Radiation defeats of nervous system
Radiation defeats of nervous system are a group of pathologies of TsNS caused by influence of various forms of ionizing radiation. Symptoms in many respects depend on the absorbed dose and volume of the irradiated fabrics. In clinic astenovegetativny, meningealny and intoksikatsionny syndromes, focal symptomatology, motor and sensitive frustration, their combinations can prevail. Diagnostics is based on the anamnesis, results fizikalny, laboratory, is more rare – hardware methods of a research. During treatment antiemetic, vascular, analgetic, metabolic and haemo static means, plasma substitutes and medicines of blood are applied.
Radiation defeats of nervous system
Radiation defeats of nervous system – rather rare form of the radiation sickness (RS). The low indicator of incidence is caused by small prevalence of potentially dangerous etiologichesky factors and that circumstance that pronounced defeat of nervous system arises only at sublethal and lethal doses of radiation. At the moment in the territory of the former USSR the most significant incidents connected with these pathologies are accidents on the CNPP and nuclear submarines, unforeseen circumstances during the work with radio isotope installations during which, according to statistical data, more than 300 people suffered. The universal indicator is ranging from 20 to 200 cases.
Sharp or chronic impact of ionizing radiation is the cornerstone of an etiology of radiation defeat of nervous system. Radiation can be both external, and internal – at hit of radioactive materials inside with water, food or the inhaled air, is rare – by absorption through integuments. Treat the possible reasons of radiation injury of TsNS:
- Direct work with radioactive materials. The persons working on nuclear power plants in research centers and on the productions using radioactive elements, and also the military scientists developing nuclear weapon enter into risk group.
- Work with the medical equipment. Includes the medical personnel working with computer tomographs and X-ray installations. The probability of development of radiation defeat of TsNS exists at the doctors who are carrying out radiation therapy and cancer patients of the patients needing similar treatment.
- Stay in the infected area. Include people who voluntarily or when performing professional duties stay in the territory with the raised radiation background – in zones of tests of nuclear weapon, technogenic catastrophes with participation of radioactive elements in this category.
Primary changes at radiation defeat of TsNS in a dose to 50 Gr are observed in synapses, are presented by "adhesion" of the mediator bubbles which are in terminal departments of a presynaptic membrane or in a synoptic crack. Then there is a swelling of cages of nervous system, pycnosis of cerebellar granular cages. In some cases these changes are combined with vaskulita, meningitis, an inflammation of a vascular texture of ventricles of a brain and infiltration by granulocytes. Radiation of a brain in a dose from 10 to 30 Gr conducts to inhibition of processes of oxidizing phosphorylation. Possibly, it is caused by an acute shortage of ATP which at LB is spent for processes of a reparation of the damaged DNA.
One-stage radiation of nervous system in the dose exceeding 50 Gr makes the direct destroying impact on neurons. Such dose causes a large number of damages of nuclear chromatin and excess activation of the enzymes which are responsible for DNA reparation. DNK-ligaznye the reactions proceeding in similar conditions are characterized by disintegration of ATP to ADF which, in turn, together with enzyme ADF-transferase leads to bystry use of all intracellular stock of NAD+. The last normal plays a coenzyme role in the course of cellular respiration, disintegration of glucose and the return synthesis of ATP.
After radiation defeat in structures of the central nervous system signs of the general hemorrhagic syndrome appear. Morphological characteristics of process include venous stagnation and restretchings of arterial vessels provoking a plasma exit out of borders of the blood course, lacunary or extensive hemorrhages in a brain. In the TsNS parenchymatous fabrics there are inflammatory and dystrophic-nekrobiotichesky processes. According to some scientists, one of the leading roles in development of defeat of nervous system is played by dysfunction of a hematoencephalic barrier owing to dying off of endoteliotsit of brain blood vessels.
Symptoms of defeat of NANOSECOND
Symptoms of dysfunction of nervous system occupy an essential share in symptomatology of radiation sickness only on condition of one-stage receiving a dose of ionizing radiation more than 50 Gr or local radiation of area of the head. In other situations they are combined with other somatic manifestations, depend on a dose and time which passed from the moment of influence. At LB of easy and average degree (a dose – to 4 Gr) in a clinical picture asthenic and neurovisceral symptoms prevail. At a severe form of LB (from 4-6 Gr above) in the neurologic status all-brain symptoms, a meningealny syndrome are defined, is more rare – focal symptomatology, an incoordination.
