For the body to function properly, it is essential that it maintains an appropriate acid-base balance. Normal blood pH is between 7.35 and 7.45. Anything higher than 7.45 indicates alkalosis or an excess of base in the body. This is the opposite of acidosis, in which there is too much acid. There are two types of alkalosis and multiple causes to consider.
Acid-Base Balance
Maintaining an appropriate acid-base balance involves several organs and complicated chemical reactions, and in a healthy person, the body is well-equipped to make adjustments to correct any problems that do arise. Generally, alkalosis occurs through the loss of acid or excess bicarbonate production. A person may develop respiratory alkalosis or metabolic alkalosis.
Respiratory Alkalosis
Respiratory alkalosis occurs when the lungs excrete too much carbon dioxide (CO2), a compound that lowers blood pH. Too much CO2 in the blood results in respiratory acidosis, but when the lungs are exhaling an excessive amount of CO2, the pH rises, resulting in alkalosis. Generally, anything that causes someone to breathe too fast for too long can lead to respiratory alkalosis.
Metabolic Alkalosis
Bicarbonate acts as a buffer that generally protects the body from becoming too acidic. The process by which bicarbonate is released into the body is complicated and is carried out by the kidneys. In metabolic alkalosis, the amount of bicarbonate is always elevated and the problem is usually caused by a loss of acid.
Compensation
The body is well-equipped to maintain its pH balance, but correcting alkalosis can be tricky. Compensation for metabolic alkalosis involves slowing down the respiratory system to retain more CO2, but this can result in low oxygenation, which has its own issues. It is for this reason that compensation is somewhat limited. In respiratory alkalosis, the kidneys compensate by lowering the bicarbonate slightly, but the effects of this response are not immediate.
Causes of Respiratory Alkalosis
Respiratory alkalosis is marked by a low level of CO2 and anything that leads the body to breathe faster than normal for an extended period could cause it. This includes panic attacks, fever, hyperventilation, pregnancy, tumors, severe pain, liver disease, anemia, and trauma. Taking too much of certain medications, like salicylates or progesterone, can also cause respiratory alkalosis.
Symptoms and Treatment of Respiratory Alkalosis
Someone with respiratory alkalosis may experience lightheadedness, dizziness, numbness in the hands and feet, chest discomfort, and confusion. Breathing into a paper bag may reduce symptoms if they are related to anxiety or panic, by causing the person to re-breathe CO2. Medically, doctors usually aim to treat the underlying cause of respiratory alkalosis, rather than the symptoms.
Causes of Metabolic Alkalosis
An excess of bicarbonate in the blood, usually from a loss of acid, causes metabolic alkalosis. Frequent vomiting or excessive suctioning through a nasogastric tube are common causes. Diuretics, hypovolemia, and low potassium levels can also lead to elevated bicarbonate levels. Metabolic alkalosis related to kidney failure is not common but can occur with the ingestion of antacids or large amounts of calcium carbonate. Lastly, it can occur as a complication in those with cystic fibrosis.
Symptoms and Treatment of Metabolic Alkalosis
In most cases, metabolic alkalosis has mild, self-limiting symptoms. In critically ill patients, however, it can become very serious or life-threatening. Metabolic alkalosis also increases the chances of arrhythmias and seizures if calcium and potassium levels become elevated. Treatments depend on the underlying cause and include administering IV fluid and maintaining proper potassium levels.
Arterial Blood Gas
The definitive test for alkalosis is an arterial blood gas. The doctor draws blood from an artery in the wrist, arm, or groin. Test results provide the pH level of the blood, in addition to the amount of oxygen, pulse oxygenation, CO2, and bicarbonate. These results show the severity of the alkalosis and whether or not the body is compensating.
Additional Testing and Outlook
Other tests that can provide insight into the cause of alkalosis basic metabolic panels and urinalysis. The former checks electrolytes, while the latter monitors kidney function. Most cases of alkalosis respond well to treatment, though people who are critically ill or have other health problems could be significantly impacted by the diagnosis.