Cestodes (tapeworms) Flashcards
Tapeworm infection is from?
Consumption of undercooked meat containing cysts
Beef tapeworm name? Life cycle?
How big does it get?
Taenia saginata
-Humans consume cysts enclosed in muscles of herbivores
-Worm then attaches to small intestine with suckers
-Slowly grows more segments from its head
-May grow up to 10m and live 25 years producing 50k eggs a day
-Eggs out in stool which infect cattle
Which worm causes cysticercosis? life cycle? difference to taeniasis
Taenia Solium
Cysticercosis
Consumption of food contaminated with T solium eggs
->Hatch into larvae and migrate to muscle /brain
-> form cysts
Taeniasis
Eat Pig meat containing cysts (with larvae)
-> adult T solium hatch in gut -> Taeniasis
Usual Sx of taeniasis?
Minimal with abdo discomfort and vauge sx.
May pass large segment of worm or vomit it out
Dx taenia ? 2 ways to differentiate saginata and solium?
Microscopy of stool for eggs / scolex
-PCR
-Saginata has >12 branches on uterus on microscopy
Size of tissue cysts in cysticercosis? where are they found?
1-2cm
Muscle (palpable) - eventually form calcified streaks
brain - seizures
Most common cause of non-epileptic seizures worldwide
Neurocysticercosis
Neurocysticercosis rx? What else is needed?
praziquantel and Albendazole
Dexamethasone
Needs antiepileptics if seizures
Fish tapeworm called?
Dibothriocephalus latum/Adenocephalus pacificus (formerly
diphyllobothrium latum)
Usual drug for all intestinal cestode (tapeworm)?
Main alternative?
Praziquantel single dose (around 10mg/kg)
[Niclosamide is alternative]
What causes hydatid disease
Echinococcus granulosus
Tapeworm from dogs / sheep / cattle
-Usually in areas of sheep / cattle farming
Echinococcus granulosus life cycle
dogs (definative host) harber 3-6mm adult tapeworm which lays eggs -> faeces
-> Ingested by sheep / humans and develop into cyts with fibrous capule (hydatid cyst) which may grow over several years
-> Dogs eat meat with cysts in
Where do hydatid cysts usually develop? sx?
70% in liver (usually right lobe)
-Usually painless (unless secondary bacterial infection which is common)
20% in lungs -> general respiratory sx and may cough up cyst
[may be single or multiple]
Bone enters bone marrow - may cause pathological fractures
Brain, spleen, heart, kidneys …
What is ‘water lily’ appearance on CXR
Collapse hydatid cyst
Hydatid cysts ix?
CXR
CT - eg water-lilly sign
US - Snowflake sign
-Either see Single cyst or with daughter cysts
ELISA for IgG (sensitive but not specific)
Western blot
Hydatid cysts rx options?
Albendazole
Percutenous aspiration under US
-PAIR - Puncture, aspirate, Inject (hypertonic saline / alcohol) Re-aspirate
ONLY for liver cysts
Surgery
[Albendazole +/- praziquantel before and after procedure]
Prevention / control hydatid
Mostly around dog control measures (prevent eating infected cysts or treat with praziquantel
Vaccination of sheep / dogs
What is the difference in host and cysts between Echinococcus multilocularis vs E granulomatosus? Rx?
Multilocularis - mostly foxes
Doesnt tend to have fibrous capsules -> invades similar to a malignant liver Ca
Sugery with pre and post albendazole
Dwarf tapeworm real name
Hymenolepis nana
2-3mm
Hymenolepis nana life cycle?
Infected when injest eggs (either from infected insects or human fecaes)
Develop in intestines
Autoinfection
Hymenolepis nana clinical features? Infective vs diagnostic stage?
Often Asx
Non-specific symptoms often abdo/ headaches
Children get sleep and behaviour disturbance
[Nana annoys the kids]
-Infective stage: embryonated egg
infected arthropods (beetles, fleas)
-Diagnostic stage: eggs ,
Hymenolepis nana Dx rX?
