Decortical tonicity
1.Definition: It is a kind of waking coma, which is a special disorder of consciousness with the presence of “waking state” and the loss of “conscious content”. The clinical manifestations are severe loss of language and motor response.
2.Common diseases: ischemic-hypoxic encephalopathy, cerebrovascular diseases with extensive cortical damage and trauma, etc.
3.Typical signs: flexion of the upper limbs, extension of the lower limbs “flexion of the elbow, inward shoulder, extension of the legs and ankles”
4, Pathogenesis basis.
Loss of cortical or subcortical functions, while most of the subcortical functions and autonomic functions of the medulla oblongata are preserved or have been restored.
The midbrain and the pontine superior reticular activation system are not damaged, and there may be unconscious swallowing movements and wake-sleep cycles.
5. Common manifestations.
The eyes can be opened and closed unconsciously, and the eyeballs can move. The pupil-to-light reflex and corneal reflex exist. Increased muscle tone of the limbs and positive pathological reflexes. Sucking reflex, strong grip reflex, and tense neck reflex may be present. Unconscious swallowing may occur with feeding, but there is no spontaneous movement. There is no conscious response to external stimuli. Urinary and fecal incontinence. Wake-sleep cycle is present.
Deactivation of the brain
1. Common diseases: midbrain damage, posterior cranial fossa lesions, hypoxia or hypoglycemia.
2. Typical signs: coracoacusis, tonicity of limbs, increased muscle tone. “Elbow extension, internal rotation of the shoulder and forearm, and straightening of the lower limbs”.
3, pathogenetic basis: decerebrate tonicity is mainly a reflexive hypertonicity of the extensor muscles, which is an overstretched detrusor reflex. The over-strong detrusor reflex is caused mainly by the interruption of the connection between the red nucleus of the midbrain and the inferior structures. Downward inhibitory influences from above the red nucleus are blocked, the activity of the reticular inhibitory system is reduced, and the central response of the spinal cord above the ? motor neuron inhibitory impulses are diminished, while the cerebellum, vestibular nucleus with reticular structures to ? motor neurons susceptibility impulses still exist, thus causing tonic spasms of the trunk extremities.
4, Common manifestations.
The consciousness disorder manifests as wakeful coma, where the patient appears to be awake but has no conscious activity, does not respond to verbal stimuli, and is diphtheric incontinent, similar to decortical tonicity.
Motor disorders were manifested as tonic extension of the limbs, corkscrewing of the trunk, irregular breathing, and generalized muscle tonic spasms.
5.Disease regression.
Progression: extensional tonicity gradually changes to upper limb flexion, inversion and internal rotation. This means that the lesion is gradually confined to above the level of the midbrain and the disease is improving.
Deterioration: The consciousness is impaired in a comatose state, and the extensional tonicity gradually changes into delayed paralysis, indicating that the lesion has spread below the pontocerebrum, and the condition gradually develops into a dying state.
To summarize.
1, both are mostly caused by severe diffuse lesions in the brain, so it is often impossible to accurately locate the lesion site.
The latter is more serious, and the two can be seen to transform into each other in the clinic.
3.Typical signs of both.
Decortical ankylosis: upper limb flexion, lower limb straightening.
Decerebral ankylosis: coracoelasticity, extensional ankylosis of all four limbs.