- At a stage of primary reaction at most of patients the general weakness, increased fatigue, apathy, a headache, dizziness, sleeplessness, diarrhea, nausea and vomiting is noted, is more rare – spasms. At some patients morbidity at a palpation of trigeminalny and vascular points comes to light. All above described manifestations are formed in an interval of 10 minutes till 1 o'clock from the moment of defeat. Degree of their expressiveness and speed of emergence directly are defined by a radiation dose.
- The second period – latent or "imaginary wellbeing". In it reduction of intensity of primary symptoms without their total disappearance is observed.
- The third stage – a heat. It is followed by sharp strengthening of neurologic deficiency, formation of hypostasis of a brain, scattered symptomatology of violations of TsNS. Clinically is followed by a horizontal nistagm, an anizorefleksiya, emergence of pathological-foot and subkortikalny reflexes, disorders of functions of craniocereberal nerves, dystonia of skeletal muscles, koordinatorny violations. Often this simptomokompleks is combined with vegetative dysfunction: fluctuations of arterial pressure and body temperature, gipergidrozy, gipersalivatsiy.
- The last stage – restoration or the resistant residual phenomena – is characterized by extremely slow improvement of the general condition of the patient, disappearance of neurologic and intoksikatsionny symptomatology at preservation of vegetososudisty frustration and an asthenic syndrome.
One of typical forms of a disease can prevail. The radiation adynamy imitates neurosis symptoms, is shown by weakness, excessive irritability, appetite loss, nausea, is more rare – dizziness, euphoria. In the heat period the hyper reflection, muscular hypotonia, a tremor a century, language and the top extremities can join them. The Meningealny syndrome is observed at patients with severe forms of radiation sickness. At it unstable specific symptoms of Kerniga and Brudzinsky, hypotonia of skeletal muscles are noted. The coma form develops when involving in pathological process of the vital structures, differs in sudden emergence of feeling of "burning" of all body with the subsequent loss of consciousness, cardiovascular and respiratory insufficiency.
The radiation entsefalomiyelopatiya can have sharp or chronic character. In the first case pathology debuts an atactic syndrome because of what there is a confusion of consciousness, pronounced meningealny signs. Characteristic – existence of the focal symptomatology which is defined by localization of destruction in TsNS. The sudden losses of consciousness, repeated vomiting, paresis and paralyzes which are combined with a hemorrhagic syndrome and gastroenterokolity are possible. The chronic option of this entsefalomiyelopatiya can be followed by the similar symptoms which are formed throughout a long time.
Syndrome of radiation and toxic encephalopathy
This form is often noted in the period of a heat and can have various clinical forms. Liquorodynamic differs in changeable all-brain symptomatology, focal symptoms and cognitive frustration. The Gipertenzionny option is shown by the accruing tsefalgiya (in certain cases – up to vomiting), an obolochechny syndrome, decrease in reflexes, psychomotor excitement. At an epileptic form there are attacks of toniko-clonic or clonic spasms, . Psychotic radiation encephalopathy is characterized by violation of orientation in time and space, visual and acoustical hallucinations, a catatonic stupor.
Beam neuralgia develops at local damage of separate peripheral nerves. Often it is combined with an eritematozny or bullous dermatosis. Typical manifestations – paresteziya as an itch, sleeps, the burnings and pains having jet or spontaneous character. Gipesteziya, dryness of skin, local are observed, an alopetion, it is rare – hypostases. The radiation polyneuropathy is result of radiation of nervous textures and is combined with a necrosis of skin, hypodermic fatty cellulose, muscles and fastion. Neurologic this form is followed by difficult stopped local pain syndrome, a gipesteziya or anesthesia, muscular atrophies, hyporeflections or arefleksiya, vegetative dysfunction in the field of an innervation of the affected nerves.
In 1-2 months after focal radiation of the head there can be early radiation encephalopathy. Clinically it imitates development of new growths of a brain then spontaneously regresses. 1-2 years later after passing of radiation therapy formation of a late beam necrosis can be observed. Its symptoms often repeat clinic of a disease in connection with which X-ray therapy was carried out. Through 6 months – 1 year emergence of symptoms of the cerebral atrophy which is followed by cognitive frustration, violation of functions of pelvic bodies, walking and other displays of normotenzivny hydrocephaly is probable.
