Parasitic diseases of the nervous system: basic information

Parasitic diseases of the nervous system combine a group of diseases caused by helminths (worms) and protozoa. Pathogens can cause damage not only to the nervous system, but also to other organs and systems. More often there is a combined defeat of different structures of the body. From this article you can learn about the most common parasitic diseases of the nervous system: about which pathogen they are caused, than are shown, what methods are used for treatment, and what to do in order not to become infected.

Parasitic diseases of the nervous system include:

• neurocysticercosis;
• toxoplasmosis encephalitis;
• amoebic meningoencephalitis;
• echinococcosis of the brain;
• cerebral malaria.

Neurocysticercosis

Neurocysticercosis is the defeat of the nervous system by the larvae of the pork chain. Pork Chopin (pork tapeworm) is a tape worm 2-3 meters in length. Parasitizes in the human intestine. The source of infection is a sick person. With the feces of such a person eggs of pork chopsticks are allocated which, if the rules of personal hygiene are not observed, fall into food, water, settle on household items.

If the eggs of the pork tapeworm get into the stomach to the person, the gastric juice dissolves their shell, and they penetrate into the circulatory system. With the current of the blood are carried throughout the body, they can settle in any organs, but the nervous system (especially the brain), the muscles and the eyes are the favorites. In these structures, eggs develop into larvae - cysticerci, which look like bubbles with liquid. Inside the bubble there is a head of the larva with hooks-suckers. The size of the cysticercum is about 3-15 mm. The number of such larvae in the brain depends on how many eggs have got into the body. Vesicles can be located in the brain substance, inside the ventricles, in the subarachnoid space. Over time, larvae can die, and then calcium salts are deposited in their shell. Even the dead larva supports the inflammatory process in the brain, and the fact of death can be difficult for the patient, as it is accompanied by the release of toxins into the blood.

Symptoms of neurocysticercosis

What exactly will bother the patient depends on the location of the cysticerci, their number and stage of development (a living, dead larva).

Basically, with neurocysticercosis, patients complain of a headache (bursting nature), a feeling of pressure on the eyes, nausea, sometimes vomiting that does not bring relief. Perhaps the appearance of meningeal signs: rigidity of the neck muscles, photophobia. All these are symptoms of increased intracranial pressure, a violation of the normal circulation of cerebrospinal fluid. Sometimes cysticerci freely floating in the ventricles of the brain can completely block the outflow of liquor from the ventricles to the subarachnoid space. Then there is a sharp deterioration of the condition, blurred consciousness, sweating, a violation of the heart and breathing, which can lead to sudden death.

Another common symptom of neurocysticercosis is epileptic seizures. They can be very diverse: with motor (convulsions), sensitive (crawling sensation, visual or auditory hallucinations), mental (a feeling of "already seen", "already heard", etc.) and other manifestations. Consciousness during seizures can be completely lost, and can remain unchanged.

Perhaps the emergence of mental disorders: the emergence of hallucinations, delusions, excitement, depression.

Also, neurocysticercosis can manifest itself by the appearance of muscle weakness in the limbs, visual impairment, dizziness and shakiness, speech problems, mental disorders.

There are also asymptomatic forms of neurocysticercosis.

Treatment

Perhaps medical and surgical treatment.Of the drugs used Praziquantel and Albendazole, which cause the death of larvae. Surgical treatment consists in removing cysticerci, if possible (allows operative access). A persistent increase in intracranial pressure with the development of hydrocephalus can be eliminated with the help of ventricular shunting, but this is only a symptomatic treatment.

How not to get infected?

To avoid this disease, you must strictly observe the rules of personal hygiene and hygiene of cooking (for example, carefully wash raw vegetables and fruits and pour them with boiling water).

