Brain injury is a type of traumatic brain injury accompanied by limited morphological changes in cerebral tissues. It is manifested by loss of consciousness, amnesia, vomiting, dizziness, anisocoria, various focal symptoms, meningeal symptom complex, changes in cardiac and respiratory rhythm. The main diagnostic method is CT of the brain. Conservative treatment: correction of vital functions, normalization of intracranial pressure, neuroprotective therapy. Surgical treatment is carried out strictly according to indications, including trepanation of the skull, decompression and removal of contusion foci.
General information
Brain injury (BI) accounts for about 25-30% of all traumatic brain injuries (TBI). The difference between brain injury and concussion is the presence of morphological post-traumatic changes in cerebral tissues. There are three degrees of injury severity. The first, along with concussion of the brain, refers to mild TBI, the second — to moderate TBI, the third — to severe TBI. Assessment of the severity of the injury is carried out according to the degree of disorders of consciousness, the severity of the victim’s condition, the severity of neurological deficit, and tomographic studies. According to statistics, in the USA, brain injury is distributed by severity as follows: mild — 33%, moderate — 49%, severe — 18%.
Brain injury is 2-3 times more common in males. According to various data, alcohol intoxication of the victim is detected in 5-20% of cases of this type of TBI. Currently, severe brain injury is one of the leading causes of mortality and disability among people under the age of 45. In this regard, the timeliness of diagnosis and the search for optimal ways to treat BI are priorities of traumatology, neurosurgery, neurology and rehabilitation.
Causes
Brain injury is possible as a result of a transport accident, professional, domestic, criminal or sports injury. In preschool age, BI is mainly caused by various kinds of falls. Brain injury can occur when patients suddenly fall during a paroxysm of epilepsy or a drop attack. BI is often accompanied by a skull fracture, in half of cases — intracranial bleeding (subarachnoid hemorrhage, formation of subdural or intracerebral hematoma).
The pathophysiology of BI includes primary and secondary damage. Primary damage occurs directly during trauma and is caused by the displacement of the brain in the cranium, the displacement of the hemispheres relative to the brain stem, hydrodynamic factor. As a result, there are structural damage to neurons and glial cells, ruptures of synaptic connections, vascular damage and thrombosis. The foci of BI can have a single and multiple character, are localized not only in the impact zone, but also in the area of shock. Secondary damage is a consequence of destructive metabolic processes initiated by primary damage. Aseptic inflammation and edema develop in the area of the injury, blood circulation and metabolism of neurons are disrupted. All this leads to the expansion of the injury zone. The outcome of primary and secondary damage is neuron necrosis, which causes the occurrence of neurological deficit.
Symptoms
Mild BI is accompanied by loss of consciousness for up to tens of minutes. Then there is moderate deafness, drowsiness, there may be incomplete orientation in time and in the environment. The victims complain of constant cephalgia (headache), weakness, nausea, dizziness. Vomiting that does not give relief is noted, possibly multiple. Amnesia is observed: the patient does not remember the events preceding the TBI (retrograde amnesia) and for some time after the injury cannot remember what is happening to him (anterograde amnesia). Tachycardia or, conversely, bradycardia often develops, less often arterial hypertension.
In neurological status: anisocoria, nystagmus, asymmetry of tendon reflexes, unexpressed meningeal symptom complex, there may be mild hemiparesis. When BI is accompanied by subarachnoid hemorrhage, the meningeal symptom complex is pronounced. With a mild degree of injury, all these manifestations regress in the period from 2 to 3 weeks.
BI of moderate degree is manifested by unconsciousness for tens of minutes to 4-5 hours . When consciousness is restored, intense cephalgia, repeated vomiting, con-, antero- and retrograde amnesia are observed. Amnesia, moderate or deep deafness and disorientation can persist for up to several days. Mental abnormalities are possible. Often there is subfebrility, bradycardia or tachycardia, hypertension, rapid breathing. In the neurological status, focal symptoms are detected, varying depending on the localization of the injury zone. As a rule, there are various severity of hemiparesis and hemihypesthesia, speech disorders (motor aphasia), anisocoria and oculomotor disorders. Usually, these symptoms gradually disappear 4-6 weeks after TBI.
