There are two main types of alkalosis: respiratory alkalosis and metabolic alkalosis.
Respiratory alkalosis occurs when there is a decrease in carbon dioxide levels in the body due to hyperventilation or rapid breathing. This can be caused by various factors such as anxiety, panic attacks, high altitude, fever or certain lung diseases. When the carbon dioxide levels in the body are too low, it causes a shift in the acid-base balance towards alkalinity.
Metabolic alkalosis occurs when there is an excess of base or a decrease in acid in the body. This can happen due to various factors such as vomiting, use of diuretics, excess ingestion of alkali substances, or hormonal disorders such as Cushing’s syndrome or hyperaldosteronism. When the acid levels in the body are too low, it causes a shift in the acid-base balance towards alkalinity.
Other less common types of alkalosis include hypochloraemic alkalosis, which occurs when there is a loss of chloride ions from the body.
Respiratory alkalosis
Respiratory alkalosis is a medical condition characterised by an abnormally high blood pH, typically above 7.45, due to excessive breathing that leads to excessive loss of carbon dioxide from the body. Carbon dioxide is a weak acid, so a decrease in its concentration in the blood leads to an increase in blood pH, making it more alkaline or basic.
Respiratory alkalosis can occur due to a variety of factors, including anxiety, fever, hyperventilation, and certain medical conditions such as asthma or pneumonia. In these cases, rapid or shallow breathing leads to a decrease in carbon dioxide levels in the blood, which in turn leads to an increase in blood pH.
The symptoms of respiratory alkalosis can vary depending on the underlying cause and the severity of the condition, but common symptoms can include:
- Rapid or shallow breathing
- Shortness of breath or feeling like you can’t catch your breath
- Lightheadedness or dizziness
- Tingling or numbness in the fingers, toes or around the mouth
- Muscle spasms or cramps
- Palpitations or irregular heartbeat
- Confusion or disorientation
- Anxiety or agitation
- Seizures (in severe cases)
The pathophysiology of respiratory alkalosis involves a shift in the balance between carbon dioxide and bicarbonate ions in the blood. When there is too much carbon dioxide in the body, it combines with water to form carbonic acid, which dissociates into hydrogen ions and bicarbonate ions. This reaction helps to maintain the balance of acids and bases in the body, and it is regulated by the respiratory and renal systems.
In respiratory alkalosis, hyperventilation causes an excessive loss of carbon dioxide from the body. This leads to a decrease in the partial pressure of carbon dioxide (PaCO2) in the blood, which in turn causes a shift in the carbonic acid equilibrium towards the formation of more carbonic acid. As a result, there is an increase in the concentration of bicarbonate ions in the blood, which raises the blood pH.
The compensatory mechanisms for respiratory alkalosis involve the kidneys, which excrete bicarbonate ions in the urine and retain hydrogen ions to help lower the blood pH. This compensatory mechanism may take several days to fully take effect, so respiratory alkalosis may persist for some time after the initial hyperventilation episode.
The underlying causes of respiratory alkalosis may include anxiety, pain, fever, hypoxia, altitude sickness and certain medications. Treatment of respiratory alkalosis depends on the underlying cause and may involve measures to reduce hyperventilation or provide supplemental oxygen, as well as treatment of any underlying conditions.
Metabolic alkalosis
Metabolic alkalosis is a medical condition characterised by an abnormally high blood pH, typically above 7.45, due to an excess of bicarbonate, a base that helps maintain the normal pH range. Bicarbonate is produced by the body and acts as a buffer to help regulate blood pH.
Metabolic alkalosis can occur due to various factors, including excessive vomiting, use of certain medications such as diuretics, or conditions such as Cushing’s syndrome or hyperaldosteronism. In these cases, the loss of acid from the body, such as from vomiting or from the action of diuretics, causes an excess of bicarbonate, which leads to an increase in blood pH.
The symptoms of metabolic acidosis can vary depending on the underlying cause and the severity of the condition, but common symptoms can include:
- Rapid breathing or shortness of breath
- Fatigue and weakness
- Headache and confusion
- Loss of appetite or nausea
- Increased heart rate
- Flushed or pale skin
- Muscle tremors or twitching
- Abdominal pain
- Jaundice (in severe cases)
- Coma (in severe cases)
The pathophysiology of metabolic alkalosis involves a shift in the balance between acids and bases in the body. The body normally maintains a delicate balance between acids and bases in the blood, which is essential for normal cell function. One of the ways this balance is maintained is by the kidneys, which excrete excess bicarbonate ions and retain hydrogen ions.
In metabolic alkalosis, there is an excess of bicarbonate ions in the blood, which can occur due to several reasons such as:
- Loss of acid: Vomiting, gastric suction, use of diuretics, and excess aldosterone secretion can cause the body to lose acid, leading to an increase in bicarbonate ion concentration.
- Gain of bicarbonate: The ingestion of excessive amounts of antacids or baking soda, or the administration of sodium bicarbonate can cause an excess of bicarbonate ions in the blood.
- Compensation: The body may try to compensate for respiratory acidosis by increasing bicarbonate ion concentrations in the blood.
The pathophysiology of metabolic alkalosis involves a compensatory mechanism that involves the kidneys. The kidneys can excrete excess bicarbonate ions in the urine and retain hydrogen ions to help reduce the bicarbonate ion concentration and lower the blood pH.