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Why Insulin Causes Hypokalemia

Diabetes Mellitus And Electrolyte Disorders

Diabetes Mellitus And Electrolyte Disorders

Go to: Abstract Diabetic patients frequently develop a constellation of electrolyte disorders. These disturbances are particularly common in decompensated diabetics, especially in the context of diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. These patients are markedly potassium-, magnesium- and phosphate-depleted. Diabetes mellitus (DM) is linked to both hypo- and hyper-natremia reflecting the coexistence of hyperglycemia-related mechanisms, which tend to change serum sodium to opposite directions. The most important causal factor of chronic hyperkalemia in diabetic individuals is the syndrome of hyporeninemic hypoaldosteronism. Impaired renal function, potassium-sparing drugs, hypertonicity and insulin deficiency are also involved in the development of hyperkalemia. This article provides an overview of the electrolyte disturbances occurring in DM and describes the underlying mechanisms. This insight should pave the way for pathophysiology-directed therapy, thus contributing to the avoidance of the several deleterious effects associated with electrolyte disorders and their treatment. Keywords: Glucose, Osmotic diuresis, Hyponatremia, Hyperkalemia, Hypomagnesemia Core tip: Diabetic patients frequently develop a constellation of electrolyte disorders. These patients are often potassium-, magnesium- and phosphate-depleted, especially in the context of diabetic ketoacidosis or nonketotic hyperglycemic hyperosmolar syndrome. Diabetes is linked to both hypo- and hyper-natremia, as well as to chronic hyperkalemia which may be due to hyporeninemic hypoaldosteronism. This article provides an overview of the electrolyte disturbances occurring in diabetes and describes the underlying mechanisms. This insight should pave the way for pathophysiology-direct Continue reading >>

Hypokalemia And Hyperkalemia

Hypokalemia And Hyperkalemia

Physiology of Potassium Handling Potassium (K+) is the most abundant cation in the body. About 90% of total body potassium is intracellular and 10% is in extracellular fluid, of which less than 1% is composed of plasma. The ratio of intracellular to extracellular potassium determines neuromuscular and cardiovascular excitability, which is why serum potassium is normally regulated within a narrow range of 3.5 to 5.0 mmol/L. Dietary K+ intake is highly variable, ranging from as low as 40 mmol/day to more than 100 mmol/day.1, 2 Homeostasis is maintained by two systems. One regulates K+ excretion, or external balance through the kidneys and intestines, and the second regulates K+ shifts, or internal balance between intracellular and extracellular fluid compartments. Internal balance is mainly mediated by insulin and catecholamines. Cellular Shifts Ingested K+ is absorbed rapidly and enters the portal circulation, where it stimulates insulin secretion. Insulin increases Na+,K+-ATPase activity and facilitates potassium entry into cells, thereby averting hyperkalemia. β2-Adrenergic stimulation also promotes entry of K+ into cells through increased cyclic adenosine monophosphate (cAMP) activation of Na+,K+-ATPase. Renal Handling An increase in extracellular potassium concentration also stimulates aldosterone secretion (via angiotensin II), and aldosterone increases K+ excretion. In the steady state, K+ excretion matches intake, and approximately 90% is excreted by the kidneys and 10% in the stool. Renal K+ excretion is mediated by aldosterone and sodium (Na+) delivery (glomerular filtration rate [GFR]) in principal cells of the collecting ducts.3 K+ is freely filtered by the glomerulus, and almost all the filtered K+ is reabsorbed in the proximal tubule and loop of Henle (Fig. Continue reading >>

Potassium Shifts

Potassium Shifts

Sort What causes potassium to shift out of cells? --Causing Hyperkalemia Pt has hyperkalemia? DO Insulin LAB: -Heart drug? -Osmolarity? -Diabetes hormone? -Cell death? -Acid-base? -SNS? Pt has hyperkalemia? DO Insulin LAB Digitalis hyperOsmolarity Insulin deficiency Lysis of cells Acidosis Beta-antagonists Continue reading >>

