What Is Decerebrate Posturing?
An Involuntary Body Position Caused by Brain Damage
Medically reviewed by Nicholas R. Metrus, MD
Decerebrate posturing is an uncontrollable physical reflex that occurs as a result of substantial brain damage. With decerebrate posturing, a person is not conscious, and they don’t have voluntary control over their movements.
A person who develops this posture has rigid muscles, with arms and legs held out straight, toes pointed down, and the head and neck arched back. This is often considered a sign of irreversible brain injuries.
A stroke, head trauma, or a severe brain infection can cause decerebrate posturing. Sometimes treatable conditions, such as seizures, mental health conditions, or medication side effects, appear similar to decerebrate posturing.
This article describes decerebrate posturing and what to expect if your loved one has this condition.
Illustration by Michela Buttignol for Verywell Health
Decerebrate Posturing and the Brain
Typically, a diagnosis of decerebrate posturing is part of a comprehensive neurological evaluation.
This type of physical reaction occurs along with many other signs and symptoms of brain damage. A person would not have decerebrate posturing as the only sign of a disease—it accompanies other signs and symptoms.
Decerebrate posturing can come. It can also occur with intermittent seizures, decorticate posturing, fencing response, or complete immobility.
A number of serious conditions can lead to decerebrate posturing:
Severe head trauma
A severe inflammatory condition affecting the brain
Extensive bleeding in the brain
Brain swelling and pressure due to a brain tumor
These medical conditions can lead to decerebrate posturing if they cause profound damage to both sides of the brain. This physical sign can develop slowly or quickly. The rate at which it develops does not have a clear relationship to the potential outcome—the outcome of decerebrate posturing is poor, regardless of the cause or the length of time that it took to develop.
Related: Encephalitis of the Brain: Short and Long-Term Effects
Effects
Decerebrate posturing is characterized by:
Rigid muscles
Extended legs
Extended arms
Arched back
Wrists flexed back
How Brain Damage Causes Decerebrate Posturing
Normally, the brain controls thinking skills, physical actions, and physical survival through well-organized communication pathways between nerve cells. Nerve cell communication triggers and inhibits messages, resulting in well-coordinated actions.
When nerve cells in the brain are damaged, they cannot send or receive triggering or inhibitory messages. Thinking, physical actions, and survival functions can be lost when extensive brain damage occurs.
Decerebrate posturing is a response to extensive brain damage, which prevents normal activation and inhibition of neurons.
Is It Permanent?
The brain damage that causes decerebrate posturing is usually permanent. However, this type of posture can fluctuate with other involuntary movements, such as decorticate posturing, seizures, and a lack of muscle tone.
Other Conditions That Can Appear Similar to Decerebrate Posturing
Medical disorders that can appear similar to decerebrate posturing include:
Advanced neurological conditions
Psychiatric conditions
Seizures
Drug or alcohol withdrawal
Drug intoxication
Immediate and Life-Saving Treatment
In some cases, decerebrate posturing is anticipated before it occurs, and a person’s physician may have already explained this likelihood to the loved ones. For example, a person who is demonstrating decerebrate posturing may have already experienced a large stroke.
However, this posture can sometimes develop unexpectedly, such as in the setting of a major brain injury from head trauma.
Prevention and Treatment
Therapy can often be started to prevent decerebrate posturing when there is a known injury or disease process affecting the brain.
Steroids or diuretic medication (water pills) to remove excess fluid from the body may be given. Sometimes a procedure can be done to remove excess fluid from around the brain, often followed by placement of a temporary tube to allow excess fluid to drain.
The healthcare team may initiate treatment to prevent further brain damage, especially if a decision has not yet been made regarding life support or if the cause is not well understood.
Treatment may consist of medication to reduce swelling in the brain, anti-seizure medication if a person is having seizures, respiratory support with intubation (mechanically assisted breathing), and medication to support heart function.
It is possible for this sign to develop at the end of a person’s life.
Decerebrate Posturing Lesions on Scans
Typically, decerebrate posturing is diagnosed based on clinical observation and medical assessment of a person’s medical history.
If your loved one is having a diagnostic evaluation for their condition, they may have a brain imaging test or electrical diagnostic studies of the brain function.
Brain imaging tests include brain computerized tomography (CT) or magnetic resonance imaging (MRI). Often a person who has decerebrate posturing may not be stable enough to undergo a brain MRI, and may have a brain CT, which is faster.
Generally, a brain CT will not show the same level of detail as a brain MRI, but a person who has decerebrating posturing will usually have changes that are consistent with this type of brain damage that can be visualized on their brain CT.
An electroencephalogram (EEG) is a diagnostic study that examines the electrical activity of the brain. An EEG can often differentiate seizures from severe, irreversible brain damage. This study may show a pattern that is consistent with severe damage on both sides of the brain.
Generally, the EEG pattern of decerebrate posturing is different than the electrical pattern of brain death. Often, the type of brain damage that accompanies decerebrate posturing proceeds to brain death.
Risks and Complications
Decerebrate posturing doesn’t cause damage to the brain—it is a sign of brain damage. If a person has this type of posture, they could also quickly develop other health complications related to their health deterioration. This may include damage or failure of other organs in the body, such as the liver, kidneys, heart, and gastrointestinal system.
Prognosis With Decerebrate Posturing
Decerebrate posturing usually indicates profound damage to the cerebral cortex on both sides of the brain. While it is not dangerous and does not cause any damage, it only happens when there is severe damage to the brain. It is an indication of an unfavorable prognosis and a low likelihood of survival.
In rare instances, a person may have decerebrate posturing as a sign of an extensive, yet treatable medical condition. For example, severe liver failure can cause rapid and substantial damage to the brain—and in some cases, the brain effects can be reversible if the liver condition is treated.
Additionally, it is possible that another condition, such as a seizure or a psychiatric condition, could be misdiagnosed as decerebrate posturing. In this type of situation, treatment of the underlying condition could lead to a good prognosis.
Decorticate Posturing
Decorticate posturing and decerebrate posturing are two different involuntary body positions that result from significant brain damage. Neither is considered better or worse than the other.
Support and Ongoing Care
If you have a loved one who has demonstrated decerebrate posturing, then you may need to have a discussion about life-support decisions with your loved one’s physicians. Be sure all your questions are answered before you make a decision.
You may need to discuss the plan with a neurologist, an intensive care physician, or another specialist who is overseeing your loved one’s medical care.
Related: Stroke Recovery and Rehabilitation
Summary
Decerebrate posturing is a sign of severe brain damage. With this type of involuntary physical position, a person is rigid and extends their legs and arms, typically with the wrists rotated outward. A person may have intermittent episodes of decerebrate posturing or the posturing remains stable for hours or longer.
You may need to discuss life-support decisions with your loved one’s healthcare team if they are displaying this neurological sign of brain damage.
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