Lab results showed eosinophilia (1,490/uL) and increased erythrocyte sedimentation rate (30 mm/h). The patient was hospitalised and
Albendazole was started. Her serology for
Echinococcus was positive. Eleven days later, her fever returned with a worsening cough. Chest x-ray (Figure 2) revealed signs of cyst rupture. A cyst excision and lobectomy were performed, and the presence of
Echinococcus was confirmed in the cystic fluid. She completed 6 months of
Albendazole and had no recurrence after 3 years of follow-up.
Hydatidosis is a zoonotic disease with worldwide distribution, and humans are an accidental host.
1 Definitive hosts, usually dogs, hold adult tapeworms in their small intestine which release numerous eggs through faeces to the environment. The eggs are ingested by intermediate host (domestic animals) or accidental hosts (humans, through contaminated water or vegetables) and from them hatch oncospheres, which migrate through blood and lymphatic system to visceral organs, primarily the liver. There, they form vesicles which in a few days maturate into fluid-filled cysts (hydatid cysts). Within these cysts, protoscolices develop and, if ingested by definitive host, they evaginate and develop into adult tapeworms, completing echinococcus life cycle.
1 In humans, hydatic cysts are mostly caused by
Ecchinococcus granulosus and
Ecchinococcus multilocularis and have a highly variable growth rate.
2
The diagnosis of a hydatid cyst on the lung (the second most common location) is often an incidental finding in an asymptomatic patient.
1 Eosinophilia may be present in less than 15% of cases.
2 Symptoms may develop from compression (cough, chest pain, dyspnoea) or due to cyst rupture, either with respiratory distress or anaphylaxis.
1,2 Treatment may be conservative (either observational or pharmacological) for simple cysts, although surgical excision or percutaneous drainage may be necessary for complex or complicated cysts.
3 A follow-up period of 3-5 years is recommended due to the risk of recurrence.
3
This diagnosis should be considered in the presence of suggestive imaging results in order to begin treatment early and reduce the risk of complications.
[Figure2]
| References : |
- Lupia T, Corcione S, Guerrera F, et al. Pulmonary Echinococcosis or Lung Hydatidosis: A Narrative Review. Surg Infect (Larchmt). 2021 Jun;22(5):485-495. doi: 10.1089/sur.2020.197. Epub 2020 Dec 9. PMID: 33297827.
- Moro, PL. Clinical Manifestations and Diagnosis of Echinococcosis, In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on July 30, 2021.)
- Moro, PL. Treatment of Echinococcosis, In: UpToDate, Post TW (Ed), UpToDate, Waltham, MA. (Accessed on July 30, 2021.)
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