Alkalosis

What is alkalosis?

Every person has a certain pH value in the blood, which ensures the functions of the cells and should maintain the body's function. In healthy people, this pH value is between 7.35 and 7.45 and is regulated by buffer systems in the blood.
If this pH value exceeds 7.45, one speaks of alkalosis, which can also be described as a disruption of the acid-base balance.

Reasons for an alkalosis

In alkalosis one differentiates between

• respiratory alkalosis and
• metabolic alkalosis

Both differ in the causes of the formation.

Please also read:

• pH in humans
• pH in the blood

Respiratory alkalosis

In respiratory alkalosis, the cause is a so-called ventilation disorder in the form of hyperventilation. The breathing rate is increased and more CO2 is emitted. Examples of the development of respiratory alkalosis are:

• psychogenic causes (stress / excitement),
• Hypoxemia (high altitude, pulmonary embolism),
• Pulmonary fibrosis,
• restrictive lung diseases

In the context of anesthesia procedures, respiratory alkalosis can also occur unintentional hyperventilation is provoked.

You may also be interested in this topic: Pulmonary embolism

Metabolic alkalosis

In metabolic alkalosis, a distinction is made between two groups.

• Addition alkaloses
• Subtraction alkaloses

With addition alkaloses, more bases are taken up, while subtraction alkaloses arise from the loss of protons (acid equivalents). In both cases, the acid-base balance is unbalanced and the pH value exceeds the normal value of 7.45.

Addition alkalosis can arise, for example, from the increased intake of sodium hydrogen carbonate, the sodium salt of carbonic acid, lactate or citrate. Sodium hydrogen carbonate is used in food technology, sports nutrition, medicine and agriculture.
Normally it is used in medicine as a buffer substance for acidosis to compensate for it. Conversely, an excessive intake can lead to alkalosis.

Subtraction alkalosis, on the other hand, is caused by the loss of acid. Common causes here are chronic vomiting or gastric lavage. However, subtraction alkalosis can also be caused by certain medications such as laxatives or loop diuretics.

In the case of liver insufficiency, metabolic alkalosis can also occur, as basic protein degradation products can arise here.

You might also be interested in the following articles:

• potassium
• Hepatic insufficiency
• Loop diuretics

Renal failure

Renal insufficiency is characterized by a decrease in kidney function with less urea excreted than usual. The reduced excretion can lead to acidification of the blood as the urea accumulates in the organism.

Renal insufficiency is often treated with certain dehydrating agents (loop diuretics), which can lead to metabolic alkalosis. Treatment with loop diuretics can reduce the potassium and calcium levels in the blood, which can disrupt the acid-base balance, as these are important blood salts.

The increased excretion of these salts and electrolytes ultimately leads to an increase in the pH value in the blood and thus to alkalosis.

Please also read: Diuretics

diagnosis

The diagnosis can be made by a doctor using a so-called blood gas analysis (BGA), in which pH value, standard bicarbonate, base deviation, partial pressures and O2 saturation be measured. The following values ​​suggest an alkalosis:

• Base deviation positive: base excess = metabolic alkalosis,
• Carbon dioxide partial pressure decreased: respiratory alkalosis,
• O2 saturation decreased: ventilation disorders = alkalosis,
• Hypokalemia: metabolic alkalosis

Furthermore, the determination of the chloride excretion in the urine can be of diagnostic value. In the case of metabolic alkalosis, which is caused by vomiting and loss of gastric acid, the chloride concentration in the urine is very low.

In addition, it is important in any case that the patient fills in a precise anamnesis, which may reveal certain medication or underlying diseases that can explain an alkalosis.

Read more on the subject at: Hypokalemia, potassium deficiency

How does potassium change in alkalosis?

With metabolic alkalosis, the level of potassium in the blood is lower than normal. One also speaks of hypokalaemia.

• This can be explained by the electrolyte loss through vomiting and diarrhea, in which potassium is excreted and the serum potassium level can slip below 3.6 mmol / l.
• Potassium levels can also be lowered by taking certain water tablets (diuretics).

In alkalosis, potassium ions migrate into the intracellular space. This can be explained by the fact that the pH value rises excessively in an alkalosis and the body reacts to this by transporting more potassium into the cells. However, this creates a potassium deficiency in the serum.

You might also be interested in the following articles:

• Recognize potassium deficiency
• Hypokalemia

Alkalosis can be recognized by these symptoms

Respiratory alkalosis can occur with hyperventilation. In spite of increased breathing, the patients feel that they are short of breath. This can make you panic and close

• cold sweats,
• Tremble,
• Dizziness,
• Palpitations and
• Headache comes.