Toxoplasmic encephalitis

Toxoplasmosis encephalitis is caused by the simplest one called toxoplasm (Toxoplasma gondii). This pathogen affects many mammals, including humans. Sick animals (cats, dogs, pigs, cattle, etc.) give toxoplasm to the environment with feces, urine, saliva, milk. Meat of sick animals also contains a pathogen. Infection of a person can occur in various ways:

• food: by ingestion of a person with contaminated products (thermally poorly processed meat, unwashed vegetables and fruits);
• parenteral route: with damage to the skin and mucous membranes, getting into the blood (most often infected workers meat processing plants, slaughterhouses with accidental injuries of hands in the process of work, doctors and patients with blood transfusion or organ transplantation);
• transplacental pathway: transmission from mother to child during pregnancy;
• with the bite of insects: in this case, insects can simply carry the pathogen on their paws.

The most common source of infection for a person are domestic cats. Toxoplasma enters the gastrointestinal tract, penetrates the intestinal walls into the lymph nodes, and from there into the blood. With blood, the pathogen penetrates into various organs and tissues. Primarily affects the skeletal muscles, heart, eyes, nervous system, causes an increase in the liver and spleen.

In persons with normal immunity, asymptomatic carriage is formed, i.e., all active toxoplasma are destroyed by the immune system, only the so-called tissue cysts remain, which last indefinitely (over time, and they die). With a decrease in immunity (for example, HIV infection, the use of cytostatics and glucocorticoids), tissue cysts become active form of toxoplasma and cause the development of the disease.

Symptoms

After an incubation period of from 3 to 21 days, symptoms appear that indicate the onset of an infectious diseases: fever, chills, pain in the muscles and joints, enlarged lymph nodes. Toxoplasmosis encephalitis is manifested by such symptoms as severe headache, tonic-clonic convulsions, violation coordination, weakness in the limbs, memory impairment, orientation in place, time, impaired consciousness. If meningeal signs (neck muscle tension, Kernig and Brudzinsky symptoms, nausea, vomiting, photophobia, etc.) join, then meningoencephalitis develops. It is possible to form single or multiple brain abscesses.

The analysis of blood determines the increase in the number of leukocytes, an increase in ESR, a decrease in the number of red blood cells (anemia). In the cerebrospinal fluid protein content increases, the number of lymphocytes increases.

A very serious, often fatal form of the disease is congenital toxoplasmosis. It occurs if a woman becomes infected with toxoplasmosis during pregnancy. In the early stages of pregnancy, this leads to the death of the fetus, at later stages of pregnancy, the developmental defects of many organs are formed, including severe brain damage. Symptoms appear immediately after birth, the child has signs of meningoencephalitis: a variety of epipripeds, paresis of the limbs (lack of strength), muscle contractures (pronounced increase in tone), delay in neuropsychological development. Three symptoms are considered typical for congenital toxoplasmosis: hydrocephalus (an increase in the size of the child's head due to excess of cerebrospinal fluid), chorioretinitis (inflammation of the choroid and retina), deposition of intracranial calcifications. More than 50% of these children die. Those who survived remain disabled for life. They sharply lag behind in mental development, are often chained to a wheelchair.

Most often, toxoplasmosis encephalitis develops in people with AIDS (and causes death).

Treatment

Toxoplasmosis is difficult to treat, because effective exposure is only possible to active forms of toxoplasm. To do this, apply Chloridine, sulfonamides and antibiotics (Linkomycin, Rovamycin). On tissue cysts, capable of being in the body for years, all these drugs have no effect. In addition to specific treatment, the above listed chemotherapeutic agents use symptomatic agents (for example, anticonvulsants with convulsions, antipyretic with increasing temperature, etc.)

When detecting toxoplasmosis in a pregnant woman, the question of treatment, maintenance or termination of pregnancy is decided by a doctor's consultation.

Prophylaxis of toxoplasmosis

Prevention of the disease consists in the elimination of the methods of infection: it is necessary to eat only thermally processed meat, do not taste raw mince, wash hands thoroughly after working with meat, work in the garden, play with animals, wash vegetables and fruits. Observance of sanitary and hygienic conditions in everyday life and in the preparation of food is a reliable way to prevent disease. Pregnant women should be screened for toxoplasmosis.

