What Are the Different Types of Brain Parasites?

Cerebral parasitic disease is caused by parasites, larvae or eggs invading human brain tissue, causing mechanical damage to the brain tissue and immune pathological reactions through migration and settlement, causing allergic inflammation, granulomatous formation, cerebrovascular or cerebrospinal fluid circulation blockage Encephalopathy. The clinical manifestations can be acute meningoencephalitis, or secondary seizures or intracranial hypertension with localized signs, mental decline or mental disorders. The clinical manifestations of cerebral parasitic disease mainly depend on the parasitic position, scope and number of parasites, the response of surrounding tissues and the degree of impaired blood circulation and cerebrospinal fluid circulation. There are many types of cerebral parasitic diseases, the clinical manifestations are complex and diverse, and it is easy to be misdiagnosed and mistreated. We must pay attention to distinguish them from other brain diseases caused by other factors.

Cerebral parasitic disease is caused by parasites, larvae or eggs invading human brain tissue, causing mechanical damage to the brain tissue and immune pathological reactions through migration and settlement, causing allergic inflammation, granulomatous formation, cerebrovascular or cerebrospinal fluid circulation blockage Encephalopathy. The clinical manifestations can be acute meningoencephalitis, or secondary seizures or intracranial hypertension with localized signs, mental decline or mental disorders. The clinical manifestations of cerebral parasitic disease mainly depend on the parasitic position, scope and number of parasites, the response of surrounding tissues and the degree of impaired blood circulation and cerebrospinal fluid circulation. There are many types of cerebral parasitic diseases, the clinical manifestations are complex and diverse, and it is easy to be misdiagnosed and mistreated. We must pay attention to distinguish them from other brain diseases caused by other factors.

Chinese name

Cerebral parasitic disease

Foreign name

brain parasite disease

Cerebral parasitic disease I. Pathogenesis and related diseases

Parasites can pass through the blood circulation, venous anastomotic branches, lymphatic system, arteriovenous extravascular space, intervertebral foramen, ocular conjunctiva, and nasal mucosa through the human brain and reside in any part of the brain, such as intracellular, intravascular, and meningeal Interstitial spaces, interstitial spaces, cerebrospinal fluid, cerebral ventricles, and spinal canals, etc., cause mechanical damage to tissues and induce allergies caused by worm body migration, occupying, squeezing, obstruction, and proliferation, leading to brain tissue damage and systemic disorders.

1.Mechanical damage

Trauma: After the larva of the lung fluke enters the skull, it can migrate in the brain marrow and spinal cord tissue, causing necrosis of the tunnel-like tissue. If the worm body damages the blood vessels in the brain, the brain tissue will bleed.

Oppression: cysts and cysts formed by pulmonary flukes and cysticercosis, granulomas formed by eggs of schistosomiasis, trophozoites of protozoa form abscesses in brain tissue, or chlamydial sacs produced by merozoites invading the brain, making local brains The tissue is compressed, producing symptoms of parenchymal compression.

Obstruction: The asexual reproduction of worm eggs and protozoa can occlude microvessels at the branches of arterioles or arteriovenous junctions in the brain, which in turn can cause bleeding or inflammatory reactions around the walls of the blood vessels, causing brain tissue ischemia and hypoxia, resulting in brain cell damage. Degeneration or necrosis. If the adult or larvae parasitic to the brain enter the ventricle of the human, they can block the circulation of the cerebrospinal fluid and increase the intracranial pressure, and clinically show symptoms such as cerebral edema or headache, vomiting, and optic papillary edema.

Proliferation: Some protozoa that are parasitic in cells, such as the asexual reproduction stage of Toxoplasma, are parasitic in the nerve cells of the host and repeatedly proliferate by the budding method and the mitotic method, causing the destruction of these cells. Trypanosoma cruzi can invade many kinds of cells and transform into Leishman-type division and reproduction in the cells. Cells are filled with cells that eventually swell and rupture. Leishman-type escaped from ruptured cells can invade new tissue cells and continue to divide. Multiply and enlarge the lesion.

2, secretion of toxins

Parasites can directly or indirectly act on the brain or spinal cord through secretion of toxins. For example, amoeba trophozoites secrete phytohemagglutinin, porogenic peptides, proteolytic enzymes, glycosidases, neuraminidases, and phospholipids. Enzymes, relying on the mechanical movement and secreted material of the pseudofoot first contact the tissue through the plasma membrane, and then produce tissue dissolution.

3.Allergies

Parasite allergens include parasites and parasite secretions, metabolites, and enzymes. For example, when the eggs of schistosomiasis deposited in the brain tissue mature, the pupa secretes SEA and sensitizes T lymphocytes. When the latter contacts the egg antigen again, it produces a variety of cytokines and produces an inflammatory response around the eggs. A large number of lymphocytes, macrophages, and eosinophils infiltrate to form granulomas. With the aging and death of trichomes in eggs and the regulation of host suppressor T cells and anti-idiotypic antibodies, granulomas degenerate and local fibrosis; African trypanosomiasis can cause diffuse vasculitis and meningoencephalitis due to damage to the vascular wall by circulating immune complexes in the blood. Hydatid shock is induced by allergic shock caused by cyst wall rupture and cyst fluid overflow, which causes death of each patient.

Common cerebral parasitic diseases include cysticercosis, pulmonary fluke disease, schistosomiasis and echinococcus disease, cerebral malaria, cerebral amoebiasis, cerebral trypanosomiasis, cerebral filariasis, and cerebral trichinellosis.

Cerebral parasitic disease

The diagnosis of cerebral parasitic disease, like other encephalopathy, must be related to the relationship between the anatomical structure and function of the central nerve and the epidemiological characteristics. In addition to the mutual identification of different parasitic encephalopathy, it needs to be distinguished from primary epilepsy, brain tumors, bacterial and viral encephalitis meningitis and cerebrovascular disease. The diagnosis of parasitic encephalopathy is generally based on the following:

Has a history of parasitic infections. Clinically, patients must be asked about their living history and eating habits.

Consistent with the endemic area of the parasite, that is, the majority of patients come from the endemic area

Cerebral parasitic diseases are mostly secondary to worm infections at the primary site, and their onset is generally slow, with a long course. It often presents with multifocal localization signs or mobile focal signs that are difficult to locate.

In peripheral blood and cerebrospinal fluid, eosinophilia is a characteristic of helminth infection; in the cerebrospinal fluid, worm bodies or eggs can sometimes be found.

In addition to pathogen detection, immunological methods can also be used. In particular, immunodiagnosis of cerebrospinal fluid. EEG, CT and MRI examinations are helpful for diagnosis.

Deworming drugs can improve or reduce the occurrence of sequelae to a certain extent.

Cerebral parasitic disease

Albendazole was used for medical treatment of hydatid disease, and the rest were orally administered with praziquantel, and combined with low-dose glucocorticoids for 1 to 2 weeks. Patients with frequent seizures after medical treatment may require surgery. Cerebral parasite cases with atypical imaging findings need to rely on the results of serum immunological tests to increase the reliability of clinical diagnosis.