Abnormal posturing


Refers to abnormal posturing is an involuntary flexion or extension of the arms and legs, indicating severe brain injury.

It occurs when one set of muscles is incapacitated while the opposing set is not.

An external stimulus, such as pain, causes the working set of muscles to contract,although the posturing may also occur without a stimulus.

It is an important indicator of the amount of damage that has occurred to the brain, and used to measure the severity of a coma with the Glasgow Coma Scale (for adults) and the Pediatric Glasgow Coma Scale (for infants).

The presence of abnormal posturing indicates a severe medical emergency requiring immediate medical attention.

Decerebrate and decorticate posturing are strongly associated with poor outcomes.

Changes in the condition of the patient may cause the patient to alternate between different types of posturing.

Posturing can be caused by conditions that lead to large increases in intracranial pressure due to: traumatic brain injury, stroke, intracranial hemorrhage, brain tumors, encephalopathy and malaria.

Posturing due to stroke usually only occurs on one side of the body and may also be referred to as spastic hemiplegia.

Posturing with decerebrate and decorticate posturing can indicate that brain herniation is occurring, or is about to occur.

In brain herniation syndrome, decorticate posturing occurs, and, if the condition is left untreated, develops into decerebrate posturing.

Posturing has also been displayed by patients with Creutzfeldt-Jakob disease, diffuse cerebral hypoxia, and brain abscesses.

In children younger than age two the nervous systems are not yet developed, and posturing is not a reliable finding.

Reye’s syndrome and traumatic brain injury can both cause decorticate posturing in children.

Children with malaria frequently exhibit decorticate, decerebrate, and opisthotonic posturing.

There are 3 types of abnormal posturing:

Decerebrate posturing is also called decerebrate response, decerebrate rigidity, or extensor posturing.

It is the involuntary extension of the upper extremities in response to external stimuli.

In decerebrate posturing, the head is arched back, the arms are extended by the sides, and the legs are extended.

Extended elbows is a classical manifestation of decerebrate posturing.

In decerebrate posturing the arms and legs are extended and rotated internally.

In decerebrate posturing the patient is rigid, with the teeth clenched.

Decerebrate posturin signs can be unilateral or bilateral, and it may be just in the arms and may be intermittent.

A person displaying decerebrate posturing in response to pain gets a score of two in the motor section of the Glasgow Coma Scale and the Pediatric Glasgow Coma, due to muscles extending because of the neuro-muscular response to the trauma.

Decerebrate posturing is a reflection of brain stem damage, specifically it is damage below the level of the red nucleus.

Decerebrate posturing is seen by patients with lesions or compression in the midbrain and lesions in the cerebellum.

Decerebrate posturing is commonly seen in pontine strokes.

A patient with decorticate posturing may begin to show decerebrate posturing, or may go from one form of posturing to the other.

Progression from decorticate posturing to decerebrate posturing often suggests uncal or tonsilar brain herniation.

Patients displaying decerebrate or decorticate posturing are usually in a coma and have poor prognoses, associated with risks for cardiac arrhythmia, arrest and respiratory failure.

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