Acidosis and Alkalosis Complete Overview


Acidosis and Alkalosis

(Acid-Base disorders)

What are Alkalosis and Acidosis?

Disturbance of balance in the PH of blood due to excess of acid and alkali (base) is termed as acidosis and alkalosis. Both are abnormal conditions. Diseases and some underlying conditions are the causes of this imbalance in acid and base

For all the metabolic processes occurring in our body and for proper delivery of oxygen to the tissues (in a right amount), maintenance of normal blood PH within a narrow range of 7.35-7.45 is compulsory. The fall in PH below 7.35 tends to happen when the amount of acid increases in blood and termed as acidosis while in the second case the rise of the base in the blood may lead to alkalosis and PH reaches to above 7.45. The control of PH in the body is disturbed by many diseases and conditions. Once the imbalance or disturbance occurs a person may cross the healthy limit line.

Acidosis and Alkalosis Complete Overview

Acidosis and Alkalosis Complete Overview

To maintain the balance in Blood PH, Body must neutralize or eliminate the large quantities of acids which are produced during metabolism and normal body functions. Mostly the acid is in the form of carbonic acid, created from water and carbon dioxide. Ketoacids, lactic acids, and other organic acids are also produced in a lesser amount.

The regulation of blood PH is done by major organs lungs and kidney.

  • The flushing of acid out of the body is done by the lungs due to exhalation of CO2. The change in the respiratory rate means raising and lowering can change the amount of CO2.

  • The excretion of acid through urine is done by the kidney and in the result the regulation of bicarbonates takes place. The change in acid-base concentration due to rise and fall of bicarbonates is slowly as compared to the changes about CO2 that mostly take hours or days.

The blood PH in the healthy people is strictly controlled by these two processes which are always at work.

To regulate the acid and base concentration, the buffering system also resists the change in PH. Phosphate, bicarbonates, hemoglobin, plasma protein are the major buffers in blood.

The balance between the acid and base and the effect caused by them at a PH of blood is more important than their absolute quantities.

Alkalosis takes place when the PH of blood rises above 7.45 and the reasons can be:

  • Dehydration and vomiting for a long time which may lead to electrolyte disturbance.

  • Consumption or intake of the base.

  • Abnormal and prolonged rapid breathing which causes the decrease of the CO2 level (hyperventilation)

Acidosis takes place when the fall in PH occurs and it reaches to below 7.35 and the reasons can be:

  • The production rate of acid increases in the body.

  • Intake of such a kind of substances which can be metabolized to acid.

  • Fall in the rates of excretion of acid.

  • Increase in excretion rate of a base.

Important points:

  • The normal PH of blood is 7.35 to 7.45.

  • The balance between the production and elimination of acid and base is the major goal of the body.

  • Acidosis and alkalosis are caused by imbalance.

  • By decreasing the flow and increasing the elimination body can restore balance

We can divide acid-base disorders into further categories:

  • By which respiration is affected and concentration change of CO2 takes place, are referred as respiratory alkalosis (High PH) and respiratory acidosis (low PH). Diseases of lungs and all that conditions which affect the normal breathing process, are the causes of respiratory acid-base disorders.

  • The disorders due to which bicarbonates concentration is affected are termed as metabolic acidosis (low PH) and metabolic alkalosis (High PH). Disturbance in an electrolyte, lung diseases, intake of some drugs, toxins, diarrhea, vomiting, and the diseases which can disturb the normal metabolism (for example diabetes) are the causes of metabolic acid-base disorders.

Symptoms and Signs

Acidosis is unrelated to any specific symptoms but non- specific symptoms such as nausea, vomiting, fatigue. The body may face rise and depth of breathing, confusion, headaches which may further lead to coma, seizure and death (in some cases).

Potassium loss (k) is associated with the symptoms of alkalosis and may lead to cramping, weakness, irritability.

Causes of Acid-base Disorders

Respiratory Acidosis Reduction in the CO2 elimination

  • Disorders of central nervous system or drugs may lead to decrease in breathing rate. The presence of air between the lungs and chest walls
    (pneumothorax) in an abnormal way may lead to lungs movement and impairment in breathing.

  • Respiratory muscles and nerve diseases botulism, amyotrophic,  myasthenia gravis, ALS, Guillain-Barre syndrome

  • Hindrance in airways.

