Abstract

A 35 year old woman with clinical features of hyperkalaemic periodic paralysis confirmed on provocative exercise testing was investigated. DNA sequence analysis of the gene for the α-subunit of the skeletal muscle voltage gated sodium channel (SCN4A) on chromosome 17q23 identified a point mutation at nucleotide position 2188. This results in a threonine to methionine substitution at amino acid position 704. The patient was intolerant of diuretic medication but showed a striking clinical and electrophysiological improvement with salbutamol therapy. Treatment with β-adrenergic agents should be considered in patients with hyperkalaemic periodic paralysis who are intolerant of, or resistant to, diuretic medications.