Brainstem injury
Brainstem injury is an injury to the midbrain, pons and medulla oblongata, and is a serious cranial injury, often divided into two types: primary brainstem injury and secondary brainstem injury. Primary brainstem injury is a brainstem injury caused by the direct action of external violence; secondary brainstem injury is secondary to other serious brain injury, caused by brain herniation or brain edema.
Symptoms and signs
The brainstem contains most of the cerebral nuclei (except the olfactory and optic nerves), the whole body sensory and motor conduction bundles, and the respiratory and circulatory centers, and the brainstem reticular formation is involved in and maintains consciousness. Therefore, after the injury appears ……
1, impaired consciousness. Patients with primary brainstem injury, coma often occurs immediately after the injury, the milder ones can respond to painful stimuli, the heavier ones have a deep coma and all reflexes disappear. If there is a coma lasting longer, rarely appear intermediate wakefulness or intermediate improvement period, should be thought of combined intracranial hematoma or other causes of secondary brainstem injury.
2. Pupillary and oculomotor changes. Eye activity and pupil regulation function by the moving eye, carriage and abduction and other brain nerve management, their nuclei are located in the brainstem, brainstem injury can have corresponding changes, clinical significance of localization. In the case of midbrain injury, the pupils on both sides are not equal in size at the beginning, the pupil on the injured side is dilated, the response to light disappears, and the eye is tilted outward; in the case of injury on both sides, the pupils on both sides are dilated and the eye is fixed. In the case of cerebral bridge injury, there can be signs such as extreme narrowing of the two pupils, disappearance of light reflex, inward slanting of the two sides of the eyeballs, simultaneous obliquity or separation of the two sides of the eyeballs.
3, decortical tonicity. It is one of the important manifestations of midbrain injury. Because there is a center at the level of the vestibular nucleus of the midbrain that promotes the contraction of the extensor muscle, while the red nucleus of the midbrain and its surrounding reticular structures are the center that inhibits the contraction of the extensor muscle. When the two are severed from each other, decortical tonicity occurs. This is characterized by increased extensor tone, hyperextension and internal rotation of both upper extremities, hyperextension of the lower extremities, and head tilting back in an anteverted position. The injury may be paroxysmal in milder cases, or persistent in severe cases.
4, cone bundle signs. Is one of the important signs of brainstem injury. Including limb paralysis, increased muscle tone, tendon reflex hyperactivity and pathological reflexes. In the early stage of brainstem injury, due to the influence of a variety of factors, the appearance of the cone bundle signs are often not constant. However, in the case of basal injury, the signs are often more constant. If the brainstem is injured on one side, the signs are crossed paralysis, including limb paralysis, increased muscle tone, hyperactive tendon reflexes and positive pathological reflexes. In severe injury in acute shock, all reflexes may disappear and may appear only after the condition is stabilized.
5.Vital signs changes
(1) respiratory dysfunction: brainstem injury often appears immediately after the injury respiratory dysfunction. When the lower part of the midbrain and the upper part of the brain bridge respiratory regulation center is damaged, there is a disturbance of respiratory rhythm, such as Chen-Sch respiration; when the lower part of the brain bridge long inhalation center is damaged, sob-like breathing can occur; when the medulla oblongata inhalation and expiration center is damaged, respiratory arrest occurs. In the early stage of secondary brainstem damage, such as the formation of cerebellar curtain incisional herniation, respiratory rhythm disorders appear first, Chen-Sch respiration, in the late stage of brain herniation intracranial pressure continues to rise, cerebellar tonsillar herniation appears, compressing the medulla oblongata, respiration is stopped first.
(2) cardiovascular dysfunction: when the medulla oblongata injury is serious, it is manifested as rapid cessation of respiration and heartbeat, and the patient dies. Higher brainstem injury when the respiratory and circulatory disorders often first have a period of excitation, when the pulse is slow and strong, blood pressure rises, breathing deep and fast or wheezing breathing, later turning into failure, pulse frequency, blood pressure drops, breathing tidal, and finally heartbeat respiratory arrest. Generally, breathing stops first, and under the condition of artificial respiration and drugs to maintain blood pressure, the heartbeat can still be maintained for several days or months, and finally, death is often due to heart failure.
(3) temperature changes: brainstem injury can sometimes appear after the hyperthermia, which is mostly due to impaired sympathetic nerve function, sweating dysfunction, affecting the body heat dissipation. When the brainstem failure, the body temperature can be reduced to below normal.
6.Visceral symptoms
(1) Upper gastrointestinal bleeding: caused by acute gastric mucosal lesions caused by brainstem injury stress.
(2) Intractable erratic reflux.
(3) Neurogenic pulmonary edema: It is due to sympathetic excitation, which causes increased resistance of body circulation and pulmonary circulation.
