Acidosis occurs when the body fluids have too much acid. The kidneys and the lungs are the major organs that are involved in the regulation of the body’s pH. When these organs are not able to keep the body's pH in balance, you are likely to suffer from acidosis.
The majority of the biological processes in the body produce acid. The lungs and the kidneys compensate for the slight pH imbalances. The standard blood ph is 7.4. Acidosis occurs when the blood pH is below the standard value.
Metabolic acidosis is a clinical condition that is characterized by a low blood pH. Metabolic acidosis results from the accumulation of acid in the body due to kidney failure. It occurs when the kidneys are not able to eliminate enough acid or when too much base gets removed at the expense of acid.
Types of Acidosis
There are three types of metabolic acidosis, they include:
This is observed in people with diabetes and occurs when the accumulation of ketones due to low amounts of insulin leads to the acidification of the blood.
This type of acidosis is caused by the loss of sodium bicarbonate from the body. The base helps keep the blood pH neutral. Individuals who are suffering from Hyperchloremic acidosis present with vomiting and diarrhea.
The presence of too much lactic acid in the body can lead to lactic acidosis. Lactic acidosis can be triggered by several factors such as heart failure, seizures, cancer, liver failure, and insufficient oxygen in the body. Prolonged exercise and workouts can also cause lactic acidosis.
Signs and Symptoms of Metabolic Acidosis
Most signs and symptoms of metabolic acidosis result from the underlying disease or condition. Symptoms may differ from one patient to another.
However, patients with metabolic acidosis will often present with:
· confusion and dizziness
· feeling tired, weak, and irritated
· fruity-smelling breath (in the case of diabetic ketoacidosis)
· gastrointestinal disturbances such as abdominal pain, nausea, indigestion, and vomiting
· increased heart rate and arrhythmias
· shortness of breath, rapid, and shallow breathing
Complications of Metabolic Acidosis
Patients with metabolic acidosis as a result of kidney disease or failure may experience osteoporosis which can lead to bone fractures of the hips and backbone.
Metabolic acidosis may also enhance the progression of kidney disease. However, it is not understood how metabolic acidosis worsens an already existing kidney disease.
Another common complication of metabolic acidosis is muscle loss. Muscle growth and development relies on an important protein in the body called albumin. Metabolic acidosis lowers the amount of albumin that is present in the body. As a result, an individual experiences muscle loss.
Metabolic acidosis may also lead to endocrine disorders. It alters the normal production of hormones by the endocrine organs in the body. The body may become resistant to insulin if it is left untreated and this can lead to diabetes.
Diagnosis of Metabolic Acidosis
Physicians diagnose metabolic acidosis using a series of tests. The levels of oxygen and carbon dioxide in blood are determined using an arterial blood gas test. Kidney function and the pH balance is determined using a basic metabolic panel. The test determines protein, calcium, blood sugar, and electrolyte levels. It can be used to diagnose the different types of acidosis.
A urine sample can be taken to determine pH. The urine sample will help the doctors to determine whether the kidneys are eliminating acids and bases properly.
Other tests include lactic acid test, urine ketones, and arterial blood gas analysis.
Causes of Metabolic Acidosis
Several factors can lead to the development of metabolic acidosis.
The most common causes of metabolic acidosis include:
The condition develops when the body burns fats instead of carbohydrates. Ketoacidosis is common in diabetic patients who don't get enough insulin and get dehydrated. The breakdown of fats leads to the production of ketones in the body.
The high amounts of ketones turn blood acidic. Elevated levels of the ketone are seen in individuals who drink alcohol for a long time and do not eat healthily. Persons who starve themselves are also at risk of developing ketoacidosis.
Lactic acid is produced by the body cells when they do not receive sufficient oxygen supply. Lactic acid can build up in the body when a person exercises intensely.
Lactic acidosis can also result from medical conditions such as heart failure, cardiac arrest, low blood pressure, and infections of the body. Other causes of lactic acidosis include liver failure, drugs such as salicylates, cancer, and seizures.
Renal Tubular Acidosis
Acids get secreted into the renal tubules from where they get excreted in urine. Kidney diseases and other genetic disorders can damage the kidneys. As a result, the excretion of acid gets impaired, leading to the accumulation of acid in the body.
