32 Echinococcus
Intermediate hosts get hydatid cysts (in liver or lungs)
Two main types of hydatid
e. granulosis - cystic disease
e. multilocularis - alveolar disease
32.1 e. granulosis
32.1.1 Epi
The definitive host is the dog! Dogs get the the worms
1-3 million world wide
extensive morbidity (only 1000 deaths)
central asia, middle east, north/east africa
Kenya Turkana nomads - 2-9% prevalence
32.1.2 Pathogenesis
3-6mm (tiny)
Attaches to wall of intestine in dog
You get cysts, predominantely in liver (60%). but also lungs (20%), spleen (6%), bones/muscles/ 4% kidney, heart 2% brain (<2%) (in that order). Mainly liver and lung
32.1.3 Pathology
Patients can get anaphylactoid type reaction from hydatid sand.
If you burst a cyst you can either cause anaphylaxis or spread new cysts.
32.1.4 Clinical Features
Liver and lung cysts can get massive. Can get secondarily infected.
Treat depending on:
Type 1 - simple cyst 2 lots of daughter cysts 3 dying cysts 4 5 dead calcified cysts
Symptoms come from pressure effect also.
32.1.5 Diagnosis
32.1.5.1 Imaging
- Ultrasound
- CT/MRI
32.1.5.2 Bloods
- Serology (reasonably sens/spec)
- Don’t aspirate them
- Eosinophils only if cysts leaking
32.1.6 Treat
- Albendazole (400mg BD)
- Praziquantel (20mg/kg BD)
Alllbendazole against the germinalllll The prraaziquantal against the pppprrrrrotoscoleses
In the context of lung cysts you’d want to use albendazole as less risk of rupture
You can do US guided aspiration Puncture, Aspirate, Infiltrate (protoscoleses), Reaspirate (PAIR). You’d prob only do this for type one cysts.
Evidence?
Albendazole seems better than placebo, but 1/4 relapse. Type 2 more likely to relapse than type one.
Praziquantel seems to be a bit better than albendazole alone.
Lung cyst - surgical removal with prasiquantel before, albendazole after
liver cyst - drugs before and after procedure for 2 weeks (albendazole plus praziquantel)
1 - albendazole plus surg 2 - alb plus surg 3 - alb plus pair or surgery 4 - watch 5 - watch
Albendazole may be given for months/years
32.1.7 Prevention
You can stop dogs eating sheep, you can give dogs praziquantel
You can vaccinate cattle and dogs
You can inspect the meat
32.2 multilocularis
Now you have foxes and rodents
found in north america, europe (not UK) and asia
32.2.1 Clinical Features
The germinal layer is on the outside of the cyst, so you get external budding, heading out like a tumour. They can metastasise!
Symptoms are due to mass effect
Much more serious.
90% 10 yr mortality if untreated.
Vast majority in liver (>98%)
32.2.2 Diagnosis
Imaging Serology
32.2.3 Treat
They only way is with surgery, needs radical approach (plus albendazole)
If inoperable, life long albendazole as suppressive. Month on, two weeks off.
This turns it into a 80% 10 year mortality.
32.2.4 Prevent
Treat/kill foxes
Treat rural dog populations
Educate people living in regions to wash fruit first.
32.3 polycystic
central and south america
extremely rare ~100 cases ever
rodents and wild felines/canines
disease found in liver. kind of half way between both of the other two