Acidosis is not a disease. It is the serious consequence of a disorder that prevents the body from functioning normally. There are different types of acidosis: metabolic acidosis, respiratory acidosis and lactic acidosis. The difference between these three types of acidosis lies in their causes. What can trigger acidosis? How does it manifest? How to treat it? TipsForWomens interviewed Professor Stéphane Gaudry, professor of intensive medicine – intensive care.
What is blood pH?
To fully understand what acidosis is, it is essential to remember that, to function optimally, the body must have a pH of 7.40. pH is a scale that expresses the acidity or alkalinity of a solution, including blood. The pH scale ranges from 0 (very acidic) to 14 (very basic or alkaline). A pH of 7.0, at the center of this scale, is neutral. Blood is normally weakly basic, with a pH varying between approximately 7.35 and 7.45.
The body usually maintains blood pH around 7.40. This is called acid-base balance. A person’s acid-base balance can be assessed by measuring pH and the levels of carbon dioxide (an acid) and bicarbonate (a base) in the blood. Metabolic acidosis occurs when the body’s pH falls below 7.40.
What is an acidosis attack?
Metabolic acidosis results in a drop in pH, it becomes lower than 7.40. This drop in pH is linked to the excessive loss of bicarbonates in the blood. Bicarbonate ions are basic elements. When their concentration decreases, the pH becomes acidic. “All enzymatic reactions in the body take place at pH 7.40. Below this value, enzymatic reactions do not take place normally.explains Professor Gaudry.
Respiratory acidosis occurs when the amount of carbon dioxide (CO2) increases in the blood due to poor lung function or respiratory depression.
Lactic acidosis occurs when there is too much lactic acid in the blood. Lactic acid is a substance produced by red blood cells, muscle cells, kidneys, skin cells and heart, during the breakdown of glucose.
When does metabolic acidosis occur?
Metabolic acidosis can be linked to two factors:
- An excess of negative charges (anions) in the body;
- Excessive loss of bicarbonates in the blood.
The most common causes of excess anions in the blood
When there are too many negative charges in the body, it can be the consequence of diabetic ketoacidosis. It is an acute complication of diabetes which leads to an increase in blood acidity following the accumulation of substances toxic to the body, ketone bodies. Diabetic ketoacidosis occurs when the concentration of insulin in the blood is too low, in cases of undiagnosed diabetes or poorly controlled by treatment. This is a medical emergency that requires hospitalization.
The excess of negative charges in the blood can also be the consequence of intoxication with products that are too negatively charged. “This happens in people who swallow antifreeze for example, a chemical mixture which helps prevent the freezing of liquids necessary for the proper functioning of the car, and which is very negatively charged.”, specifies Professor Gaudry.
The most common causes of excessive loss of blood bicarbonates
Metabolic acidosis due to loss of bicarbonates in the body is most often linked to a severe diarrhea. “This generally concerns elderly people, who are already fragile.“underlines the specialist in intensive medicine.
Metabolic acidosis may have a nephrological originthat is to say that the loss of bicarbonates occurs through the urine.
When does respiratory acidosis occur?
Respiratory acidosis sets in when the lungs do not properly eliminate carbon dioxide. This can occur in serious lung diseases such asa chronic obstructive pulmonary disease (COPD)severe pneumonia or even heart failure.
It can also occur in people who have difficulty breathing normally because they have a disorder of the brain, nerves, or chest muscles (Guillain-Barré syndrome, amyotrophic lateral sclerosis).
Taking opioids (narcotics), alcohol or strong sedatives can also cause respiratory acidosis due to low blood oxygen levels resulting from slowed breathing.
Finally, l’Sleep Apnea is a disorder that can lead to temporary respiratory acidosis when breathing pauses are repeated and occur over a long period of time.
When does lactic acidosis occur?
Lactic acidosis is a metabolic acidosis that develops when there is an excess of negative ions in the body due to high blood lactate concentration. “It occurs in states of shock. This can be septic shock, hemorrhagic shock or even a very serious infection.”, reveals Professor Gaudry.
Acidosis or alkalosis: what is the difference?
Acidosis sets in following an accumulation of acid or a loss of alkalis. Alkalosis is the physiological processes that cause alkaline buildup or acid loss. We speak of acidosis when the serum pH is lower than 7.40 and alkalosis when the serum pH is higher than 7.45.
What are the symptoms of acidosis?
The symptoms of acidosis are related to the cause. There are therefore no symptoms specific to acidosis.
Possible symptoms of metabolic acidosis
“In cases of metabolic acidosis, the patient may have amplified breathing to correct the acidosis by eliminating more carbon dioxide. But this very specific symptom can only be detected by a doctor”says Professor Gaudry.
People with mild metabolic acidosis may be asymptomatic. Or they may possibly present the following symptoms:
- Unexplained fatigue;
- Nausea ;
When metabolic acidosis worsens, these symptoms intensify. In the most severe cases, heart problems may develop and blood pressure may drop, leading to shock, coma and death.
Possible symptoms of respiratory acidosis
In respiratory acidosis, increased CO2 in the blood can lead to drowsiness and headaches. If left untreated, drowsiness can progress to coma as the amount of oxygen in the blood decreases.
How to diagnose acidosis?
The diagnosis of acidosis is based on a blood sample to measure several parameters. “A blood gas analysis is performed. It consists of measuring the pH, the partial pressure of carbon dioxide and the level of bicarbonates in the blood.explains the professor of intensive medicine.
Treatment: how to treat acidosis?
Acidosis is a condition that requires hospitalization, most often in intensive care. To treat acidosis, you must treat the cause.
- In patients with diabetic ketoacidosis, Treatment is based on insulin injection and rehydration.
- In patients with septic shock, Management is based on treatment with antibiotics and treatment of the symptoms of shock which involves rehydration and injection of norepinephrine to raise blood pressure.
- In patients suffering from chemical poisoningtreatment is based on the administration of an antidote.
- In patients with metabolic acidosis linked to significant diarrheawe will administer bicarbonates intravenously.
Other acid-base disorders
Acid-base disorders are pathological changes in the partial pressure of carbon dioxide or the level of bicarbonates in the blood, which produce abnormalities in arterial pH values. Metabolic acidosis and respiratory acidosis are some of them. But there are two other acid-base disorders: metabolic alkalosis and respiratory alkalosis.
Metabolic alkalosis results in an increase in bicarbonate ions in the blood, accompanied or not by an increase in the partial pressure of carbon dioxide to rebalance the pH. The pH can be high or almost normal. It is most often linked to prolonged vomiting, hypovolemia (progressive or sudden decrease in the volume of blood in the blood circulation), taking diuretics or hypokalemia (low level of potassium in the blood).
Respiratory alkalosis is characterized by a decrease in the partial pressure of carbon dioxide, accompanied or not by a decrease in bicarbonate ions in the blood. In cases of respiratory alkalosis, the pH may be high or close to normal. It occurs when the respiratory rate and/or minute volume increases (hyperventilation).