Acid Base Imbalance Disorders

Acid-Base Imbalance 

Acid-base imbalance is an abnormality normal balance of acids and bases of the human body's that causes the deviation of plasma pH from normal range (7.35 - 7.45).

Know the role of buffers in acid-base balance.

Acid-base Disorders Result From-

1. Acidosis


When pH is lesser than normal range, condition is called Acidosis.


Acidosis is a condition in which there is build-up too much acid in the body fluids.


Acidosis condition states build-up of acid in blood stream. Acid accumulates and bases are lost.


Acidosis is the opposite of alkalosis (a condition in which excessive base in the body fluids).


2. Alkalosis


When pH is more than normal range, condition is called Alkalosis.


Alkalosis condition refers excessive blood alkalinity caused by overabundance of bicarbonate in blood or loss of acid from blood.


In this state base accumulates or acid is lost.

Alteration in Acid-Base Balances

Metabolic Causes are Responsible for –


1. Metabolic acidosis

2. Metabolic alkalosis



Respiratory Causes Result in –


1. Respiratory acidosis

2. Respiratory alkalosis



1. Metabolic Acidosis


Metabolic acidosis is most common acid-base disturbance in clinical practice.


Metabolic acidosis has three main root causes –


1. Increased acid production and loss of sodium bicarbonate.

2. Concentration of HCO3 ion is reduced due to increased production of acids.

3. Reduce ability of kidney to excrete excess Acids.


Know the role of the kidney in acid-base balance.

This condition compensated by respiratory system through lowering pCO2 and carbonic acid concentration in blood or through renal compensation by increasing excretion of H+ in urine.


Causes of Metabolic Acidosis are -


1. Uncontrolled diabetes mellitus

2. Kidney failure

3. Diarrhoea

4. Vigorous exercise

5. Salicylate toxicity, metformin toxicity, sulfate toxicity

6. Organic acidemias (defect in protein metabolism; essential enzyme is absent or malfunctioning). This disorders characterized by the excretion of organic acids in the urine. 



2. Metabolic Alkalosis


Metabolic alkalosis occurs due to Increased HCO3- concentration in plasma which raises pH and abnormal loss of acid.


This condition result of decreased H+ ion concentration, and increased bicarbonate concentration.


Metabolic alkalosis compensated by rise in pCO2 by hypoventilation following increased excretion of HCO3- in urine.


Metabolic Alkalosis Occur in -


1. Prolonged vomiting

2. Gastric lavage - clearing out content of stomach

3. Bicarbonate ingestion in peptic ulcer

4. Urea cycle defects

3. Respiratory Acidosis


Respiratory acidosis is condition occurs when high levels of acid in the blood due to increased levels of carbon dioxide (CO2) in the body, results in retention of CO2 and fall in blood pH.

Arise due to hypoventilation, excess CO2 causes the decrease in pH of blood, making them too acidic.


Inadequate Ventilation Occurs due to Obstruction of Respiration, seen in -


1. Pneumonia

2. Asthma

3. Emphysema

4. Respiratory center depression

5. Alcohol ingestion


To overcome Respiratory acidosis Kidney compensates respiratory acidosis by increasing the secretion of H+ in urine and more reabsorption of HCO3.


4. Respiratory Alkalosis


Respiratory Alkalosis caused by hyperventilation that leads to decrease concentration of CO2.  Decreased pCO2 results in less production of H+ and rise in pH of blood plasma.


Respiratory Alkalosis Occurs due to-


1. Anxiety

2. CNS injury

3. Fever

4. Lack of oxygen at high altitude  

5. Hot bath, increased environmental temperature


To overcome this condition Kidneys compensate for respiratory alkalosis by decreased H+ secretion and reduced reabsorption of HCO3-.

Diagnostic Tests for Acid- Base Disorders

1. Arterial Blood Gases (ABG) Analysis


Analysis of blood gases pO2, pCO2, O2, HCO3, and pH level


Blood sample taken from artery (femoral artery of groin, brachial artery in the arm or radial artery in wrist)


2. Serum electrolytes


Measure level of body’s main electrolytes.


3. Bicarbonate ion estimation


4. Anion gap


5. Serum creatinine, Blood urea estimation, and Urine PH

Post a Comment