Renal: Potassium

Renal: Potassium

Sort Six things that shift K+ out of cell (cause hyperkalemia) Digitalis Hyper-O-smolarity Insulin deficiency deficiency Lysis of cells Acidosis (because of H/K+exchanger) Beta blockers "DO Insulin LAB" Seven events in kidney that can cause excess loss of potassium Loop diuretics Thiazide diuretics NG drainage Aldosterone excess Genetic disorders Renal tubule acidosis Uncontrolled diabetes *All caused by increasing [Na] delivery to collecting duct Continue reading >>

Potassium Disorders: Hypokalemia And Hyperkalemia

Potassium Disorders: Hypokalemia And Hyperkalemia

Hypokalemia and hyperkalemia are common electrolyte disorders caused by changes in potassium intake, altered excretion, or transcellular shifts. Diuretic use and gastrointestinal losses are common causes of hypokalemia, whereas kidney disease, hyperglycemia, and medication use are common causes of hyperkalemia. When severe, potassium disorders can lead to life-threatening cardiac conduction disturbances and neuromuscular dysfunction. Therefore, a first priority is determining the need for urgent treatment through a combination of history, physical examination, laboratory, and electrocardiography findings. Indications for urgent treatment include severe or symptomatic hypokalemia or hyperkalemia; abrupt changes in potassium levels; electrocardiography changes; or the presence of certain comorbid conditions. Hypokalemia is treated with oral or intravenous potassium. To prevent cardiac conduction disturbances, intravenous calcium is administered to patients with hyperkalemic electrocardiography changes. Insulin, usually with concomitant glucose, and albuterol are preferred to lower serum potassium levels in the acute setting; sodium polystyrene sulfonate is reserved for subacute treatment. For both disorders, it is important to consider potential causes of transcellular shifts because patients are at increased risk of rebound potassium disturbances. Potassium disorders are common. Hypokalemia (serum potassium level less than 3.6 mEq per L [3.6 mmol per L]) occurs in up to 21% of hospitalized patients and 2% to 3% of outpatients.1–3 Hyperkalemia (serum potassium level more than 5 mEq per L [5 mmol per L] in adults, more than 5.5 mEq per L [5.5 mmol per L] in children, and more than 6 mEq per L [6 mmol per L] in neonates) occurs in up to 10% of hospitalized patients and ap Continue reading >>

Hypokalemia & Diabetes

Hypokalemia & Diabetes

According to a 2011 national diabetes fact sheet from the Centers for Disease Control and Prevention, over 25 million people, or 8.3 percent of the United States population, have diabetes. Diabetes is the condition that results from the lack of insulin production or from insulin resistance; in diabetes, there is abnormal metabolism of glucose, which results in elevated blood glucose levels. Diabetes is associated with dysregulation of potassium, but several studies suggest that hypokalemia may mediate the development of diabetes. Video of the Day According to "Davidson's Principles & Practice of Medicine," hypokalemia, or low blood potassium, is defined as blood potassium levels below 3.5 millimoles per liter, or mmol/L, of blood. Potassium facilitates the function of insulin in the delivery of glucose to cells; when insulin binds to its receptors on the cell membrane, it causes potassium to flow into the cells. As levels of insulin increase in the blood, more potassium is driven into cells; therefore, hyperinsulinemia, or high blood insulin, is commonly associated with hypokalemia. Hypokalemia and Diabetes Studies Since a clear relationship exists between insulin and potassium, researchers have speculated the possibility of potassium's involvement in the development of diabetes. According to a 2008 article in the journal "Hypertension," several studies have collectively demonstrated a strong inverse relationship between blood glucose levels and potassium levels during the use of thiazides diuretics; therefore, as potassium levels decrease, blood glucose levels should increase. This inverse relationship between glucose and potassium, concurs with the notion that total body potassium has a role in determining person's sensitivity to insulin. In diabetics, excessive use o Continue reading >>

