Decerebration syndrome corresponds to a disruption of the brainstem and neocortex, which can vary in severity. In addition to disturbances in waking consciousness, sensory and motor disturbances present. Treatment depends on the primary cause and, in the case of inflammation, corresponds, for example, to anti-inflammatory drug administration followed by rehabilitation.
What is decerebration syndrome?
The brainstem lies just below the so-called neocortex. This is a motor and multisensory portion of the cerebral cortex common to all mammals. Between the brainstem and the neocortex lies a medullary layer, which is referred to by physicians as the white matter. It consists of glial cells and myelinated nerve fibers. Myelin is the insulating substance of nerve tissue. Without an insulating myelin sheath, the individual excitation pathways would lose excitation potential to the surrounding area. Action potentials could thus not reach their destination in the brain without losses. The neocortex and the underlying medullary canal together form the so-called neopallium. Decerebration syndromes are the term used for demyelinating diseases that sever the connection between the neocortex and the brainstem. Functional decoupling of the brainstem and neocortex usually results in a variety of motor, sensory, and consciousness disorders. Depending on the severity of the damage, coma may occur. Decerebration syndrome is often referred to as entrainment syndrome.
Causes
Causes of decerebration syndromes are many. The most common cause of decerebration is inflammation of the brain, which can be caused by autoimmune diseases such as multiple sclerosis. However, bacterial infections can also cause inflammation that results in decerebration syndrome. In addition to inflammatory processes, poisoning can also result in a decline of myelin, thus breaking the connection between the neocortex and brainstem. Decerebration syndromes have also been reported after mechanically severe brain injury. An additional cause may be hypoxia. Depending on the exact location of the disruption, neurologists differentiate decerebration syndrome into different variants. For example, decerebration rigidity is present when the neocortex and brainstem are interrupted between the nucleus ruber and Deiters nucleus. In rare cases, brain tumors cause interruptions between the neocortex and brainstem.
Symptoms, complaints, and signs
Patients with decerebration syndrome present with different symptoms depending on the location and severity of the interruption. In addition to loss of consciousness and paralysis, disorders of eye movement and autonomic dysfunction may be characteristic. Disturbances of waking consciousness occur in varying degrees depending on the site of damage and the stage of progression. There may be sopor with reduced reactivity to stimuli. The loss of waking consciousness can extend to a deep coma from which the affected person can no longer be awakened. In particularly severe cases of decerebration syndrome, there is talk of an apallic syndrome. In this clinical picture, the unconscious patient has his or her eyes open and responds to stimuli, but can no longer access any cerebral functions. For this reason, the affected person directs his or her gaze into the void instead of fixating on persons or objects. Reflexes such as the cough and gag reflex remain intact because they are subject to control by the brainstem. The affected person’s sleep-wake rhythm is also unaffected by the clinical picture.
Diagnosis and course
Neurologists diagnose decerebration syndrome by clinical symptoms and imaging of the brain. Slice imaging reveals clearly identifiable lesions between the neocortex and brainstem, which manifest clinically as decerebration of the two structures. Fine diagnosis involves determining the severity and differentiation from or assignment to specific subtypes such as apallic syndrome, locked-in syndrome, or decerebrate rigidity. The prognosis for patients with deterebration syndrome depends on the primary cause and the extent of the lesions. In some cases, symptoms are entirely reversible. If the state of coma occurs, a less favorable prognosis applies. Nevertheless, decerebration syndrome is not equivalent to brain death.
Complications
Complications from decerebration syndrome depend on the cause of the syndrome. In the worst cases, they can lead to severe disabilities and motor disorders that limit the patient’s life and daily routine. Disturbances of consciousness also occur, and the patient may fall into a coma in the worst case. In the case of a disturbance of waking consciousness, the affected person can no longer move his eyes or communicate with other people. The paralysis can also spread to other regions of the body and cause pain there as well. Although the movement and fixation of the eyes is disturbed, the patient can still sleep with his eyes closed. Decerebration syndrome also affects family members in the form of psychological discomfort and depression, and can place a heavy burden on their lives. Treatment of decerebration syndrome is causal and depends on the underlying disease. In most cases, this takes place with the help of antibiotics. Tumors can be surgically removed. However, further complications depend on the spread of the cancer. In many cases, life expectancy is reduced by decerebration syndrome.
When should you see a doctor?
Because decerebration syndrome can lead to irreversible sequelae in the patient, treatment is definitely necessary. The affected person must see a doctor immediately if there are paralyses in various parts of the body that occur without any particular reason and also do not disappear on their own. Also after an accident these disturbances of the sensibility can occur, which must be examined in any case. Furthermore, a loss of consciousness can also indicate this disease. If there is a loss of consciousness, an emergency physician should be called. As a rule, however, patients with decerebration syndrome are in a coma, so that they are dependent on an inpatient stay in a hospital. A doctor should also be consulted in case of sleep complaints related to a negative influence on reflexes. Several tests are usually necessary to diagnose decerebration syndrome. A general practitioner may order them or identify initial indications of the disease. Whether treatment is possible in the process cannot be universally predicted.
