Renal echinococcosis is a parasitic disease caused by small tapeworms of the genus Echinococcus. The symptoms are variable and correlate with the evolution of a cystic tumor and its localization. Small formations may not be clinically manifested for several decades, with growth, lumbar pain, unexplained hyperthermia, weakness are bothering. Diagnosis is based on ultrasound, CT or MRI data, laboratory tests. Surgical treatment is carried out after taking anthelmintic agents. Surgical intervention is performed in the volume of puncture and sclerosing of an echinococcal tumor, radical echinococcectomy. With a completely destroyed kidney, a nephrectomy is performed.
ICD 10
B67.3 B67.6 B67.9
Meaning
Renal echinococcosis has been known since the time of Hippocrates, but then the pathology was mistaken for dilated lymphatic vessels. In 1801, the disease acquired a name, the term was introduced by the German naturalist and founder of helminthology Rudolfi (from the Greek “echinatus” — “possessing thorns”). Zooanthroponous invasion is widespread everywhere, where animal husbandry is developed. Women are more susceptible to the disease, the average age of detection of echinococcus is 30-40 years. In children, pathology is diagnosed by chance, it may take from 5 to 20 years before the first symptoms appear.
Causes
The adult worm E. Granulosus lives in the colon of foxes, dogs, less often cats, which are the final hosts. They become infected by eating the organs of fallen pets or getting dirty on their fur with feces. Cattle get sick on pastures where the grass is seeded with larvae. A person is an intermediate host of the helminth, he cannot infect anyone himself. The rate of growth of an echinococcal tumor is affected by the number of oncospheres, the immune status, and the age of the patient. The risk group consists of people engaged in animal husbandry, hunters, berry pickers. The main causes of zooanthropohelminthiasis:
- Alimentary infection. The parasite enters the gastrointestinal tract with fecally infected food (berries, mushrooms), water. This transmission path is most common. In sick animals, larvae are released through the anal opening onto the wool. If hygiene rules are not followed after communicating with pets, contact with their excrement (through dirty hands), the germ of helminth reaches the human intestine.
- Aspiration infection. When inhaling dry feces of sick animals, echinococcus larvae settle on the mucosa of the bronchopulmonary tract. When coughing during ingestion of sputum with oncospheres, they enter the gastrointestinal tract, and then are transferred through the blood or lymph circulation system to the kidney, where they attach and initiate the development of education. Primary lung or liver damage may be absent. Why this happens is not known for certain.
Pathogenesis
In the human intestine, echinococcus is exposed to enzymes that destroy the larval shell. Oncospheres are released by hooks pushing through the mucous membrane to the vessels. The parasite moves into the portal system with the blood flow, and from there it migrates through the inferior vena cava to the right parts of the heart and the small circle of blood circulation. With blood, the larvae can reach the lungs and further — a large circle of blood circulation. If this happens, there is a risk of spreading to any organs.
In the kidney, the precipitated larva initiates a pathological process. A bubble with an echinococcus germ is similar to a sphere that, with integration and further development, begins to grow by 1 mm per month. The lack of timely diagnosis leads to the formation of large neoplasms, which is typical for cystoid echinococcosis. The contents are a whitish liquid with protoscolexes and acephalocysts. In alveolar echinococcosis, the maternal cyst is absent, the organ tissues are filled with multiple alveoli of different sizes. Growth is carried out due to exophytic proliferation (budding).
Classification
Renal echinococcosis is mainly a unilateral process, left—sided lesion is more common. Zooanthroponous invasion can be secondary (the parasite enters with blood or lymph flow from other organs) or primary (the pathogenesis is not clear enough). The two most common forms of pathology are cystic (the causative agent of E. Granulosus) and alveolar (E. Multilocularis). The latter is extremely rare, proceeds more heavily. Urologists distinguish the following types of parasitic neoplasms:
- Closed with an intact wall. There is no communication with any cavities; all three layers (pericyst, ectocyst and endocyst) are not damaged.
- Pseudoclosed cyst. The cavity is connected to the renal calyx, washed with urine. There is no pericyst.
- An open cyst. The integrity of all three shells is broken. There is a communication with the cup-pelvic system, which causes echinococcuria.
On a quantitative basis, echinococcal cysts are single (solitary) and multiple. If the pathology is present in several organs, they speak of a combined pathological process. Small (up to 5 cm), medium (5-10 cm), large (10 cm or more) formations are determined by size. Modern imaging methods allow us to potentially assess the viability of a cyst: with live parasites, with signs of “aging”, a dead bladder (fibrosis, imitation of a tumor, calcification). According to morphology , there are four types:
- The first. A simple cyst without partitions, manifests itself as a clear rounded formation filled with fluid. This pattern is more typical for nonparasitic tumors, with renal echinococcosis, an acephalotic cyst is formed if daughter blisters do not develop from the scolexes.
