What is an Anoxic Brain Injury?

Anoxic brain injury is a type of brain injury that isn’t usually caused by a blow to the head. Instead, anoxic brain injury occurs when the brain is deprived of oxygen. Left without oxygen for too long, neural cells begin to die through a process called apoptosis. And though cell death is a normal part of the human experience, when a large number of brain cells simultaneously die, patients can be left with diminished brain function. If the oxygen deprivation continues, anoxic brain injuries may even become fatal.

What Causes Anoxic Brain Injury?

Anything that deprives the brain of oxygen can lead to an anoxic brain injury. Some of the most common causes include:

How Long Can the Brain Survive Without Oxygen?

Every brain is different, of course, and the extent of oxygen deprivation varies depending on the injury. Some causes of anoxic brain injuries only reduce oxygen and blood flow, while others eliminate it entirely. On average, the brain can survive a mere four minutes without oxygen, so if you suspect a stroke or other injury that is cutting off oxygen to the brain, you need to act immediately.

As easily as 30 seconds in, brain damage can begin, and at two minutes brain damage becomes almost inevitable. Even if you or your loved one feel fine after a loss of oxygen to the brain, you need to seek prompt medical treatment to reduce the potential long-term harm.

Signs and Symptoms of Anoxic Brain Injury

Immediately after an anoxic brain injury occurs, some telltale symptoms include:

The longer term effects of an anoxic brain injury vary greatly, and are largely dependent upon the area of the brain affected. For instance, if the brain’s speech centers are affected, it’s common to have difficulty speaking, remembering words, or even understanding speech. Anoxic brain injury sufferers can therefore suffer hundreds of symptoms, and one person’s symptom profile might be quite different from the next. Some common signs, though, include:

Degree and Extent of Anoxic Brain Injury

Doctors typically classify anoxic brain injuries into one of four categories. The classification can provide some insight into the long-term prognosis: