Zaporozhyan state medical university departement of infectious diseases

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Features of lung involvement depend on localization of the cyst. If it is close 

to pleura, pain syndrome is the early manifectation. If it localizes close to 

pulmonary trunk, patient can have cough, haemoptysis, dyspnoea. 

Other presentations are due to the involvement of bone (invasion of the 

medullary cavity with slow bone erosion producing pathologic fractures), the CNS 

(space-occupying lesions with intracranial hypertension and epilepsy), the heart 

(conduction defects, pericarditis), and the pelvis (pelvic mass). 

ECHINOCOCUSS 

 

Complications. One of the most severe complications is rupture of 

echinococcus cyst, which can occur spontaneously or at surgery and may lead to 

multifocal dissemination of protoscolices, which can form additional cysts. 

Rupture of the cyst may also lead to allergic manifestations such as pruritus, 

oedema, dyspnoea, anaphylactic shock and appearance of peritonitis, pleuritis, 

meningitis or other inflammatory reactions.  

Specific diagnostics. A number of serological tests have been developed for 

detection of antibody to specific echinococcal antigens, for example, an immune-

enzyme analysis, a Western blot assay. Cysts in the liver elicit positive antibody 

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responses in 90% of cases, whereas up to 50% of individuals with cysts in the 

lungs are seronegative. That’s why a negative test does not exclude the diagnosis 

of echinococcosis. Another drawback in serological diagnostics is cross-reactivity 

with sera of patients with Taenia solium.  

Radiographic and related imaging studies are important in detecting and 

evaluating echinococcal cysts. Plain x-rays will define pulmonary cysts of E. 

granulosus – usually as rounded masses of uniform density – but may miss cysts in 

other organs unless there is cyst wall calcification (as occurs in the liver). MRI, 

CT, and ultrasound reveal well-defined cysts with thick or thin walls. However, the 

most pathognomonic finding, if demonstrable, is that of daughter cysts within the 

larger cyst. This finding, like eggshell or mural calcification on CT, is indicative of 

E. granulosus infection and helps to distinguish the cyst from carcinomas, bacterial 

or amebic liver abscesses, or hemangiomas. In contrast, ultrasound or CT of 

alveolar hydatid cysts reveals indistinct solid masses with central necrosis and 

plaquelike calcifications. 

Examination of sputum, duodenal juice, faeces can be done to find 

protoscolices in case of rupture of the cyst into hollow organs.  

In general blood analysis can be seen nonpermanent eosinophilia to 15 % 

and increased ESR. 

Treatment. Therapy for cystic echinococcosis is based on considerations of 

the size, location, and manifestations of cysts and the overall health of the patient. 

Surgical removal of hydatid cysts remains the treatment of choice in many 

countries. In some countries PAIR (percutaneous aspiration, infusion of scolicidal 

agents, and reaspiration) is now recommended instead of surgery. PAIR is 

contraindicated for superficially located cysts (because of the risk of rupture), for 

cysts with multiple thick internal septal divisions, and for cysts communicating 

with the biliary tree. For prophylaxis of secondary peritoneal echinococcosis due to 

inadvertent spillage of fluid during PAIR, the administration of albendazole (15 

mg/kg daily in two divided doses) should be initiated at least 4 days before the 

procedure and continued for at least 4 weeks afterward. PAIR, when implemented 

by a skilled practitioner, yields rates of cure and relapse equivalent to those 

following surgery, with less perioperative morbidity and shorter hospitalization. 

Surgery is the treatment of choice for complicated E. granulosus cysts (e.g., 

those communicating with the biliary tract) or for areas where PAIR is not 

possible. For E. granulosus, the preferred surgical approach is pericystectomy, in 

which the entire cyst and the surrounding fibrous tissue are removed. Albendazole 

should be administered adjunctively, beginning several days before resection and 

continuing for several weeks after it.  

Chemotherapy. Benzimidazole compounds have been shown to be effective 

against hydatid disease. The administration of 3-4 courses of albendazole in a dose 

of 10 to 15 mg/kg body weight per day (divided in two doses) for 28 days with 

drug-free periods of 2 weeks is used. This regime cures approximately one-third of 

cases of liver hydatid disease and causes partial regression of cysts in another third 

of patients. Small liver or lung hydatid cysts may be treated with albendazole. 

Albendazole is also indicated, when surgery is contraindicated. Mebendazole may 

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also be used, although it is less effective than albendazole. Albendazole, 

mebendazole, and other benzimidazole compounds should not be used in pregnant 

women because of their potentially teratogenic effects. Since benzimidazoles are 

potentially hepatotoxic, liver enzymes should be monitored before and during 

treatment. 

Regular medical check-up of patient with Echinococcosis after operation 

lasts not less than 8 years. Patients should be examined by different doctors 

(gastroenterologist, pulmonologist, neuropathologist and others, dependently on 

prior localization of cyst) not less than 1 time in two years. Instrumental and 

serological examination should be done to them. 

 

HYMENOLEPIASIS NANA Infection with H. nana, the dwarf tapeworm, 

is the most common of all the cestode infections. H. nana is endemic in both 

temperate and tropical regions of the world. Infection is spread by fecal/oral 

contamination and is common among institutionalized children. 

Etiology and Pathogenesis. H. nana is the only cestode of humans that does 

not require an intermediate host. Both the larval and adult phases of the life cycle 

take place in the human. The adult—the smallest tapeworm parasitizing humans—

is 2 cm long and dwells in the proximal ileum. Proglottids, which are quite small 

and are rarely seen in the stool, release spherical eggs 30–44 

m in diameter, 

each of which contains an oncosphere with six hooklets. The eggs are immediately 

infective and are unable to survive for >10 days in the external environment. When 

the egg is ingested by a new host, the oncosphere is freed and penetrates the 

intestinal villi, becoming a cysticercoid larva. Larvae migrate back into the 

intestinal lumen, attach to the mucosa, and mature into adult worms over 10–12 

days. Eggs may also hatch before passing into the stool, causing internal 

autoinfection with increasing numbers of intestinal worms. Although the life span 

of adult H. nana worms is only 4–10 weeks, the autoinfection cycle perpetuates the 

infection. 

The life cycle of Hymenolepis nana starts, when microscopic eggs are 

passed with the stool of an infected human. They then get ingested either by 

rodents, humans (definite hosts) or insects (intermediate hosts). If a person ingests 

eggs (from contaminated fingers, water, food or soil), oncospheres (hexacanth 

larvae) hatch in the small intestine.  

A larva penetrates an intestinal villus and develops into a cysticercoid. A 

cysticercoid develops to look more like an adult having a scolex (head) and a neck. 

It bursts out of the villus, attaches to the intestinal mucosa and matures into an 

adult in the last part of the small intestine, ileum. Its long neck starts producing 

segments, proglottids, which make up the body.  

A proglottid absorbs nutrients from the surroundings and grows bigger 

before it detaches from the tail. Each proglottid has both male and female 

reproductive organs. It copulates with itself or with other proglottids of the same 

individual or nearby tapeworms. A gravid proglottid releases thousands of eggs 

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