Abnormal circulating potassium concentration Hyperkalemia while symptomatic 2024-06-30T12:14:21Z Hyperkalemia during attack For instance, in hyperkalemic periodic paralysis, one may observe an increase of serum potassium concentration of at least 1.5 mmol/L during an attack of weakness. Increased concentration of potassium in the blood circulation specifically measured during a disease flareup, attack, or exacerbation.