Acidosis

When a person develops acidosis, their body’s pH balance (i.e. the balance between acids and bases) is disrupted. The pH value of the blood drops, making the chemistry of the blood excessively “acidic”. Acidosis can be caused by diseases of the lungs or by metabolic disorders.

At a glance

  • With acidosis, the body’s pH balance (i.e. the balance between acids and bases) is disrupted. This results in excessive acidity in the blood and tissues.
  • A distinction is made between two types of acidosis – respiratory and metabolic.
  • Acidosis can be caused by diseases such as type 1 diabetes or renal insufficiency, as well as by breathing problems, accidents or poisoning.
  • A blood test is a reliable way to diagnose acidosis.
  • It is important to treat the underlying illness.

Note: The information in this article cannot and should not replace a medical consultation and must not be used for self-diagnosis or treatment.

A laboratory worker wearing blue protective gloves fills out an evaluation sheet on a clipboard. He is holding a pen in his right hand and a sample container in his left.

What is acidosis?

For the human body to function properly, it requires a healthy chemical balance between acids and bases. When a person is breathing, moving or eating, their body makes products of metabolism, which change this balance.

To maintain a healthy balance between acids and bases, the body transports these metabolic products out of the body via the lungs and kidneys. There are also buffers in the blood and tissues, which serve to balance temporary shifts in the body’s pH balance.

If this balancing system no longer works, for example due to diseases of the lungs or kidneys or other conditions, the pH balance may be disrupted, leading to excessive acidity (acidosis).

The body’s pH value indicates its balance of acids and bases. Normal healthy individuals have a pH value between 7.35 and 7.45. If this value drops below 7.35, the blood becomes too acidic – a condition known by doctors as acidosis.

There are two different types of acidosis – respiratory and metabolic.

Respiratory acidosis occurs when breathing is impaired, too shallow or too slow, with the result that too much carbon dioxide remains in the body.

Metabolic acidosis occurs when the body creates too many acidic products of metabolism. One possible reason for this is renal insufficiency (poor kidney function), where the kidneys are no longer able to eliminate a sufficient volume of metabolic products. In other cases, the body may take in too many acids from the external environment – as in the case of poisoning due to an overdose of painkillers or drugs.

Important: Eating alkaline foods is of no benefit in a case of acidosis because food alone cannot change the body’s acid-base balance.

What are the symptoms of acidosis?

Acidosis is often only diagnosed when the condition – which causes excessive acidity in the body – starts to cause symptoms.

People with acute respiratory acidosis show symptoms of oxygen deficiency – their skin has a bluish tone, they experience shortness of breath and may lose consciousness. Due to a lack of oxygen, the amount of carbon dioxide in the blood increases, which may trigger muscle twitches, fatigue and headaches.

People with acute respiratory acidosis show symptoms of oxygen deficiency.

People with metabolic acidosis usually have markedly deep, rhythmic and loud breathing. This is how the body tries to breathe out more carbon dioxide than normal to counteract the excessive acidity. Other possible signs of metabolic acidosis are diarrhea, nausea and vomiting.

Other symptoms may also be present, as acidosis can be caused by various conditions, including diabetes, renal insufficiency, poisoning or a drug overdose. These possible additional symptoms include:

  • difficulty concentrating
  • anxiety
  • disorientation
  • headaches at night
  • restlessness
  • delusions

What causes acidosis?

Acidosis usually occurs as a result of another condition.

Acidosis usually occurs as a result of another condition.

In the case of respiratory acidosis, breathing may become too slow and too shallow as a result of asthma, chronic obstructive pulmonary disease (COPD), pulmonary emphysema, chest injuries or impaired respiratory drive due to a severe head injury.

As a result, not enough carbon dioxide (CO2) is exhaled, leading to an elevated partial pressure of carbon dioxide. This is a measure of how much carbon dioxide is dissolved in the blood. If the partial pressure of carbon dioxide rises, the pH value drops and the blood becomes more acidic.

Metabolic acidosis may be caused by poisoning with alcohol or painkillers like paracetamol or acetylsalicylic acid (ASA). Severe diarrhea, renal insufficiency or renal failure, medical emergencies such as blood poisoning (sepsis) or a heart attack may also cause the blood’s pH value to drop.

Important: One particular type of acidosis is ketoacidosis. It can develop due to poorly managed diabetes or if the body is experiencing an extreme stage of hunger – which may occur in anorexia or when fasting.

What is the outlook for acidosis?

In respiratory acidosis, the blood receives too little oxygen. As a result, the lips and skin become gray or blue in color. Shortness of breath usually also occurs. Later on, the pulse quickens, blood pressure is elevated, and circulatory disorders and feelings of weakness may occur.

In metabolic acidosis, breathing becomes rapid and deep.

If the underlying condition causing the acidosis is not treated, this can result in coma and death. However, doctors can easily detect acidosis and begin suitable treatment.

How can acidosis be prevented?

People with diabetes, renal insufficiency or chronic obstructive pulmonary disease (COPD) can avoid acidosis by managing their disease effectively and having it monitored on a regular basis.

For people with diabetes, this includes monitoring their blood glucose level (blood sugar) regularly. It’s also important to make sure that the correct dosage of medication is being taken and that treatment measures are adjusted to suit the individual patient.

How is acidosis diagnosed?

Doctors use a blood gas analysis to detect acidosis. This involves measuring the pH value and the amount of bicarbonate and carbon dioxide in the blood. Bicarbonate is normally used to chemically balance fluctuations in the body’s pH value.

If a person has metabolic acidosis, the level of bicarbonate in the blood is too low. With respiratory acidosis, the amount of bicarbonate in the blood is elevated because this is how the body tries to balance the excessive acidity.

How is acidosis treated?

Doctors treating patients with acidosis will first treat the underlying condition that is causing the excessive acidity. Bronchodilators, i.e. medication to widen the airways, are used to treat patients with respiratory diseases like COPD. If the acidosis is due to an overdose of an opioid like heroin, naloxone can be used to counteract the effects of the drug.

As acute respiratory acidosis is associated with an oxygen deficiency, providing the patient with an oxygen supply is a priority. Patients are also treated with bicarbonate. This acts as a buffer in the blood and balances fluctuations in the pH value.

People with metabolic acidosis are also treated with bicarbonate to stabilize their chemical balance.

  • DynaMed (Internet). Ipswich (MA). Respiratory Acidosis. EBSCO Information Services. Record No.T115187. 2018 (1995). Aufgerufen am 14.12.2021.
  • DynaMed (Internet), Ipswich (MA). Lactic Acidosis. EBSCO Information Services. Record No. T909110. 2018 (1995). Aufgerufen am 14.12.2021.
  • DynaMed (Internet). Ipswich (MA). Hyperchloremic Metabolic Acidosis. EBSCO Information Services. Record No. T115404. 2018 (1995). Aufgerufen am 14.12.2021.
  • Burger MacK, Schaller DJ. Metabolic Acidosis. (Updated 2021 July 26). In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Aufgerufen am 14.12.2021.
  • UpToDate (Internet). Approach to the adult with metabolic acidosis. Wolters Kluwer 2021. Aufgerufen am 14.12.2021.

In cooperation with the Institute for Quality and Efficiency in Health Care (Institut für Qualität und Wirtschaftlichkeit im Gesundheitswesen – IQWiG). As at:

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