Amoebic meningoencephalitis

This is a rare defeat of the nervous system of the amoeba Naegleria fowleri, which lives in freshwater rivers, hot springs. The microorganism enters the brain through the nose during bathing (it penetrates the skull cavity through the olfactory nerve). The incubation period is from 2 to 15 days.

Symptoms

Develops fulminant meningoencephalitis. The body temperature rises sharply, there is a headache, typical meningeal signs (rigidity of muscles nape, nausea, vomiting, hypersensitivity to sounds and light, symptoms of Kernig and Brudzinsky). At the same time, there is a loss of the ability to smell, which is associated with the damage to the olfactory nerves when the pathogen enters the brain. There are signs of damage to the brain substance: paralysis, speech loss, sensitivity disorders in the limbs. Usually there are convulsions, there is a violation of consciousness up to the coma. Most often within 1-2 weeks patients die.

Treatment

Amoebic menengoencephalitis requires specific treatment: Amphotericin B is prescribed, cases of effective use of Amphotericin B in combination with Rifampicin and Tetracyclin are described. The complexity of treatment is that it is very difficult to suspect amoebic meningoencephalitis, because meningoencephalitis is an infectious disease that can be caused by any microorganisms. There are no specific symptoms that characterize exactly amoebic meningoencephalitis. When the disease is diagnosed late, the patient does not have time to save. In the case of early treatment, the outcome is favorable.

How to protect yourself from amoebic meningoencephalitis?

Given the habitat of the pathogen, you can protect yourself from the disease only by refusing to swim in fresh water and hot springs, especially in hot weather.

Echinococcosis of the brain

Echinococcosis of the brain is caused by the larva of a small ribbon echinococcus worm. The worm itself lives in the intestines of carnivorous animals: dogs, wolves, foxes, jackals, etc. These animals become infected by eating meat that contains echinococcus larvae. The larva in the intestine develops into an adult - a full-fledged worm that produces thousands of eggs. With feces, eggs are released into the environment. They settle in the soil, on grass, vegetables, fall into the water. A person becomes infected by eating contaminated eggs with echinococcus products or not following the rules of personal hygiene. The latter can happen in a variety of situations: stroked a dog whose hair contains eggs, and did not wash his hands; carved up the carcass of an animal killed on the hunt (on the skin there could also be eggs), and again did not wash his hands, etc. The most significant vector of infection for a person is a dog.

In the human stomach, the egg shell dissolves, so-called oncospheres are released, which penetrate the bloodstream and are carried throughout the body. Most often they fall into the liver, but it is possible to drift into other organs, including the brain.

In the brain, the oncosphere turns into a larva. This process takes approximately five months. The larva of echinococcus looks like a bubble with a dense shell - a cyst. The cyst inside is filled with liquid. Sometimes a bubble can be multi-chambered (like several soap bubbles connected together). The sizes of cysts are different, in the brain they average up to 1-5 cm in diameter. In other organs, giant cysts up to 30 cm in diameter are possible. The larva grows slowly, sometimes 20-25 years without any sign of itself.

Symptoms

Symptoms of echinococcosis of the brain are associated with the pressure of the cyst on the surrounding cerebral tissue. Very often, the signs of echinococcosis are similar to those of a brain tumor, because both the tumor and the echinococcal cyst are growing "extra" structures inside the skull.

The person gradually develops a hydrocephalus syndrome: headaches, dizziness, a bit worse vision, there are bouts of nausea and vomiting, convulsive attacks. The movements of the eyeballs are painful. On the eyeground, stagnant discs of the optic nerves are detected.

