Neurocysticercosis is a parasitic lesion of the brain that develops when pig tapeworm larvae enter the human body. Focal epileptic seizures, intracranial hypertension with crises, and mental abnormalities are clinically noted. A slight neurological deficit is possible. The diagnosis is established by ophthalmoscopy, blood and cerebrospinal fluid examination, cerebral CT or MRI, electroencephalography. Treatment is complex and long-term with the use of anthelmintic and antiepileptic drugs, dehydrating and anti-inflammatory drugs.
ICD 10
B69.0 Cysticercosis of the central nervous system
General information
Neurocysticercosis is a separate form of helminthiasis that occurs when larvae of pork tapeworm penetrate into the cerebral tissues and form cysticercus — larval vesicles with a helminth head inside. About 60% of cysticercosis is associated with brain damage. There is also a lesion of the eyes and skeletal muscles. Among the cerebral structures, the cerebral membranes of the base, the surface of the cerebral cortex, and the ventricles of the brain are most susceptible to larval penetration.
Globally, the greatest incidence is observed in Asia, Latin America and Africa. In our country, neurocysticercosis is common in areas with developed pig farming. Adults get sick more often than children. Gender differences in morbidity were not found. In modern neurology, timely detection and treatment of cerebral cysticercosis is of great practical importance, since widespread brain lesions with cysticerci can lead to death.
Causes
When cysticerci enter the human body, an intestinal form of helminthiasis develops — teniosis, and when larvae of pork tapeworm enter, cysticercosis develops. You can get infected with larvae through unwashed hands from a person or pig with teniosis, as well as by eating infected pork. When the larvae in the shells end up in the human stomach, their shells are destroyed by the action of gastric juice. Larvae are absorbed into the blood and its current can enter the brain, eyes, muscles. Upon penetration into the brain, the larva turns into a cysticercus with a diameter of 3-15 mm. In this form, she can live up to 30 years. If the larva dies, calcification of the cysticercus occurs.
Pathogenesis
In rare cases, single cysticerci are found in brain tissues, which may not give clinical symptoms. But more often the lesion has a multiple character and is accompanied by pronounced symptoms caused, first of all, by irritation of cerebral tissues at the site of localization of parasites. In response to the penetration of larvae, an inflammatory process develops, which is accompanied by hyperproduction of cerebrospinal fluid with the appearance of hydrocephalus.
In addition, in the process of vital activity, larval vesicles secrete substances that are toxic to brain cells. Thus, the lesion in neurocysticercosis has 3 components: irritation, inflammation and toxic effects. Even calcified cysticerci continue to support chronic inflammation of cerebral tissues.
Symptoms
The clinic is dominated by symptoms of irritation and cerebrospinal hypertension. As a rule, irritation leads to epileptic paroxysms. Since the brain lesion has a focal character, epi-paroxysms characteristic of symptomatic focal epilepsy are observed. These are partial simple and complex epiprimes, possibly with secondary generalization and transition to epileptic status.
Most often, neurocysticercosis occurs with attacks of Jackson’s epilepsy. Polymorphism of the latter (a combination of motor and sensory paroxysms with different clinics) indicates multiple foci of cysticercosis in the cerebral cortex.
Intracranial hypertension is manifested by cerebrospinal hypertension crises with paroxysms of intense cerebalgia (headache), accompanied by vomiting and dizziness. Most patients with neurocysticercosis have various deviations in the mental sphere: from mild neurotic symptoms to severe mental disorders (depression, aggression, delirium, hallucinatory syndrome, etc.).
Since cysticerci are predominantly small in size, the symptoms of loss of neurological functions may be absent or expressed insignificantly. Neurological deficit can be represented by mild paresis, a slight speech disorder, minor sensory disturbances.
Neurocysticercosis is characterized by a long remitting course. Deterioration of the condition is interspersed with “light” periods, which can take several months or even years. Cases of spontaneous healing were not observed.
Cysticercosis of the membranes of the brain
When the membrane is affected in the region of the base of the brain, the picture of meningitis with bradycardia and damage to the cranial nerves prevails. According to the involvement of nerves, visual disturbances, strabismus and central paresis of the facial nerve are observed.
