Bilirubin encephalopathy (also called nuclear jaundice) is a condition characterized by the death of brain cells due to the toxic effect of a high concentration of bilirubin (indirect fraction) on them. This condition is most often found in newborns and requires immediate treatment, otherwise it can lead to disability and even death of the patient.
Etiology of the disease
Possible causes of bilirubin encephalopathy in newborns are as follows:
- hemolytic disease (Rhesus or group incompatibility of mother and baby);
- diabetes in the mother;
- sepsis of the newborn;
- child trauma during childbirth with the formation of extensive hematomas;
- toxoplasmosis (intrauterine infection);
- jaundice in premature babies.
Under the influence of any of these processes, indirect bilirubin (that is, untreated hepatocytes) is released in large quantities into the bloodstream, exerting a neurotoxic effect on brain tissue.
Pathomorphological signs
The surface of the brain has a pale yellow tint. A slice of the drug reveals a characteristic yellow color of the brain structures (cerebellum, hippocampus, thalamus, trunk and others). However, unpainted areas also undergo pathological changes.
In the affected areas due to the death of neurons, gliosis is formed and atrophy of the nervous tissue occurs. Moreover, the pathomorphological picture is similar to that of a hypoxic lesion, which means that with a high degree of probability it can be assumed that unbound bilirubin, damaging the cell membranes, leads to impaired oxygen utilization in the brain tissues. And hypoxic damage leads to an even greater increase in the sensitivity of neurons to the toxic effects of bilirubin.
That is, nuclear jaundice (bilirubin encephalopathy) is not only a change in the color of brain structures under the influence of bilirubin. It is also a number of pathological specific processes occurring at the cell level.
Adult bilirubin encephalopathy
The causes of damage to brain structures by bilirubin in adults lie in severe decompensated liver pathologies (cirrhosis, hepatitis).
The disease in adults develops gradually and is accompanied by an increase in neurological symptoms. At the same time, mental disorders and motor activity, which are manifested by insomnia, cognitive changes, decreased activity, and so on, come to the fore.
Clinical manifestations
Most often, the first signs of pathology occur in full-term babies at 2-5 days, and in premature babies - at 7 days. But the presence of hyperbilirubinemia can lead to the development of the disease throughout the entire neonatal period (up to 28 days).
The early symptoms of such encephalopathy are non-specific and may coincide with those with hypoglycemia, sepsis, intracranial hemorrhage, hypoxia and other pathological acute conditions of the newborn.
As a rule, the first signs of a beginning brain damage are a decrease in the sucking reflex, drowsiness, the disappearance of the Moro reflex. As the disease worsens (progresses), tendon reflexes disappear, breathing is disturbed, opistotonus occurs, the large fontanel is tense, the facial muscles and muscles of the limbs twitch convulsively, the child screams piercingly.
Then convulsions appear, accompanied by a sharp extension of the handles and the rotation of the hands, compressed into fists, inward.
Further activity of the process often leads to death, in another case, the condition of the child improves, and development corresponds to the norm. However, by the year muscle stiffness, opisthotonus, and hyperkinesis reappear. By the second year of life, convulsions and opistotonus disappear, but involuntary erratic movements, combined with hypotension or muscle stiffness, persist and become stable.
At the age of three, bilirubin encephalopathy in children acquires a persistent and clear character, which is manifested by hearing loss with high frequency sounds, choreoathetosis, convulsions, dysarthria, strabismus, oligophrenia, extrapyramidal disorders. Ataxia, hypotension and pyramidal disorders are sometimes found.
With a mild course of bilirubin encephalopathy, the consequences can be manifested in the form of hearing loss, moderate or mild impaired motor coordination, hyperactivity disorder combined with impaired attention (minimal cerebral dysfunction). Such symptoms may be combined or present separately. In this case, encephalopathy may not be diagnosed until admission to school.
Process stage
Pathology has four stages of development:
- Symptoms of bilirubin encephalopathy are nonspecific: there is weakness, vomiting, monotonous emotionless cry. Muscle tone and appetite are reduced.
- Symptoms of encephalopathy appear, the limbs of the baby are bent, it is impossible to straighten them, the chin is brought to the chest, the child cries out unnaturally. In some cases, hyperthermia and episodes of apnea are possible.