If respiratory alkalosis then occurs, paresthesias can occur, in which unpleasant sensations in certain areas of the skin manifest themselves. A painless “tingling sensation” occurs because proteins in the blood release their protons and can then absorb the doubly positively charged calcium from the serum. A relative calcium deficiency develops, which can cause tingling and muscle cramps (tetany).

In the worst case, there is a so-called paw position in the hands. Hyperventilation also leads to a low pCO2 value, which leads to vasoconstriction. This can lead to headaches, dizziness and visual disturbances.

Muscle spasms

The potassium deficiency (hypokalaemia) leads to changes, especially in muscle cells, as these are particularly sensitive to changes in potassium concentrations. It can lead to paralysis of the muscles and certain muscle reflexes are weakened.

The effects on the heart muscle are particularly dangerous. The hypokalemia can lead to cardiac arrhythmias. The muscle cramps also arise from the calcium deficiency described above (hyperventilation tetany).

• The free calcium concentration in the blood is reduced, which can cause muscles to contract and cramps.

How is alkalosis treated?

In treatment, a distinction is again made between respiratory and metabolic alkalosis.

• The respiratory alkalosis caused by hyperventilation is not life-threatening and does not require an active lowering of the pH value. Rather, Co2 rebreathing should be aimed for and the respiratory minute volume should be reduced.

If necessary, the patient can be sedated if the panic attack does not subside by itself. In any case, the patient should be reassured so that he no longer hyperventilates and breathing can normalize.

• Metabolic alkaloses, on the other hand, are metabolically corrected by correcting the pH value.

This is done by substituting NaCl (in the case of volume deficiency and normal potassium concentration) or potassium (hypokalaemia). In severe cases, hydrochloric acid can also be substituted to treat the alkalosis.

An alkalosis caused by medication (e.g. loop diuretics) must be treated immediately by stopping the medication. A potassium-sparing diuretic can then be prescribed to remedy the potassium deficiency.

When is alkalosis dangerous?

In most cases, alkalosis caused by hyperventilation is harmless and can be easily remedied (e.g. by breathing a bag). However, in more severe cases one can also lose consciousness, which can be dangerous.

In the case of metabolic alkalosis, on the other hand, a permanently increased pH value can lead to an undersupply of the tissue. If the body does not manage to compensate for this undersupply, organs can also be damaged because they are not adequately supplied.
Read about it too: long-term consequences of an increased pH.

The hypokalaemia can also lead to life-threatening cardiac arrhythmias that must be treated by a doctor.

If chronic vomiting, for example in anorexia or bulimia, is the cause of the alkalosis, this can also be life-threatening. Often a psychologist has to be called in here, with whom one tries to fight the disease together.

A long-lasting disturbance of the acid-base balance should always be clarified by a doctor and treated accordingly.

Consequences / Risks

In most cases, respiratory alkalosis is not life-threatening and does not involve long-term consequences or risks. By normalizing breathing, the acid-base balance can often be regulated and the pH value stabilizes again. In severe cases, however, muscle spasms (hyperventilation tetanus) or loss of consciousness can occur.

In the case of strong, long-lasting alkalosis, on the other hand, there can be life-threatening danger as organs can be damaged and cardiac arrhythmias can occur. The volume deficit can lead to hypotension (drop in blood pressure), which is often associated with weakness. Neurological abnormalities such as paresthesia, convulsions or confusion can occur.

In summary, the following consequences of metabolic alkalosis can be mentioned:

• neurological changes (Impaired consciousness, neurological abnormalities)
• Cardiac arrhythmias
• Left shift of the O2 dissociation curve with more difficult O2 release in the tissue
• alveolar hypoventilation with hypoxemia (Lack of oxygen in the blood)
• Hypokalemia

Duration / forecast

In the case of respiratory alkalosis as a result of hyperventilation, the duration depends on how long the patient breathes more intensely and this leads to an increase in the pH value. Often, the patients are still a bit ailing afterwards and need a little rest to calm the body again.

In the case of metabolic alkalosis, on the other hand, various causes can lead to an increase in the pH value.

• If an alkalosis occurs as a result of chronic vomiting, this can be an indication of a serious illness such as anorexia or bulimia. Such an eating disorder is a lifelong illness that will always accompany the sufferer. The prognosis depends on various factors. Read more about this:
  
• Patients with alkalosis often suffer from difficulty concentrating, tiredness, weakness or tremors. In most cases, symptoms improve quickly after the cause has been rectified and the general condition of the person concerned improves.
  
• In the rarest of cases, life expectancy is reduced by alkalosis.

Patients should always consult their doctor and investigate the cause.