Locked-in syndrome is a severe neurological disease in which the patient loses the ability to move, talk, express emotions, but he retains consciousness, cognitive functions and sensory perception. The condition occurs as a complication of stroke, traumatic brain injury, tumor or degenerative lesion of the ventral bridge area. For diagnostic purposes, neurological status assessment, neuroimaging (CT, MRI, PET), electroencephalography are performed. Treatment includes medical care and correction of vital functions, lifelong rehabilitation, the use of neurocomputer technologies.
ICD 10
G83.5 Locked-in syndrome
General information
The “locked-in person” syndrome is extremely rare, today only 44 cases have been studied in detail. In the medical literature, pathology has many names: “locked-in”, “closure” syndrome, “locked-in” syndrome. For the first time, the characteristic clinical manifestations were described by scientists I. Plumm and J. Posher in 1966. Despite the rare occurrence, the condition does not lose relevance in modern neurology, which is explained not only by physical limitations, but also by forced isolation from the outside world, the lack of adequate means of communication.
Causes
The disease has a polyethological nature and can be caused by any severe organic lesions of the brain stem, which are irreversible, accompanied by the destruction of nerve fibers of the pathways. The most common neurological causes of the locked-in syndrome are grouped into several groups:
- Strokes. Pathology develops both in ischemic stroke due to occlusion in the vertebrobasilar basin, and in hemorrhagic variant on the background of hemorrhage in the bridge.
- Traumatic brain injuries. The disease is provoked by severe brain bruises with the predominant application of force along the vertebrobasilar axis.
- Neoplasms. With the infiltrative growth of malignant tumors in the ventral parts of the bridge, there is a possibility of irreversible damage to the motor nerve pathways.
- Degenerative processes. The disease of the “locked person” occasionally appears in multiple sclerosis, if the focus of demyelination is located in the stem zone of the brain. Rare etiological factors include pontine myelinolysis.
- Neuroinfections. Among the causal causes are abscesses or inflammatory infiltrates in severe forms of encephalitis, if they are localized in the pontine part of the central nervous system.
Pathogenesis
The pathomorphological basis of the “locked man” syndrome is the cerebromedullary block. It occurs when corticonuclear (corticobulbar) pathways are affected, which depart from the nuclei of cranial nerves, and corticospinal fibers that transmit impulses from the brain to the spinal cord. A characteristic feature of the disease is the preservation of the structures of the tire, the reticular formation, so the “locked person” remains conscious.
During autopsy, bilateral softening of the ventral bridge zone is often determined, there may be cysts as a result of the organization of intracerebral hemorrhage. Occasionally, an organic lesion spreads to the ventral surface of the midbrain. Microscopically, there is swelling of the axons of the conductive pathways with their secondary degeneration, which is the leading mechanism of axonal transport disruption.
Classification
More often, the disease has a progressive character, but based on the characteristics of the clinical course, stable and transient variants of the condition are also distinguished. Modern neurologists use the classification proposed by Bauer, according to which 3 forms of the “locked—in person” syndrome are distinguished:
- Complete (total) – immobility of the patient, the absence of any arbitrary reactions, including blinking.
- Classic — the absence of arbitrary body movements while maintaining blinking, eye movements up and down.
- Incomplete — in addition to the mobility of the eyeballs, there are several more arbitrary movements, which are determined by the severity of damage to the central nervous system.
Symptoms
One of the main signs of the disease is central tetraparesis — lack of mobility in all four limbs, which may initially occur as hemiparesis with subsequent spread to the second half of the body. Tetraparesis is joined by a lesion of the cranial nerves, which is manifested by the inability to speak, swallow, and demonstrate facial expressions. Most patients develop paresis of the horizontal gaze.
An important differential diagnostic feature is the preservation of consciousness, higher mental functions, as a result of which the patient continues to be aware of his condition, understands the speech addressed to him, although he cannot give a verbal answer. The ability to feel touch and pain stimuli is also not impaired. The only possible communication in such a situation is blinking, eye movements up and down.
