Echinococcus multilocularis: Difference between revisions
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Echinococcus multilocularis
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=== Life Cycle === |
=== Life Cycle === |
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− | * Definitive hosts are canid carnivorous animals |
+ | * Definitive hosts are canid carnivorous animals, including urban coyotes |
* Eggs contaminate the environment, including produce |
* Eggs contaminate the environment, including produce |
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** They are infective after a few days, and are viable for up to 16 months at 4ºC |
** They are infective after a few days, and are viable for up to 16 months at 4ºC |
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** Rare in North America |
** Rare in North America |
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* Within Canada: |
* Within Canada: |
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+ | ** Associated with arctic foxes and wolves |
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** Alberta has highest number of cases, with 19 cases from 2013 to 2021 |
** Alberta has highest number of cases, with 19 cases from 2013 to 2021 |
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** 0 to 3 case reports in other provinces |
** 0 to 3 case reports in other provinces |
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**May also mimic [[hepatocellular carcinoma]], [[cirrhosis]], and [[tuberculosis]] |
**May also mimic [[hepatocellular carcinoma]], [[cirrhosis]], and [[tuberculosis]] |
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**Causes continuously-growing tumour-like polycystic mass, made up of multiple vesicles that are lined by laminated germinal layer |
**Causes continuously-growing tumour-like polycystic mass, made up of multiple vesicles that are lined by laminated germinal layer |
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− | *Can cause cholestatic |
+ | *Can cause cholestatic [[jaundice]], [[cholangitis]], [[portal hypertension]], and [[Budd-Chiari syndrome]] |
== Diagnosis == |
== Diagnosis == |
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*A single negative serologic test does not rule out infection |
*A single negative serologic test does not rule out infection |
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* May be confirmed by biopsy |
* May be confirmed by biopsy |
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+ | |||
+ | === Case Definition (Alberta) === |
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+ | |||
+ | * Typical organ lesion detected by imaging with US or CT |
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+ | * AND histopathology compatible with alveolar echinococcosis |
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+ | * AND |
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+ | ** Detection of ''E. multilocularis'' by serology |
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+ | ** OR detection of ''E. multilocularis'' by molecular diagnostic methods |
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+ | |||
+ | === Imaging === |
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+ | |||
+ | * Ultrasound or CT demonstrates lesions which typically have an irregular contour, no well-defined wall, central necrosis, and irregular intralesional and wall calcifications |
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+ | |||
+ | === PNM Classification === |
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+ | |||
+ | * P=parasitic mass in the liver, N=neighbouring organ involvement; M=metastases |
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+ | |||
+ | {| class="wikitable" |
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+ | ! |
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+ | !P |
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+ | !N |
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+ | !M |
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+ | |- |
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+ | |X |
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+ | |Primary tumour cannot be assess |
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+ | |Not evaluable |
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+ | |Not evaluable |
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+ | |- |
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+ | |0 |
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+ | |No detectable tumour in liver |
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+ | |No regional involvement |
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+ | |No metastasis |
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+ | |- |
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+ | |1 |
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+ | |Peripheral lesions without proximal vascular and/or biliary involvement |
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+ | |Regional involvement of contiguous organs or tissues |
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+ | |Metastasis |
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+ | |- |
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+ | |2 |
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+ | |Central lesions with proximal vascular and/or biliary invovlement of 1 lobe |
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+ | | rowspan="3" | |
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+ | | rowspan="3" | |
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+ | |- |
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+ | |3 |
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+ | |Central lesions with hilar vascular or biliary involvement of both lobes and/or with involvement of 2 hepatic veins |
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+ | |- |
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+ | |4 |
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+ | |Any liver lesion with extension along the vessels and biliary tree |
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+ | |} |
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== Management == |
== Management == |
Latest revision as of 12:09, 2 March 2023
Background
Microbiology
- Cestode in the Echinococcus family
- Disease is caused by the larval form
Life Cycle
- Definitive hosts are canid carnivorous animals, including urban coyotes
- Eggs contaminate the environment, including produce
- They are infective after a few days, and are viable for up to 16 months at 4ºC
- Intermediate hosts (metacestode) are rodents, possibly pigs, and and incidentally humans
- Intermediate host is eaten by the definitive host, completing the life cycle
Epidemiology
- Estimated 18,000 cases annually
- Worldwide in the northern hemisphere
- Most cases in China (90%), followed by Japan and Russia
- Rare in North America
- Within Canada:
- Associated with arctic foxes and wolves
- Alberta has highest number of cases, with 19 cases from 2013 to 2021
- 0 to 3 case reports in other provinces
Clinical Manifestations
- Causes alveolar echinococcosis
- Incubation period 5 to 15 years
- Vague abdominal pain may precede diagnosis by years
- Presents as a metastatic malignancy of unknown primary, mot commonly with malaise, weight loss, and right upper quadrant discomfort
- May also mimic hepatocellular carcinoma, cirrhosis, and tuberculosis
- Causes continuously-growing tumour-like polycystic mass, made up of multiple vesicles that are lined by laminated germinal layer
- Can cause cholestatic jaundice, cholangitis, portal hypertension, and Budd-Chiari syndrome
Diagnosis
- Combination of radiologic and serologic investigations
- A single negative serologic test does not rule out infection
- May be confirmed by biopsy
Case Definition (Alberta)
- Typical organ lesion detected by imaging with US or CT
- AND histopathology compatible with alveolar echinococcosis
- AND
- Detection of E. multilocularis by serology
- OR detection of E. multilocularis by molecular diagnostic methods
Imaging
- Ultrasound or CT demonstrates lesions which typically have an irregular contour, no well-defined wall, central necrosis, and irregular intralesional and wall calcifications
PNM Classification
- P=parasitic mass in the liver, N=neighbouring organ involvement; M=metastases
P | N | M | |
---|---|---|---|
X | Primary tumour cannot be assess | Not evaluable | Not evaluable |
0 | No detectable tumour in liver | No regional involvement | No metastasis |
1 | Peripheral lesions without proximal vascular and/or biliary involvement | Regional involvement of contiguous organs or tissues | Metastasis |
2 | Central lesions with proximal vascular and/or biliary invovlement of 1 lobe | ||
3 | Central lesions with hilar vascular or biliary involvement of both lobes and/or with involvement of 2 hepatic veins | ||
4 | Any liver lesion with extension along the vessels and biliary tree |
Management
- Main treatment is surgical resection followed by at least 2 years of antihelminthic therapy (e.g. albendazole)
- Poor prognosis, with 90% 10-year mortality if untreated