Pancreatic echinococcosis is one of the forms of helminthiasis, which is caused by the larvae of the echinococcal tapeworm and leads to the formation of parasitic cysts in the pancreas. The disease is manifested by discomfort and pain in the epigastric region, nausea, and stool disorders. When the pancreatic ducts and gallbladder are compressed, skin and sclera ictericity, fecal discoloration, and dark urine coloration occur. Diagnosis is based on data from serological tests, physical examination, ultrasound, CT, endosonography of the pancreas. In the treatment, along with antiparasitic drugs, partial removal of the gland with an echinococcal bladder, closed echinococcectomy and marsupialization of the cyst are used.
B67.9 Echinococcosis of other organs and unspecified
Pancreatic echinococcosis is a disease caused by the penetration and parasitization of the tapeworm Echinococcus with the formation of one or more cystic cavities in the parenchyma of the organ. Isolated lesion of the gland is rare, more often it is combined with parasitic invasion of other organs. The prevalence of pancreatic echinococcosis is 0.25-2% among all diseases caused by echinococcus. Pathology is more common in countries with pastoral cattle breeding, especially where dogs are used for animal protection (Uruguay, Argentina, Libya, Australia).
Transmission of infection to humans occurs from the final host (dogs, wolves, jackals, etc.). Echinococcus larvae (lavrocysts), located in the small intestine of animals, enter the environment with feces. Infection of people occurs alimentary (when using poorly processed fruits, vegetables, water) or by contact (during the collection of mushrooms, berries, butchering carcasses or in contact with infected animals).
The eggs of the biohelminth enter the human gastrointestinal tract, where they lose their shells, turn into embryos and are absorbed into the blood. At the same time, a person acts as an intermediate host of the larval stage of the parasite, does not secrete echinococcal lavrocysts and is not a source of infection. The group at increased risk of the incidence of echinococcosis includes people whose professions and occupations are related to cattle breeding and animal husbandry (hunters, shepherds, butchers, etc.). There are cases of transmission of the disease from the mother to the fetus by placental route.
Echinococcus embryos, once in the vascular bed, penetrate the liver through the portal vein system. Having overcome the hepatic barrier, they are directed through a small circle of blood circulation to the lungs. From the pulmonary veins, parasites enter the left atrium and then penetrate into the pancreas in a large circle. Having settled in the gland, the biohelminth changes and takes the form of a two-layer single-chamber bubble, the cavity of which is filled with a transparent liquid with free-floating daughter bubbles. The parasitic formation gradually grows and can grow to huge sizes (20-30 cm).
The pathogenesis of echinococcosis is caused by the sensitizing and mechanical effects of a growing larva. A parasitic cyst, increasing in size, squeezes the surrounding tissues, causing a violation of the blood supply to the pancreas, dysfunction and gradual atrophy of the organ. The sensitizing effect is characterized by the accumulation of echinococcal waste products in the body and the development of an allergic reaction of an immediate or delayed type, which may manifest as itching, rash or anaphylactic shock.
Echinococcal cysts can be single or multiple. Small (up to 5 cm), medium (up to 10 cm) and large (more than 10 cm) parasitic bladders are distinguished by size. According to the nature of the course of the pathological process in clinical gastroenterology , there are 2 variants of pancreatic echinococcosis:
- Hydatid (bubble). The causative agent of this form is E. granulosus. The hydatid cyst has a single-chamber structure. It grows rapidly, squeezing the pancreatic tissue and causing its dystrophic changes. This form is typical for the countries of the Mediterranean, Central Asia, the North Caucasus, Latin America.
- Alveolar (alveococcosis). E. multiocularis is called. Alveococcal cysts increase slowly, have a multicameral structure, a thick-walled shell. The disease is characterized by a malignant course and a tendency to infiltrating germination into the tissues and blood vessels of the gland. This form of echinococcosis is more often registered in Siberia and the Far East.
Symptoms of pancreatic echinococcosis
Clinical manifestations of the disease depend on the size, location of the parasitic cyst and the degree of compression of the organ tissues. The most common localization of echinococcosis is the head of the gland. In this case, compression of the main pancreatic or common bile ducts occurs with the development of mechanical jaundice. Patients complain of intense pain in the upper abdomen, nausea, vomiting, jaundice of the skin and mucous membranes, fecal discoloration and dark urine. With partial obstruction of the ducts, chronic pancreatitis develops, which proceeds with periods of exacerbation and clinical remission.
