Serum potassium measurement is used to assess electrolyte balance, cardiac arrhythmias, muscle weakness, hepatic encephalopathy, and renal failure. Potassium should be monitored during the treatment of many diseases, but mainly in diabetic and in any intravenous fluid therapy.
Potassium (K) is the major intracellular cation and is present only in small amounts in the extracellular fluid. There is an inverse relationship between potassium and sodium. Potassium is responsible for maintaining the acid-base balance, regulating the cellular osmotic pressure and electrical conductivity in muscle cells, especially the heart muscle and skeletal muscle. Serum potassium levels are often used to evaluate patients with cardiac arrhythmias, renal impairment, mental confusion, and gastrointestinal disorders.
Patients with elevated serum potassium levels (hyperkalemia) have weakness, malaise, nausea, diarrhea, muscle irritability, oliguria, and bradycardia. Patients with hypokalaemia, ie potassium levels below normal, are mentally confused, have anorexia, muscle weakness, hallucinations, hypotension, rapid and weak pulse, and decreased reflexes.
Hypokalaemia enhances the effect of digitalis preparations, making the patient prone to digitalis toxicity. Many patients receive both digitalis toxicity and diuretics that cause potassium loss. The resulting hypokalaemia can lead to potentially fatal cardiac arrhythmias. All patients with hyperkalemia or hypokalaemia may develop cardiac arrhythmias.
Possible Interpretations of Pathological Values
- Increase (Hyperkalaemia): Acidosis, Addison's disease, adrenal cortex deficiency, hemolytic anemia, anxiety, asthma, burns, hemodialysis, diet (excessive potassium intake), arrhythmia, hemolysis, hemolysis, hypoventilation, increased osmolality, acute infection, ketoacidosis, leukocytosis, malignant hyperthermia, massive rapid transfusion of red blood cells, metabolic acidosis, muscle necrosis, drowning, intestinal obstruction, pneumonia, pseudo-hypoaldosteronism, renal failure, renal hypertension, sepsis, shock, seizures, syndrome of inappropriate antidiuretic hormone secretion (SIADH), thrombocytosis, tissue trauma, uremia, Waterhouse-Friderichsen syndrome. Medications: aldosterone antagonists, amiloride, aminocaproic acid, antineoplastic agents, beta-adrenergic blockers, calcium, captopril, cyclophosphamide, cyclosporin, digoxin, enalapril, ephedrine, epinephrine, estrogens, heparin, histamine, hydrochlorothiazide, ibuprofen, indomethacin, isoniazid, lithium, mannitol, methicillin, non-steroidal anti-inflammatory agents, potassium bicarbonate, potassium chloride, potassium citrate, potassium gluconate, penicillin, phenformin, propranolol, salt substituents, spironolactone, succinylcholine, tetracyclines, timolol maleate, triamterene, tromethamine, valsartan.
- Decrease (Hypokalaemia): After sigmoidoscopy, acute tubular necrosis (diuretic phase), alcoholism, primary aldosteronism, alkalosis, anorexia, barium poisoning, Bartter syndrome, bradycardia, carcinoma, colon cancer, Crohn's disease, Cushing's disease, dehydration, diabetes mellitus, diarrhea, arrhythmias, Fanconi syndrome, fever, fistulas, folic acid deficiency, hyperaldosteronism, hypertension, hypomagnesemia, hypothermia, hysterectomy, kwashiorkor, ketoacidosis, laxative abuse, lymphoma, malabsorption, malignant hyperthermia (late phase), metabolic alkalosis, nephritis, organic cerebral syndrome, acute pancreatitis, paralytic ileus, pseudo-aldosteronism, chronic pyelonephritis, pyloric obstruction, renal tubular acidosis, salicylate poisoning, renal disease with salt loss, sweating, gastric aspiration, surgery (postoperative), hunger, stress, toxic shock syndrome, villi adenoma, VIPoma, vomiting, Zollinger-Ellison syndrome (diarrhea). Medications: acetazolamide, albuterol, ammonium chloride, amphotericin B, aspirin, barium, beta-2 agonists, bicarbonates, bisacodyl, bronchodilators, carbenicillin, carbenoxolone, chlorthalidone, cisplatin, corticosteroids, corticotropin, digoxin, EDTA, diuretic, ethacrynic acid, furosemide, gamma-hydroxybutyrate (GHB), gentamicin sulfate, glucose, insulin, laxatives, mercury diuretics, penicillin G, piperacillin, risperidone, salicylates, sodium bicarbonate, sodium chloride, succinylcholine, theophylline, thiazides, thiopental, ticarcillin, trimetaphane. Herbs or natural remedies including aloe (long-term use), licorice (Glycyrrhiza glabra), and products containing aristolochic acids.
Laboratory test results are the most important parameter for the diagnosis and monitoring of all pathological conditions. 70%-80% of diagnostic decisions are based on laboratory tests. Correct interpretation of laboratory results allows a doctor to distinguish "healthy" from "diseased".
Laboratory test results should not be interpreted from the numerical result of a single analysis. Test results should be interpreted in relation to each individual case and family history, clinical findings, and the results of other laboratory tests and information. Your personal physician should explain the importance of your test results.
At Diagnostiki Athinon we answer any questions you may have about the test you perform in our laboratory and we contact your doctor to get the best possible medical care.