brain stem damage
Introduction
Introduction to brain stem injury Brain stem injury refers to the damage of the midbrain, pons and medulla, and is a serious craniocerebral injury, which is often divided into two types: primary brain stem injury, brain stem injury caused by external violence; secondary Brain stem injury is secondary to other severe brain damage, resulting in brain stem damage due to cerebral palsy or cerebral edema. The disease is generally heavier and has a high mortality rate. basic knowledge The proportion of sickness: 0.01% Susceptible people: no special people Mode of infection: non-infectious Complications: urinary tract infections acne
Cause
Causes of brain stem injury
Violence (45%)
Simple brain stem injury is rare. The brain stem includes the midbrain, pons and medulla. When external force acts on the head, both direct and indirect violence will cause collision and movement of brain tissue, which may cause brain stem damage.
Cerebral palsy and cerebral edema (25%)
Other serious brain damage leads to cerebral palsy and cerebral edema, oppression of brain stem tissue, or inflammation of the brain stem tissue can induce the disease.
Pathogenesis:
The brainstem is located in the center of the brain, with a slope underneath, carrying a large and small brain. When an external force acts on the head, the brain stem can be directly pulled against the hard sloped bone, and can be pulled and twisted by the brain and cerebellum. Swelling and impact injuries, among which the whipping, torsion and post-occipital violence have the greatest damage to the brain stem. Usually, when the frontal injury occurs, the brain stem can hit the slope; the side side violence causes the brain stem to be embedded. Frustrated on the ipsilateral cerebellar incision, the post-occipital force causes the brain stem to directly hit the slope and the occipital foramen; the torsion and pulling motion can cause the brain stem to be injured by the action of the large and small brain, and the head is suddenly tilted In the whipping injury caused by the bulging movement, there is more chance of medullary damage; when the occipital occipital fracture occurs when the feet or hips are stressed, the medulla can be directly damaged; in addition, when the head is hit, the skull is severely deformed, and the cerebrospinal fluid shock wave is transmitted through the ventricle. It can also cause damage around the midbrain aqueduct or the bottom of the fourth ventricle.
The pathological changes of primary brain stem injury are often contused with focal hemorrhage and edema. It is more common in the midbrain cover area, the pons and medulla is covered by the cover area, the brain stem is under pressure, and the deformation causes the blood vessel to break and cause bleeding. Secondary lesions such as softening.
Diffuse axonal injury (DAI) is a nervous axonal injury caused by shear stress when the head is subjected to accelerated rotational violence. The pathological changes are mainly located in the central part of the brain, ie the corpus callosum, the cerebral peduncle. , brain stem and cerebellum on the upper foot, etc., mostly contusion, hemorrhage and edema, axonal rupture under the microscope, axoplasmic spillage, a long time can be seen round retracted ball and blood cell dissolved hemosiderin, and finally cystic And gliosis, foreign scholars suggest that the so-called primary brain stem injury is actually a part of DAI, should not be an independent symptom, usually DAI has brain stem injury performance, and no increased intracranial pressure, it depends on CT Or MRI examination to diagnose.
The secondary brain stem injury is the temporal lobe sputum, and the brain stem is squeezed to cause brain stem ischemic injury.
Prevention
Brain stem injury prevention
(1) Take appropriate position according to the condition, turn the head to one side when lying down, avoid vomiting into the trachea, and go to the pillow when the blood pressure is low.
(2) Patients with dentures should remove the dentures to prevent the dentures from falling off, block the respiratory tract and cause suffocation, and prevent the tongue from being bitten.
(3) Keep the airway open. If the tongue is falling, the mouth can be placed in the airway, and the oral secretions are removed regularly. Patients with cough and phlegm are not easy to absorb, and should be cut open by early tracheal tube.
Complication
Brain stem injury complications Complications, urinary tract infection, acne
Visceral symptoms. Pulmonary infections, urinary tract infections, and acne may occur after prolonged bed rest.
1, brain stem shock: symptoms of brain stem damage appear, but no obvious pathological changes.
2, brain stem contusion: brain stem itself has bleeding, edema, can be combined with damage to the brain nerve, more common in skull base fracture.