At radiation of area of a neck the miyelopatiya which are shown Lermitt's symptom, Broun-Sekar's syndrome come to light. Defeat of lumbar and sacral department of a backbone is characterized by a syndrome of a motor neuron: fastsikulyation, muscular atrophies, sluggish paralyzes of the innervated areas. The remote complications which are observed years or decades later are dysfunctions thyroid and gonads, a hypothalamus, TsNS new growth (a glioma, sarcoma, a shvannoma, a meningioma), occlusions of arteries of a brain. The last become the reasons of the tranzitorny ischemic attacks, strokes.
Diagnostics and inspection
Diagnosis of defeat of nervous system at LB is carried out mainly on the basis of data of the anamnesis and objective inspection. Resort to use of radiological techniques only according to vital indications as they are capable to aggravate the course of radiation defeat. The major aspect is establishment of the fact of impact of radiation on an organism. The full program of inspection includes the following items:
- Fizikalny research. At the general survey vital functions, a condition of integuments, existence of trophic changes and fastsikulyation are estimated, muscular atrophies, morbidity of these or those parts of the body are defined. When studying the neurologic status the doctor focuses attention to functions of cranial nerves, the muscular force and a tone, volume of active movements, a tone of tendinous and periostalny reflexes, existence of pathological reflexes, sites of a gipesteziya or anesthesia.
- Laboratory tests. In the general blood test it is noted neytrofilny with a limfopeniya which are replaced by a leykopeniya, a neytropeniya, thrombocytopenia, an anemichesky syndrome, anizotsitozy and poykilotsitozy, sharp increase in SOE. Later in OAK megalotsita, megaloblasta, toxic granularity of neutrophils, and pan-cytosinging can come to light. Level of leukocytes is in direct dependence on weight of radiation injury.
- Neurovisualization. KT or MRT of a head and spinal cord are applied for the purpose of differential diagnostics with other potential defeats of TsNS at impossibility to establish the diagnosis in other way. Techniques are also informative in cases with brain atrophies as they allow to reveal expansion of ventricles, , solderings of a web cover. In need of assessment of level of metabolism of glucose in TsNS apply PET-KT.
Treatment of radiation defeat of NANOSECOND
The basic principles of treatment of this pathology are early knocking over of neurologic symptomatology, prevention of secondary complications, complexity of treatment taking into account a stage of development of pathology. Use of various therapeutic approaches depending on the place and time, since the radiation moment is recommended. Thus, it is accepted to allocate the following stages of delivery of health care:
- Pre-medical and first aid. Consist of evacuation of the patient from a zone of radiation pollution, primary sanitary processing of affected areas of a body, introduction of antiemetic and cardiovascular medicines, analgetics, tranquilizers, anticonvulsive and other symptomatic means, restoration of OTsK.
- Medical stationary care. Means correction and addition of treatment of the previous stage. On the basis of results of laboratory analyses antibiotics of a broad spectrum of activity, diuretic, haemo statics, plasma substitutes, solutions for correction of an electrolytic range of blood can be appointed.
- Specialized help. It is carried out throughout the entire period of radiation sickness. Taking into account a condition of the patient transfusion of uniform elements of blood and plasma, correction of violations of stem functions can be carried out. If necessary antibiotics, narcotic analgetics, neurometabolites and vitamins of group B are used.
- Restoration period. It is presented by the physiotherapeutic procedures directed to elimination of the residual phenomena, normalization of blood supply and metabolism of TsNS. Includes different types of massage, physiotherapy exercises, magnetotherapy, sanatorium treatment.
Forecast and prevention
The forecast at LB depends on the level of the received dose, efficiency of the carried-out treatment and presence at the patient of the burdening factors: arterial hypertension, diabetes, other endokrinopatiya. In hard cases when receiving ultrahigh doses so-called "death under a beam" develops. Prevention of pathology is based on a complete elimination or normalization of conditions of radiation: observance of the recommended duration of the working day and rules of protection (shielding, individual dosimeters), annual passing of medical commission with suitability assessment to the related professional activity. In emergencies the emergency chemoprophylaxis is applied.