Lactic Acidosis: Quick, Practical Guide

High lactate in the blood can be silent until things get serious. Lactic acidosis means your body is making more lactic acid than it can clear. That can happen fast and needs quick action. Read this so you know what to watch for and what to do if you or someone you care for might be affected.

What causes lactic acidosis?

There are two simple ways this starts: low oxygen to tissues or a metabolic problem that blocks lactate removal. Common triggers you should know:

• Severe infection (sepsis) — tissues aren’t getting enough blood or oxygen.
• Shock, major bleeding, or heart failure — poor circulation raises lactate.
• Medications and toxins — metformin (if kidneys fail), some antivirals, alcohol in large amounts, and toxins like cyanide.
• Organ failure — liver problems stop lactate from being cleared.
• Intense exercise, seizures, or severe asthma — sudden high demand for oxygen.

Metformin-associated lactic acidosis gets lots of attention because metformin is common. The risk rises if kidneys are weak, there is dehydration, or during acute illness. That’s why doctors check kidney function before and during metformin use.

How it shows up and how doctors check it

Symptoms can be vague: fast breathing, feeling very weak, nausea, stomach pain, confusion, or an unusual sleepiness. If you see these during a serious illness, treat them as red flags.

Key tests doctors use:

• Serum lactate — values above 2 mmol/L are raised; levels over 4 mmol/L are worrisome.
• Arterial blood gas — shows pH and how acidic the blood is.
• Basic labs — kidney and liver tests, glucose, electrolytes, and anion gap.

Higher lactate and low pH mean a worse situation and usually need urgent care.

Treatment focuses on fixing the cause. For sepsis that means antibiotics and fluids. For low blood pressure, doctors use IV fluids and sometimes medicines that raise blood pressure. If metformin is the cause and the kidneys are failing, dialysis can remove metformin and lactate. Oxygen and improving circulation are central steps.

What about bicarbonate? It’s sometimes used when pH is very low (often below 7.1), but it’s not a routine fix and has risks. Your care team will weigh the benefits. Close monitoring in a hospital setting is usually needed.

How to reduce your risk at home: keep hydration during illness, avoid heavy alcohol, check kidney tests if you take metformin, and seek care quickly for infections or trouble breathing. If someone is dizzy, breathing fast, confused, or very weak after a major illness or medication change, go to the ER and mention lactic acidosis risk.

Knowing the causes and early signs lets you act fast. Lactic acidosis is treatable when caught early—so don’t wait if something feels seriously off.