Encephalopathy

Encephalopathy is a generalizing name for pathological processes that are diverse in their genesis, the basis of which is the degeneration of brain neurons due to a violation of their metabolism. Encephalopathy is manifested by polymorphic neurological disorders, disorders in the intellectual-mnestic and emotional-volitional sphere. The diagnostic search consists of a comprehensive neurological examination and the establishment of causal pathology. Treatment of encephalopathy is reduced to eliminating the pathological condition that caused it, treating the causal disease and maintaining optimal metabolism of cerebral neurons.

ICD 10

G93.4 Unspecified encephalopathy

General information

Encephalopathy is a complex concept that combines numerous syndromes of diffuse cerebral lesion, which is based on dysmetabolism and neuronal death. The idea of combining polyetiological cerebral diseases into one group arose due to the commonality of their pathogenesis and morphological changes. The term is formed by merging the Greek words “encephalon” – brain and “pathos” – disease. Encephalopathy includes 2 groups of diseases: perinatal and acquired encephalopathy.

The concept of perinatal encephalopathy was introduced in 1976 and implies cerebral lesions that occur during the period from the 28th week of pregnancy to the 7th day of life. Perinatal encephalopathy manifests in children of the first months of life. Acquired encephalopathy has a secondary character and is noted mainly in adults, more often in middle-aged and elderly people, in the presence of severe chronic diseases, after injuries, intoxication, etc. Encephalopathy is an interdisciplinary pathology that, in accordance with the etiology, requires attention from specialists in the field of neurology, pediatrics, traumatology, narcology, toxicology, urology.

Causes

Perinatal encephalopathy

Trigger factors, as a result of which perinatal encephalopathy may occur, include:

• fetal hypoxia;
• intrauterine infections and intoxication;
• rhesus conflict;
• asphyxia of a newborn;
• birth trauma;
• genetically determined metabolic disorders and developmental abnormalities (for example, congenital heart defects).

The risk of perinatal pathology increases with anomalies of labor, a large fetus, premature birth and prematurity of the newborn, a narrow pelvis, entanglement with the umbilical cord.

Acquired encephalopathy

The acquired form of pathology can develop due to:

• suffered a traumatic brain injury;
• effects of ionizing radiation;
• intoxication with neurotropic chemical (ethyl alcohol, lead, chloroform, drugs, barbiturates) and bacterial (with diphtheria, tetanus, botulism, etc.) toxins;
• vascular disorders: atherosclerosis, arterial hypertension, venous dyscirculation, cerebral vascular angiopathy in amylomidosis, leading to chronic cerebral ischemia;
• complications of various diseases of internal organs: acute pancreatitis, acute and chronic renal failure, liver cirrhosis and liver failure;
• lung diseases leading to pulmonary ventilation disorder (pulmonary tuberculosis, lung abscess, bronchiectatic disease, PE). Encephalopathy has a similar hypoxic genesis, observed in a number of patients after resuscitation;
• metabolic disorders: encephalopathy can develop both with a decrease in glucose levels (hypoglycemia) and with an increase in it (hyperglycemia), which is often observed in diabetes mellitus. The cause of metabolic cerebral disorders is hypovitaminosis (primarily a lack of vitamins gr. C);
• drops in osmotic pressure and hyponatremia caused by water retention with hypersecretion of antidiuretic hormone (with hypothyroidism, adrenal insufficiency, tumor processes, etc.);
• rare include leukoencephalopathy, which has a viral etiology and is observed in immunocompromised patients.

Pathogenesis

Encephalopathy of any genesis is a diffuse, i.e. affecting various cerebral structures, process. It is based on oxygen deficiency (hypoxia) and metabolic disorders of neurons. The latter can be caused by hypoxia itself (with dyscirculatory and hypoxic encephalopathies), deficiency of individual metabolites and exposure to toxins (with metabolic and toxic encephalopathies). These disorders lead to degeneration and death of cerebral neurons.

