Lactic Acidosis

Lactic acidosis is a medical condition caused by excessive buildup of lactic acid in the body. Our body requires oxygen to carry out several metabolic processes that yield energy. In the absence of oxygen, anaerobic metabolism occurs, producing lactic acid as a byproduct. Excessive accumulation of lactic acid in the body makes the pH of your blood slightly acidic, as opposed to normal pH. Lactic acidosis is considered a separate form of metabolic acidosis. It can be treated by addressing the underlying cause. If left untreated, it can lead to serious complications. 

There are various causes of lactic acidosis. It is caused either by too much lactic acid buildup or reduced uptake by the cells. Liver and kidney diseases are major factors because these organs are involved in the breakdown of lactic acid and its removal from the body. Life-threatening causes of lactic acidosis include cardiac shock, hypovolemic shock, heart failure, sepsis, and severe traumatic injury. Heart conditions can reduce the blood and oxygen supply to tissues, which leads to an increase in anaerobic metabolism.

Certain antiviral medications, especially nucleoside reverse transcriptase inhibitors, which are used to treat HIV, can also cause lactic acidosis and liver damage. Individuals with cancer may also suffer from this condition as cancer cells also release lactic acid. Excessive use of alcohol can lead to liver damage and alcoholic ketoacidosis. Uncontrolled diabetes has also been reported as a major cause of lactate buildup in the body. The incidence is higher among those people who have diabetes along with other conditions such as liver or kidney disease. Other causes of lactic acidosis include strenuous exercise, short bowel syndrome, generalized tonic-clonic seizures, cholera, malaria, and some medications. 

Lactic acidosis is categorized into two types based on its underlying cause: type A and type B.

Type A lactic acidosis is associated with low perfusion and decreased oxygen supply. This can occur in sepsis, cardiogenic shock, hypovolemic shock, etc. Reduced oxygen supply increases anaerobic metabolism, which leads to a buildup of lactic acid.

Type B lactic acidosis is not related to decreased perfusion or oxygen supply. It is caused by impaired cell function of certain organs or genetic metabolic impairment. Some examples include liver disease, kidney disease, diabetic ketoacidosis, etc. 

Risk factors of lactic acidosis are associated with its causes. If you have a positive family history of liver diseases, kidney diseases, diabetes, or other medical issues that cause this condition, then you are at risk. Excessive intake of alcohol is another risk factor as it can damage your liver and increase lactic acid production. Factors that risk the health of your heart and vascular system are equally dangerous because this may result in low perfusion to organs.

The exact prevalence of lactic acidosis is difficult to measure as it is caused by various reasons. It is seen more often among critically ill patients already suffering from a heart, liver, kidney disease, or any other medical condition.

The signs and symptoms of lactic acidosis are hard to distinguish as they can occur in many medical conditions. Some common symptoms include increased heart rate, rapid or shallow breathing, jaundice, confusion or disorientation, and extreme fatigue. If you notice a fruity-smelling breath, it can be a sign of diabetic ketoacidosis. Some other symptoms of lactic acidosis may include muscle cramps, generalized discomfort, abdominal pain, weakness, drowsiness, loss of appetite, nausea/vomiting, Diarrhea, and headache. 

History is required at the beginning of the diagnostic process. If the person is unable to give history themselves, an attendant is asked about their relevant medical conditions. Lactic acidosis is diagnosed by arterial blood gas tests or venous blood tests. Arterial blood gas tests may indicate a pH level below 7.35, which is slightly acidic. Blood tests are also done to measure electrolyte levels. In many cases of lactic acidosis, plasma bicarbonate levels are below 22 mmol/L. Your doctor may ask you to fast for a few hours and avoid physical activity to obtain accurate results. 

Lactic acidosis itself is a manifestation of multiple other medical conditions such as cardiogenic shock, sepsis, liver failure, seizures, cancer, etc. The exact cause should be identified and differentiated from other conditions based on history, physical examination, and diagnostic tests. 

Treatment options for lactic acidosis vary depending on its cause. The best option is to treat the cause leading to the buildup of lactic acid. In case of a medical emergency, immediate supportive care is given to the patient regardless of the cause. Oxygen support is provided to improve breathing and treat low perfusion. This can be done through an oxygen face mask or positive pressure ventilator. Intravenous fluid is given to promote circulation. In some cases, hemodialysis can be done to reduce bicarbonate levels in the body.

Medications are given according to the underlying cause. If you develop symptoms of lactic acidosis, avoid taking over-the-counter medications without consulting with your doctor. Certain medications such as acetaminophen can further damage your liver or kidney. 

Patients with lactic acidosis are monitored for 12 or 24 hours, and their prognosis is partially dependent upon lactate clearance in that time frame. Even if lactate levels fall, it is still possible that the condition may remain worse if the underlying cause has not been treated. 

Prevention of lactic acidosis can be achieved by preventing or managing its possible causes. If you have diabetes, HIV, liver disease, heart disease, or kidney disease, consult with a healthcare specialist to obtain suitable medications and guidelines to manage your condition. Excessive intake of alcohol should be avoided. Those with alcohol issues should be referred to a doctor or counsellor who can handle them. Eat a balanced diet, maintain a healthy weight, and exercise regularly to improve blood circulation. Exercise should also be done with a balance, as too much exercise can also lead to an increased buildup of lactic acid.