What is Hydatid Cyst?

It is a parasitic hydatid cyst disease caused by Echinococcus Granulosus. It is a parasitic disease in which larvae living in the small intestines of carnivores such as dogs, cats, foxes and wolves cause cyst formation in the internal organs. The disease can affect all organs in the body, but it most commonly affects the liver, lungs and spleen.

In our country, the incidence of hydatid cysts is reported as 2/1000000-1/2000 in different studies. Since it can progress without symptoms, only 10-20% of patients under the age of 16 can be diagnosed. Although the cyst is most commonly seen in the liver, lung localization is more common in children. Lung involvement spreads from the liver through blood and lymph. Lung cysts are more commonly located in the lower lobe of the right lung. The main symptoms in lung involvement are chest pain, cough and hemoptysis.

What is the Evolution (Life Cycle) of the Parasite?

The eggs that are released from the parasite that sticks to the final host animals such as dogs, cats, foxes, wolves, etc. are scattered around. These eggs survive in water for 7 days, in ice for 4 days, and in soil for 10 months. Later, as a result of the consumption of food (grass, water, etc.) contaminated with parasite eggs by animals such as sheep and goats, which we call intermediate hosts, the eggs pass into the intestines and hatch, mixing with the bloodstream and causing cyst formation in the internal organs.

Later, when the organs containing the cysts are eaten by carnivores, the parasite reaches the intestines of these animals again and becomes an adult. Humans can also serve as intermediate hosts from time to time. If vegetables and fruits contaminated with parasite eggs are taken orally, the eggs hatch in the intestines and the life cycle of the parasite continues in the same way. At the same time, uncontrolled animal movements between regions or countries also play an important role in spreading the infestation.

Is Cyst Hydatid Transmitted Through the Respiratory Tract (Breathing)?

Since the shells of parasite eggs taken through the respiratory tract are dissolved by enzymes in the tissue, transmission through this route is not possible.

 

Figure: Life Cycle of Hydatid Cyst

Who is at Risk for Lung Hydatid Cyst?

The person's profession, hobbies, living conditions, education and socioeconomic level affect the risk of contracting the disease. The highest risk group consists of people who have contact with infected dogs that have been left to roam free without any parasite control and who are engaged in animal husbandry such as sheep, goats and cows. In recent years, it has also started to be seen commonly in people who keep cats and dogs at home but do not engage in animal husbandry.

The least at-risk group in contact with these animals is people who consciously keep cats and dogs at home. The fur of cats and dogs that are consciously cared for does not pose any risk.

What are the General Symptoms of Hydatid Cyst in Children?

Cyst is a pathology that grows and matures slowly and over the years. Since the cysts are very well encapsulated, the disease may not show systemic symptoms such as fever, weakness and weight loss in the early stages. Therefore, patients appear quite healthy whether the cyst is in the liver or another organ. Although the case may progress for a while without any clinical symptoms, some complaints may occur depending on the organ it is located in due to the rupture or infection of the cyst. These complaints are usually in the form of abdominal pain, nausea, vomiting, jaundice, difficulty breathing, cough, headache, hearing, vision, perception and coordination disorders.

What are the Clinical Symptoms of Lung Hydatid Cyst in Children?

Hydatid cyst, which shows a very slow development (1-3 cm per year), can reach larger sizes and show symptoms earlier than other organs due to the spongy structure of the lung tissue. Cough, chest pain, weakness, fever, sputum and developmental delay in children are the most common symptoms. Symptoms vary depending on the location and size of the cyst. If the cyst is located close to the airways and cardiovascular system in the lung, symptoms are seen earlier. In some patients, the cyst can be opened to the airway and expelled with coughing. In this case, the fertile layer of the cyst, which is in the form of a large amount of clear liquid (rock water) or a substance with the consistency of cooked egg white (membrana mere), can be expelled from the lungs with coughing.

In long-term hydatid cyst cases, red rashes on the skin and asthma-like breathing difficulties can be seen. As a result of a rupture of a section of the sac forming the cyst, the cyst fluid leaks into the chest cavity and can cause a picture similar to a lung abscess if it is not noticed. In cases where lung abscess occurs, nonspecific chronic infection symptoms such as fever, weight loss, and bleeding from the respiratory tract are noted. In cases where the sac forming the cyst ruptures completely, parasite spread, allergic reaction, and anaphylactic shock (severe allergic reaction) may be observed. Anaphylaxis is the rare but most feared complication of lung hydatid cysts.