Treatment and therapy
Treatment of patients with decerebration syndrome depends on the primary cause of injury. Acute inflammation is initially treated with medication to limit the damage. In the autoimmune disease multiple sclerosis, cortisone is given to contain an acute flare. In cases of intolerance, autoimmune inflammation can be contained by plasmapheresis, which removes autoantibodies from the blood. It is also imperative that bacterial inflammation be contained to prevent it from assuming life-threatening proportions. Drug treatment in this case depends on the pathogen, but often includes the administration of penicillin. Antibiotic treatments have often been combined with high-cortisone treatments by neurologists since the recent past, as cortisone is the only anti-inflammatory drug that can cross the blood-brain barrier. If the decerebration syndrome is not related to inflammation but to a tumor, the causative treatment is excision. If the tumor is inoperable, noninvasive measures are used to shrink the lump. Mechanical damage and brain damage due to lack of oxygen cannot be treated causally. The only treatment option in this case is rehabilitation, which also follows the acute phase of inflammation and tumors. Depending on the severity of the entrainment syndrome, intensive medical treatment may be required. In such a case, a tracheotomy is performed, through which the patient can be connected to a ventilator. In addition, a feeding tube may be required.
Outlook and prognosis
Recovery from deterebration syndrome must be evaluated on an individual basis. There is a possibility of complete recovery in some patients. Others suffer lifelong impairment. The primary cause and existing underlying disease are largely responsible for the prognosis of the disease. The extent of the lesions present and their treatability must be assessed in order to evaluate relief from deterebration syndrome.Some patients receive a favorable prognosis. In them, there is complete regression of symptoms. The lesions are only mild and do not trigger permanent tissue damage in the brain. Once they minimize, relief of symptoms occurs. If the patient falls into a comatose state, the prognosis worsens considerably. No cure for deterebration syndrome is likely to occur. In addition, however, there may be further impairment or sequelae. Brain damage suffered is often not treatable at all or is difficult to treat. Particularly unfavorable are brain damages that have occurred due to a lack of oxygen. They are often irreparable. Cognitive losses or dysfunctions of individual systems occur. In the case of an unfavorable prognosis, the patient requires lifelong care and is unable to go about his or her daily life independently. In addition, artificial respiration or nutrition may be required.
Prevention
The entrainment syndrome can be prevented only to the extent that its causes can be prevented. Because a wide variety of processes can cause functional disruption of the brainstem and neocortex, no promising preventive measures exist. At best, traumatically severe brain damage in the context of an accident can be prevented in moderation.
Aftercare
In decerebration syndrome, the focus is usually on early detection and treatment of this condition so that further complications or, in the worst case, death of the affected person can be prevented. Measures of aftercare are very limited in this disease, so that the affected person is primarily dependent on treatment by a physician. The earlier the treatment of the decerebration syndrome is initiated, the better the further course of this complaint usually is. Self-healing cannot occur with this syndrome, so treatment is necessary in any case. The treatment itself is usually carried out with the help of medications that can alleviate the symptoms. The patient should follow the doctor’s instructions. In many cases, it is also necessary to take antibiotics, and alcohol should be avoided completely during the course of treatment. In many cases, the antibiotics must be taken for several days even after the symptoms have disappeared. Furthermore, regular examinations of the body should take place in order to detect tumors possibly at an early stage. Possibly, the decerebration syndrome thereby reduces the life expectancy of the affected person.
What you can do yourself
In addition to a serious accident, inflammatory and bacterial disease-related processes, as well as autoimmune diseases, multiple sclerosis, cancer and poisoning, such as after a toxic suicide attempt, can also trigger decerebration syndrome at any time. Therefore, sufferers need to be aware of the cause in order to be able to self-help as much as possible in their daily lives. A clean hygienic environment as well as a sensible diet and taking prescribed medication are important components in maintaining one’s level of living for the time being. Provided that the affected person can be treated with medication, he should seek rehabilitation and adjust his lifestyle habits. The immediate renunciation of cigarettes, alcohol and drugs is inevitable and serves the self-help. Likewise, if the patient is overweight, his diet should be reconsidered and changed. As long as it is possible for the patient, he or she can do quiet training such as Tai-Chi, yoga or light gymnastics. Rather more difficult to cope with as the syndrome progresses is the permanent risk of falling into a vegetative state, especially for patients living alone. It is advisable to seek assisted living, especially since the course of the disease leads to considerable disabilities in the cognitive and motor areas. Due to the loss of movement and increasing pain, severe depressive episodes occur. Affected persons should therefore seek therapeutic measures and supportive assistance in everyday life in good time, also for the immediate family.