Hyperchloremic acidosis can be caused by several factors such as laxative abuse, severe diarrhea, and kidney failure. Hyperchloremic acidosis occurs as a result of low levels of the bicarbonate base in the body. Bicarbonate helps neutralize acids present in the blood.
Alkali therapy is recommended to raise and maintain the blood pH to greater than 7.20. Failure to restore the pH balance can affect the bones, kidneys, and muscles. Severe cases of metabolic acidosis can lead to shock or death. Diabetic ketoacidosis can put a patient into a coma.
The goal of treatment is to manage the underlying cause. Hemodialysis is recommended to patients with renal failure. Treatment with sodium bicarbonate is only indicated in certain circumstances. Sodium bicarbonate is deleterious in other patients.
Sodium bicarbonate is suitable when metabolic acidosis results from the loss of bicarbonate ions. The remedy is also suitable when an accumulation of inorganic acids causes the acidosis.
However, bicarbonate therapy is controversial when metabolic acidosis is caused by an accumulation of organic acids. Sodium bicarbonate therapy does not clearly reduce mortality rate in patients suffering from metabolic acidosis resulting from organic acids.
The management of the underlying condition leads to the metabolism of keto acids and lactate into bicarbonates. Loading of exogenous bicarbonate ions may worsen the metabolic acidosis. Bicarbonate may also cause an overload of sodium and volume overload.
Despite the controversies surrounding the bicarbonate therapy, experts recommend the use of IV bicarbonate for the management of severe metabolic acidosis. Treatment of metabolic acidosis involves two calculations. The first count is aimed at determining the level of which bicarbonate should be raised.
It is calculated using the Kassirer-Bleich equation.
Exogenous Sodium bicarbonate is administered over several hours to achieve the required level of hydrogen bicarbonate. The blood pH and the levels of bicarbonate ions are checked one hour after administration to enable equilibration with the extravascular bicarbonate ions.
Therapy with bicarbonate ions is highly recommended for patients with Hyperchloremic acidosis. The central problem in these patients is with the reabsorption or synthesis of the bicarbonate ions. Sodium bicarbonate therapy is highly recommended for patients with severe metabolic acidosis.
Bicarbonate therapy can cause certain complications such as volume overload, central nervous system acidosis, hypokalemia, and hypercapnia. Patients may also experience tissue hypoxia.
The alternatives to sodium bicarbonate include tromethamine. The amino alcohol buffers both metabolic and respiratory acids. Carbicarb can also be used in place of sodium bicarbonate. It is an equimolar mixture of sodium hydrogen carbonate and carbonate. The carbonate reacts with carbon dioxide to give rise to bicarbonate ions. Dichloroacetate is also used as an alternative to sodium bicarbonate. Once administered, it enhances the oxidation process of lactate.
However, these alternatives do not have proven benefits over sodium bicarbonate. When they are administered alone, they may cause complications to the patient. Depletion of potassium is a common problem that occurs with metabolic acidosis.
Frequent serum potassium monitoring should be done to identify the problem. Potassium ion depletion should be treated using oral or parenteral potassium chloride.
Prevention Of Metabolic Acidosis
The key to preventing metabolic acidosis is to avoid the underlying causes. Healthy living lifestyles such as eating healthy are useful in the prevention of metabolic acidosis. Healthy living habits such as limiting alcohol intake, avoiding smoking cigarettes, and limiting exercise can help prevent the occurrence of metabolic acidosis.
Drinking a lot of water together with other non-alcoholic drinks can help prevent the development of metabolic acidosis. Proper management of the underlying health conditions, such as type one diabetes, is also useful in the prevention of metabolic acidosis.
Metabolic Acidosis Review Summary
Metabolic acidosis results from the accumulation of acid due to an increased production of acid in the body.
Other causes may include increased ingestion of acid and reduced acid secretion. Metabolic acidosis can be categorized according to the anion gap. High anion gap results from ketoacidosis, renal failure, lactic acidosis, and toxic ingestions.
Gastrointestinal loss of bicarbonate ions can cause normal anion gap. It is advisable to calculate the delta gap to find out the concomitant metabolic acidosis. The most effective way of preventing the development of metabolic acidosis involves treating the underlying cause.
Sodium bicarbonate is recommended when the metabolic acidosis is a result of a change in the bicarbonate ions balance. Sodium bicarbonate therapy is controversial in high gap anion metabolic acidosis.