Electrolyte imbalance, or water-electrolyte imbalance, is an abnormal concentration of electrolytes in the body. Electrolytes play a vital role in maintaining homeostasis in the body and serve in many biological processes. Anions are a well known form of electrolytes and include things like calcium, magnesium, potassium, though electrolytes can form differently charged types of ions in solution (or when melted). Cations (or positively charged ions), i.e., sodium ions, are a well-known form of electrolytes. A combination of sodium (Na) with a chloride anion. Other forms of anions are for example chloride phosphate ions) and are anions (negatively− charged). Electrolytes cross barriers in (cellular membranes) in the body, such as in muscles and nerves, in the intestine, and filtered (to be controlled) by the kidney (as well as the intestine filtering minerals, for example magnesium).
Electrolytes help to regulate heart and neurological function, fluid balance, oxygen delivery, acid–base balance for example. Electrolyte imbalances can develop by consuming too little or too much electrolyte as well as excreting too little or too much electrolyte. Examples of electrolytes include calcium, chloride, magnesium, phosphate, sodium, and potassium. Electrolytes levels in the blood (used to calculate the anion gap) are Chloride (as Cl-) + bicarbonate (HCO3-, used as a buffer to control the amount of Co2 in the blood) - Sodium (Na+) + Potassium (K+).
If electrolyte concentrations are abnormal in the body (such as by overloading it with electrolytes, or the body being unable to maintain homeostasis), signs and symptoms can arise, such as those related to disease, disorders or syndromes. Electrolyte disturbances are involved in many disease processes and are an important part of patient management in medicine. The causes, severity, treatment, and outcomes of these disturbances can differ greatly depending on the implicated electrolyte. The most serious electrolyte disturbances involve abnormalities in the levels of sodium, potassium or calcium. Other electrolyte imbalances are less common and often occur in conjunction with major electrolyte changes. The kidney is the most important organ in maintaining appropriate fluid and electrolyte balance, but other factors such as hormonal changes and physiological stress play a role.
Causes Chronic laxative abuse or severe diarrhea or vomiting can lead to dehydration and electrolyte imbalance.
Malnutrition People with malnutrition are at especially high risk for an electrolyte imbalance. Severe electrolyte imbalances must be treated carefully as there are risks with overcorrecting too quickly, which can result in arrhythmias, brain herniation, or refeeding syndrome depending on the cause of imbalance. Restrictive eating disorders such as anorexia nervosa and atypical anorexia nervosa are also associated with electrolyte imbalance.
General function of electrolytes Electrolytes are important because they are what cells (especially nerve, heart, and muscle cells) use to maintain voltages across their cell membranes. Electrolytes have different functions, and an important one is to carry electrical impulses between cells. Kidneys work to keep the electrolyte concentrations in blood constant despite changes in the body. For example, during heavy exercise, electrolytes are lost in sweat, particularly in the form of sodium and potassium. The kidneys can also generate dilute urine to balance sodium levels. These electrolytes must be replaced to keep the electrolyte concentrations of the body fluids constant. Hyponatremia, or low sodium, is the most commonly seen type of electrolyte imbalance.
Treatment of electrolyte imbalance depends on the specific electrolyte involved and whether the levels are too high or too low. The level of aggressiveness of treatment and choice of treatment may change depending on the severity of the disturbance. If the levels of an electrolyte are too low, a common response to electrolyte imbalance may be to prescribe supplementation. However, if the electrolyte involved is sodium, the issue is often water excess rather than sodium deficiency. Supplementation for these people may correct the electrolyte imbalance but at the expense of volume overload. For newborn children, this has serious risks.
Electrolytes and their imbalances
Calcium Though calcium is the most plentiful electrolyte in the body, a large percentage of it is used to form the bones. It is mainly absorbed and excreted through the GI system. The majority of calcium resides extracellularly, and it is crucial for the function of neurons, muscle cells, function of enzymes, and coagulation. The normal range for calcium concentration in the body is 8.5 - 10.5 mg/dL. The parathyroid gland is responsible for sensing changes in calcium concentration and regulating the electrolyte with parathyroid hormone.
Hypercalcemia
Hypercalcemia describes when the concentration of calcium in the blood is too high. This occurs above 10.5 mg/dL.
Causes The most common causes of hypercalcemia are certain types of cancer, hyperparathyroidism, hyperthyroidism, pheochromocytoma, excessive ingestion of vitamin D, sarcoidosis, and tuberculosis. Hyperparathyroidism and malignancy are the predominant causes. It can also be caused by muscle cell breakdown, prolonged immobilization, or dehydration.
Symptoms The predominant symptoms of hypercalcemia are abdominal pain, constipation, extreme thirst, excessive urination, kidney stones, nausea, and vomiting. In severe cases where the calcium concentration is >14 mg/dL, individuals may experience confusion, altered mental status, coma, and seizure.
Treatment Primary treatment of hypercalcemia consists of administering IV fluids. If the hypercalcemia is severe and/or associated with cancer, it may be treated with bisphosphonates. For very severe cases, hemodialysis may be considered for rapid removal of calcium from the blood.
Hypocalcemia
Hypocalcemia describes when calcium levels are too low in the blood, usually less than 8.5 mg/dL.
