Hypokalemia (low level of potassium in plasma) affects 20 to 30% of the feline population with chronic kidney disease and is more frequent in the initial stages of the disease (IRIS 2 and 3a, up to 3.5 mg / dl of creatinine ) while it is less present in advanced stages (creatinine above 3.5 mg / dl).
Among the causes of hypokalemia, insufficient intake of potassium with the diet and the increased urinary loss caused by the polyuria of patients in these stages should be mentioned. Increased activation of the renin-angiotensin-aldosterone system (RAS) may also play a role in the development of this condition.
In support of the identification of the aforementioned causes, there is evidence that increasing the content of potassium renal diets for cats has reduced the number of cases of patients affected by hypokalemia in the more recent years.
Cats suffering from severe hypokalemia may have symptoms and specific clinical signs, such as "hypokalemic myopathy", characterized by muscle weakness, which generally manifests by ventroflexion of the neck and / or plantigrade attitude. In less severe forms, the symptomatology is characterized by muscle weakness, lethargy, loss of appetite and constipation.
Potassium supplementation results in the resolution of the clinical signs; the consensus on its usefulness is unanimous, although there is no univocal sharing about the dosage to be used.
Intravenous or subcutaneous administration of potassium-containing fluids is usually reserved for cats who need to quickly correct the imbalance of this electrolyte, or to those who do not accept potassium administration by mouth. These patients may present a condition of severe muscle weakness that, compromising the motor activity, in some cases also makes it impossible to feed causing a progressive worsening of the clinical picture as well as a further reduction of the plasma potassium. The Veterinarian, based on the patient's values, will decide for the amount of potassium to be supplemented.
In the presence of hypokalemia accompanied by mild symptoms, cats are considered treatable with administration of potassium by mouth, which can be carried out using both liquid and solid products, usually administered every 8-12 hours.
Although symptoms usually resolve within 2 - 4 days, it is advisable to check potassium level weekly, to correct the supplementation as well as to avoid the onset of hyperkalemia, thus determining the final maintenance dosage for that patient. Unlike oral therapy, fluid therapy should be carried out in cases of severe hypokalemia and patients be monitored at least every 24 hours to ensure that they do not incur hyperkalemia.
Hypokalemia is common in cats with CKD (affecting 20 to 30% of the population) and is found, more often, in the less severe stages of the disease. Clinical signs are variable and depending on the severity of the electrolyte alteration. Laboratory tests allow to get a final diagnosis of hypokalemia as well as its correct management.
The treatment of hypokalemia in cats with CKD has proven effective in improving quality of life, motor activity and food intake.