The morphological signs that characterize encephalopathy include: degeneration and a decrease in the number of neurons in the medulla, which means its diffuse atrophy; foci of demyelination and necrosis, as well as glial growths localized in the white matter; microhemorrhagia and swelling of cerebral tissues; fullness of cerebral membranes. The predominant localization of these changes and the degree of their severity may vary depending on the type of encephalopathy.

Classification

According to the etiological factor, encephalopathy is classified into post-traumatic, toxic, metabolic, vascular (dyscirculatory), radiation.

1. Post-traumatic encephalopathy refers to the long-term consequences of TBI and can develop several years after it.
2. Toxic variants include alcoholic encephalopathy, observed in chronic alcoholism, as well as cerebral disorders that occur in drug addicts.
3. Metabolic variants: hepatic (portosystemic, bilirubin), uremic (azotemic), diabetic, pancreatic, hypoglycemic, hypoxic, anoxic encephalopathy and Gaye-Wernicke syndrome.
4. Dyscirculatory encephalopathy is divided into atherosclerotic, hypertensive, venous. Binswanger’s disease is a separate form of hypertensive encephalopathy.

In clinical practice, a gradation of encephalopathy by severity is used, but this distinction is very conditional:

• The I degree of severity implies a subclinical course, i.e. the absence of manifestations in the presence of cerebral changes recorded by instrumental diagnostic methods. At this stage, pathology can be diagnosed during a dispensary examination of patients with chronic, primarily vascular, diseases.
• The II degree of severity is characterized by the presence of mild or moderate neurological symptoms, often of a transient nature.
• At grade III, severe neurological disorders are observed, in most cases causing disability of the patient.

Symptoms

Chronic encephalopathy is more common, characterized by a low-symptom onset and gradual development. Most often it has a dysdirculatory and post-traumatic character. Acute encephalopathy is characterized by a sudden onset and rapid aggravation of the patient’s condition, the presence of disorders of consciousness. It can occur with intoxication and dysmetabolic disorders. Examples are acute pancreatic, uremic, hepatic encephalopathy, Gaye-Wernicke syndrome, hypoxic encephalopathy in PE.

Chronic encephalopathy

In the early stages, it is manifested by difficulties when trying to recall recent events or recently received information, decreased attentiveness and mental performance, fatigue, sleep disorders, insufficient flexibility when changing the type of activity, psychoemotional lability. Patients may notice increased irritability, daytime drowsiness, noise in the head, headache that does not have a specific localization.

Symptoms may vary in different patients. In the neurological status, nystagmus, moderate hyperreflexia and muscle hypertension, the presence of reflexes of oral automatism and stop signs, instability in the Romberg pose, discoordination, insufficiency of CN (decreased vision, hearing loss, mild ptosis, paresis of the eye), signs of autonomic dysfunction are possible.

The progression of encephalopathy is accompanied by an aggravation of symptoms with the formation of one or another clearly dominant neurological syndrome: vestibulo-atactic, parkinsonian, hyperkinetic, pseudobulbar. The increase in intellectual and emotional-volitional disorders leads to the formation of dementia. Mental disorders are possible.

Acute encephalopathy

Debuts with sudden psychomotor agitation with intense headache, visual disturbances, nausea and vomiting, shakiness, in some cases — numbness of the tongue, distal parts of the hands and feet, mental disorders. Excitement is quickly replaced by apathy, often there is a violation of consciousness of various depths: deafness, disorientation, sopor and coma. Various types of epiprimes can be observed. Acute encephalopathy refers to urgent conditions and without urgent medical care can lead to death due to cerebral edema, impaired function of vital cerebral centers.

Diagnostics

The primary diagnosis of encephalopathy is carried out by a neurologist based on the results of a survey and neurological examination. Additionally, a comprehensive instrumental neurological examination is carried out:

• Electroencephalography. EEG, as a rule, reveals diffuse disorganization of bioelectric activity of the brain with the appearance of slow waves. Epi-activity detection is possible.
• Echoencephalography. Echo-EG allows you to assess intracranial pressure.
• Vascular research. Rheoencephalography or ultrasound of the vessels of the head gives information about the state of cerebral circulation.
• Tomography. To analyze the degree of morphological changes, you can use an MRI of the brain. This method also makes it possible to differentiate encephalopathy from other cerebral diseases: Alzheimer’s disease, intracerebral tumor, encephalitis, multiple encephalomyelitis, stroke, corticobasal degeneration, Creutzfeldt—Jakob disease, etc.

