Educational Blog about Anesthesia, Intensive care and Pain management

Hydatid Disease

 Hydatid Disease

Hydatid Cyst


-Hydatid cysts are the larval stage of the tapeworm, Echinococcus granulosus.

-Dogs are the main hosts. Man and sheep are intermediate hosts.

-Hydatid disease is not uncommon amongst the mid-Wales farming communities, and up to 26% of farm dogs in this area have E. granulosus.

-The incidence is also high in some regions of the Mediterranean, North Africa, the Middle East, and Australia.

-If the ova are ingested by man, embryos are released when the chitinous coat is digested.

-These enter the liver by the portal vein. They may be destroyed, or they may develop into a cyst.

-In man, the cysts are found in the liver (65%), lung (25%), muscles (5%), bone (3%), and brain (1%). Each cyst is two-layered and contains straw-colored fluid in which there are free scolices, brood capsules containing scolices, and daughter cysts.

-Around the cyst is an area of compressed host tissue and fibrosis known as the pericyst. In 5–10% of cases, the cyst will die, and calcification may occur.

Preoperative Findings:

1. Hepatic cysts occur most frequently in the right lobe. A bacterial infection may result in a liver abscess. Rupture into a bile duct, or bile duct obstruction can occur and produce biliary colic. There may be jaundice. The number and location of the cysts are shown on a CT scan or ultrasound.

2. Pulmonary cysts can present with hemoptysis, dyspnea, cough, or chest pain. Chest X-ray may show a variety of appearances including an oval opacity, evidence of bronchial fistula formation, or rupture of the cyst with the development of a fluid level.

3. Eosinophilia occurs in about 30% of cases. The Casoni skin test is still used for screening. Immunoelectrophoresis is the most specific test. The complement fixation test is positive in up to 80% of cases. The hemagglutination test detects a specific antibody.

Anesthetic Problems:

1. Pulmonary hydatid cysts can cause bronchial obstruction, and occasionally they may rupture into the airway. If this happens, flooding of the lungs occurs, with widespread dissemination of the scolices.

2. Hydatid fluid is highly antigenic, and the rupture of a cyst has occasionally produced sudden death from an anaphylactic reaction. Anaphylaxis to hydatid was confirmed by increased serum histamine and tryptase levels, with elevated levels of total and echinococcus-specific IgE antibodies.

3. Patients can develop anaphylaxis of unknown origin as interventricular hydatid cystic mass.

4. Cerebral cysts can cause increased intracranial pressure.

5. Scolicidal agents are potentially toxic and their use in combination with surgery may increase the complication rate.

6. Postoperative complications following surgery for hydatid cyst of the lung included prolonged air leak and aspiration pneumonia.

Anesthetic Management:

1. Surgical removal is indicated, except in older patients with small cysts. Meticulous care must be taken to avoid the rupture and spread of the fertile scolices.

2. Relatively new drugs, such as mebendazole and albendazole, are being tested as scolicidal agents. However, there is no evidence that they are effective in the treatment of pulmonary hydatid.

3. Pulmonary cysts. Protective formalin-soaked packs are placed around the wound, an incision is made through the pericyst, and the cyst is carefully extruded by the anesthetist, using gentle hand ventilation.

4. Because of the risk of an anaphylactic reaction, epinephrine (adrenaline), metaraminol, isoprenaline, and steroids must be immediately available.