When cysts are localized in the body and tail of the gland, symptoms of pancreatitis of varying intensity occur: patients note pressing pains in the epigastric region, which increase with physical exertion, weight loss, abdominal discomfort, nausea, stool disorder. With large cyst sizes, a rounded tumor-like formation in the epigastric region is determined during palpation of the abdomen. The toxic effect of echinococcus can cause allergic reactions (rash, itching), headaches, fever to febrile values, chills, general weakness.
One of the frequent complications of pancreatic echinococcosis is infection of the parasitic bladder with the formation of an abscess. The breakthrough of the pancreatic abscess leads to the penetration of the contents of the suppurated cyst into the abdominal cavity with the development of peritonitis. Spontaneous rupture of the echinococcal bladder as a result of a blow, fall, and sudden physical exertion is accompanied by the spread of larvae to other organs with the formation of multiple foci of echinococcosis. In addition, when the cyst ruptures, a severe allergic reaction occurs, up to anaphylaxis. Obstruction of the pancreatic and bile ducts can lead to cholangitis, and prolonged compression of the gland structures can lead to the development of pancreatic necrosis.
Echinococcosis pancreas is a rare and difficult to diagnose disease that is of interest to doctors of various specialties (epidemiologists, surgeons, gastroenterologists, etc.). To verify the diagnosis, the following examinations are carried out:
- Examination of a gastroenterologist. When collecting anamnesis, the specialist notes the atypical course of pancreatitis, draws attention to exacerbations not related to errors in diet and alcohol abuse. When questioned, an important role is played by the epidemiological history and the patient’s stay in endemic areas.
- Ultrasound of the pancreas. Allows you to determine the presence and localization of the cyst, calcification of its walls. For differential diagnosis, in the absence of a clear visualization of the formation, increased gas formation in the intestine and a large thickness of the fat layer, endoscopic ultrasonography (EUS) is performed. This method gives high image clarity and allows you to see the most inaccessible areas of the organ.
- CT scan of the pancreas. With the help of tomography, the exact dimensions of the echinococcal bladder are determined, its location in relation to adjacent anatomical structures. During the study, a dense calcified shell and membranes of daughter vesicles are visualized.
- Laboratory tests. Blood test determines persistent eosinophilia, leukocytosis, acceleration of ESR. A positive reaction of Cazzoni is noted. Serological reactions (RPH, ELISA) make it possible to detect antibodies to echinococcus in the blood.
A fine needle cyst biopsy with cytological examination is rarely performed due to the high risk of infection spreading through the puncture canal. Echinococcosis should be differentiated with abscess, benign and malignant tumors of the pancreas, cysts of non-parasitic etiology.
The most effective method of treatment is surgery. Surgical manipulations are aimed at removing all cyst structures, preventing the dissemination of echinococcus and the development of complications. With echinococcosis of the tail of the pancreas, distal resection of the organ is performed together with the bladder. If the cyst is localized in the tail or body and there is no fusion with the surrounding tissues, a closed echinococcectomy is performed.
To prevent contamination of the abdominal cavity at the initial stage of this operation, the destruction of echinococcal scolexes and drainage of the contents of the bladder is carried out. To do this, a solution toxic to echinococcus is injected into the cyst cavity with a thin needle. Then carefully evacuate the contents of the cyst, followed by washing the bladder cavity with a hypertonic NaCl solution. After complete aspiration of the bubble fluid, the abdominal cavity in the intervention area is intensively treated with antiseptic agents.
In some cases, the cyst is marsupialized – partial removal of one of the walls of the bladder and subsequent stitching it to the parietal peritoneum. To prevent relapses in the postoperative period, as well as with small sizes of parasitic formation and the inability to perform surgery (severe condition of the patient, age), antiparasitic therapy is prescribed.
Prognosis and prevention
With timely detection and treatment of echinococcosis, the prognosis is favorable. Infiltrating growth, large size of a parasitic cyst, developed complications (rupture, abscess of the cyst) can cause life-threatening conditions (anaphylaxis, peritonitis) up to death.
In order to prevent infection, it is recommended to follow the rules of individual hygiene (wash hands, vegetables and fruits before eating), use protective equipment when working with animal skins and meat. Programs for the prevention of echinococcosis include deworming of domestic animals and stray dogs, compliance with sanitary standards in slaughterhouses, regular examination for echinococcosis of persons at risk (hunters, workers of meat processing plants, etc.).