In endemic areas, the annual incidence of cystic echinococcosis is 1 to 200/100.000, and that of alveolar echinococcosis from 0.03 to 1.2/100,000. Although most of the cases encountered in Western Europe are imported (return from vacation, immigration), the incidence has recently doubled in France, Switzerland, Germany, and Austria. Parasitic disease (zoonosis) caused by a plathelminth (tapeworm) of the  Echinoccocus family.

There are 4 forms:

• cystic echinococcosis, or hydatidosis or hydatid echinococcosis caused by Echinococcus granulosus sensu lato; endemic in North Africa, South America and Asia;  there are 10 different genotypes depending on the host (sheep, camel, lion, horse, pig ..) or endemic area (Canada, South America, Tibet)
• alveolar or multilocular echinococcosis caused by Echinococcus multilocularis or alveolaris; endemic in the Northern hemisphere
• polycystic echinococcosis caused by Echinococcus vogeli (Central and South America)
• unicystic echinococcosis caused by Echinococcus oligarthrus (Central and South America).

The reproductive cycle is complex: different hostes have been identified

• a definitive carnivorous host, which hosts the adult parasite that produces eggs eliminated with the faeces
• and an intermediate host, usually herbivorous, which ingests the eggs, allows the development of larvae (hydatids) and must be eaten by the definitive host

Hydatid echinococcosis: definitive host: dog, fox but also lynx, raccoon, cat; intermediate hosts: sheep, roe deer, beaver, wild boar. Usual cycle: dog-sheep-dog

Alveolar echinococcosis: definitive host: fox but also cat and dog; intermediate hosts: rodents. Usual cycle: fox-rodent-fox

Man can be contaminated with eggs produced by a definitive host (all  wild or domestic carnivores): these eggs are then present in the faeces or on the coat of this host. Man is, however, a deadlock for the parasite: it can be contaminated but cannot contaminate anybody thereafter.

The eggs are very resistant: they resist even at a temperature of -18°C; it is necessary to cook potentially contaminated food at 60°C for more than 30 minutes.

SYMPTOMATOLOGY:

Hydatid echinococcosis: the incubation period may be very long and depends on the growth and localization of hydatid cysts:

• liver (70 %): abdominal pain, jaundice, fever
• lung (20 %, more common in children): cough, dyspnea, chest pain, clear fluid vomiting, hemoptysis
• larvae can migrate to other organs: brain (1 %), bone (< 1 %), kidneys (4 %), heart (1 %), muscles
• the cyst consists of a periparasitic membrane and an endocyst composed of a thick laminated outer membrane and a thin proligerous membrane that produces the proligerous capsules; it is rich in antigens: anaphylactic shock (10 % of cases) in case of passage into the blood or intraperitoneal rupture

Diagnosis: ultrasound, RX (calcifications in the liver, hydroaeric image in the chest), CT scan, MRI.

Serology:

• negative in 5-20 % of EC2 and CE3 liver cysts, 30-58 % of EC1 cysts, 50-87 % of CE4 and CE5 cysts
• negative in 30-50 % of lung cysts.

The WHO has established an ultrasound classification of hepatic echinococcosis to standardize its treatment: CE1 and CE2 are called "active", C3a and C3b called "transient" and CE4 and CE5 "inactive".

CL: thin-walled anechoic cyst

CE1: thick-walled (double) unilocular anechoic cyst, with or without "hydatid sand"

EC2: multilocular cyst, honeycomb appearance

CE3a: partial or total detachment of the inner membrane (image of the water lily)

CE3b: cyst with daughter vesicles in a solid matrix

CE4: heterogeneous cyst without daughter vesicles

EC5: intracystic solid degeneration with partial or total wall calcification

Treatment: WHO recommendations have been established based on the location and size of cystic lesions:

• medical: albendazole (10-15 mg / kg twice a day for at least two years), or mebendazole (40-50 mg / kg in 3 oral doses) which stops the evolution of the parasite but does not eliminate it!
• puncture-aspiration of the cyst (PAIR for puncture-aspiration-injection-reaspiration), to destroy the germ layer of the cyst: ultrasound-guided aspiration of the cyst into which 20 % NaCl or 95 % ethanol is injected for 20 minutes before reaspirating; reserved for CE1 and CE3a cysts
• surgery: avoid opening the liver cyst because there is a risk of anaphylactic shock and spread of hydatids with reinfection; it is therefore prudent to sterilize it by injecting a solution of hypertonic NaCl

Alveolar echinococcosis: large painful liver (especially right lobe), jaundice, fever, blood eosinophilia. There are no cystic lesions because the larva does not produce a weedy membrane. The lesion is infiltrative and pseudotumoral with multiple cavities. The prognosis is disastrous. Medical treatment and surgery if possible (hepatectomy).

Anesthetic implications: 

-        looking for a pulmonary localization is necessary in case of hepatic hydatid cyst

-         hepatic cyst: risk of anaphylactic shock at the opening of the cyst; intracystic injection, prior to dissection, of an hypertonic NaCl solution with aspiration of the liquid does not always prevent it

-         pulmonary cyst: if unilateral,  unipulmonary ventilation to protect the healthy lung. If bilateral, double thoracotomy in 1 or 2 sessions without unipulmonary ventilation which could cause a rupture of the cyst on the  ventilated side.

-         warning: the use of hypertonic NaCl use is associated with a risk of hypernatremia

References : 

-          Baraka A, Slim M, Dajani A, Lakkis S. 
One lung ventilation of children during surgical excision of hydatid ysts of the lung. 
Br J Anaesth 1982; 54: 523-7.

-         Sola JL, Vaquerizo MJ. 
Intraoperative anaphylaxis caused by a hydatid cyst. 
Acta Anaesth Scand 1995; 39: 273-4.

-         Jacob R, Sen D. 
The anaesthetic management of a deliberately created bronchoatmospheric fistula in bilateral pulmonary hydatids. 
Pediatr Anesth 2001; 11: 733-6.

-         Dabir S, Boloursaz M-R, Javaherzadeh M, Radpay B, Parsa T. 
The anesthetic management of an intrabronchial escape of a hydatid’s ruptured laminated membrane during rigid bronchoscopy. 
Pediatr Anesth 2004; 14: 886-8.

-         Dave N, Halbe AR, Kadam PP, Oak SN, Parelkar SV. 
Bilateral pulmonary hydatid cysts in a child: anesthetic management. 
Pediatr Anesth 2004; 14: 889-90.

-         Chhabra A, Arora MK, Gupta A, Dehran M, Agarwala S. 
Intraoperative anaphylaxis with a complicated pulmonary hydatid cyst. 
Pediatr Anesth 2007; 17: 195-7.

-         Singh A, Kholi H, Grawal A, Budhiraja S. 
Anaesthetic considerations in a child with bilateral hydatid cysts of lung. 
Ind J Anaesth 2008; 52: 849-52.

-         El Koraichi A, Azizi R, Ghannam A, Mekkaoui N et al. 
Choc anaphylactique au cours de la chirurgie du kyste hydatique du foie chez l’enfant: à propos d’un cas. 
Ann Fr Anesth Réanim 2011 ; 30 : 369-71.

-         McManus D, Gray DJ, Zhang W, Yang Y. 
Diagnosis, treatment and management of echonococcosis. 
BMJ 2012; 344: e3866, 13p Wen H, Vuitton L, Tuxun T, Li J, Vuitton DA, Zhang W, McManus DP. Echinococcosis: Advances in the 21st Century. Clinical Microbiology Reviews 2019; 32: e00075-18

Updated: May 2022