Pseudocholinesterase deficiency

Infobox_Disease
Name = PAGENAME


Caption =
DiseasesDB = 10829
ICD10 =
ICD9 = ICD9|289.89
ICDO =
OMIM = 177400
MedlinePlus =
eMedicineSubj = med
eMedicineTopic = 1935
MeshID =

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. [ Maiorana, Anthony & Roach, Robert B. (2003). "Heterozygous pseudocholinesterase deficiency: a case report and review of the literature". Journal of Oral and Maxillofacial Surgery. 61 (7), 845-847. [http://www.joms.org/ JOMS] . Retrieved Mar. 13, 2007.] Exhaustive list of drugs to avoid listed in following section. These drugs are normally metabolized by the pseudocholinesterase enzyme.

Impacted Groups

Arya Vysyas

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. [Manoharan, Indumathi. (2006). "Naturally occurring mutation Leu307Pro of human butyrylcholinesterase in the Vysya community of India". Pharmacogenetics & Genomics. 16(7), 461-468 [http://www.ncbi.nlm.nih.gov/pubmed/16788378 NCBI] Retrieved June 16, 2008.]

Effects

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. [Alexander, Daniel R. (2002). [http://www.emedicine.com/med/topic1935.htm Pseudocholinesterase deficiency] . Retrieved Mar. 13, 2007.]

Drugs to avoid

Drugs containing Succinylcholine - e.g. QUELICIN & ANECTINE

These drugs are commonly given as muscle relaxants prior to surgery.

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.Bin Li , Ellen Duysen , Michaela Carlson , Oksana Lockridge. (2007). "The butyrylcholinesterase knockout mouse as a model for human butyrylcholinesterase deficiency". Journal of Pharmacology And Experimental Therapeutics Fast Forward. [http://jpet.aspetjournals.org/cgi/content/abstract/jpet.107.133330v1 JPET] Retrieved June 16, 2008.]

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.

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.

Drugs containing Butyrylcholine

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

Drugs containing Huperzine A and Donepezil

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

Drugs containing Propionylcholine and Acetylcholine

Drugs containing Parathion

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

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.Daniel R Alexander. (2006). "Pseudocholinesterase Deficiency". [http://www.emedicine.com/med/topic1935.htm eMedicine] Retrieved June 16, 2008]

Testing

This inheritable condition can be diagnosed by a simple blood test and treated by avoiding certain muscle relaxants. The test of pseudocholinesterase enzyme activity can be performed using the Acholest Test Paper. When a drop of the patient's plasma is applied to the substrate-impregnated test paper, a colorimetric reaction occurs. The time it takes the exposed Acholest Test Paper to turn from green to yellow is inversely proportional to the pseudocholinesterase enzyme activity in the plasma sample.

References