These disorders are characterised by defective skeletal muscle voltage sensitive ion channels channelopathies

Hypokalacmic periodic paralysis

Autosomal dominant. Chromosomal location and defective gene unknown. Onset in second decade. Precipitated by: exercise, carbohydrate load. Commences in proximal lower limb muscles and rapidly becomes generalised. Onset usually in morning on wakening. Bulbar muscles/respiration unaffected.

K* falls as low as 1.5 meq/1. Treatment : Acute - oral K.C1. Prophylactic - acctazolamide; low carbohydrate, high K ' diet. With age, attacks become progressively less frequent.

Hyperkalaemic periodic paralysis

Autosomal dominant or recessive. Chromosome 17 location. Na" channel gene defect Onset in infancy/childhood. Precipitated by: rest after activity or by cold.

Commences in lower limbs and evolves rapidly.

Attacks are of short duration (less than 60 min).

Myotonia is evident in some patients.

K ' rises only slightly. Treatment:

Acute - intravenous calcium gluconate or sodium chloride. Prophylactic - Na ' channel blockers, Tocainide or Mexiletine.

Paramyotonia Congenita

Autosomal dominant. Chromosome 17 location. Na ' channel gene defect Onset in infancy.

Precipitated by: rest after exercise, fasting and cooling. Commences in proximal muscles. Repetitive muscle contractions produce increasing stiffness. EMG findings are specific with marked spontaneous activity in limb cooling.

Treatment. Na ' channel blockers, Tocainide or Mexiletine.

Non-familial hypokalaemic periodic paralysis may occur in patients suffering from hyperthyroidism or on potassium-depleting diuretics.

Was this article helpful?

0 0
30 Day Low Carb Diet Ketosis Plan

30 Day Low Carb Diet Ketosis Plan

An Open Letter To Anyone Who Wants To Lose Up To 20 Pounds In 30 Days The 'Low Carb' Way. 30-Day Low Carb Diet 'Ketosis Plan' has already helped scores of people lose their excess pounds and inches faster and easier than they ever thought possible. Why not find out what 30-Day Low Carb Diet 'Ketosis Plan' can do for you by trying it out for yourself.

Get My Free Ebook


Post a comment