出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2013/01/11 09:49:02」(JST)
| 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.
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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]
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]
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 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]
This inheritable condition can be diagnosed by a simple blood test and managed 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.[6]
| Reaction Time | Pseudocholinesterase Enzyme Activity |
|---|---|
| <5 min | Above normal |
| 5-20 min | Normal |
| 20-30 min | Borderline low |
| >30 min | Below normal |
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| リンク元 | 「偽コリンエステラーゼ欠損症」 |
| 関連記事 | 「deficiency」「pseudocholinesterase」 |