- Second. An echinococcal cyst contains daughter cysts with scolexes and a matrix. According to the density and localization of secondary structures, specialists determine the stage of the pathological process. Daughter formations can be defined along the periphery (I art.) or occupy the entire volume of the maternal cyst, which visually resembles a rosette or honeycomb (III art.). At the initial stage, the maternal bladder is denser than the rest, then scattered calcifications and multiple high-density cysts are visible.
- Third. Dead formations with calcification. Sometimes, for unknown reasons, the parasite dies (under the action of the body’s defenses, due to lack of nutrition), the cyst stops developing. Potentially, such an outcome is likely against the background of taking anthelmintic drugs. Hydatid sand consists of dead scolexes and chitinous hooks.
- Fourth. The group includes parasitic cysts complicated by rupture or infection.
Symptoms
For many years after infection, clinical manifestations may be absent. As the invasion progresses, the kidney is displaced, and the cups and pelvis are deformed, which gradually leads to atrophy of structural units — nephrons. The process is accompanied by a dull lumbar pain on the side of the lesion. In case of violation of the outflow of urine, classical renal colic develops with severe pain syndrome, nausea, vomiting. Taking painkillers brings temporary relief.
On palpation in patients with an insignificant layer of adipose tissue, a large volume formation can be defined as a tumor mass in the hypochondrium. The cyst is smooth or bumpy, of a dense elastic consistency, moderately painful. Pasternatsky’s symptom is weakly positive, sharp soreness when beating over the kidney indicates concomitant pyelonephritis or a violation of the passage of urine.
Echinococcal infection is accompanied by intoxication, asthenia, hyperthermia. Body temperature is subfebrile or febrile. Patients complain of a progressive decrease in body weight, lack of appetite, aching bones and muscles. An allergic reaction of a delayed type develops with an open echinococcal cyst, manifested by skin itching and urticaria rash as with urticaria. Symptoms of renal insufficiency (nausea, decreased diuresis, edema) are more typical for echinococcosis of a single or only functioning kidney.
Complications
Complications of renal echinococcosis include an independent breakthrough of a tense cyst with the outpouring of fluid into the abdominal cavity, which more often occurs during childbirth, falling, compression. The situation is aggravated by an immediate hyperallergic reaction and anaphylaxis. The condition is life-threatening, accompanied by a sharp collapse of blood pressure and a violation of hemodynamics. Sometimes there is a rupture of the involved vessels with bleeding.
The addition of a secondary infection initiates pyelonephritis, which sometimes becomes purulent. This is facilitated by the spontaneous opening of the bladder into the cup-pelvis system and the persistence of microbial flora. A large parasitic formation compresses the renal structures, causing the death of functional tissue. In 10-15% of patients, total wrinkling of the cortical and cerebral layers is diagnosed, which requires organ-bearing surgery. A healthy contralateral organ in 80-85% of patients copes with a double load. CRF is observed with a bilateral lesion, burdened with a urological history.
Renal echinococcosis can lead to nephrolithiasis. Stone formation occurs due to a violation of the outflow of urine, the persistence of infection, the presence of a suitable matrix. Hydatiduria in open forms is more often detected microscopically, sometimes large daughter cysts can provoke acute urinary retention. Another complication is the recurrence of echinococcosis after surgery, which is rare with the modern approach to treatment.
Diagnostics
The preliminary diagnosis before the intervention is established in 70-80% of patients, the final one can be clarified intraoperatively. About 10% of cases of pathology are determined morphologically. Alveolar renal echinococcosis visually resembles a tumor process, therefore, an oncologist’s consultation is indicated. The patient’s medical history is carefully collected, paying attention to contact with animals, trips to endemic areas. In addition to the urinary system, other organs are evaluated, since echinococcosis is often manifested by combined lesions. Examination algorithm for zooanthropohelminthiasis:
- Laboratory diagnostics. Leukocyturia, micro- and macrohematuria are non-pathognomonic for echinococcosis, occur in 20%. A sign confirming the pathology (hydatiduria) is detected in 10-20% of patients. UAC in 65% of patients shows accelerated ESR, in 30-50% — an increased number of eosinophils, in 30% there is leukocytosis. Anemia is typical for long-term invasions, especially with permanent hematuria. Serological tests for the presence of antibodies to E. Granulosus and E. Multilocularis in 30% give false negative results, therefore, confirmatory tests are often required: RLA, RNGA, RIFA, AE.