Cysticercosis of the ventricles of the brain
When the larvae enter the cerebral ventricles, the cysticerci float freely in the cerebrospinal fluid and can periodically cause occlusion of the outflow pathways of the cerebrospinal fluid, provoking a severe cerebrospinal hypertension crisis. The symptoms are largely similar to brain tumors of similar localization.
Cysticercosis of the IV ventricle is accompanied by a clinic of Bruns syndrome — paroxysm of acute cephalgia and vomiting with a disorder of cardiovascular activity and respiration. The syndrome is a consequence of irritation of the ventricular fundus or obturation of its opening by the cystocercus. When the lateral ventricle is affected, there are attacks of disorder of consciousness caused by the obturation of the hole connecting it to the III ventricle.
Diagnostics
It is not easy to establish neurocysticercosis. This requires thorough clinical, laboratory and instrumental diagnostics:
- Neurological examination. A neurologist can suspect the disease by the predominance of symptoms of irritation, polymorphism of symptoms, indicating polyococcal cerebral lesion, low manifestation of neurological deficit, remitting course with long periods of remission. The focal nature of epileptogenic activity is confirmed by electroencephalography data.
- Ophthalmological examination. After neurological examination of patients for consultation with an ophthalmologist. Congestive optic nerve discs during ophthalmoscopy indicate chronic intracranial hypertension. Sometimes cysticerci are detected on the fundus.
- Laboratory tests. Often, neurocysticercosis is accompanied by increased sensitization of the body, which is manifested by eosinophilia in the general blood test. Examination of the cerebrospinal fluid reveals cytosis with a predominance of lymphocytes and eosinophils, an increase in protein concentration is possible. In some cases, pieces of capsules of cysticerci are detected. It is possible to accurately determine the etiology of the identified formations only with the help of specific immunological studies (IFT, ELISA) of blood or cerebrospinal fluid.
- Radiation methods. Clusters of cysticerci in the form of a bunch of grapes or individual cysticerci are visualized using CT or MRI of the brain as focal formations. Calcified cysticerci are found on the X-ray of the skull in the form of fine-focal shadows.
During the diagnostic search, neurocysticercosis is differentiated from epilepsy, intracranial tumors, meningitis of other etiology, encephalitis, neurosyphilis, etc.
Treatment
Conservative treatment
Therapy is carried out inpatient and includes deworming, the fight against increased intracranial pressure, anti-inflammatory and anticonvulsant treatment. Deworming is carried out by praziquantel and albendazole. Against the background of such therapy, the patient’s condition may worsen and the number of epi-paroxysms may increase, which is due to the destruction of cysticerci and intoxication of cerebral tissues by decay products. During this period, additional administration of anti-inflammatory drugs, including glucocorticosteroids, is effective.
Diuretics (furosemide, acetazolamide) are used to relieve intracranial hypertension. Anticonvulsant therapy is performed with one of the antiepileptic drugs (carbamazepine, diazepam, valproic acid, etc.). However, its result depends on the success of treatment of cysticercosis.
Surgical treatment
Surgical treatment is possible with sufficiently large single cysticerci, damage to the IV ventricle with the risk of occlusion, the development of persistent focal epilepsy with a clear localization of the epileptogenic focus. Focal resection of the brain in such cases in most patients leads to recovery.
Prognosis and prevention
The most serious prognosis is if neurocysticercosis is polyococcal in nature or is accompanied by the penetration of cysticerci into the IV ventricle. A fatal outcome is possible during an epileptic status or an attack of hydrocephalus, due to occlusion of the outflow of cerebrospinal fluid from the cavity of the IV ventricle. Often, long and repeated courses of combination therapy are necessary for a complete cure. Even after the cure of helminthiasis, patients may persist: persistent intracranial hypertension, focal epilepsy, some deviations in the mental sphere.
The best means of preventing neurocysticercosis is careful personal hygiene and the use of pork only tested by veterinary and sanitary examination. For preventive purposes, a survey of persons engaged in pig breeding and meat processing is carried out, timely identification of sick animals, epidemiological surveillance at meat markets.