Introduction
A cyst is an abnormal sac of membranous tissue filled with fluid, semi-solid substances, or air; mostly benign, sometimes cancerous, and causes pain. There are many different types of cysts; they can grow in any part of the body. Most cysts do not cause any problems and fade away on their own. Some do cause pain, turn cancerous, and get infected and inflamed.
What Is a Hydatid Cyst?
Hydatid disease, a zoonotic ailment, is transmitted from animals to humans. This condition stems from infestation by a tapeworm belonging to the Echinococcus genus. It is also known as hydatidosis or echinococcosis. This potentially grave condition, occasionally fatal, arises due to hydatid cysts containing the larval stages of the echinococcus granulosus tapeworm.
The adult E. granulosus tapeworms inhabit the excrement of infected dogs and similar canines. These tapeworms expel eggs within this excrement. Human infection occurs when these eggs are ingested inadvertently. This can transpire through direct contact with dogs, followed by hand-to-mouth interaction, or through the consumption of contaminated food, water, or objects.
Hydatid cysts primarily affect the liver, comprising approximately 50 to 70% of cases. In rare instances, they may also impact the lungs, spleen, bones, kidneys, and even the brain. The consequences of a ruptured cyst can be profound. It may lead to the dissemination of the infection or even trigger anaphylaxis. In the liver, a cyst-induced infection can give rise to liver abscesses and provoke local mechanical complications. These complications can manifest as obstructions in bile ducts and vessels, resulting in cholestasis (obstructed bile flow), portal hypertension (increased pressure in the portal vein due to constrained blood flow), and Budd-Chiari syndrome (hepatic vein blockage and narrowing).
How Is Hydatid Cyst Transmitted?
Hydatid disease, a zoonotic ailment, transfers from animals to humans. Infected dogs and their feces are sources of transmission; the cysts can endure in soil and gardens for months. Animals such as sheep, cattle, pigs, horses, goats, and kangaroos can contract it by consuming grass tainted by dog feces. These animals' meat might develop hydatid cysts. When dogs ingest the uncooked meat of these infected animals, the cycle concludes. About five to seven weeks post-infection, dogs begin secreting eggs in their feces.
In humans, the lone route of infection is consuming or encountering contaminated eggs from infected dogs or canines. The disease doesn't transmit from person to person or through consuming meat from infected animals.
Who Is at More Risk of Getting Infected With Hydatid Cyst?
This disease is mostly found in people who raise sheep and cattle. Young children are more at risk of getting infected with tapeworm eggs, but symptoms do not appear for many years.
What Are the Signs and Symptoms of Hydatid Cyst?
Hydatid cysts grow to the extent that triggers clinical signs. It includes:
-
Abdominal pain.
-
Nausea and vomiting.
-
Anorexia (an eating disorder that leads to excessive loss of body weight).
-
Weight loss.
-
Weakness.
-
Malaise.
-
If this condition affects the lungs, signs like a chronic cough are seen.
-
Chest pain.
-
Sometimes the signs depend on the cyst location and pressure exerted on surrounding tissues.
-
Cysts leak or rupture may lead to severe infection and even death.
How Is Hydatid Cyst Diagnosed?
The diagnosis of hydatid cyst was done with the help of the following investigations:
-
Ultrasonography: This imaging method serves as the primary diagnostic tool, often supported by a CT scan or MRI to provide comprehensive visualization.
-
Radiography: Cysts may be unexpectedly identified through radiographic examinations.
-
Serological Test: Specific antibodies are detected through serological testing, aiding in the accurate identification of the cyst.
-
Timely identification of E. granulosus and E. multilocularis infections significantly reduces the likelihood of hydatid cyst development.
What Are the Complications of a Hydatid Cyst?
Hydatid cysts can cause complications in about 40 % of cases. The most common complications are:
Infection - It is the most common complication and is mostly asymptomatic. An infected hydatid cyst is usually latent, subacute, and clinically shown by pain in the right hypochondrium, fever, and hepatomegaly (enlarged liver).
