine[5]

Drugs containing Parathion

Parathion is used as an agricultural pesticide. Exposure to pesticides with Parathion should be avoided.[5]

Procaine drugs e.g. Novocaine

This drug is injected before and during various surgical or dental procedures or labor and delivery. Procaine causes loss of feeling in the skin and surrounding tissues.[6]

Testing[edit]

This inherited condition can be diagnosed with a blood test. If the the total cholinesterase activity in the patient's blood is low, this may suggest an atypical form of the enzyme is present, putting the patient at risk of sensitivity to suxamethonium and related drugs. Inhibition studies may also be performed to give more information about potential risk. In some cases, genetic studies may be carried out to help identify the form of the enzyme that is present.[7]

References[edit]

  1. ^ Maiorana, A; Roach Jr, RB (2003). "Heterozygous pseudocholinesterase deficiency: A case report and review of the literature". Journal of Oral and Maxillofacial Surgery 61 (7): 845–7. doi:10.1016/S0278-2391(03)00163-0. PMID 12856264. 
  2. ^ Manoharan, I; Wieseler, S; Layer, PG; Lockridge, O; Boopathy, R (2006). "Naturally occurring mutation Leu307Pro of human butyrylcholinesterase in the Vysya community of India". Pharmacogenetics and genomics 16 (7): 461–8. doi:10.1097/01.fpc.0000197464.37211.77. PMID 16788378. 
  3. ^ Cedars-Sinai Medical Genetics Institute. (2009). "Genetic Screening in the Persian Jewish Community". [1] Retrieved July 20, 2011.
  4. ^ Alexander, Daniel R. (2002). Pseudocholinesterase deficiency. Retrieved Mar. 13, 2007.
  5. ^ a b c d e f g Li, B.; Duysen, E. G.; Carlson, M.; Lockridge, O. (2007). "The Butyrylcholinesterase Knockout Mouse as a Model for Human Butyrylcholinesterase Deficiency". Journal of Pharmacology and Experimental Therapeutics 324 (3): 1146–54. doi:10.1124/jpet.107.133330. PMID 18056867. 
  6. ^ Daniel R Alexander. (2006). "Pseudocholinesterase Deficiency". eMedicine Retrieved June 16, 2008
  7. ^ "Cholinesterase Test". Lab Tests Online. Retrieved 21 July 2014. 

External links[edit]