3, brain stem hemorrhage: spotted or focal hemorrhage in the parenchyma of the brain stem, bleeding is light and heavy, the hemorrhage is larger, the disease is heavier, most of the death soon after the injury.
4, brainstem softening: brain stem caused by focal ischemic necrosis, early stage of focal tissue necrosis, structural dissociation, a large number of lattice cells appear in the later stage, will soften and necrotic tissue phagocytosis and clearance.
5, brain stem localized edema: obvious edema changes in the brain stem injury site.
Symptom
Symptoms of brain stem injury Common symptoms Blood pressure drop Brain stem damage signs Eyeball oblique wheezing High heat conscious disorder Shock Heart failure Light reflex disappears Hiccup
The brain stem not only contains most of the cranial nerve nucleus (except the olfactory nerve and optic nerve), the whole body feels, the motor conduction beam passes through the brainstem, and the respiratory circulatory center is also located here, while the brainstem reticular structure is important for participating in maintaining consciousness. Structure, so after brain stem injury, in addition to the performance of local cranial nerve damage, disturbance of consciousness, motor dysfunction is often more severe, and may also have respiratory and respiratory failure, life-threatening.
Consciousness disorder
In patients with primary brain stem injury, coma often occurs immediately after injury. Lightness may respond to painful stimuli. Heavy coma is deep, all reflexes disappear, coma is persistent, time is long, and there is little middle waking or In the middle of the period of improvement, if any, should be thought of combined with intracranial hematoma or other causes of secondary brain stem injury.
2. Pupil and eye movement changes
Eye movement and pupillary function are managed by cerebral nerves such as oculomotor, trochlear and abduction. Their nucleus is located in the brainstem, and there may be corresponding changes in brain stem injury. It has clinical significance. When the midbrain is damaged, the initial two The lateral pupils are not equal, the pupils on the injured side are scattered, the response to light disappears, and the eyeballs are inclined downwards. When the two sides are damaged, the pupils on both sides are scattered, the eyeballs are fixed, and when the pons is damaged, the two pupils may be extremely reduced, and the light is reflected. Disappeared, both sides of the eyeball oblique, the same direction of deflection or separation of the two sides of the eyeball and other signs.
3. Go to cortical rigidity
It is one of the important manifestations of midbrain injury, because the midbrain vestibular nucleus has a center that promotes the contraction of the extensor muscle, while the midbrain red nucleus and its surrounding reticular formation are the centers that inhibit the contraction of the extensor muscle. The cortex is straightened, and the tension of the extensor muscle is increased. The upper extremities are overextended and internal rotation, and the lower extremities are also over-extended. The back of the head is angulated with a horned arch. The injury is mild and may be paroxysmal. The person continues to attack.
4. Pyramid bundle sign
It is one of the important signs of brain stem injury, including limb paralysis, increased muscle tone, hyperreflexia and pathological reflex. In the early stage of brain stem injury, the appearance of pyramidal tract sign is often not constant due to various factors. However, when the basal part is damaged, the signs are often constant. For example, the lateral injury of the brain stem is characterized by cross-sectional paralysis, including limb paralysis, increased muscle tone, hyperreflexia and pathological reflex, and severe injury in the acute shock phase. The reflection can disappear and the condition can only appear after the condition is stable.
5. Changes in vital signs
(1) Respiratory dysfunction: brain stem injury often occurs immediately after injury. Respiratory dysfunction occurs. In the middle of the brain and the upper respiratory tract of the pons, the respiratory rhythm disorder occurs, such as Chen-Shi breathing; When the long suction center is damaged, sobbing-like breathing may occur; when the inhalation of the medulla and the expiratory center are damaged, respiratory arrest occurs, in the early stage of secondary damage of the brain stem, such as the formation of the cerebellar incision When the respiratory rhythm disorder occurs first, Chen-Shi breathing, the intracranial pressure in the cerebral palsy continues to rise, the cerebellar tonsil sputum appears, the compression of the medulla, the breathing stops first.
