Hyperkalemic Periodic Paralysis

Use of Corticotropin-lnduced Potassium Changes in the Diagnosis of both Hypo- and Hyperkalemic Periodic Paralysis

“…3, 7, 8] while the frequency and severity of paralytic episodes may be reduced or completely prevented by restricted sodium intake [2,9] with or without spironolactone (Aldactone®) therapy [2,[10][11][12] and/or by the administration of acetazolamine [13]. Hyperkalemic periodic paralysis is strik ingly reduced in frequency and severity or completely pre vented by the prescription of chlorothiazide or acetazolamide (Diamox®) alone [14][15][16] or together with fludro cortisone (Florinef8) [6].…”

A role for external Ca2+ in maintaining muscle contractility in periodic paralysis

“…The empirical use of calcium gluconate as abortive therapy for an episode of HyperKPP dates back to the 1950s (Gamstorp, 1956), before it was known that this dominantly inherited disorder is caused by gain-of-function missense mutations in the skeletal muscle isoform of the α subunit of the voltage-gated sodium channel, Na V 1.4 (Cannon, 2015;Lehmann-Horn et al, 2004). Controlled trials on the effectiveness of Ca 2+ in HyperKPP have never been performed, and anecdotal reports describe mixed results (reviewed in Samaha, 1965), although there is one convincing example wherein low serum total Ca 2+ (<2.1 mM; normal 2.1-2.6) and Mg 2+ (<0.5 mM, normal 0.6-1.1 mM) secondary to chemotherapy dramatically worsened the symptoms of HyperKPP (Mankodi et al, 2015). To address the question of a role for extracellular Ca 2+ in modulating susceptibility to weakness in HyperKPP, Uwera et al (2020) performed ex vivo contraction studies and microelectrode measurements of V m in an established mouse model for HyperKPP (Na V 1.4-M1592V knock-in; Hayward et al, 2008).…”