Pseudocholinesterase Deficiency

Pseudocholinesterase deficiency is a rare genetic disorder that affects the production or function of the enzyme pseudocholinesterase, also known as butyrylcholinesterase. This enzyme plays a crucial role in breaking down certain medications, such as succinylcholine and mivacurium, which are used to induce muscle relaxation during surgical procedures.

Causes

Pseudocholinesterase deficiency is caused by mutations in the BCHE gene, which provides instructions for making the pseudocholinesterase enzyme. These mutations can lead to reduced or absent enzyme activity, resulting in impaired breakdown of certain medications.

Symptoms

The symptoms of pseudocholinesterase deficiency typically occur after administration of succinylcholine or other affected medications. These symptoms may include:

• Prolonged muscle relaxation or paralysis
• Respiratory failure
• Cardiac arrest
• Apnea (temporary cessation of breathing)

Diagnosis

Diagnosis of pseudocholinesterase deficiency is typically made through a combination of:

• Clinical evaluation and medical history
• Genetic testing to identify mutations in the BCHE gene
• Enzyme activity assays to measure pseudocholinesterase activity
• Dibucaine inhibition test, which measures the enzyme's response to dibucaine, a local anesthetic

Treatment and Management

Treatment of pseudocholinesterase deficiency focuses on managing symptoms and avoiding medications that can trigger adverse reactions. This may include:

• Alternative muscle relaxants or anesthetics
• Close monitoring of vital signs during surgical procedures
• Supportive care, such as mechanical ventilation, in cases of respiratory failure

Inheritance and Prevalence

Pseudocholinesterase deficiency is inherited in an autosomal recessive pattern, meaning that a person must inherit two copies of the mutated gene (one from each parent) to express the condition. The prevalence of pseudocholinesterase deficiency varies among populations, but it is estimated to affect approximately 1 in 3,200 people.