Hydatid disease in people is mainly caused by infection with the larval stage of the dog tapeworm Echinococcus granulosus. It is an important pathogenic, zoonotic and parasitic infection (acquired from animals) of humans, following ingestion of tapeworm eggs excreted in the faeces of infected dogs. Hydatid disease is a major endemic health problem in certain areas of the world.
Cystic hydatid disease usually affects the liver (50–70%) and less frequently the lung, the spleen, the kidney, the bones and the brain.
Liver hydatidosis can cause dissemination or anaphylaxis after a cyst ruptures into the peritoneum or biliary tract. Infection of the cyst can facilitate the development of liver abscesses and mechanic local complications, such as mass effect on bile ducts and vessels that can induce cholestasis, portal hypertension, and Budd-Chiari syndrome.
Echinococcus granulosus is spread almost all over the world, especially in areas where sheep are raised and is endemic in Asia, North Africa, South and Central America, North America, Canada and the Mediterranean region.
The disease is more prevalent in temperate climate than in tropical areas. In India, the highest prevalence is reported in Andhra Pradesh and Tamil Nadu.
In many countries, hydatid disease is more prevalent in rural areas where there is a closer contact between people and dogs and various domestic animals which act as intermediate vectors.
LIFE CYCLE OF PARASITE
Dogs are the main hosts of the adult worm. Sheep, cattle, rodents, and deer are the natural hosts for the larvae. Humans, especially children, can be attacked by larvae by swallowing eggs, which are shed in the stool of infected dogs.
The disease is most common in countries where animals are raised with the help of dogs.
PATHOLOGY OF HYDATID CYST
A primary cyst in the liver is composed of three layers
Adventitia (pericyst)- It consist of compressed liver parenchyma and fibrous tissue induced by the expanding parasitic cyst.
Laminated membrane (ectocyst)- It is a elastic white covering, easily separable from the adventitia.
Germinal epithelium (endocyst) –It is a single layer of cells lining the inner aspects of the cyst and is the only living component, being responsible for the formation of the other layers as well as the hydatid fluid and brood capsules within the cyst.
In some primary cysts, laminated membranes may eventually disintegrate and the brood capsules are freed and grow into daughter cysts. Sometimes the germinal Epithelium daughter cysts, which if left untreated may cause recurrence.
There are two main morphological forms of hydatid cysts found in humans:
Unilocular hydatid cyst
Osseous hydatid cyst.
A third form in humans is the alveolar hydatid cyst, caused by Echinococcus multilocularis.
MODE OF TRANSMISSION
Human infection occurs by ingestion of the eggs of Echinococcus inadvertently with food, unwashed vegetables or water contaminated with faeces from infected dogs. Infection can also take place while handling or playing with infected dogs, e.g., hand to mouth transfer of eggs or by inhalation of dust contaminated with infected eggs. The disease is not directly transmissible from person to person.
After infection with Echinococcus granulosus, humans are usually asymptomatic for a long time. The growth of the cyst in the liver is variable ranging from 1 mm to 5 mm in diameter per year.
Most primary infections consist of a single cyst, but up to 20%-40% of infected people have multiple cysts. The symptoms depend not only on the size and number of cysts, but also on the mass effect within the organ and upon surrounding structures.
Most common clinical presentation of the hydatid cyst is
Shortness of breath
Abnormal abdominal tenderness
Hepatomegaly with an abdominal mass
If the cysts ruptures in the body, whether during surgical extraction of the cysts or by trauma to the body, the patient would most likely go into anaphylactic shock and suffer from high fever, pruritus (itching), oedema (swelling) of the lips and eyelids, dyspnoea, stridor and rhinorrhoea.
Clinical : Based on the history of residence in an endemic area, close association with dogs and the presence of a slowly growing cystic tumour.
X-RAY : A plain X-ray permits the location of the cyst. Modern techniques of diagnosis include ultrasonography and CT scan.
Serological : Serological tests with a high degree of sensitivity and specificity have been introduced such as the indirect immunofluorescent test.
ELISA is regarded as a relatively simple method with a high sensitivity superior to that of some other serological procedures.