Practice Essentials

Practice Essentials

Hypokalemia is generally defined as a serum potassium level of less than 3.5 mEq/L (3.5 mmol/L). Moderate hypokalemia is a serum level of 2.5-3.0 mEq/L, and severe hypokalemia is a level of less than 2.5 mEq/L. Hypokalemia is a potentially life-threatening imbalance that may be iatrogenically induced. Hypokalemia may result from inadequate potassium intake, increased potassium excretion, or a shift of potassium from the extracellular to the intracellular space. Increased excretion is the most common mechanism. Poor intake or an intracellular shift by itself is a distinctly uncommon cause, but several causes often are present simultaneously. (See Etiology.) Gitelman syndrome is an autosomal recessive disorder characterized by hypokalemic metabolic alkalosis and low blood pressure. See the image below. Signs and symptoms Patients are often asymptomatic, particularly those with mild hypokalemia. Symptoms that are present are often from the underlying cause of the hypokalemia rather than the hypokalemia itself. The symptoms of hypokalemia are nonspecific and predominantly are related to muscular or cardiac function. Complaints may include the following: Weakness and fatigue (most common) Psychological symptoms (eg, psychosis, delirium, hallucinations, depression) Physical findings are often within the reference range. Abnormal findings may reflect the underlying disorder. Severe hypokalemia may manifest as bradycardia with cardiovascular collapse. Cardiac arrhythmias and acute respiratory failure from muscle paralysis are life-threatening complications that require immediate diagnosis. See Presentation for more detail. Diagnosis In most cases, the cause of hypokalemia is apparent from the history and physical examination. First-line studies include measurement of urine pota Continue reading >>

Insulin And Potassium

Insulin And Potassium

Insulin has a number of actions on the body besides lowering your blood glucose levels. Insulin suppresses the breakdown and buildup of glycogen, which is the storage form of glucose, it blocks fat metabolism and the release of fatty acids, and it puts potassium into the cells by activating the sodium-potassium cellular channels. Insulin stimulates the uptake of glucose and potassium in all cells of the body but primarily fuels the muscle cells as well as some of the fat cells. In type 2 diabetes or metabolic syndrome (a form of metabolic disease), insulin is not functioning up to its normal level. The cells of the body become resistant to insulin and the blood sugar levels are elevated. The serum potassium (K+) level is a reflection of the total body stores of potassium, although it can be inaccurate in some conditions that affect the distribution of potassium in the body’s cells. The plasma potassium level determines the resting potential of the cells of the body. A person can have low potassium (hypokalemia) or high potassium (hyperkalemia), both of which are asymptomatic conditions that can be serious as they both cause heart arrhythmias. The Relationship between Insulin and Potassium Shortly after insulin was discovered, scientists revealed that insulin had something to do with the potassium levels in both the cells and in the blood. The insulin is the hormone in the body that keeps the potassium level in the blood within the normal range. When insulin is decreased, the potassium level rises and can rise even further if you eat something high in potassium, such as salt substitutes and bananas. When the potassium level is high, it causes the pancreas to release insulin in order to counteract the effects of high potassium levels. When you eat something that is high Continue reading >>

Hypokalemia (low Potassium)

Hypokalemia (low Potassium)

