Kidneys are essential for survival as they regulate fluid and electrolyte balance in the blood. Acute renal failure leads to electrolyte disturbance, which, in severe cases, can be fatal, as it can lead to serious complications such as cardiovascular disorders, muscle wasting, and bone-mineral disease.
The prevalence of acute kidney injury depends on several factors, including population differences and classification criteria. Chronic Kidney Disease, with a worldwide prevalence of 5% to 15%, is recognized as a notable risk factor that eventually leads to acute renal failure, reversible with intensive treatment in an otherwise healthy individual.
This article gives an overview of acute kidney failure, particularly emphasizing electrolyte disturbances.
What is Acute Renal Failure?
Acute Renal Failure (ARF) is an episode of a loss of kidney function that could last for a few hours to three weeks or even longer in severe cases. An injury, trauma, infection, or otherwise obstruction in the kidneys can eventually result in ARF.
Since kidneys play a crucial role in filtering blood, renal failure builds up waste products in the circulating blood. Therefore, acute renal failure can be fatal because it malfunctions other vital organs, including the lungs, the heart, and the brain.
In extreme cases, patients have to rely on replacement therapies such as dialysis or kidney transplants for survival.
Signs and Symptoms of Acute Kidney Failure
Patients with acute renal failure usually complain of nausea, confusion, fatigue, and low urine output. Swelling in the legs, ankles, and around the eyes due to fluid retention is also a common symptom. Extreme cases can lead to more severe outcomes, including seizures, coma, and cardiac arrest.
Conversely, acute kidney failure can “rarely” show no symptoms and is only diagnosed through tests.
Electrolytes and Renal Function
In a healthy individual, kidneys are in charge of excreting waste products or fluid buildup that helps maintain the normal homeostasis of electrolytes in the body. Electrolytes are ions or charged particles that assist in transmitting muscular and nerve impulses.
Common Electrolyte Disturbances
Malfunctioning kidneys alter the balance of electrolytes, leading to a disturbance in nerve or muscle impulses throughout the body, which can have serious health outcomes and even cause death.
Acute renal failure commonly targets sodium, potassium, magnesium, calcium, and phosphorus. An imbalance of these electrolytes in the body can result in various symptoms, elaborated below.
Kidneys regulate potassium in the human body by excreting the excess, maintaining the optimal potassium levels in the blood. Kidneys excrete 98% of daily potassium intake and help maintain potassium homeostasis.
Chronic kidney diseases or end-stage renal disease lead to increased potassium levels in the body, called hyperkalemia, posing health risks such as cardiovascular diseases and mortality. Although rare, patients with acute renal failure might also have a potassium deficiency. Vomiting and diarrhea might result in potassium loss, called hypokalemia, which can also be fatal.
Symptoms and Complications of Potassium Imbalance
As an individual with acute kidney failure might not be able to secrete or retain as much potassium as needed, disturbing potassium levels in the blood can lead to several health risks. Symptoms of hyperkalemia and hypokalemia include abdominal cramps, fatigue, muscle weakness, and in severe cases, paralysis or cardiac arrest.
Sodium concentration is essential to maintain fluid and acid-base balance and helps regulate neuromuscular function. Sodium imbalance, in the aftermath of renal failure, might result in sodium deficiency or excess both – however, sodium deficiency is less common among patients of acute renal failure.
Sodium regulates water levels in the body, excess water causes sodium deficiency, called hyponatremia, and when the water level is too low, it results in abnormally higher levels of sodium, called hypernatremia. Patients with acute renal failure are more likely to experience higher sodium levels.
Symptoms and Complications of Sodium Imbalance
Both hypernatremia and hyponatremia affect the central nervous system and are associated with symptoms like disorientation, muscular twitching, hypertension, seizures, and in worst cases, coma. If not treated correctly and in time, sodium imbalance can cause permanent brain damage.
Kidneys play an essential role in maintaining magnesium levels in the body. When renal function declines, the ability to excrete magnesium properly also deteriorates.
Magnesium is critical for neuromuscular processes and is the second most crucial electrolyte. Most typically, in patients with kidney failure, the secretion of magnesium increases drastically, called hypermagnesemia. Patients with acute kidney failure are more likely to suffer from increased levels of magnesium and less likely to experience low magnesium levels or hypomagnesemia.
Symptoms and Complications of Magnesium Imbalance
Magnesium imbalance can cause adverse neuromuscular effects, muscle defects, and cardiovascular problems. Severe magnesium imbalance is associated with hypotension, reduced heart rates, and in extreme cases, cardiac arrest. Hypomagnesemia may also result in anorexia, weakness, lethargy, vomiting, and confusion.
Phosphorus and Calcium Imbalance
Phosphorus and calcium have a reciprocal relationship as excessive levels of one are associated with the deficiency of the other. The most common complication associated with renal failure is increased phosphorus, hypocalcemia, and decreased calcium levels.
Failing kidneys cannot excrete excess phosphorus, which leads to decreased calcium levels, called hypocalcemia. It is commonly associated with mineral and bone disorder, a condition affecting the heart, blood vessels, and bones of a person with acute renal failure.
Although increased calcium and decreased potassium levels, called hypercalcemia, may be rare, patients with renal failure might also experience this complication due to other underlying seasons.
Symptoms and Complications of Calcium and Phosphorus Imbalance
Symptoms associated with calcium and phosphorus imbalance are muscle spasms, seizures, muscle imbalance, and cardiac arrhythmias. The most common complications in severe cases are mineral and bone disorders and cardiac failure.
Acute renal failure, among other complications, results in an imbalance of electrolytes in the blood. Electrolytes, such as potassium, magnesium, sodium, calcium, and phosphorus, have essential functions to perform in the body, and their excess or deficiency can be fatal. The most common complications related to electrolyte disturbances are hyperkalemia, hypernatremia, hypermagnesemia, and hypocalcemia. Fortunately, if acute renal failure is reversed with replacement therapy, electrolyte imbalance and related complication can improve.