#hydatid

By Arush Emmanuel Michael

Hydatid disease is prevalent worldwide, but it is more commonly found in cattle and sheep raising countries. In India, the hydatid disease is present in many areas. The larval form of Echinococcus granulosus produces the disease in humans. The adult cestode is present in the small intestine of dogs and other canines, which gives it the common name of dog tapeworm.

Life Cycle of Echinococcus granulosus

There is an intermediate and a definitive host in the life cycle of the parasite

Definitive Host: Dog is the optimum host but other canines (wolf, fox and jackal) can also act as a definitive host. The adult parasite lives in the small intestine of the definitive host and releases eggs in the faeces.

Intermediate Host: The intermediate hosts include humans and other animals (sheep, pig, cattle, goat) as well. The larval stage is present giving rise to hydatid cyst.

Mode of Infection of Echinococcosis

The infection occurs by ingestion of the eggs which can occur through

·        Direct contact with infected canines

·        Eating from the same utensil as the canine

·        Consumption of uncooked vegetables contaminated with the canine faeces

Hydatid Cyst

The embryo secretes the cyst wall which has two layers namely the ectocyst and the endocyst.

Ectocyst:

·        It is the outer layer (1mm thick) and has the appearance of the white of a hardboiled egg.

·        It is acellular, tough, elastic and laminated hyaline membrane.

·        On incision, it curls on itself and exposes the endocyst.

Endocyst

·        It is the thin germinal or inner layer.

·        It gives rise to ectocyst on outer side and the scolices and brood capsules towards the inner side. The endocyst is also responsible for secretion of hydatid fluid.

·        Embryos which break free from the membrane and float in the fluid inside the cyst are known as hydatid sand.

·        Hydatid fluid characters:

1.      Clear, colourless or pale yellow

2.      Slightly acidic with low specific gravity

3.      Contains salts of sodium and calcium

4.      Antigenic in nature and therefore used for Casoni’s test

5.      Highly toxic (absorption leads to anaphylaxis)

Symptoms and Clinical Features of Hydatid Disease

The condition remains asymptomatic for many year but might sometimes cause pressure effects and swelling.

Organs and tissues involved:

·        Liver- Most commonly involved, particularly the right lobe. In case of liver cysts, chronic abdominal discomfort may be present.

·        Lung- Second most commonly involved. Cysts are mostly asymptomatic but might cause breathlessness, cough and chest pain

·        Brain

·        Kidney

·        Spleen

·        Heart

·        Bone

·        Muscle

Rupture of a hydatid cyst due to surgery or trauma can result in death after anaphylactic shock. Once you are diagnosed with any condition and are prescribed treatment you can now buy medicines online in India.

Diagnosis of Hydatid disease

After you consult a doctor, the doctor shall ask you your chief complaints and as to what made you come to the hospital. After this, the doctor shall ask relevant questions pertaining to your condition and your symptoms in order to complete your medical history. If you have a travel history to areas where the infection is prevalent it can imply that the diagnosis of the condition might be hydatid disease as the condition is very common in those areas. This will be followed by a physical examination to check for any more signs and symptoms that might be important in your case. The doctor will now refer some tests in order to confirm the probable diagnosis so that treatment can be started.

Laboratory Diagnosis includes following tests:

1.      Casoni Test (Immediate hypersensitivity skin test)

·        Antigen used- Sterile hydatid fluid produced after filtering hydatid fluid drawn from unilocular hydatid cysts from human cases or animals in slaughterhouses.

·        Procedure- 0.2 ml sterile normal saline is injected intradermally in one arm as the control. 0.2 ml of antigen injected intradermally in one arm as the test.

·        Positive case- Test site develops a large wheal with multiple pseudopodia in a period of 30 minutes.

2.      Blood examination: CBC shows eosinophilia

3.      Serological Tests (for antibody detection)

·        ELISA

·        IFA

·        IHA

·        Latex agglutination tests

4.      Cyst fluid examination: Diagnostic puncture of cyst is not advised as it might result in anaphylactic shock. Hydatid cysts removed surgically can be aspirated for cyst fluid which can then be examined for diagnosis. It reveals hooklets, scolices and brood capsules.

5.      Antigen detection tests:

·        ELISA

·        Countercurrent immunoelectrophoresis (CIEP)

·        Co-agglutination test

·        Latex agglutination test

6.      Radiological Examination: X-ray, ultrasonography, MRI and CT-scan may be utilised for diagnosis of  hydatid disease.

7.      Histological Examination

Treatment of Hydatid Disease

Surgical removal of hydatid cysts- There are recurrences after surgical removal therefore post-operative chemotherapy is carried out for two years.

The diagnosis of hydatid cyst is made mainly with the help of imaging methods and review of the patient's history. Serologic tests can also be useful. 

Intra Pulmonary Opacities Round

* Pleural opacities have an obtuse angle connection with the chest wall in contrast to parenchymal opacities juxtapleurales that connect to an acute angle.

* Opacities mediastinal their internal boundary coincides with the mediastinum and outer boundary connects gently sloping with it.

* Multiple round opacities (drop ball) are usually metastases.

* A doubling within 7 days or no doubling over 2…

Calcified hydatid cyst, CT