��“Hooked” on Hydatid Disease: Case-based overview of Echinococcal Infections

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Dustin Waters, PharmD, BCIDP

Infectious Diseases/Antimicrobial Stewardship Pharmacist

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ISU CAPRESE Short Rounds

January 14, 2026

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Disclosures

• No relevant financial disclosures

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Objectives

• Review cases of Echinococcal infections and identify characteristic manifestations of echinococcal disease
• Identify risk factors for developing Echinococcal disease
• Outline treatment strategies for the management of Echinococcal infection
• Discuss PAIR (Puncture, Aspiration, Injection, Re-aspiration) and when surgical management vs. PAIR vs. medical treatment alone is adequate for Echinococcal infection

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Case #1

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Patient Case

• 46 year-old man presenting to the ED after 1 month of headaches which have become progressively constant over the last 2 weeks
• Recently lost employment due to increasing confusion, forgetfulness, and was too slow to keep up with the pace of work
• One week prior to presentation at ED had a near syncopal event with weakness in legs
• Headache is associated with photo/phonophobia
• Has been using acetaminophen at home without relief

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Patient Case

• Patient is originally from Peru, in the United States and seeking asylum
• Past Medical History is relatively unknown, patient presumably healthy
• Due to presentation, MRI was ordered in the ED
• MRI Findings:

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Imaging

MRI in ED

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The Story Continues….

• Based on imaging, patient was transferred from Logan to McKay-Dee and was taken to the OR for surgical exploration of the cystic mass
• In surgery, the neurosurgeon found a large cystic mass with protrusion of brain tissue through dural opening
• Cyst was “sharply opened” with brisk egress of clear, cystic fluid with relaxation of the frontal lobe
• Fluid sent for microbiology and pathology
• Based on what you’ve seen and the limited history, what sorts of things are on your differential???

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Hospital Course

• Neurosurgeon was concerned for neurocysticercosis due to some potentially calcified lesions
• Discussed with ID provider (ID provider out of the hospital and unavailable for in house consult) and albendazole 400 mg PO BID was started
• Cysticercosis antibody sent
• Patient started on corticosteroids to help with inflammation in brain and to potentially decrease risk of seizures
• On Hospital day 6 the Cysticercosis antibody returned……

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Hospital Course (Cont’d)

Cysticercosis Antibody Negative!!!

So now what??

Hospital Course

• On hospital day 6, patient was getting ready for discharge and ID pharmacist was asked about access to medications
• ID pharmacist was somewhat aware of patient, but not actively following because albendazole doesn’t show up as anti-infective on list in clinical decision support software
• Was asked about access of medications, so looked into case
• Imaging looked less like neurocysticercosis and more like possible Echinococcus
• Echinococcus antibody ordered
• Patient discharged with albendazole 400 mg BID with coupon for access for 14 days until we could get pathology and Echinococcal serology

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Post-Hospital Course

• 4 days after hospital discharge Echinococcal antibody resulted….

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• Worked with ID physician on plan
• Added Praziquantel to albendazole for 14 days
• Plan to treat with albendazole for 3-6 months
• Utilized hospital 340b iMAP program for access to medications
• Patient is feeling much better post surgery … however….
• Is anyone concerned with recurrence/worsening in the short term with essential “lancing” of the cystic structure rather than cyst removal?

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Case #2

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Patient Case

• 20 year-old male presented to ED for complaint of abdominal pain. Had CT done which showed complex mass measuring 13.4 x 5.4 cm
• Repeat CT showed same mass with concern for Echinococcal cyst
• Patient was originally from Peru – one of the highest endemic locations for acquiring Echinococcus
• Admitted to the hospital
• Started on albendazole for management of Echinococcal cyst
• Echinococcal IgG – Positive – 16 units
• Discharged on hospital day 6 after being seen by infectious diseases with recommendations to take albendazole until surgery