What Is Hypokalemia? Hypokalemia is an electrolyte imbalance and is indicated by a low level of potassium in the blood. The normal adult value for potassium is 3.5-5.3 mEq/L. Potassium is one of many electrolytes in your body. It is found inside of cells. Normal levels of potassium are important for the maintenance of heart, and nervous system function. What Causes Hypokalemia? One way your body regulates blood potassium levels is by shifting potassium into and out of cells. When there is a breakdown or destruction of cells, the electrolyte potassium moves from inside of the cell to outside of the cell wall. This shift of potassium into the cells causes hypokalemia. Trauma or insulin excess, especially if diabetic, can cause a shift of potassium into cells (hypokalemia). Potassium is excreted (or "flushed out" of your system) by your kidneys. Certain drugs or conditions may cause your kidneys to excrete excess potassium. This is the most common cause of hypokalemia. Other causes of hypokalemia include: Increased excretion (or loss) of potassium from your body. Some medications may cause potassium loss which can lead to hypokalemia. Common medications include loop diuretics (such as Furosemide). Other drugs include steroids, licorice, sometimes aspirin, and certain antibiotics. Renal (kidney) dysfunction - your kidneys may not work well due to a condition called Renal Tubular Acidosis (RTA). Your kidneys will excrete too much potassium. Medications that cause RTA include Cisplatin and Amphotericin B. You may have hypokalemia from a loss of body fluids due to excessive vomiting, diarrhea, or sweating. Endocrine or hormonal problems (such as increased aldosterone levels) - aldosterone is a hormone that regulates potassium levels. Certain diseases of the endocrine system, s Continue reading >>

Hyperkalemia (high Blood Potassium)

Hyperkalemia (high Blood Potassium)

How does hyperkalemia affect the body? Potassium is critical for the normal functioning of the muscles, heart, and nerves. It plays an important role in controlling activity of smooth muscle (such as the muscle found in the digestive tract) and skeletal muscle (muscles of the extremities and torso), as well as the muscles of the heart. It is also important for normal transmission of electrical signals throughout the nervous system within the body. Normal blood levels of potassium are critical for maintaining normal heart electrical rhythm. Both low blood potassium levels (hypokalemia) and high blood potassium levels (hyperkalemia) can lead to abnormal heart rhythms. The most important clinical effect of hyperkalemia is related to electrical rhythm of the heart. While mild hyperkalemia probably has a limited effect on the heart, moderate hyperkalemia can produce EKG changes (EKG is a reading of theelectrical activity of the heart muscles), and severe hyperkalemia can cause suppression of electrical activity of the heart and can cause the heart to stop beating. Another important effect of hyperkalemia is interference with functioning of the skeletal muscles. Hyperkalemic periodic paralysis is a rare inherited disorder in which patients can develop sudden onset of hyperkalemia which in turn causes muscle paralysis. The reason for the muscle paralysis is not clearly understood, but it is probably due to hyperkalemia suppressing the electrical activity of the muscle. Common electrolytes that are measured by doctors with blood testing include sodium, potassium, chloride, and bicarbonate. The functions and normal range values for these electrolytes are described below. Hypokalemia, or decreased potassium, can arise due to kidney diseases; excessive losses due to heavy sweating Continue reading >>

Why Doesn't Regular Insulin Therapy Cause Hypokalemia In Patient With Diabetes Mellitus?

Why Doesn't Regular Insulin Therapy Cause Hypokalemia In Patient With Diabetes Mellitus?

Hypokalemia is low potassium. Your potassium level is maintained within a range. As part of your electrolytes that move in and out of the cells as needed. Insulin reduces serum K+ from ECF to ICF mainly because insulin increases the activity of the sodium-potassium pump. insulin is the first-line defense against hyperkalemia. a rise in plasma k+ stimulates insulin release by the pancreatic beta cell. insulin, in turn, enhances cellular potassium uptake, returning plasma k+ towards normal. the enhanced cellular uptake of k+ that results from increased insulin levels is thought to be largely due to the ability of insulin to stimulate activity of the sodium potassium atpase located in cell plasma membranes. the insulin induced cellular uptake of potassium is not dependent on the uptake of glucose caused by insulin. insulin deficiency allows a mild rise in plasma k+ chronically and makes the subject to severe hyperkalemia if a potassium load is given. conversely, potassium deficiency may cause decreased insulin release. thus plasma potassium and insulin participate in a feedback control mechanism. Continue reading >>

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