Hydatid Disease

Question 1

What is Human Echinococcosis?

Answer 1

Human Echinococcosis is a zoonotic infection caused by larval forms (metacestodes) of tapeworms of the genus Echinococcus, typically found in the small intestine of carnivores like dogs and foxes. These carnivores are the normal hosts of the tapeworm.

Question 2

Which Echinococcus species are pathogenic for humans?

Answer 2

The two Echinococcus species pathogenic for humans are E. granulosus and E. multilocularis.

Question 3

How does the World Health Organization (WHO) distinguish between the diseases caused by E. granulosus and E. multilocularis?

Answer 3

The WHO designates the disease caused by E. granulosus as Cystic Echinococcosis (CE) and the disease caused by E. multilocularis as Alveolar Echinococcosis (AE).

Question 4

Which Echinococcus species is relevant in South Africa?

Answer 4

In South Africa, only E. granulosus is relevant, causing Cystic Echinococcosis (CE).

Question 5

What is the annual incidence of Cystic Echinococcosis (CE) in various endemic areas?

Answer 5

The annual incidence of CE can range from less than 1 to 200 cases per 100,000 inhabitants, depending on the endemic area.

Question 6

How many people are at risk for Cystic Echinococcosis (CE) in China and Central Asia?

Answer 6

In China and Central Asia, more than 20 million people are at risk for Cystic Echinococcosis (CE).

Question 7

What is the mortality rate for Cystic Echinococcosis (CE) in endemic areas?

Answer 7

The mortality rate for Cystic Echinococcosis (CE) is about 2-4% in endemic areas, although it can rise significantly if medical treatment is inadequate.

Question 8

What is the annual incidence of Alveolar Echinococcosis (AE)?

Answer 8

The annual incidence of Alveolar Echinococcosis (AE) is generally low, ranging from 0.03 to 1.2 per 100,000 inhabitants.

Question 9

What is the mortality rate for untreated or inadequately treated Alveolar Echinococcosis (AE)?

Answer 9

In untreated or inadequately treated patients, the mortality rate for Alveolar Echinococcosis (AE) exceeds 90% within 10-15 years of diagnosis.

Question 10

Why is Echinococcosis considered a neglected disease?

Answer 10

Despite its significant socioeconomic impact and high mortality in untreated cases, Echinococcosis remains a neglected disease, often due to a lack of awareness and adequate medical resources in affected areas.

Question 11

What is the most frequent presentation of Echinococcosis?

Answer 11

The most frequent presentation of Echinococcosis is Cystic Echinococcosis (CE).

Question 12

What is the role of carnivores in the life cycle of Echinococcus granulosus?

Answer 12

Carnivores, such as dogs and foxes, are the definitive or final hosts in the life cycle of Echinococcus granulosus. The adult tapeworm lives in their intestines.

Question 13

What are the intermediate hosts in the life cycle of Echinococcus granulosus?

Answer 13

Herbivores like sheep, goats, cows, and camels are the intermediate hosts. They ingest tapeworm eggs and are infected by them.

Question 14

How do humans become involved in the life cycle of Echinococcus granulosus?

Answer 14

Humans are incidental intermediate hosts, meaning they can accidentally ingest tapeworm eggs, becoming infected in the process.

Question 15

What is Hydatid Cyst or Hydatidosis?

Answer 15

Hydatid Cyst or Hydatidosis refers to the larval phase of Echinococcus granulosus, where the tapeworm develops into cysts in the tissues of the intermediate hosts.

Question 16

What happens when eggs of Echinococcus granulosus are ingested by intermediate hosts?

Answer 16

Upon ingestion, the eggs morph into oncospheres, which migrate to various tissues in the intermediate host. Here, they evolve into metacestodes and form hydatid cysts.

Question 17

What are brood capsules in the hydatid cyst?

Answer 17

Brood capsules are formed on the inner lining (germinal layer) of the hydatid cyst (metacestode). These capsules contain the next stage of the parasite, the protoscolex.

Question 18

What is the function of protoscolex in the life cycle of Echinococcus granulosus?

Answer 18

The protoscolex develops within the brood capsules. It ensures the survival of the parasite, allowing it to continue its life cycle, even if the intermediate host dies or the hydatid cyst ruptures.

Question 19

What happens in secondary Echinococcosis?

Answer 19

In secondary Echinococcosis, protoscoleces spread from the primary site (the hydatid cyst) due to cyst rupture. These protoscoleces proliferate wherever they end up in the host tissue, such as the peritoneum, bronchial tree, pleura, or pelvis.

Question 20

How do protoscoleces spread to different tissues in secondary Echinococcosis?

Answer 20

Protoscoleces spread to different tissues due to the rupture of the hydatid cyst, which allows them to move into various tissues like the peritoneum, lungs, pleura, or pelvis, where they can proliferate.

Question 21

What happens to the intermediate host in secondary Echinococcosis?

Answer 21

In secondary Echinococcosis, the intermediate host eventually dies, or it may cough up hydatid material from the lungs.

Question 22

How do protoscoleces enter the final host (carnivores)?

Answer 22

If tissue or organs of the intermediate host are eaten by the final host (such as dogs, foxes, or hyenas), the protoscoleces enter the intestine of the final host.

Question 23

What happens once protoscoleces reach the intestine of the final host?

Answer 23

Once in the intestine of the final host, the protoscoleces evolve into scoleces with hooklets on the rostellum (head). They use these hooks to attach to the intestinal mucosa.

