Discussion

Because the clinical signs and symptoms of cardiac hydatid cyst are non-specific and highly variable, this disease may be difficult to diagnose. ^{Reference Salih, Celik, Topcuoğlu, Kisacikoğlu and Tokcan5}

The clinical features or the spectrum of symptoms of cystic echinococcosis are highly variable and depend on the involved organs, size of cysts, and their sites within the affected organ or organs, the interaction between the expanding cysts and adjacent organ structures, the complications caused by rupture of cysts, bacterial infection of cysts and spread of protoscolices and larval material into bile ducts or blood vessels, immunologic reactions or membranous nephropathy secondary to release of antigenic material. ^{Reference Larrieu, Del Carpio and Mercapide2,Reference Brunetti3}

Cystic echinococcosis is rarely fatal. Occasionally, deaths occur because of anaphylactic shock because of the release of cystic fluid due to cyst rupture or cardiac tamponade in heart echinococcosis. ^{Reference Bouraoui, Trimeche and Mahdhaoui6,Reference Neumayr, Troia and de Bernardis11} Individuals of all ages are affected. In some endemic countries, children have higher infection rates because they are most likely to play with dogs. ^{Reference Brunetti3}

Months or years may pass before an individual exhibits any signs or symptoms of infection with the cystic larval stages. During the natural course of infection, the fate of E.granulosus cysts is variable. Some cysts may grow to a certain size and then persist without noticeable change for many years. Other cysts may rupture spontaneously or collapse and completely disappear.

After a variable incubation period, infections may become symptomatic if cysts are growing and exerting pressure on adjacent tissue and inducing other pathologic findings.

Sudden symptomatology is usually due to spontaneous or traumatic cyst rupture.

Usually, cysts do not induce clinical symptoms before they have reached a size sufficient to exert pressure on adjacent organs. The presentation of human echinococcosis is protean. Patients come to the clinician’s attention for different reasons, such as when a large cyst has some mechanical effect on organ function or rupture of a cyst causes acute hypersensitivity reactions. The cyst may also be discovered accidentally during radiographic examination, body scanning, surgery, or for other clinical reasons. ^{Reference Nagpal, Kohli, Chowdhary, Kumar, Andley and Ravi16} Common chief symptoms are upper abdominal discomfort and pain, poor appetite, and a self-diagnosed mass in the abdomen. Physical findings are hepatomegaly, a palpable mass on the surface of the liver or other organs, and abdominal distention. If cysts in the lung rupture into the bronchi, intense cough may develop, followed by vomiting of hydatid material and cystic membranes. ^{Reference Santivanez and Garcia7}

No standard, highly sensitive, and specific serologic test exists for cystic echinococcosis antibody detection, but serologic studies can be useful in confirming a diagnosis of echinococcosis, even the false-negative rate may be as high as 50%. Children aged 3–15 years may produce minimal serologic reactions. ^{Reference Larrieu, Del Carpio and Mercapide2,Reference Brunetti, Kern and Vuitton8}

Ultrasonography is the procedure of choice when making the diagnosis of asymptomatic cystic echinococcosis because it is safe, non-invasive, and relatively inexpensive. Ultrasonography is an imaging technique that uses the reflection of ultrasound waves emitted by a probe on the bodily organs to build images of the organs explored. ^{Reference Macpherson, Bartholomot and Frider17}

In 2003, the World Health Organization Informal Working Group on Echinococcosis proposed a standardised ultrasound classification based on the active–transitional–inactive status of the cyst as suggested by its sonographic appearance. ^{Reference Brunetti, Tamarozzi and Macpherson9,12}

Although diagnostic value of transthoracic echocardiography in cardiac echinococcus is well established, the role of transesophageal echocardiography in both the diagnosis and the management of this entity is not well known. ^{Reference Atilgan, Kudat and Tükek13}

CT scanning is indicated when ultrasonography is unsatisfactory, particularly it has the advantage of inspecting any organ (lungs cannot be explored with ultrasonography), detecting smaller cysts when located outside the liver, locating cysts precisely, and sometimes differentiating parasitic from non-parasitic cysts. ^{Reference Dursun, Terzibasioglu and Yilmaz14}

Today MRI has been accepted as superior in many circumstances. MRI may have some advantages over CT scanning in the evaluation of post-surgical residual lesions, recurrences, and selected extrahepatic infections, such as cardiac infections. ^{Reference Stojkovic, Rosenberger, Kauczor, Junghanss and Hosch15}

For simple, accessible cysts, the preferred therapy involves ultrasound- or CT-guided percutaneous aspiration, instillation of hypertonic saline or another scolicidal agent, and re-aspiration (PAIR). Compared with surgical treatment alone, PAIR plus albendazole results in similar cyst disappearance with fewer adverse events and fewer days in the hospital. Compared to albendazole alone, PAIR with or without albendazole provides significantly better cyst reduction and symptomatic relief. Spillage with PAIR is surprisingly uncommon, but prophylactic albendazole therapy is routinely administered 4 hours or even 1 week prior to PAIR or surgery and continued for 1 month thereafter. ¹

Mebendazole and albendazole are the only anthelmintics effective against cystic echinococcosis. Albendazole and mebendazole are well tolerated but show different efficacy.

Albendazole is significantly more effective than mebendazole in the treatment of liver cysts. Benzimidazole treatment alone requires prolonged administration over many weeks, with an unpredictable outcome in terms of response rates in individuals. ^{Reference Stojkovic, Zwahlen and Teggi10}

Duration of therapy and doses are also important. Albendazole efficacy increases with courses of up to 3 months in the more common cyst sites. ^{Reference Brunetti, Kern and Vuitton8,Reference Liu, Wang and Wu18}

The puncture of echinococcal cysts has long been discouraged because of risks of anaphylactic shock and spillage of the fluid. ^{Reference Neumayr, Troia and de Bernardis11}

These patients must be evaluated for ultrasonographic appearance modifications and changes in serology titres after 3 months of treatment and then for about 4 years. ^{Reference Brunetti, Tamarozzi and Macpherson9,Reference Stojkovic, Zwahlen and Teggi10}