  • Diseases of lungs.

Respiratory Alkalosis Rise in the elimination of CO2

  • Pain, shock, anxiety may lead to hyperventilation.

  • Drugs (salicylate, Aspirin).

  • Embolism, Pneumonia

  • Fever

  • Exercise

  • Tumors of central nervous system, trauma, infection.

  • Failure of liver

Metabolic Acidosis Decrease in HCO3, due to rise in acid

  • Kidney failure

  • Diabetic ketoacidosis

  • Alcoholic ketoacidosis

  • Lactic acidosis

  • Toxins: due to overdose of ethylene glycol, methanol, aspirin

  • Condition of diarrhea for long time due to loss of gastrointestinal bicarbonates.

  • Loss of renal bicarbonates

Metabolic Alkalosis due to loss of acid, increase in HCO3

  • Dehydration

  • Diuretics

  • Vomiting for long period of time

  • Loss of potassium due to diseases

  • Intake of Alkali

Laboratory Tests

To check whether a person has an imbalance of acid and base or to estimate the level of severity of this imbalance, testing is done. It can help to pinpoint the conditions (intake of toxins) or diseases (diabetic ketoacidosis) which are causing a disturbance in acid-base balance. Testing is performed to monitor the individuals with chronic lung diseases, kidney diseases or the conditions which indicate the acid-base disturbance.

Usually, two tests are performed on the primary basis to diagnose, analyze, monitor and assess the acid-base imbalance.

  • Blood Gases

  • Electrolyte

Blood Gases

In this group of tests, the arterial blood of an individual is taken, instead, of blood from veins. From the snapshots of blood PH, PCO2 and PO2, calculation of bicarbonates are done. Acidosis and Alkalosis

In most of the cases, both PCO2 and HCO3 are above the reference range. Because, body tries to maintain the PH close to normal. If one of these two is abnormally low or high, the other will also change to bring PH back to its normal or healthy range. This is called compensation process. The expected values of four acid-base disorders are given below in the table






Metabolic Alkalosis


than 7.45



Slowed breathing

to decrease the

elimination of C02 (Hypoventilation)

Metabolic Acidosis

Less than 7.35





in breathing rate to increase the CO2 elimination

Respiratory Alkalosis


than 7.45



Excretion of acid and retention of HCO3

is decreased by kidney

Respiratory Acidosis

Less than 7.35


Excretion of acid and retention of HCO3

is increased by kidney


Can be referred to a group of four test including sodium, potassium, chloride, bicarbonates. In metabolic acid-base disorders, the amount of one or more than one electrolyte is disturbed. Acid-base balance, Body fluid level and electrolyte concentration are interconnected.

To analyze which metabolic disorder is responsible for acid-base imbalance, electrolyte panel is used which helps in calculating the anion gap. This is done when an individual is having metabolic acidosis.

In the case of metabolic alkalosis an individual has low potassium and calcium values and by this clue the metabolic disorder is analyzed.

Some other tests can also be performed to analyze the disease or condition which can be the cause of the metabolic disorder.

  • Lactate: in the case of high level the lactic acidosis is indicated

  • Glucose: For the monitoring of diabetes

  • Osmolality: used to estimate the water balance and to check the low sodium level and toxins such as ethylene glycol and methanol.

  • Ketones: its high level indicates the ketoacidosis

  • Overdose and drug testing: to check the drugs and toxins

  • Complete blood count CBC: it can be said a group of the general test. If high white blood cell count indicates Sepsis

  • Urinalysis: it is also a general test. The high and low PH of urine may give us clues about the alkalosis and acidosis.

For a person, it is possible to have more than one disturbance at a time. For example, if aspirin is ingested, an individual can face both metabolic acidosis and respiratory alkalosis. The individual suffering from lung diseases and taking diuretics can have both metabolic alkalosis and respiratory acidosis. The mixed acid-base disturbance can be possibly determined by using formulas to evaluate the degree of compensation.


The main step of treatment of alkalosis and acidosis is to detect and identify the causes of disturbance or imbalance by giving whatever support an individual may be needed. The increase and decrease in PH are not treated directly. But the people suffering from low blood PH level dangerously are given intravenous HCO3 by Health Practitioners.

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