Severe BI is characterized by a longer duration of unconsciousness (up to several weeks). Motor arousal often takes place. Severe brain injury occurs with dysfunction of vital systems: arterial hypotension or hypertension, tachyarrhythmia or bradyarrhythmia, violation of the respiratory rhythm against the background of tachypnea. In the initial period after TBI, stem symptoms dominate: tonic nystagmus, bilateral ptosis and mydriasis, decerebration rigidity, dysphagia, bilateral foot pathological reflexes, symmetrical hypo- or hyperreflexia. Against this background, signs of damage to the hemispheres are revealed: hemiparesis, hemihypesthesia, oral automatism, etc. Possible hyperthermia up to 41 ° C, convulsive paroxysms. Neurological symptoms have a long course and do not fully regress. Mental and/or neurological changes of varying severity remain as persistent residual consequences of TBI.
Diagnostics
The main method of diagnosis of BI in modern conditions is CT of the brain. The tomographic picture differs depending on the severity of the injury. With a mild degree, foci with reduced density are detected only in 40-50% of cases. In the area of the injury, swelling and petechial hemorrhages are noted on tomograms. Swelling can spread to the entire lobe of the brain or even to the whole hemisphere, leading to a moderate narrowing of the cevrebrospinal spaces.
A moderate injury is characterized by the presence of injury foci on tomograms in the form of zones of reduced density. With hemorrhagic impregnation, the injury focus may have an increased density. In case of severe injury, tomography visualizes foci of both increased and decreased density. In the first case, we are talking about blood clots, in the second — about areas of crushing and edema. In extremely severe lesions, the zone of destruction of cerebral tissue goes deep into the subcortical structures.
During treatment, CT is also carried out in dynamics. Observations show that in the case of mild or moderate injury, the focal changes disappear completely over time. In the case of severe BI, there is a decrease in the area of foci of destruction, and then their transformation into brain cysts or areas of atrophy. The more severe the TBI, the more slowly these changes, visualized by CT, pass.
Treatment
A brain injury is an unambiguous indication for hospitalization of the victim. Treatment is carried out by neurologists and neurosurgeons, and then rehabilitologists. Conservative therapy includes, first of all, normalization of vital functions: correction of hemodynamics with constant monitoring of blood pressure, respiratory support, monitoring and correction of intracranial pressure (furosemide, acetazolamide, mannitol). Neuroprotective treatment (erythropoietin, citicoline, progesterone, statins) and symptomatic therapy (correction of hyperthermia, anticonvulsant therapy, headache relief, antiemetics, etc.) are carried out.
Surgical treatment is carried out in 15-20% of BI. It is indicated in the development of compression of the brain and dislocation syndrome, in the presence of a crushing hearth with a volume of more than 30 cm3, a hearth with a volume of 20-30 cm3 with a mass effect and displacement of median structures of more than 5 mm, or in the presence of smaller foci accompanied by progressive aggravation of neurological symptoms.
The operation is performed by trepanation of the skull. In the presence of a volumetric center of crushing, its removal is performed. Bone-plastic trepanation of the skull is carried out, in which, after removal of the focus, bone and skin-aponeurotic flaps are installed in place. With high figures of intracranial pressure, the operation is supplemented with decompression trepanation of the skull. If the foci of crushing have a small volume, but are accompanied by pronounced swelling of the brain tissues, decompression trepanation is indicated without removing the foci.
Forecast
The consequences of BI can be posttraumatic hydrocephalus; local cerebral atrophy; the formation of subdural hygroma, chronic subdural hematoma, posttraumatic cerebral cyst; the occurrence of posttraumatic arachnoiditis, shell-brain adhesions, leading to epilepsy or various forms of psychopathy. In the distant future, a brain injury may cause the development of Parkinson’s disease or Alzheimer’s disease.
Mild BI usually has a favorable outcome with full recovery of neurological and mental functions. BI of moderate severity with timely and adequate treatment also leads to recovery. After it, hydrocephalus, vegetative-vascular dystonia, asthenia, a slight violation of coordination of movements can be observed. Severe BI leads to death in about 30% of cases. There is a large percentage of disabled people among the survivors. The main causes of disability are: epilepsy, mental disorders, paresis and paralysis, speech disorders.