What is cysticercosis?
Cysticercosis is a human parasitic disease caused by larvae of the pork tapeworm – cysticercus (Cysticersus cellulosae). In this case, a person becomes an intermediate optional host of helminth.
It occurs in 2-4% of the general population, more often in adults, equally often in men and women.
There is no exact data on the frequency of human cysticercosis: it is known that, as a rule, it is recorded in those places where teniosis is common. Cysticercosis is the most common cause of epilepsy and various neurological syndromes in Central and South Africa, Mexico, Central and South America, as well as in South Asia. In the former USSR, it is more often registered in Belarus and the western regions of Ukraine.
Causes of Cysticercosis
The causative agent of cysticercosis is the larval stage of porcine tapeworm (cysticercus). Cysticercosis develops as a result of ingestion of porcine tapeworm eggs (contaminated products, dirty hands, throwing mature segments from the intestines into the stomach, for example, when vomiting occurs in persons infected with a mature form of pork tapeworm). The main role is played by mechanical action. Impaired function depends on the location of the cysticercus.
Pathogenesis during Cysticercosis
Infection with cysticercosis occurs when eggs, oncospheres of the pork tapeworm, which develop in the human body when they enter the stomach, are the same as in the main intermediate host, the pig. In the stomach, under the influence of pepsin, the oncosphere membrane collapses, the released six-hooked embryos actively digest into the intestinal wall, enter the blood vessels and are hematogenously carried throughout the body, settling in various organs, where the oncospheres turn into cysticerci. Cystic is a transparent bubble in diameter from millet grain to 1.5 cm, filled with liquid, with scolex inside. Most often, according to many researchers, cysticercosis affects the central nervous system (74.5 – 82%), eyes and muscles.
Two ways of infection with cysticercosis are known – exogenous and endogenous. With exogenous infection, the oncospheres fall from the outside. So, patients with teniosis can become infected through their own dirty hands, laboratory assistants – in cases of violation of the rules for working with the studied material, as well as any person through vegetables, berries, fruits contaminated with oncospheres when fertilizing the soil of vegetable gardens and berry fields with uncontaminated sewage infested with pork tapeworm.
Only patients with teniosis with antiperistalsis, the ingestion of segments of pork tapeworm from the intestines into the stomach with their subsequent digestion and the release of tens of thousands of eggs become infected by the endogenous route. In these cases, the invasion is very intense. The causes of antiperistalsis are various: any food poisoning, alcohol intoxication, exit from anesthesia, as well as the introduction of a probe, etc.
The cysticerci have a local and general effect on the body: the local one is due to their mechanical action and localization, and the general one is associated with the entry into the blood and cerebrospinal fluid of toxic waste products of larvae. The most pronounced effect is associated with the process of dying off of the cysticercus, increased scarring and wrinkling processes in its body and its calcification. Depending on the localization, cysticercosis of the brain, eyes and muscles is distinguished.
Symptoms of Cysticercosis
Cysticercosis of the brain. According to the characteristics of the clinic, the following four forms of this disease are distinguished:
- cysticercosis of the cerebral hemispheres;
- cysticercosis of the ventricular system;
- cysticercosis of the base;
- mixed cysticercosis.
In the first form, the invasion is manifested by symptoms of increased intracranial pressure due to impaired cerebrospinal fluid flow (patients complain of paroxysmal headaches, dizziness, vomiting; often a congestive optic nerve is detected). A common symptom of it is epileptic seizures.
The most common form of ventricular cysticercosis is IV ventricular cysticercosis. It is characterized by a sudden and rapid onset, characterized by bouts of headaches with vomiting. Brunsian attacks associated with a change in the position of the head are typical for this form of the disease. In most patients, a forced position of the body is observed, since a change in posture causes a sharp exacerbation of the headache and vomiting.
The clinic of cysticercosis of the base of the brain is also variable, manifested by a violation of cerebrospinal fluid circulation. Quite often, a forced position of the head, pain in the occipital-cervical region, a decrease in taste sensitivity, hearing and vestibular irritability are noted. Sensitive and motor disorders, including paresis, can occur. In 1/5 of the cases of the disease, various mental disorders are observed.
A mixed form of cysticercosis of the brain is difficult prognosis of its unfavorable. The most typical for her epileptic symptom complex, gross mental disorders, hallucinations, etc .; the spinal cord is rarely affected.
Cysticercosis of the eye.
Cysticerci can be localized in all membranes of the eye, which is clinically manifested by visual impairment of various severity and nature, to its complete loss, by a sense of pressure and pain.
The most prognostically and clinically favorable form is cysticercosis of the skin, subcutaneous tissue, and muscles.
Cysticercosis of the skin.
When the larvae are located in the subcutaneous fat layer, tumor-like formations arise, towering above the surface of the skin, with their palpation, the cavity nature of the tumors can be determined. The most frequent localization: the inner surfaces of the shoulders, the upper half of the chest, palms.
The disease is accompanied by severe eosinophilia in the blood (up to 40%), urticaria.
Histology: cavitary formations with a thick fibrous wall are found, filled with a clear whitish liquid, inside of which a larva is detected.
Cysticercosis of the skin and muscles is asymptomatic.
Cysticercosis of the heart.
With the localization of parasites in the heart, in the area of the atrio-gastric bundle, the heart rhythm is disturbed.
Cysticercosis of the lungs.
Cysticercosis of the lungs in most cases, proceeds without pronounced clinical symptoms and is detected by chance during an X-ray examination. On the roentgenogram, round shadows are visible, mainly intense with clear boundaries ranging from a grain of pepper to a small cherry. These shadows, as a rule, are scattered in both pulmonary fields, their number can vary from several units to several tens. The foci of parasites can be partially or completely calcified.
Diagnosis of Cysticercosis
For cysticercosis of the brain, the clinical course of the disease is typical, characterized by sudden exacerbations and prolonged remissions, polymorphism of neurological symptoms with prevalence of irritation symptoms, lymphoid-neutrophilic cerebrospinal fluid pleocytosis (in 93%), and eosinophilia of the blood (not always). When diagnosing it, X-ray data (craniography, radiography, encephalo- and ventriculography, angiography) are also taken into account, the results of a serological examination – RSK, ELISA, NRIF, RNGA.
The diagnosis of cysticercosis of the skin and muscles can be made on the basis of a biopsy of nodules and radiography of calcified cysticerci.
Cysticercosis of the eye can be determined by ophthalmoscopy.
When soft tissues are damaged by cysticerci, if they do not cause mechanical irritation and damage to the central nervous system and eyes is excluded, treatment is not carried out, the patient remains under observation. This is due to the fact that specific drugs – mebendazole (vermox) and praziquantel (azinox) cause the death of parasites, the breakdown products of which can give severe adverse reactions of an allergic nature.
Surgical treatment of cysticercosis of the eye and single cysticerci of the brain. Additionally, etiotropic therapy with praziquantel at 50 mg / kg per day for 15 days orally against the background of the use of dexamethasone 4-16 mg per day. Etiotropic therapy with praziquantel is also carried out in inoperable cases of cerebral cysticercosis.
The prognosis for soft tissue cysticercosis, even multiple ones, is favorable, with damage to the eyes and central nervous system – poor, especially with late diagnosis and the absence of the possibility of surgical treatment.
Prevention of cysticercosis is the successful fight against teniosis and compliance with personal preventive measures.