Clinical implications of ion channel disruption

Question 1

What are channelopathies?

Answer 1

Disorder in expression or function of an ion channel or pump

Often genetic so genetic screening available to at risk couples

Question 2

Which local anaesthetics act as Na+ ion channel blockers?

Answer 2

Lidocaine
Procaine
Mepivacaine

Question 3

What are the types of block?

Answer 3

Peripheral nerve block
Regional or epidural nerve block
Bier’s

Question 4

What is a peripheral nerve block?

Answer 4

Injection of local anaesthetic around single nerves

Question 5

What is a regional or epidural nerve block?

Answer 5

Injection of local anaesthetic around the dorsal and ventral roots at the appropriate level of the spinal cord

Question 6

What is a Bier’s block?

Answer 6

Infusion of a large volume of local anaesthetic into a limb during temporary interruption of blood circulation

Question 7

How is local anaesthetic different to general anaesthetic?

Answer 7

General act by potentiating the actions of inhibitory neurotransmitters like GABA in the brain

Question 8

What is the effect of mutation in K+ ion channels?

Answer 8

Prolong the repolarisation of action potentials

Question 9

What is the mutation in K+ ion channels called and the symptoms associated with it?

Answer 9

Long QT syndrome (rare inherited condition)

Serious cardiac arrhythmias, ventricular fibrillation, risk of cardiac arrest

Question 10

How are pain syndromes formed?

Answer 10

Channelopathies/ mutations within a subunit of Na+ ion channel that alters the waveform of the AP so alters transmission of information to CNS