Cystic hydatid disease is a common zoonosis caused by the larval cysts of Echinococcus granulosus
. It is seen worldwide but most cases in Northern Europe are seen in immigrants from endemic areas.4
Hydatid cysts are most commonly found in the liver but the pulmonary cysts are not uncommon. Symptoms are generally non-specific but cyst rupture can precipitate severe allergic reactions and disease dissemination.5
In our case, iatrogenic cyst rupture triggered the development of an eosinophilic pleurisy.
The diagnosis of hydatid cysts requires a combination of radiological and serological testing. Chest radiographs and CT scans can identify specific features that are strongly associated with pulmonary hydatid cysts.6 7
Comparative studies between serological tests have shown IgG ELISA to be the preferred assay but reliability is maximised by using at least two different tests.7 8
Eosinophilia is found in less than 15% of patients and is generally only present following leakage of antigen from cysts.9
In our case, the eosinophil count was initially normal and CT appearances were not classical for pulmonary hydatid cysts. However, the CT-guided biopsy and subsequent complications could potentially have been avoided had hydatid serology been considered earlier.
Treatment options for hydatid cysts include surgical resection and the minimally invasive puncture-aspiration-injection-reaspiration technique.1 10
The long-term efficacy of treatment with drugs alone is not yet established and this method is generally reserved for inoperable disease.1
- Cystic hydatid disease has a non-specific presentation and is often initially mistaken for other pathologies due to a failure to consider the diagnosis.
- In the context of rising immigration and foreign travel, it is essential to take an accurate geographical history to ensure that we consider diagnoses that are compatible with the circumstances of the individual.
- A combination of an appropriate index of clinical suspicion and correct interpretation of radiological and serological tests will enable hydatidosis to be diagnosed in a timely manner.