Lactic acidosis

Fast facts

• Lactic acidosis is a build-up of lactic acid in your blood.
• It can be the result of intense exercise, severe dehydration, an underlying medical condition, or as a reaction to some substances and medications.
• Symptoms of lactic acidosis can initially include weakness and nausea. More severe symptoms, such as chest pain, a fast heartbeat or breathing difficulties, require immediate medical attention.
• You can reduce your risk of lactic acidosis by not abusing alcohol and by properly managing diabetes if you have it.

What is lactic acidosis?

Lactic acidosis is a build-up of lactic acid in your blood. It makes the blood too acidic.

Inside the cells of your body, there are structures called mitochondria. Their role is to supply energy to the cells. Mitochondria break down glucose for energy using oxygen, a process known as aerobic respiration.

In situations when your body is starved for oxygen, or needs a lot of energy very quickly (such as during intense exercise), your mitochondria can switch to an alternative process known as anaerobic respiration. It is much less efficient, but it does not require oxygen and can, for a brief period, produce energy more quickly.

Anaerobic respiration produces lactic acid (also known as lactate), making the blood more acidic. In most cases this is not a problem, because your liver and kidneys handle the excess lactic acid once your body starts to recover from oxygen starvation and returns to normal. However, when your body produces lactic acid faster than it can be removed, lactic acid builds up in your blood.

Causes and risk factors

Causes and risk factors of lactic acidosis include:

• Intense exercise;
• Severe dehydration;
• Low blood sugar, and;
• Some substances and medications - such as alcohol, cocaine, epinephrine, isoniazid, salicylates, and the diabetes medication metformin - can raise the level of lactate in the body.

Lactic acidosis is often the result of another medical condition, such as:

• Liver failure.
• Kidney problems.
• Mitochondrial diseases.
• HIV/AIDS - people with AIDS are more prone to infection, which can result in lactic acidosis when the bloodstream is infected. Lactic acidosis can also result from medications used to treat HIV.
• Cancer - in rare cases, lactic acidosis can occur in people with leukaemia, lymphoma, or solid tumours. It is not clear why this happens.
• Short bowel syndrome can lead to bacteria in the gut producing too much lactate, which can sometimes enter the bloodstream.
• Diabetes increases the risk of heart and kidney problems, leading to increased risk of lactic acidosis.

Signs and symptoms

Mild symptoms of lactic acidosis include:

• Weakness and lethargy, and;
• Nausea and sometimes vomiting.

The following severe symptoms may indicate a life-threating condition. Seek immediate medical attention if you have:

• Chest pain, tightness or pressure;
• High fever;
• Bluish lips or fingernails;
• Short breath and rapid breathing, and;
• An abnormally fast heart rate or an irregular heartbeat.

Methods for diagnosis

Lactic acidosis is diagnosed with a blood test. Further tests can identify the underlying cause of the lactic acidosis.

Types of treatment

Treatment for lactic acidosis starts by identifying the underlying medical condition, or by removing the drug or toxin that is causing it.

Treatment generally includes:

• Intravenous fluids;
• Oxygen therapy to boost the body's oxygen supply, and;
• In some cases, sodium bicarbonate is used to neutralise the acidosis, and/or dialysis to remove lactic acid.

Potential complications

Lactic acidosis is itself a complication, often arising as a result of another medical condition or as a side effect of certain medications.

Left untreated, lactic acidosis can result in the following complications:

• Irregular heartbeats;
• Shock, and;
• Unconsciousness, coma and death.

Prognosis

The prognosis for lactic acidosis depends on its cause. In many people, lactic acidosis is a temporary condition that can be treated effectively. In others, lactic acidosis is only one aspect of an existing medical condition, and their prognosis would depend on all aspects of their condition.

Prevention

You can reduce your risk of lactic acidosis by not abusing alcohol and by properly managing diabetes if you have it.

References

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