Causes of disease
Trauma. Simple brainstem injury is not uncommon. The brainstem includes the midbrain, pons and medulla. When an external force acts on the head, either direct or indirect violence will cause brain tissue to impinge and move, which may result in brainstem injury.
Pathogenesis
The brainstem is located in the center of the brain, under which is the slope, carrying the large and small brain, when external forces act on the head, the brainstem can be directly impacted on the hard slope of the bone, but also by the brain and cerebellum pulling, twisting, squeezing and impact injuries, among which the whiplash, torsional and posterior occipital violence on the brainstem damage is the largest usually frontal injury, the brainstem can be impacted on the slope; lateral head violence caused by the brainstem embedded in the Injuries caused by twisting and pulling movements can cause the brainstem to be injured by the action of large and small brains, and the medulla oblongata is more likely to be damaged in whiplash injuries caused by sudden supination of the head; the medulla oblongata can be directly injured by a depression fracture of the occipital bone when the feet or hips are stressed; in addition, when the head is severely deformed by a blow to the skull, the cerebrospinal fluid shock wave through the ventricles can also cause the medulla oblongata. Cerebrospinal fluid shock waves can also cause damage around the midbrain aqueduct or the base of the four ventricles.
The pathological changes of primary brainstem injury are often contusions with focal hemorrhage and edema, mostly in the midbrain periaqueductal region, followed by the pons and medulla periaqueductal region, and secondary lesions such as hemorrhage and softening due to vascular disruption caused by pressure displacement and deformation of the brainstem.
Diffuse axonal injury (DAI), which is caused by shear stress when the head is subjected to accelerated rotational violence, is mainly located in the mid-axis part of the brain, i.e., corpus callosum, cerebral peduncle, brainstem and superior cerebellar peduncle, with contusions, hemorrhage and edema. Microscopically, axonal fracture and axial pulp spillage can be seen. A little longer, round retraction spheres and hemocytolysis of iron-containing hemocyanin are seen. Finally, cystic degeneration and gliosis have been suggested by foreign scholars that so-called primary brainstem injury is actually a part of DAI and should not be treated as an independent sign. Usually DAI has brainstem injury manifestations and no intracranial pressure increase, so the diagnosis needs to rely on CT or MRI examination.
Secondary brainstem injury is ischemic brainstem injury caused by temporal lobe hook gyrus herniation and brainstem compression.
Examination
Dynamic analysis should be made according to the pathogenesis, changes in clinical manifestations, and combined with auxiliary diagnostic tools.
1, medical history questioning Injury time, cause of injury, the situation at the time of injury, to understand the post-injury coma and forgetfulness of recent events, the length of coma, whether there is intermediate improvement or waking period, whether there is vomiting and its number, whether there is incontinence, whether there are convulsions, seizures, limb movement, what kind of treatment received. The presence of alcoholism, mental disorders, epilepsy, hypertension, heart disease, stroke, etc. before the injury.
2.Neurological examination Focus on consciousness, pupils, limb movement, cone bundle signs and meningeal stimulation signs, etc.
3.Head examination Scalp injury, eyelid, conjunctiva and mastoid area for bruising, ear, nose and pharynx for bleeding and cerebrospinal fluid outflow.
4.Vital signs Focus on breathing, pulse and blood pressure changes.
5.Systemic examination Any injury to the jaw, chest and abdominal organs, pelvis, spine and extremities. If there is hypotension and shock, more attention should be paid to combined injuries.
6, cranial X-ray examination suspected of skull fracture should be taken frontal and lateral film. Occipital force injury plus the frontal occipital position (Tong’s position) film, depressed fractures take tangential position film. For suspected optic nerve injury, optic nerve foramina should be taken, and for orbital fracture, Kirchner’s view should be taken.
7, lumbar puncture to understand the extent of subarachnoid hemorrhage and intracranial pressure. Lumbar puncture is contraindicated in severe injuries with significant intracranial hypertension or signs of brain herniation.
8.CT scan is currently an important basis for the diagnosis of cranial brain injury. It can show skull fracture, cerebral contusion, intracranial hematoma, subarachnoid hemorrhage, ventricular hemorrhage, pneumothorax, cerebral edema or brain swelling, brain pool and ventricular pressure displacement deformation, midline structure displacement, etc.. CT review should be performed when the condition changes.
9, MRI Acute craniocerebral injury patients usually do not do MRI examination. However, MRI is often superior to CT scan for diffuse axonal injury, hemispheric base, brainstem, focal contusion foci and small hemorrhage foci, and isodense subacute intracranial hematoma in stable conditions.
Diagnosis
Primary brainstem injury and other cranial injuries often coexist with overlapping clinical symptoms, making differential diagnosis more difficult. The diagnosis of primary brainstem injury is basically established for patients with immediate post-injury coma with progressive worsening, variable pupil size, early onset of respiratory and circulatory failure, presence of decortical tonicity and positive bilateral pathological signs.