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Patient Case #2

Surgical Images

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Patient Case

• Patient took albendazole to prepare for surgery ~ 4 weeks after initial discharge from the hospital
• Continued albendazole for 4 weeks after surgery
• Unfortunately, patient developed a liver abscess post surgery growing Enterococcus faecalis
• Completed 4-6 week course of ampicillin/sulbactam followed by amoxicillin/clavulanate
• Patient recovered fully and was doing well at 3 month follow-up after surgery

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Case #3

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Patient Case #3

• 69 year-old female originally from Ukraine transferred from small community hospital to larger hospital for liver abscess and choledocholithiasis with obstruction.
• Patient was admitted and had Endoscopic Retrograde Cholangiopancreatography (ERCP) to clear bile duct obstruction
• Also had drainage of “liver abscess” by interventional radiology
• Later in the day, lab called saying that there were “hooklets” seen on pathology of liver “abscess”
• Sent for Echinococcal antibody
• Patient subsequently discharged on hospital day 3 on amoxicillin/clavulanate

Patient Case #3

Pathology Images

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Patient Case #3

• One week after discharge the Echinococcal antibody came back positive
• After extensive insurance/pharmacy work, patient was arranged to take albendazole
• Referred to infectious diseases and surgery
• Infectious diseases recommended continuing albendazole
• Surgery recommended PAIR via interventional radiology as this was a less invasive approach than surgery
• Patient scheduled for PAIR some time this month

Echinococcus Overview

• Echincoccus life cycle

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https://www.cdc.gov/dpdx/echinococcosis/index.html

Global Distribution of Echinococcus

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https://cdn.who.int/media/docs/default-source/ntds/echinococcosis/global-distribution-of-cystic-echinococcosis-2011.pdf?sfvrsn=15bf8521_4

Echinococcus Risk Factors

• Dog related exposures are greatest risk
• Letting dogs roam free (OR – 5.23)
• Feeding dogs with viscera (OR 4.69)
• Slaughtering animals at home (OR 4.67)
• Living in rural areas also risk factor
• Female sex also risk factor
• Endemic areas
• Central Asia
• Balkans
• Iran/Turkey
• Argentina, Peru, Chile

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6034244/

https://pubmed.ncbi.nlm.nih.gov/27820824/

Echinococcus Overview

• Cystic vs Alveolar Disease
• Cystic disease can occur in many different organs – mainly brain, liver, lungs
• Alveolar disease cysts develop in liver and may disseminate to many other organs
• Treatment with anti-helminth agents
• Albendazole – recommended for 1-6 months depending on extent of disease – not a lot of great data to guide determination of duration
• Praziquantel for 14 days
• Systematic review/meta-analysis has shown statistically significance for albendazole over surgery alone (OR ~ 48, although confidence interval VERY wide)
• Albendazole vs Albendazole + Praziquantel – Not statistically evaluable in meta-analysis, however one study showed increased numbers of non-viable scoleces in combo group

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https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6034244/

Surgical Removal

• Gold Standard is “Dowling Technique”
• 3% hypertonic saline injected around cyst to aid with intact removal
• https://youtu.be/e5eliuwZ0jg?si=JODJptPP6FQEcY5e
• PAIR
• Percutaneous aspiration, injection of chemicals and reaspiration
• Used for cysts that are not amenable to intact removal
• Scolicidal agent such as 95% ethanol commonly used

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https://www.cdc.gov/echinococcosis/hcp/clinical-care/index.html

Conclusion

• Echinococcus is a relatively rare clinical entity
• Should keep in mind, however, in patients traveling to/from endemic areas
• Importance of removing cysts whole, so as not to spread disease
• Albendazole mainstay of therapy, however some data suggest benefit of adding praziquantel for extensive disease
• Serum echinococcal antibody is the gold standard for diagnosis, however, pathology/imaging can be helpful as well
• Dogs are major reservoir, however sheep play important part in transmission

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Questions?

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