- The patient’s condition (usually 10-12 days of the baby’s life) improves markedly, but this phenomenon is not associated with recovery, on the contrary, the process is progressing. The stiffness of the muscles recedes, there are no cramps.
- It develops at 2 months of a baby's life. Symptoms are increasing. There are signs similar to those with cerebral palsy. The child is significantly behind in psycho-emotional and physical development.
Diagnostic measures
Hyperbilirubinemia can be regarded as physiological only in the case of the exclusion of absolutely all pathological factors of its appearance. Taking into account the fact that hyperbilirubinemia is most often the result of hemolytic or physiological causes, the examination of the patient should include the following tests:
- blood test (general) with the obligatory calculation of the number of reticulocytes and microscopy of a blood smear;
- Coombs test (indirect and direct);
- elucidation of the group and Rhesus affiliation of the blood of the mother and baby;
- determination of the amount of indirect and direct bilirubin;
An increase in the content of bilirubin in the umbilical cord blood, the presence of jaundice symptoms on the first day of life, if the level of the unconjugated fraction is more than 34 μmol / L indicate the presence of pathological jaundice.
In some cases, MRI, ultrasound and CT can be prescribed for bilirubin encephalopathy.
Condition therapy
The treatment of nuclear jaundice in babies (regardless of its stage) is a pediatric neurologist. As a rule, such children are hospitalized.
Treatment of an ailment in an adult is also carried out in a hospital under the constant supervision of a doctor.
The treatment of the disease is to eliminate the causes of hyperbilirubinemia and restore the normal concentration of bilirubin in the blood. As a treatment, phototherapy is used.
Under the influence of radiation, toxic indirect bilirubin is transformed into a special isomer, which is easily excreted by the kidneys and liver and does not bind to blood albumin. In cases where the concentration of bilirubin does not decrease under the influence of phototherapy, a plasma transfusion is prescribed.
If the previous methods have been ineffective, or the symptoms are rapidly increasing, direct blood transfusions are prescribed to the patient.
Used drugs
If direct transfusion is not possible for some reason, drugs are prescribed that affect the synthesis and transformation of bilirubin (Protoporphyrin).
Due to the fact that nuclear jaundice is the result of the toxic effects of bilirubin on neurons, neuroprotectors are always used in its treatment.
If indicated, anticonvulsant treatment is prescribed.
In the case of hemolytic disease with the presence of a direct positive Coombs reaction, intravenous immunoglobulin infusions are effective.
Frequency of occurrence, consequences and forecasts
According to autopsy, nuclear jaundice occurs in newborns at any gestational age in the absence of adequate therapy for hemolytic disease and bilirubin concentrations above 25-30 mg.
The incidence of the disease in premature babies with hyperbilirubinemia varies from 2 to 16%. More accurate numbers cannot be determined due to the wide variety of symptoms of the disease.
The presence of a pronounced neurological symptom complex is an unfavorable prognostic sign. Thus, mortality in this case reaches 75%, and 80% of surviving patients have bilateral choreoathetosis, accompanied by muscle involuntary contractions. In addition, complications in the form of deafness, oligophrenia and spastic tetraplegia are quite common.
Children with a history of hyperbilirubinemia should be examined for deafness.
Despite an improvement in diagnosis, nuclear jaundice still occurs. There is information about its occurrence against the background of hyperbilirubinemia without the presence of any reason. Therefore, experts recommend that all newborns carry out mandatory bilirubin monitoring for 1-2 days of life in order to identify patients with a high probability of developing severe hyperbilirubinemia and, as a result, encephalopathy.
Preventative measures
It is important to conduct a mandatory study of bilirubin concentration in the event of jaundice on the first day of life, and in the presence of hyperbilirubinemia, an exception to the development of hemolytic disease.
It is mandatory to monitor the condition of the baby within 3 days after discharge, especially for preterm (up to 38 weeks) babies who were discharged from the maternity ward before 2 days of life.
The frequency of observation is determined by the age at which the baby was discharged, and the presence of risk factors. Some children are observed during the day. Risks can be predicted by evaluating the hourly growth rate of bilirubin.