Intrabiliary Rupture of Hydatid Cyst - Common complications that can occur in 10 to 37 % of cases. This rupture may lead to other biliary complications like cholangitis (inflammation of bile ducts), sclerosis oddities (potentially disabling disease of the brain and spinal cord), and hydatid lithiasis (hydatid cyst in the kidney).
Rupture of the Thorax - Intrathoracic rupture of hepatic hydatid cyst is rare but a severe complication causing lesions to the pleura, lung parenchyma, and bronchi can occur.
Rupture of the Peritoneum - Rare and generally followed by anaphylactic reactions. This rupture may present acute abdominal pain, nausea, vomiting, and urticaria (hives, redness, and itchiness of the skin).
Other Complications - These include portal hypertension, vascular erosions, and acute abdominal pains with a sudden decrease in the volume of the cyst.
What Is the Treatment Provided For Hydatid Cyst?
Surgical Treatment is the best treatment provided for hydatid disease. The main aim of surgery is to inactivate the parasite and evacuate the cyst. It can be successfully performed in 90 % of cases. But, these surgeries can be impractical in patients with multiple cysts. Chemotherapy comes into the picture in such cases - the PAIR (puncture-aspiration-injection-respiration) technique is an alternative method.
Conservative Technique: It is safe and technically simple. Marsupialization is the most common procedure used here. The main disadvantage is the frequency of postoperative complications like bile leaks, bilomas, and bile peritonitis.
Radical Technique: This technique includes the following procedures -
- Cystectomy: The procedure is simple and has a low recurrence rate. It involves the removal of a hydatid cyst, comprising the laminar germinal layer and cyst contents.
- Precystectomy: This is technically a more difficult procedure than cystectomy and has considerable blood loss. It involves non-anatomical resection of cysts and surrounding compressed liver. This can also be hazardous in the case of large, complicated cysts.
- Hepatic Resections: This is the primary modality of the treatment.
Laparoscopic Management: Surgery using a minimally invasive approach is done. A special instrument perforator-grinder-aspirator apparatus is used for the removal of the hydatid cyst with a laparoscope. The laparoscopic technique has some more advantages than open surgery. It gives better visual control of cysts under magnification and better detection of biliary fistula. It provides a shorter stay in the hospital and faster surgery completion.
Endoscopic Management of Hydatid Cyst: This is useful in the presence of intra-biliary rupture. During this biliary tree, it is cleared of any hydatid cyst and fluid with a balloon catheter. The endoscopic sphincterotomy is performed to facilitate drainage of the common bile duct.
Chemotherapy: Medical treatment of this cyst primarily was induced by benzimidazole carbamates like Mebendazole and Albendazole. This was mainly used in inoperable cases or combined with surgery to prevent post-operative occurrence.
What Are the Preventive Measures Taken to Prevent Hydatid Cyst?
The preventive measures taken to prevent hydatid cysts are:
-
Wash hands before eating or consuming anything orally, like smoking.
-
Wash hands thoroughly after handling dogs, soil, or places that may be infected by dog feces.
-
Do not encourage the dog to lick the face or kiss the dog.
-
Prevent dogs from littering around farm areas and cattle grazing areas, and children's parks.
-
Keep a check on the dog's eating habits, and avoid giving uncooked meat.
-
Take advice from the veteran to avoid infections in dogs and get the pets a timely vaccination and check on any change or infection.
-
Focus on deworming the dogs regularly.
Conclusion
Hydatid disease, prevalent in numerous countries, particularly grazing regions, presents a significant health concern. While primarily affecting the liver (75 %), lungs (15 %), spleen (5 %), and other organs (5 %), it is a treatable condition. Surgical intervention stands as the primary approach, with PAIR serving as an alternative surgery for specific cases. Additionally, tapeworm-killing drugs, administered through injection into the cyst, are utilized. Periodic physician monitoring suffices for some, while others may require no treatment.