Defined by the presence of excessive acidity in the blood, acidosis is the result of various metabolic disorders and diseases in which excess acidity is produced. It is sometimes a vital emergency. Its management is based on treating the cause. 

The presence of metabolic acidosis in the body is linked to an increase in the production or ingestion of acids and / or the decrease in the excretion of acids. It is also sometimes the consequence of a loss by the digestive tract or the kidneys of bicarbonates (HCO3-) which usually buffer the excessive presence of acids in the blood and participate in its acid-base balance.

Normally, plasma (part of the blood without red blood cells, white blood cells and platelets) is an electrically neutral liquid, that is, it contains as many negative ionic charges as positive (HCOE-, H +, Na +, K +, CL-…). It is when the positive charges are greater in number that metabolic acidosis occurs.

There are many causes of metabolic acidosis. Metabolic acidosis is not a disease in itself, but the biological expression of an imbalance in the blood between acidity and bicarbonates. This imbalance is the consequence of several possible disorders.

Presence of too much lactic acid by accumulation in the blood

This organic metabolic acidosis is due to: 

• a state of physiological shock; 
• liver failure (the liver no longer performs its functions to clean the blood);
• a blood disease such as acute leukemia or lymphoma (cancer of the lymph nodes);
• chronic kidney disease (the kidneys no longer remove excess acid from the blood); 
• food poisoning (methanol, salicylates, ethylene glycol, etc.);
• ketoacidosis (diabetes when insulin runs out).

Presence of too much lactic acid in the blood by reducing its elimination

This mineral metabolic acidosis comes from:

• acute renal failure;
• an excess of NaCl chloride infusion (salt);
• loss of bicarbonate from the kidneys;
• loss of bicarbonate from the digestive tract (diarrhea);
• adrenal insufficiency.

Metabolic acidosis can also occur in severe respiratory failure in which the body can no longer eliminate carbon dioxide through the lungs, which causes acidification of the blood plasma. The acidosis is then called “respiratory”.

When the body’s acid-base balance is upset regardless of the cause, various symptoms can be expressed. If this imbalance is moderate, there will be no symptoms except those of the underlying cause (diarrhea, discomfort linked to unbalanced diabetes, etc.). But the imbalance is accentuated (pH <7,10), the following symptoms may occur:

• nausea;
• vomiting;
• feeling unwell;
• increased respiratory rate (polypnea in an attempt to eliminate excess metabolic acidity);
• low blood pressure (hypotension) or even cardiovascular shock with cardiac arrhythmias and coma.

When this acidosis is present in a chronic way (chronic respiratory failure…), it can cause in the medium term a loss of calcium from the bones (osteoporosis, rickets).

Beyond the search for an underlying cause by complementary examinations, a blood test at the level of the arteries measuring the blood gases and the serum electrolytes will make it possible to highlight the biological results of metabolic acidosis.

The underlying causes of metabolic acidosis will be suspected by the medical history (diabetes, respiratory, renal or hepatic insufficiency …) but also by a biological assessment exploring blood sugar levels, hepatic and renal function, sodium and blood chlorine, or a toxic product in the blood (methanol, salicylate, ethylene glycol).

The treatment of metabolic acidosis is first of all that of the cause (unbalanced diabetes, diarrhea, hepatic, renal or respiratory failure, etc.). But in emergency when the metabolic acidosis is severe, it is sometimes necessary to carry out an infusion of sodium bicarbonate to decrease the acidity of the blood plasma.

In the event of severe renal failure or poisoning, hemodialysis (filtration of toxins from the blood) will clean the blood and replace the work of the kidneys.

Finally, in the face of moderate chronic acidosis, a diet is recommended to restore the acid-base balance of the blood with several tips:

• choose a predominantly alkaline diet (lemon cure, ginger tea, pumpkin seeds, etc.);
• get oxygen by practicing a regular sporting activity in the open air;
• take food supplements that promote alkalization of the blood.