The most important thing in understanding the etiology of encephalopathy is the collection of anamnesis, examination of somatic organs and consultations of related specialists: cardiologist, nephrologist, gastroenterologist, endocrinologist, pulmonologist, narcologist. According to the indications, hormonal studies are carried out, cholesterol and blood sugar levels are determined, urine analysis, blood and urine biochemistry, liver ultrasound, pancreatic ultrasound, excretory urography, ultrasound of the urinary system, kidney CT, chest X-ray, lung CT, etc.

Treatment

Acute encephalopathy is an indication for urgent hospitalization and urgent therapy. It may require measures such as ventilation, hemodialysis, parenteral nutrition. In the treatment of both acute and chronic encephalopathy, the leading place belongs to the therapy of causal disease.

Pharmacotherapy

In case of intoxication, detoxification is performed, including the introduction of infusion solutions; in case of dysmetabolic disorders, correction of metabolism (selection of a dose of hypoglycemic drugs or insulin, administration of glucose, intravenous administration of thiamine). Hepatitis, cirrhosis, pancreatitis, nephritis, lung diseases, hypertension, atherosclerosis are treated. It is recommended to follow a diet corresponding to the underlying pathology and a regime adequate to the patient’s condition.

The presence of an ischemic component in the pathogenesis of encephalopathy is an indication for the appointment of vascular therapy: pentoxifylline, ticlopidine, vinpocetine, nicergoline. Atherosclerotic encephalopathy requires the inclusion of hypolipidemic pharmaceuticals (for example, simvastatin, gemfibrozil) in the treatment regimen. Therapy of hypertensive encephalopathy is carried out with the appointment of antihypertensive agents and monitoring of blood pressure figures.

Neuroprotective and metabolic therapy is mandatory. It includes nootropics (hopanthenic acid, piracetam, pyritinol, lucetam), amino acids (glycine, glutamic acid), vitamins (B1, B6, C, E), GABA preparations (picamilon, phenibut). For mental disorders, psychotropic drugs are needed: diazepam, bromides, droperidol, phenozepam. In convulsions, anticonvulsant therapy is performed, nootropics are contraindicated.

Pharmacotherapy is carried out in repeated courses 2-3 times a year. Physiotherapy methods are used as auxiliary treatment: reflexotherapy, electrophoresis, magnetotherapy.

Surgical treatment

If dyscirculatory encephalopathy is caused by occlusion of the carotid arteries or vertebral artery, surgical treatment is possible: reconstruction or prosthetics of the vertebral artery, carotid endarterectomy, carotid subclavian bypass surgery, creation of an extra-intracranial anastomosis.

Prognosis and prevention

In many cases, the prognosis of secondary encephalopathy determines how effectively the causal pathology can be treated. The outcome of therapy also depends on the degree of cerebral changes that have occurred. In some cases, the stabilization of encephalopathy is considered a positive effect. With further progression, encephalopathy reaches grade III and leads to severe neurological and emotional-mental disorders that invalidate the patient. In the case of perinatal or acute encephalopathy, the outcome depends on the massiveness and severity of brain tissue damage. Often acute toxic encephalopathies are accompanied by deep and irreversible brain damage.

Prevention of perinatal encephalopathy is a question of the correct choice of the method of delivery, adequate management of pregnancy, compliance with the rules of newborn care. Prevention of secondary encephalopathy consists in timely detection and adequate treatment of vascular, urological, gastroenterological diseases, pulmonary pathology, endocrine and metabolic disorders. As preventive measures, you can consider proper nutrition, an active lifestyle, quitting smoking, drugs and alcohol.