Differential diagnosis
Primary brainstem injury is often accompanied by cerebral contusion or intracranial hemorrhage, and the clinical symptoms are so mixed that it is difficult to distinguish which is more important and which is more dominant, especially in patients who present late to the clinic, it is more difficult to distinguish whether the damage is primary or secondary. The difference between primary brainstem injury and secondary brainstem injury lies in the early and late appearance of symptoms and signs. In secondary brainstem injury, the signs and symptoms develop gradually after the injury. Continuous monitoring of intracranial pressure can also differentiate: primary intracranial pressure is not high, while secondary is significantly elevated. Also, CT and MRI are effective tools for differential diagnosis. MRI is significantly better than CT in showing small foci of hemorrhage or contusions in the brain parenchyma, especially for subtle damage to the corpus callosum and brainstem. brainstem auditory evoked potentials can more accurately reflect the plane and extent of brainstem injury. Usually the waves below the focal point of the auditory pathway are normal, while the waves at the level of the focal point and above show abnormalities or disappearance. Continuous intracranial pressure monitoring is also useful to identify primary or secondary brainstem injury, although the clinical manifestations of both are the same, but the intracranial pressure is normal in the primary case and significantly elevated in the secondary case.
Laboratory tests
Lumbar puncture, cerebrospinal fluid pressure is normal or mildly elevated, mostly bloody.
Other auxiliary examinations
1.Cranial X-ray plain film has a high incidence of skull fracture, and the brainstem injury can also be inferred according to the site of fracture, combined with the mechanism of injury.
2.Cranial CT and MRI scans Primary brainstem injury shows brainstem enlargement, somewhat lamellar hyperdense area, interpeduncular pool, pontine pool, tetraspanic pool and fourth ventricle compression or occlusion. MRI can show small foci of hemorrhage and contusions in the brainstem, which are clearer than CT because they are not affected by bony artifacts.
3.Intracranial pressure monitoring can help to identify primary or secondary brainstem injury, and there can be a significant increase in intracranial pressure in secondary cases, but not in primary cases.
4.Brainstem auditory evoked potential (BAEP) is the electrophysiological activity in the auditory pathway of the brainstem, conducted through the cerebral cortex to the far-field potential of the scalp. The electrophysiological activity it reflects is generally not disturbed by other external lesions and can reflect the plane and degree of brainstem injury more accurately.
Treatment options
For severe primary brainstem injury with a long duration of coma, tracheotomy, ventilator-assisted breathing and subhypothermia should be performed as early as possible.
Medication safety
1. regular daily bowel movements.
2.Eat a light diet and soft food.
3.Drink moderate amount of water, test daily urine volume, and test blood pressure.
4, every two to three hours to turn and pat the back; daily washing the whole body with soap and water to prevent bedsores; do massage to prevent muscle atrophy; can do acupuncture-assisted treatment.
5.Nursing attention.
(1) according to the condition to take the appropriate lying position, lying flat with the head turned to the side to avoid vomit accidentally into the trachea, low blood pressure should go to the pillow lying down.
(2) Patients with dentures should remove them to prevent asphyxia caused by dislodged dentures and blocked airways, and prevent biting of the tongue.
(3) Keep the respiratory tract unobstructed. If there is a posterior tongue drop, a ventilator can be placed in the oral cavity and the secretions in the oral cavity can be removed regularly. If the patient coughs and sputum is not easily removed, tracheotomy should be performed early.
Treatment
The treatment of brainstem injury with severe disease is not yet satisfactory. For patients with mild brainstem injury, can be treated according to brain contusion, some patients can get good results, while for the heavy, its mortality is very high, so the rescue work should be careful and serious, to have a long-term plan, and nursing care is particularly important, at the same time, pay close attention to the prevention and treatment of various complications.
1, protection of the central nervous system, hibernation therapy, as appropriate, to reduce brain metabolism; active anti-brain edema; the use of hormones and neurotrophic drugs.
2.Systemic support therapy, maintain nutrition, prevent and correct water and electrolyte disorders.
3.Actively prevent and manage complications, the most common ones are pulmonary infection, urinary tract infection and decubitus ulcer. Strengthen care, close observation, early detection, timely treatment, for patients with serious impairment of consciousness, respiratory disorders, early implementation of tracheotomy to the necessary, but after tracheotomy should strengthen care to reduce the opportunity for infection
4, for secondary brainstem injury should be clearly diagnosed as soon as possible, timely removal of the cause. If delayed too long, the treatment effect is not good.
5, the recovery period should focus on the improvement of brainstem function, available sobriety drugs, hyperbaric oxygen chamber treatment, enhance body resistance and prevention of complications.
Prognosis
Severe brainstem injury has a high mortality rate, accounting for almost 1/3 of the craniocerebral injury mortality rate, and if the medulla oblongata is traumatized, there is little hope for salvation.