Parasitic diseases of the brain include cysticercosis and echinococcosis.

Cysticercosis is an invasion of the central nervous system by larvae of the pork tapeworm. The migration of the parasite (oncosphere) in the body, penetrating through the gastric mucosa, occurs through the blood vessels of the portal venous system and the systemic circulation. Cysticercus (finna) is a bubble with a three-layer wall structure and filled with transparent liquid. A reactive capsule is formed around the bubble in the brain, and diffuse inflammation with the dominance of toxic vasculitis occurs in the distance. A distinction is made between solitary and branched (racemose) cysticerci. The most common localization is the pia mater and the superficial layers of the cortex. Less common is cysticercosis of the cerebral ventricles.

Echinococcosis is a lesion of the central nervous system by larvae (finna) of the echinococcus. The migration routes of the echinococcus oncosphere in the human body are the same as those of the pork tapeworm. There are two types of echinococcus: unicameral, or hydatid, and multicameral, or alveolar. The wall of a unicameral echinococcus consists of an internal germ layer bearing the scolex and an external chitinous membrane. The cyst cavity is filled with a yellowish liquid containing succinic acid and other components. The size of the parasite is very variable and can reach the size of a large apple. Multicameral echinococcus is a conglomerate of small vesicles united into a single node by intermediate connective tissue. They are localized mainly in the subcortical white matter of the cerebral hemispheres, less often in the ventricles of the brain. The perifocal reaction of the brain tissue around the parasite is always sharply expressed, especially with multicameral echinococcus. 

Symptoms

The clinical picture of parasitic diseases of the brain is similar to the clinical picture of a tumor. Cysticercosis may be accompanied by paroxysmal headaches, nausea, vomiting, epileptiform seizures. Sometimes the psyche is disturbed in the form of hallucinatory states, which can suddenly disappear and reappear. Cysticercosis of the cerebral ventricles is accompanied by increased intracranial pressure. With echinococcosis, headache, dizziness, vomiting are observed. Paralysis, paresis, mental disorders, convulsions are possible. If parasitic lesions of the brain are suspected, a thorough diagnosis should be carried out, including a study of the cerebrospinal fluid.