Depending on the location of the echinococcal cyst, focal symptoms appear in the brain, that is, the function of that part of the brain that is compressed by the cyst is broken. Focal symptoms can be very diverse, but the most frequent and noticeable are muscle weakness, impaired vision, loss of sensitivity, speech impairment, the ability to read (count) or write. Possible mental disorders: the appearance of delusions, hallucinations, psychoses, hysterical fits; mental disorders: memory impairment, attention, development of dementia.

Symptoms are steadily progressing as the echinococcal cyst grows. Sometimes spontaneous death of the larva is possible. Then the calcium salt is deposited in the capsule, and a cyst remains, which does not resolve.

In the cerebrospinal fluid, the protein content rises, eosinophils appear (normally there are no cells in the cerebrospinal fluid), the number of leukocytes increases. It is enough to diagnose accurately the echinococcosis of the brain with CT or MRI.

Treatment

Treatment of echinococcosis of the brain, as a rule, operative. It consists in the removal of the cyst formed. Surgery requires special care. Extraction of the cyst should not lead to the ingress of its contents into surrounding tissues, as this may cause the recurrence of cysts. Multiple echinococcal cysts do not operate because of the impossibility of technically performing the operation.

After the operation, the course of Albendazole is prescribed to prevent relapse.

Prevention of echinococcosis of the brain

Measures to combat a possible infection are reduced to compliance with sanitary and hygienic standards in everyday life: wash hands after contact with animals (dogs in particular), do not eat dirty vegetables and fruits, greens from the garden, do not drink water from sources in the forest, etc.

Cerebral malaria

Malaria is an infectious disease caused by protozoa of the genus Plasmodium, which are carried by mosquitoes of the genus Anopheles. When you bite an infected mosquito with its saliva, the pathogen gets to the person.

There are several types of malaria. Cerebral malaria is caused by Plasmodium falciparum, a type of tropical malaria (the most frequent).

Symptoms

The incubation period is 8-16 days, at the end of which the most severe meningitis is almost instantaneous. Symptoms are formed within 24-40 hours. In the beginning there is a sharp headache, expressed general weakness (sometimes it is possible, on the contrary, motor excitement and anxiety), rigidity of the occipital muscles. The body temperature rises to 40 ° C, it disturbs the aching muscles and joints. Consciousness is quickly broken: from dusk to a coma is only a few hours. In a coma, the patient's head is thrown back, legs are unbent, arms are half-bent. Periodically, muscle tone increases, right up to cramps. In addition to signs of brain damage, kidneys and lungs develop, cardiac activity and breathing are disrupted, and the shock state may develop. Mortality is high and reaches 20%.

The diagnosis is made when a malarial plasmodium is detected in the blood.

Treatment

Treatment of cerebral malaria consists in the use of drugs containing Quinine, Chloridine, Artemisinin (specific antimalarial drugs). Naturally, the whole complex of measures is carried out in the conditions of the intensive care unit in order to eliminate the insufficiency of many organs at the same time.

How not to get malaria?

There is no specific prevention. It is necessary to beware of mosquito bites (special creams, ointments, mosquito nets, screens, clothing that closes the body as much as possible). In countries where the incidence of malaria is high, mass destruction of mosquitoes and their larvae is carried out.

Persons who are going to areas with a high prevalence of the disease are recommended preventive reception Chloridin, Akrihina, Meflokhin, Doxycycline, Malaron. The choice of the drug depends on the sensitivity of the pathogen of malaria in this or that zone of human presence.

Parasitic diseases of the nervous system can wait for a person at every step: when walking in a park or forest, riding a hunt or a pond, at home while eating food, etc. It is difficult to imagine all situations. And the emerging symptoms do not always help the doctor in establishing the correct diagnosis. But infection can often be prevented by banal activities: careful washing of hands, appropriate culinary processing of products (meat, fruits, vegetables, greens), drinking of boiled water (and the temptation to drink from the spring in the forest is so great!), bathing in strictly designated places for this purpose, using insect repellent. Do not neglect the rules familiar to all from childhood, and you will protect yourself and your loved ones from formidable (sometimes fatal) infections!