The features of the clinical picture are determined by the root cause of the disease. With ischemic brain lesions, the disease is often accompanied by precursors in the form of numbness of the extremities, transient diplopia, bulbar disorders. In most cases, the condition develops “stepwise” with a gradual increase in symptoms within 24 hours. With TBI as the cause of the “locked inside” syndrome, there are visible head injuries indicating trauma.
Complications
The main problem of the “locked person” syndrome is the inability to socialize the patient, because of which he experiences no less suffering than from physical limitations. At an early stage of the disease, even before the diagnosis, doctors may mistake locked-in syndrome for a coma, freely discuss unpleasant medical moments with the patient, further aggravating the severity of his emotional state.
With early diagnosis and the absence of somatic diseases, life expectancy decreases moderately. Retrospective studies have established a 5- and 10-year survival rate of 83%, and a 20-year survival rate of 40%. In the absence of comprehensive medical and social support, the results deteriorate, so about 27% of patients could not restore a single voluntary movement, 51% of patients could not establish communication independent of eye movements.
Diagnostics
The diagnosis of the “locked person” syndrome is based on the assessment of symptoms, the detection of the function of blinking and eye movement, the patient’s willingness to communicate in this way. A differential diagnosis of pathology with coma, vegetative state, akinetic mutism is required from a neurologist. To make a correct diagnosis, the results of instrumental studies are necessary:
- CT of the brain. Neuroimaging is used to detect hemorrhages, heart attacks or tumors of the corresponding part of the brain. In case of insufficient information content, the method is supplemented by MRI.
- EEG. According to the electroencephalogram, a normal reactive bioelectric rhythm is determined, which is typical for the “locked-in person” syndrome, but not typical for comatose states.
- PET of the brain. The diagnostic method is used to visualize the metabolic activity of the neural tissue, demonstrates its normal level, which indicates the integrity of the remaining structures of the central nervous system.
Treatment
At the initial stage, non-specific therapy is carried out, aimed at correcting vital functions, preventing early complications. The patient is connected to an artificial lung ventilation system, a gastrostomy is installed for nutrition, and placed on a special medical bed for the prevention of bedsores. After stabilization of the condition, lifelong rehabilitation begins, including the following areas:
- Drug therapy. Neuroprotectors, neurometabolic drugs, vitamin and mineral complexes are prescribed to improve trophic nervous tissue, increase its resistance to hypoxia. Anticoagulants and antiplatelet agents are recommended for lesions of cerebral vessels.
- Non-drug methods. There is a chance to partially restore motor functions with the help of electromyostimulation, kinesiotherapy, massage. If necessary, orthopedic correction is carried out, special wheelchairs are used to facilitate the movement of patients.
- Special training. A simple and accessible way for a person to communicate with doctors and relatives is to use eye signals: up and down movements, blinking. Less often, communication is carried out using a board with an alphabet so that the patient can indicate the necessary letters with his eyes.
- Neurocomputer technologies. To facilitate communication, devices with special software have been developed that read information from nerve impulses and transmit it to an electronic device.
According to the indications, neurosurgeons are connected to the treatment. Brain surgery may be required for drainage of abscesses and evacuation of hematomas that compress the area of the bridge, excision of neoplasms, if technically possible, elimination of circulatory disorders. The decision on the need for surgical treatment is made taking into account the causes of the “locked person” syndrome, the general condition of the patient.
Prognosis and prevention
Life expectancy directly depends on the completeness of medical care, proper support from loved ones. After confirmation of the diagnosis, patients live an average of 10-20 years, however, with vascular causes of the disease, the presence of somatic pathologies, the fatal outcome occurs much earlier. A higher probability of partial recovery of motor functions in young people, if the cause of the condition was a traumatic brain injury.
The only possible primary prevention of the syndrome is the timely detection and treatment of neurological diseases (strokes, TBI) in order to prevent extensive irreversible damage to the central nervous system. Secondary and tertiary prevention consists in timely comprehensive rehabilitation of patients, their maximum possible socialization, provision of electronic devices to maintain communication with the outside world.
