ADD-ONS

Decorticate and decerebrate posturing

David Goldemund M.D.
Updated on 14/07/2024, published on 11/07/2024

Pathophysiology

  • decorticate and decerebrate posturing result from damage to the structures that control motor tone associated with the corticospinal tract
    • the brainstem is thus disconnected from inhibitory cortical and subcortical pathways
  • decorticate posturing – the lesion is rostral to the midbrain (e.g., cortex or internal capsule)
  • decerebrate posturing – the lesion is at or below the level of the midbrain/caudal diencephalon
  • patients with posturing are typically comatose and often have a poor prognosis; they are at risk for respiratory failure, cardiac arrhythmias, and cardiovascular collapse
    • decorticate posturing has a more favorable prognosis than decerebrate posturing
  • a progression from a decorticate to a decerebrate posture is associated with progressive destruction/compression of brain structures (→ rostrocaudal deterioration)
  • both types of posturing require immediate medical evaluation and intervention

Clinical Presentation

  • decorticate posturing
    • arms are flexed at the elbows and held inward and close to the body; the wrists and fingers are clenched and held tightly to the chest
    • the legs and feet are usually extended and turned inward;  feet are at plantar flexion
  • decerebrate posturing
    • patients exhibit rigidity with arm and leg extension, wrist flexion, and foot plantar flexion
    • these signs can be intermittent, unilateral or bilateral and may involve the upper extremities only
  • mixed decerebrate rigidity (reverse decerebrate syndrome)
    • extensor posture in the upper limbs and a flaccid or flexed posture in one or both lower limbs
    • results from primary lesions in the pontine tegmentum, particularly affecting the vestibular nuclei and vestibulospinal tracts
    • prognosis is fatal (mortality 100%)
Decorticate and decerebrate posturing
Motor response Lesion location
Mortality
decorticate rigidity  cortico-subcortical level
~ 50%
decerebrate rigidity caudal diencephalon-upper brainstem ~ 85%
mixed decerebrate rigidity pons ~ 100%

Diagnostic evaluation

  • neurological examination and neuroimaging (CT or MRI) are used to identify the underlying cause (hematoma, contusion, brain edema with herniation, etc.)
    • non-contrast computed tomography (NCCT) – baseline imaging in the acute setting
    • magnetic resonance imaging (MRI) may better show cerebral edema or tumor progression; however, it is reserved for stable patients

Management

  • focused on the underlying cause
    • surgical intervention
    • medical management and supportive care
Send this to a friend
Hi,
you may find this topic useful:

Decorticate and decerebrate posturing
link: https://www.stroke-manual.com/decorticate-and-decerebrate-posturing/