The intradermal (Casoni) test is still in wide use, since it is simple to perform. This test often lacks specificity .
The first phase is that of growth during which rupture can occur when the pressure of the hydatid liquid becomes more important than resistance of the hydatic wall (pericyst). Finally, the complications such as acute allergic manifestations, infection, jaundice, vomiting are only the consequence of the rupture of the cystic wall.
The second phase is a phase of ageing and of progressive involution. It is the consequence of the overproduction of scolices and daughter cysts. During this phase, the hydatid cyst will be full of scolices and membranes which replace the hydatic liquid. Calcifications occur in the pericyst. The host is at the origin of the image of pericystic wall. Then the reaction of the host leads to a progressive calcification of the walls.
The hydatid cyst is unique and localized in the right lobe of the liver in 65%. The most frequent extrahepatic locations are the lungs, the spleen and the peritoneum.
Liver (55–70%) is the obvious first site after entry through the gut and passage in the portal circulation. There may be generalized with upper abdominal pain and discomfort or more specific. Such as obstructive jaundice, biliary rupture may occur through a small fissure or bile duct fistula.
A wide perforation allows the access of hydatid membranes to the main biliary ducts, which can cause symptoms simulating cholelithiasis.
Alternatively, it may produce a picture very similar to ascending cholangitis with fever, pain and jaundice.
COMPLICATIONS OF HYDATID CYST IN LIVER
Echinococcal cysts of the liver can cause complications in about 40% of cases.
The evolution of an infected hydatid cyst is usually latent, subacute and is clinically translated by pains in the right hypochondrium, hepatomegaly and fever.
INTRABILIARY RUPTURE OF HYDATID CYST
It is a common complication and may occur in two forms:
An occult rupture, in which only the cystic fluid drains to the biliary tree and is observed
in 10-37% of patients.
Frank rupture, which has an overt passage of intracystic material to the biliary tract and is observed in 3-17% of the patients.
The rupture of the hydatid cyst in the biliary ducts and the migration of the hydatid material in the biliary tree lead to the apparition of other biliary complications like: cholangitis, sclerosis odditis, hydatid biliary lithiasis etc.
Intrathoracic rupture of hepatic hydatid cyst is a rare but a severe condition causing a spectrum of lesions to the pleura, lung parenchyma, and bronchi. Cyst erosion is associated with pericystic inflammation. Adhesion formation determines whether the rupture is confined to lung parenchyma or the free pleural space or both. Bronchobiliary fistula leads to haemoptysis and cyst expectoration.
RUPTURE IN THE PERITONIUM
Rupture into the peritoneum may present as acute abdominal pain. Antigenic fluid released into the peritoneal cavity and absorbed into the circulation may present with acute allergic manifestations. Abdominal pain, nausea, vomiting and urticaria are the most common symptoms. Allergic reactions may be seen in 25% of the cases.
There is no specific treatment except surgical removal of cysts which is not without considerable risk in as much as the accidental penetration of one of the cysts can lead to anaphylactic shock which may prove fatal.
HOMEOPATHIC APPROACH TOWARDS HYDATID CYST
Homeopathic medicine is prescribed on the basis of symptom similarity in each and every individual case of disease.
There are several remedies available for hydatid disease. These include Areca, Calc-carb., Causticum, Cucurbita, Cup-ars., Filix mas, Fragaria vesca, Granatum, kamala, koussa, Plat., Puls., Sab.a, Salicylicum acidium, Stann., Terbinthina.
HOME REMEDIES FOR HYDATID CYST
Raddish leaves: The leaf of raddish is an excellent herbal remedy for liver ailments. It acts like a tonic for the liver and strengthens and fortifies it. Raddish leaves facilitate body detoxification.
Dandelion root: Dandelion roots effectively treat the symptoms associated with hepatic cysts; they help allay nausea and vomiting and soothe abdominal discomfort. Take 1 spoon of the powdered root and boil it well in a bowl of water. Consume thrice daily for 15 days.
Lime: Lime and lemon are very important for good liver health. They tone up and stimulate the hepatocytes to function optimally.