How is Lung Hydatid Cyst Diagnosed?

Lung Hydatid Cyst is diagnosed with history and physical examination, and the diagnosis is confirmed with blood tests and imaging methods.

What kind of complaints may be present in the history was explained above. Lung cysts can sometimes be detected while being investigated for liver hydatid cysts, and sometimes during investigations for recurrent lung infections. It may present with allergy symptoms, respiratory complaints, and recurrent cough attacks.

Different findings suggestive of hydatid cysts are observed on the chest radiographs of patients with pulmonary hydatid cysts who have the symptoms described above. Cystic structures can be largely determined by computerized chest tomography taken after the chest radiograph.

The diagnosis of hydatid cysts can be supported by some blood tests. However, some serological tests used in the diagnosis of liver hydatid cysts are also used in lung hydatid cysts. However, the sensitivity of these tests is lower in lung hydatid cysts.

These tests are; Immunofluorescent Antibody (IFA) Test, Western Blot Test, Casoni Skin Test, Indirect Hemagglutination (IHA) Test, Enzyme-Linked Immunosorbent Assay (ELISA) Test. For more detailed information about these tests, please see the article on liver hydatid cysts.

 

Image: Lung Hydatid Disease Chest X-ray and Tomography Images

How is Lung Hydatid Cyst Treatment Performed in Children?

The basic treatment for lung hydatid cysts is surgery. Surgery can be performed openly or thoracoscopically. The aim of surgical treatment is to eradicate the parasite, to avoid intraoperative rupture to prevent dissemination (spreading to the environment), and to eliminate the cavity by preserving the lung parenchyma as much as possible. In order to prevent recurrences, it is beneficial to take medication (Albendazole) for a certain period before and after the surgery.

In cases where the hydatid cyst is found in both the lung and the liver (10-20%), surgical intervention is required for cysts in both organs. It is beneficial to perform the surgeries in separate sessions, and the lung hydatid cyst should be removed first.

 

Picture: Appearance of vesicles during surgery for hydatid cysts

What are the Complications of Lung Hydatid Cyst Surgery in Children?

Since the surgery will be performed under general anesthesia, there may be some complications of anesthesia. These may include bleeding, sometimes long-term air leaks, and the most important complication is recurrence (recurrence of the cyst) if adequate precautions are not taken against the spread of cysts to the surrounding area, and even a cyst may recur as more than one cyst. Other complications that can be encountered frequently include abscess in the cyst area and wound infection. While many of these resolve spontaneously with a thoracic drain and appropriate treatment, some may require a second surgery.

How to Protect Yourself from Hydatid Cysts?

• Raw foods should never be given to dogs and cats.
• Personal hygiene principles should be followed,
• Drinking and utility water should be clean,
• Raw vegetables and fruits should be washed thoroughly with plenty of water before consumption.

 

Animal slaughtering should be done in slaughterhouses and under the supervision of a veterinarian. The organs of slaughtered or dead animals, especially those containing water-filled sacs, should be buried and disposed of in a way that dogs and other carnivorous animals cannot reach. More attention should be paid to these issues, especially during Eid al-Adha.

• Owned dogs and cats must be treated for ‘echinococcus granulosus’ by special law, and if they defecate while being walked by their owners, the feces should be disposed of appropriately.
• Owner dogs should be collected by the relevant persons in the municipalities and the necessary procedures should be carried out.
• When dogs sniff each other’s anuses, parasite eggs can get on their noses and fur. Parasite eggs can be transferred to the hands when dogs roam freely without fighting against parasites. Parasite eggs are taken by putting contaminated hands in the mouth without washing them. Therefore, children in particular should not be allowed to play with stray dogs, and hands should be washed with plenty of soap and water in case of contact.

The embryo (oncosphere) in the 'Echinococcus granulosus' egg can be killed with hot water at 60°C for 10 minutes, at 70°C for 5 minutes, and at 100°C for 1 minute.

*** The information provided here and the content of the website are designed to inform visitors, especially families. No information should be considered as advice by visitors and should not lead to any decision or action. Families should definitely have a pediatric surgeon examine them on the subject, consult with them and make a decision based on their personal knowledge.