Question 24

What is the final step in the Echinococcus granulosus life cycle?

Answer 24

After attaching to the intestinal mucosa, the protoscoleces develop into adult tapeworms, completing the life cycle of Echinococcus granulosus.

Question 25

How does Hydatid disease typically present?

Answer 25

Hydatid disease usually presents with symptoms related to the body cavity or organ(s) in which the cysts develop. Symptoms often arise once the cysts have grown to a significant size.

Question 26

How is Hydatid disease often discovered?

Answer 26

Hydatid disease is frequently discovered by chance, such as when an abdominal mass is found by a parent while bathing a child, or during an ultrasound or chest radiograph conducted for other reasons, such as investigating dyspnoea (shortness of breath) or a persistent cough.

Question 27

When do neurological symptoms typically develop in Hydatid disease?

Answer 27

Neurological symptoms generally develop fairly late in the disease process, typically when the cysts have reached a significant size and are affecting the nervous system.

Question 28

What is the focus of the clinical exam for Hydatid disease?

Answer 28

The clinical exam is focused on assessing the overall health of the patient and documenting the extent of the disease’s effects, particularly neurological or respiratory compromise. There are no pathognomonic findings specific to Hydatid disease.

Question 29

When should Hydatid disease be suspected in a patient?

Answer 29

Hydatid disease should be suspected in patients who live in or have traveled to an endemic area, especially when presenting symptoms suggestive of Hydatid disease.

Question 30

What are some common abdominal symptoms that suggest Hydatid disease?

Answer 30

In the abdomen, symptoms may include an incidental mass in the right upper quadrant and abdominal pain.

Question 31

What chest symptoms can suggest Hydatid disease?

Answer 31

Chest symptoms may include cough, productive cough with "grape peels," cough with fever, and dyspnoea (shortness of breath).

Question 32

What brain symptoms may indicate Hydatid disease?

Answer 32

Involvement of the brain can lead to focal neurological symptoms, seizures, confusion, and coma.

Question 33

What is the mainstay of diagnosis for Hydatid disease?

Answer 33

Imaging is the mainstay of diagnosis for Hydatid disease.

Question 34

What imaging methods are used to diagnose Hydatid disease?

Answer 34

Abdominal Ultrasound: To confirm the location of intra-abdominal cysts. Chest Radiographs: To confirm lung cysts, their size, location, and number. CT scan and MRI: Used in very selected cases for further assessment.

Question 35

What are the three main treatment options for Hydatid disease?

Answer 35

The three main treatment options for Hydatid disease are: 1. Surgery alone 2. Drugs alone 3. Combination of surgery and drugs

Question 36

Why is Hydatid disease considered a public health problem?

Answer 36

Hydatid disease is a public health problem because it involves the transmission cycle between humans and animals, especially dogs. Addressing pets' deworming and improving slaughtering practices is crucial in preventing the disease.

Question 37

What surgical approaches are used for treating Hydatid disease?

Answer 37

Surgical approaches include: - Open access (laparotomy or thoracotomy) - Laparoscopy - In selected cases, thoracoscopy - Ultrasound-guided needle aspiration ("PAIR" procedure)

Question 38

What is the "PAIR" procedure for Hydatid disease treatment?

Answer 38

The "PAIR" procedure stands for Percutaneous Aspiration, Injection (of scolicidal), and Re-aspiration. It is a minimally invasive technique for treating Hydatid disease.

Question 39

What is the medical treatment for Hydatid disease?

Answer 39

The medical treatment typically involves Albendazole taken orally for 3 to 6 months. It is given for 28 days with a 14-day break, repeated as needed depending on the cyst's response (measured by size reduction).

Question 40

Can Albendazole be combined with other drugs?

Answer 40

Yes, Albendazole can be combined with Praziquantel. The length of treatment remains the same as with Albendazole alone.

Question 41

What should be done if there is no reduction in cyst size after 3 months of medical treatment?

Answer 41

If there is no reduction in cyst size after 3 months, or if drug side effects become intolerable, medical treatment should be abandoned.

Question 42

What monitoring is necessary when using Praziquantel for medical treatment?

Answer 42

Liver function tests should be done monthly when Praziquantel is used as part of the treatment.

Question 43

What is the rationale for combining surgery and drugs in Hydatid disease treatment?

Answer 43

The combination of surgery and drugs is used to pre-treat the hydatid cysts before surgery: Albendazole kills the metacestode, stopping brood capsule and protoscolex production. Praziquantel kills the protoscoleces, rendering the hydatid fluid sterile, reducing the risk of spillage and disease dissemination during surgery.

Question 44

When should a patient with Hydatid disease be referred to a specialized center?

Answer 44

Patients should be referred to centers with sufficient radiology and surgical experience to manage Hydatid disease. Once the diagnosis is confirmed, medical treatment can be started while coordinating with surgeons to avoid delays.

Question 45

What is the long-term outcome after surgery for Hydatid disease?

Answer 45

Surgery is curative for Hydatid disease. If there is a recurrence, it is most likely due to re-infection rather than a failure of the surgery.

Question 46

Why might recurrence of Hydatid disease occur after surgery?

Answer 46

Recurrence is most often caused by re-infection, not by surgical failure. Patients and their families need to understand how re-infection happens to prevent it.

Question 47

What is important for patients and their families to understand after treatment for Hydatid disease?

Answer 47

Patients and families need to understand how the infection occurs in the first place, so they can take measures to prevent re-infection, such as proper deworming of pets and addressing hygiene practices.