Alkalosis is the result of a process reducing
hydrogen ion
A hydrogen ion is created when a hydrogen atom loses or gains an electron. A positively charged hydrogen ion (or proton) can readily combine with other particles and therefore is only seen isolated when it is in a gaseous state or a nearly particl ...
concentration of
arterial
An artery () is a blood vessel in humans and most other animals that takes oxygenated blood away from the heart in the systemic circulation to one or more parts of the body. Exceptions that carry deoxygenated blood are the pulmonary arteries in ...
blood plasma
Blood plasma is a light Amber (color), amber-colored liquid component of blood in which blood cells are absent, but which contains Blood protein, proteins and other constituents of whole blood in Suspension (chemistry), suspension. It makes up ...
(alkalemia). In contrast to
acidemia (serum pH 7.35 or lower), alkalemia occurs when the serum pH is higher than normal (7.45 or higher). Alkalosis is usually divided into the categories of
respiratory alkalosis and
metabolic alkalosis or a combined respiratory/metabolic alkalosis.
Signs and symptoms
Metabolic alkalosis is usually accompanied by
low blood potassium concentration, causing, e.g., muscular weakness,
muscle pain, and muscle cramps (from disturbed function of the skeletal muscles), and muscle spasms (from disturbed function of smooth muscles).
It may also cause
low blood calcium concentration. As the blood pH increases, blood
transport proteins, such as
albumin
Albumin is a family of globular proteins, the most common of which are the serum albumins. All of the proteins of the albumin family are water- soluble, moderately soluble in concentrated salt solutions, and experience heat denaturation. Alb ...
, become more ionized into anions. This causes the free calcium present in blood to bind more strongly with albumin. If severe, it may cause
tetany.
Causes
Respiratory alkalosis is caused by
hyperventilation
Hyperventilation is irregular breathing that occurs when the rate or tidal volume of breathing eliminates more carbon dioxide than the body can produce. This leads to hypocapnia, a reduced concentration of carbon dioxide dissolved in the blo ...
,
resulting in a loss of
carbon dioxide
Carbon dioxide is a chemical compound with the chemical formula . It is made up of molecules that each have one carbon atom covalent bond, covalently double bonded to two oxygen atoms. It is found in a gas state at room temperature and at norma ...
. Compensatory mechanisms for this include release of hydrogen ion from tissue buffers and excretion of
bicarbonate
In inorganic chemistry, bicarbonate (IUPAC-recommended nomenclature: hydrogencarbonate) is an intermediate form in the deprotonation of carbonic acid. It is a polyatomic anion with the chemical formula .
Bicarbonate serves a crucial bioche ...
in the kidneys, both of which lower blood
pH.
Hyperventilation-induced alkalosis can be seen in several deadly
central nervous system
The central nervous system (CNS) is the part of the nervous system consisting primarily of the brain, spinal cord and retina. The CNS is so named because the brain integrates the received information and coordinates and influences the activity o ...
diseases such as
stroke
Stroke is a medical condition in which poor cerebral circulation, blood flow to a part of the brain causes cell death. There are two main types of stroke: brain ischemia, ischemic, due to lack of blood flow, and intracranial hemorrhage, hemor ...
s or
Rett syndrome.
In
McArdle disease (glycogen storage disease type V), the inability to utilize muscle glycogen leads to a shortage of ATP during exercise and subsequent exercise-induced premature
muscle fatigue
Muscle fatigue is when muscles that were initially generating a normal amount of force, then experience a declining ability to generate force. It can be a result of vigorous exercise, but abnormal fatigue may be caused by barriers to or interfer ...
, muscle cramps, muscle pain (myalgia), inappropriate rapid heart rate response to exercise (
tachycardia
Tachycardia, also called tachyarrhythmia, is a heart rate that exceeds the normal resting rate. In general, a resting heart rate over 100 beats per minute is accepted as tachycardia in adults. Heart rates above the resting rate may be normal ...
), rapid depletion of phosphocreatine, insufficient ATP production, increased ADP and AMP, increased rise in venous ammonia (from the
purine nucleotide cycle), increased epinephrine (adrenaline), increased plasma free fatty acids (lipolysis), increased venous pH (alkalosis), rapid (
tachypnea
Tachypnea, also spelt tachypnoea, is a respiratory rate greater than normal, resulting in abnormally rapid and shallow breathing.
In adult humans at rest, any respiratory rate of 1220 per minute is considered clinically normal, with tachypnea b ...
) and commonly (approx. 50%) also heavy breathing (
hyperpnea), that is exercise hyperventilation.
During exercise, due to the inability to utilize muscle glycogen as a substrate for ATP synthesis, plasma lactate does not significantly rise (and may fall below) compared to resting levels; consequently, McArdle disease individuals do not experience lactic acidosis.
The rise in venous pH (alkalosis), may be due to increased ammonia production,
increased epinephrine, and/or increased oxygen demand for oxidative phosphorylation of blood borne substrates (free fatty acids and blood glucose).
Metabolic alkalosis can be caused by repeated vomiting,
resulting in a loss of
hydrochloric acid
Hydrochloric acid, also known as muriatic acid or spirits of salt, is an aqueous solution of hydrogen chloride (HCl). It is a colorless solution with a distinctive pungency, pungent smell. It is classified as a acid strength, strong acid. It is ...
in the stomach contents. Severe
dehydration
In physiology, dehydration is a lack of total body water that disrupts metabolic processes. It occurs when free water loss exceeds intake, often resulting from excessive sweating, health conditions, or inadequate consumption of water. Mild deh ...
, and the consumption of
alkali
In chemistry, an alkali (; from the Arabic word , ) is a basic salt of an alkali metal or an alkaline earth metal. An alkali can also be defined as a base that dissolves in water. A solution of a soluble base has a pH greater than 7.0. The a ...
,
[ are other causes. It can also be caused by administration of diuretics]
See also
References
External links
*
{{Authority control
Acid–base disturbances