17: Potassium

Where is most of the K

ICF!!!

Clinical signs of hypokalemia

• Muscle weakness

• Cardiac arrhythmias (uncommon)

Clinical signs of hyperkalemia

• Cardiac arrhythmias

• Muscle weakness

Equine genetic condition that results in spikes of K

Hyperkalemic periodic paralysis

Factors that control K excretion

• GFR

• Aldosterone (Na/K antiporter!)

What homeostatic mechanism is K related to

A/B balance

How does K change with A/B disturbances

• During acidosis, cells pull in H⁺ from the blood and replace it with K to maintain electroneutrality, causing hyperkalemia

• During alkalosis, cells push out H⁺ and pull in K to maintain electroneutrality, causing hypokalemia

Hormone that drives K into cells

Insulin

General causes of hyperkalemia

• Decreased renal excretion

• Change in metabolic balance (acidosis, diabetes)

• Increased intake

• Iatrogenic: meds/fluids

General causes of hypokalemia

• GI loss

• Renal loss

• Change in metabolic balance (alkalosis, high insulin)