Causes Hypoparathyroidism and vitamin D deficiency are common causes of hypocalcemia. It can also be caused by malnutrition, blood transfusion, ethylene glycol intoxication, and pancreatitis.
Symptoms Neurological and cardiovascular symptoms are the most common manifestations of hypocalcemia. Patients may experience muscle cramping or twitching, and numbness around the mouth and fingers. They may also have shortness of breath, low blood pressure, and cardiac arrhythmias.
Treatment Patients with hypocalcemia may be treated with either oral or IV calcium. Typically, IV calcium is reserved for patients with severe hypocalcemia. It is also important to check magnesium levels in patients with hypocalcemia and to replace magnesium if it is low.
Chloride Chloride, after sodium, is the second most abundant electrolyte in the blood and most abundant in the extracellular fluid. Most of the chloride in the body is from salt (NaCl) in the diet. Chloride is part of gastric acid (HCl), which plays a role in absorption of electrolytes, activating enzymes, and killing bacteria. The levels of chloride in the blood can help determine if there are underlying metabolic disorders. Generally, chloride has an inverse relationship with bicarbonate, an electrolyte that indicates acid-base status. Overall, treatment of chloride imbalances involves addressing the underlying cause rather than supplementing or avoiding chloride.
Hyperchloremia
Causes Hyperchloremia, or high chloride levels, is usually associated with excess chloride intake (e.g., saltwater drowning), fluid loss (e.g., diarrhea, sweating), and metabolic acidosis.
Symptoms Patients are usually asymptomatic with mild hyperchloremia. Symptoms associated with hyperchloremia are usually caused by the underlying cause of this electrolyte imbalance.
Treatment Treat the underlying cause, which commonly includes increasing fluid intake.
Hypochloremia
Causes Hypochloremia, or low chloride levels, are commonly associated with gastrointestinal (e.g., vomiting) and kidney (e.g., diuretics) losses. Greater water or sodium intake relative to chloride can also contribute to hypochloremia.
Symptoms Patients are usually asymptomatic with mild hypochloremia. Symptoms associated with hypochloremia are usually caused by the underlying cause of this electrolyte imbalance.
Treatment Treat the underlying cause, which commonly includes increasing fluid intake.
Magnesium Magnesium is mostly found in the bones and within cells. Approximately 1% of total magnesium in the body is found in the blood. Magnesium is important in the control of metabolism and is involved in numerous enzyme reactions. A normal range is 0.70 - 1.10 mmol/L. The kidney is responsible for maintaining the magnesium levels in this narrow range.
Hypermagnesemia
Hypermagnesemia, or abnormally high levels of magnesium in the blood, is relatively rare in individuals with normal kidney function. This is defined by a magnesium concentration >2.5 mg/dL.
Causes Hypermagnesemia typically occurs in individuals with abnormal kidney function. This imbalance can also occur with use of antacids or laxatives that contain magnesium. Iatrogenic cases of hypermagnesemia can be prevented by avoiding magnesium-containing medications.
Symptoms Mild symptoms include nausea, flushing, and tiredness. Neurologic symptoms are seen most commonly, including decreased deep tendon reflexes. Severe symptoms include paralysis, respiratory failure, and bradycardia progressing to cardiac arrest.
Treatment If kidney function is normal, stopping the source of magnesium intake is sufficient. Diuretics can help increase magnesium excretion in the urine. Severe symptoms may be treated with dialysis to directly remove magnesium from the blood.
Hypomagnesemia
Hypomagnesemia, or low magnesium levels in the blood, can occur in up to 12% of hospitalized patients. Symptoms or effects of hypomagnesemia can occur after relatively small deficits.
Causes Major causes of hypomagnesemia are from gastrointestinal losses such as vomiting and diarrhea. Another major cause is from kidney losses from diuretics, alcohol use, hypercalcemia, and genetic disorders. Low dietary intake can also contribute to magnesium deficiency.
Symptoms Hypomagnesemia is typically associated with other electrolyte abnormalities, such as hypokalemia and hypocalcemia. For this reason, there may be overlap in symptoms seen in these other electrolyte deficiencies. Severe symptoms include arrhythmias, seizures, and tetany.
Treatment The first step in treatment is determining whether the deficiency is caused by a gastrointestinal or kidney problem. People with no or minimal symptoms are given oral magnesium; however, many people experience diarrhea and other gastrointestinal discomfort. Those who cannot tolerate or receive magnesium or those with severe symptoms can receive intravenous magnesium.
Hypomagnesemia may prevent the normalization of other electrolyte deficiencies. If other electrolyte deficiencies are associated, normalizing magnesium levels may be necessary to treat the other deficiencies.
Phosphate
Hyperphosphatemia
Hypophosphatemia
Potassium Potassium resides mainly inside the cells of the body, so its concentration in the blood can range anywhere from 3.5 mEq/L to 5 mEq/L. The kidneys are responsible for excreting the majority of potassium from the body. This means their function is crucial for maintaining a proper balance of potassium in the blood stream.
Hyperkalemia
Hyperkalemia means the concentration of potassium in the blood is too high. This occurs when the concentration of potassium is >5 mEq/L. It can lead to cardiac arrhythmias and even death. As such, it is considered to be the most dangerous electrolyte disturbance.
Causes