- Instrumental visualization methods. Kidney ultrasound locates daughter cysts, floating membranes, hydatid sand. Changing the patient’s posture in real time leads to shifting of the sand, which resembles falling snow. A kidney CT scan usually visualizes a rounded formation with a clearly defined double wall and daughter blisters along the inner edge of the maternal tumor or throughout the cavity. MRI has no advantages over CT. Cystoscopy determines the hyperemia of the bladder mucosa, sometimes you can see cysts born from the ureter or freely moving cysts.
Differential diagnosis
Differential diagnosis is carried out with a non-parasitic cyst, a malignant neoplasm. Sometimes, according to pathomorphological research, the biomaterial contains neoplastic cells, that is, the two processes can be combined with each other. Specific laboratory tests for renal echinococcosis can confirm or exclude pathology by 90%. There is no unambiguous point of view on the expediency of conducting a biopsy. The high risk of dissemination does not allow all patients to perform it, especially in non-specialized clinics.
Treatment
Pathology treatment is mainly surgical. If the formation has a small size (less than 30 mm), some specialists adhere to the tactics of active observation, the operation is performed only when signs of growth are detected. With inactive cysts that have lost their viability, conservative management is also acceptable. To reduce the parasitic load, special drugs with an anthelmintic effect are prescribed. The dosage and frequency of administration are determined individually.
Medical treatment
As an independent method, drug therapy is used in patients with the inability to perform surgery or with small parasitic cysts. It has been proven that taking anthelmintic agents before and after surgery reduces the risk of relapses to a minimum (1%). Medications affect echinococcus at any stage of development. Modern parasitology prefers albendazole. The drug has significantly fewer side effects compared to the previously used mebendazole.
Albendazole is effective in monoinvasions and polyinvasions. The action is carried out by suppressing the polymerization of beta-tubulin and the destruction of the cytoplasmic tubules of intestinal helminth cells. The drug blocks ATP synthesis and glucose utilization, which leads to the death of the parasite. The negative sides include the development of the effect in some patients only after a second course of treatment. Since the drug is mainly metabolized by the liver, there is no need to titrate the dose for CRF.
Surgical treatment
Previously, mainly invasive interventions were performed: open pericystectomy, cystectomy, cyst resection. Today, these methods are reserved for the treatment of parasitic neoplasms with exogenous proliferation, massive calcification of the fibrous capsule. Some studies have shown that the results of operations are comparable regardless of the degree of their traumatism, provided that pre- and postoperative anthelmintic therapy is carried out, and appropriate treatment is carried out. The following types of surgical care are used:
- Cystectomy, pericystectomy, resection. Superficial echinococcal tumors (without involvement of the renal parenchyma) are eliminated by cystectomy or pericystectomy. If the formation has sprouted a renal parenchyma, partial resection of the organ is performed. Interventions are carried out in an open or laparoscopic way. To restore large defects, omentoplasty is performed. A simple echinococcectomy, which does not involve the removal of a fibrous capsule, allows to minimize tissue damage.
- Nephrectomy. Complete degeneration of the renal tissue and loss of the functional ability of the organ is an indication for nephrectomy. If appropriate equipment is available, the intervention can be performed laparoscopically, which is easier for patients to tolerate. According to statistics, the need for the use of organ-bearing techniques is noted in 25% of patients. Before the invention of antiparasitic drugs, kidney removal was performed more often, now even with confirmed residual cysts, they try to preserve the organ.
- Percutaneous intervention. Percutaneous cyst treatment (PAIR puncture, aspiration, injection of a scolicidal agent, repeated aspiration) refers to gentle operations. With ultrasound control, PAIR can become an alternative to invasive techniques for the elimination of hydatid cysts that are not associated with the urine collection system. The disadvantages are the risk of the spread of daughter bladders, the likelihood of anaphylaxis.
Prognosis and prevention
With timely treatment of cystic echinococcosis, the outcome is favorable, with the alveolar form, the prognosis worsens due to the more frequent addition of chronic renal failure. In case of rupture of the echinococcal bladder and contamination of the abdominal cavity with contents without the appointment of anthelmintic therapy, the outcome may be unfavorable. Relapses with modern approaches to treatment, as well as re-infection, are rare.
Prevention includes avoiding the use of unboiled water and raw berries harvested in endemic areas, adequate hygiene. It is unacceptable to feed pets with meat from uncontrolled slaughter or after death. Food, dishes should be kept closed to prevent the ingress of helminth larvae with the wind. Dogs of sheep-breeding areas should receive preventive anthelmintic therapy. The population is informed about the contagiousness of echinococcosis, the consequences and measures to prevent zooanthroponotic invasions.