(2) Cardiovascular dysfunction: When the medullary injury is severe, the respiratory heartbeat is rapidly stopped, the patient dies, and the respiratory cycle disorder that occurs in the higher brain stem injury often has an excitatory period. At this time, the pulse is slow and powerful, and the blood pressure rises. High, breathing fast or breathing-like breathing, later into exhaustion, pulse rate, blood pressure, breathing is tidal, finally heartbeat breathing stops, general breathing stops first, under the conditions of artificial respiration and drugs to maintain blood pressure, The heartbeat can still last for days or months, and in the end it often dies as a result of heart failure.
(3) changes in body temperature: sometimes high fever after brain stem injury, which is mostly due to sympathetic nerve function, sweating dysfunction, affecting body heat divergence, when brain stem function is depleted, body temperature can be reduced to below normal .
6. Visceral symptoms
(1) Upper gastrointestinal bleeding: caused by acute gastric mucosal lesions caused by brain stem injury stress.
(2) Refractory hiccups.
(3) Neurogenic pulmonary edema: due to sympathetic excitation, causing increased circulation and increased resistance to pulmonary circulation.
Correspondence between brainstem reflex and brainstem damage plane: In severe brain injury, the extent and extent of damage from the subcortex to the brainstem are different, and its clinical manifestations are also different, so it can be reflected from some physiological reflexes or pathologies. Performance, to determine the location of brain stem damage, to guide the clinical, to predict the prognosis.
Examine
Examination of brain stem injury
Lumbar puncture, cerebrospinal fluid pressure is normal or slightly elevated, mostly bloody.
1. Skull X-ray film: The incidence of skull fracture is high, and the brain stem injury can be estimated according to the fracture site and the injury mechanism.
2. Cranial CT, MRI scan: primary brain stem injury manifested as brain stem enlargement, a little flaky density increased area, inter-foot pool, bridge pool, quadruple pool and fourth ventricle were compressed or occluded, following In addition to the signs of secondary lesions, brainstem injury of the cerebral palsy can also show that the brain stem is deformed to the contralateral side, and MRI can show small hemorrhage and contusion within the brain stem. The effect of artifacts is clearer than CT.
3. Intracranial pressure monitoring: It is helpful to identify primary or secondary brain stem injury. Secondary patients may have a significant increase in intracranial pressure, and the initial increase is not obvious.
4. Brainstem auditory evoked potential (BAEP): is the electrophysiological activity on the brainstem auditory pathway, which is transmitted to the far field potential of the scalp through the cerebral cortex. The electrophysiological activity reflected by it is generally not interfered by other external lesions. It can accurately reflect the plane and extent of brain stem injury.
Diagnosis
Diagnosis of brain stem injury
diagnosis
Primary brain stem injury and other craniocerebral injuries often exist at the same time, clinical symptoms overlap, differential diagnosis is more difficult, immediately after the injury, coma and progressive aggravation, pupil size change, early respiratory failure, degaussing In patients with positive and bilateral pathological signs, the diagnosis of primary brain stem injury is basically established.
Differential diagnosis
Primary brain stem injury is often accompanied by brain contusion or intracranial hemorrhage, and the clinical symptoms are mutually wrong. It is difficult to distinguish between phlegm and phlegm, which is the main cause, especially for patients who are late in treatment. It is more difficult to distinguish the primary. Sexual injury or secondary damage, the difference between primary brain stem injury and secondary brain stem injury lies in the symptoms, signs appear sooner or later, symptoms of secondary brain stem injury, signs are gradually produced after injury, intracranial Continuous monitoring of pressure can also be identified: primary intracranial pressure is not high, and secondary is significantly increased, at the same time, CT and MRI are also effective means of differential diagnosis, in the display of small hemorrhage or contusion in the brain parenchyma MRI is superior to CT in brain lesions, especially brainstem auditory evoked potentials. The brainstem auditory evoked potentials can accurately reflect the plane and extent of brain stem injury. Usually, the waves below the auditory pathway lesions are normal, the lesion level and The waves on it show abnormality or disappearance. The continuous pressure measurement of intracranial pressure monitoring also has the effect of identifying primary or secondary brain stem injury. Although the clinical manifestations of the two are the same, the primary intracranial pressure is normal. Secondary The number is obviously higher.