Eggs in stools / ELISA
Praziquantel dose then dose after 10 days
[Niclosamide for 7 days, Nitrazoxanide for 3 days]
18 fever, jaundice, RUQ pain, Respiratory distress,
CT - hepatomegaly with cholangitis and large cystic lesions
Hydatid
3 species of hydatid
Echinococcus granulosus: Cystic HD
- E. multilocularis: Alveolar HD
- E. vogeli, (E. oligarthra): Polycystic HD
Intermediate vs definitive host Echinococcus
Sheep - intermediate
Dogs - definitive
How does hydatid cysts cause issues (3 parts)
- Mass effect: Compression, obstruction, erosion
- Allergy, anaphylaxis
- Infection
Rupture of hydatid cyst causes what issues
Allergic reaction
Peritoneal seeding - may develop 100s of cysts
Cholangitis - especially if communication with bile duct
Liver abscess
Hydatid looks like some big bubbles with smaller ones inside or near what species is this?
Echinococcus granulosus
Main cysts which forms lots of daughter (smaller than main) cysts around
Hydatid stage 1 vs 2 vs 3 vs 4 vs 5
1 single cyst
2 - Single with daughter cysts
3a - Transitional with partial detachement of membrane
3b - cyst with solid components and daughter cysts
4 - Solid compnents predominate
5 - Inactive - with complete calcification of boarder
When surgery for hydatid?
Cyst >10cm
Presense of daughter cysts
Infected
Likely to rupture
compression of vital structures…..
Mortality 1%
Albenzadole monitoring
Monitor WBC and transaminases every 2 weeks
[then monthly after 2 months]
Contra indications albendazole
Pregnancy
Chronic liver disease
Bone marrow depression
2 options for perisurgical chemo in hydatid
Albendazole or praziquantel
Who is PAIR used for in hydatid
Liver: CE1 and CE3a
Abdominal cavity, spleen, kidney
Bar PAIR what is the other percutaneous option for hydatid ? In who? differences to PAIR ?
Modified Catheterization Techniques (MoCAT)
- Liver: CE2 and CE3b
- Evacuation of the entire parasitic membranas
- Catheter left in place
Dont need to check bilirubin
When using PAIR for liver cysts what do you need to check?
After aspirate make sure no bilirubin -> otherwise when inject alcohol will cause necrosis of bile duct
Hydatid stages and rx?
1 - < 5 cm ABZ
> 5 cm PAIR + ABZ
2 Non-PAIR PT + ABZ
Surgery + ABZ
3a < 5 cm ABZ
> 5 cm PAIR + ABZ
3b Non-PAIR PT + ABZ
Surgery + ABZ
[W&W]
4 Watch and Wait
5 Watch and Wai
Echinococcus multilocularis called? Key difference in host?
alveolar hydatid
Fox
Where alveolar cyst (E multilocularis) most common
LIVER - 99%
[Echinococcus multilocularis]
Rx Echinococcus multilocularis
Radical surgery
Long term albendazole for minimum 2 years
CT showed Multiple cysts in liver without daughter cysts in ‘bunch of grapes’ = which hydatid?
Rx
Echinococcus vogeli, E. oligarthra
[polycystic hydatid]
Looks more like a bunch of grapes
Radical surgery
Long term albendazole for minimum 2 years
Dog tapeworm called ? Life cycle
Dipylidium caninum
Eggs → flea larvae → cysticercoid (adipose tissue and muscles) → adult flea
→ human swallows → adult tapeworm
Where do the fleas live for dog tapeworm
Dogs and cats
Dipylidium caninum - key clinical features ?
Rx?
General abdo / eosinophilia
Proglottids pass out of the anus, seen moving in
stools, contain egg packets
Praziquantel
[or Niclosamide]
Which intestinal tapeworm classically causes b12 deficiency
Diphyllobothrium latum (fish)
Taenia general life cycles for solim/saginata
Hymenolepis nana scloex
Hymenolepis nana egg
[nana has the dolies round her egg]
echinococcus granulosus
echinococcus granulosus
Dipylidium caninum proglotid
Dipylidium caninum egg packet
Diphyllobprthroid tapeworm life cycles
Taenia egg
- thick, radially striated shell
-six hooked embryo
Taenia egg
- thick, radially striated shell
-six hooked embryo
Taenia egg
- thick, radially striated shell
-six hooked embryo
T saginata - 4 suckers (may be pigmented), no rostellum, no hooks, thin and long
T saginata - >12 uterine branches (range 12 30), motile , lateral genital pore
T saginata - >12 uterine branches (range 12 30), motile , lateral genital pore
T Solium - 4 suckers , rostellum with double crown of hooks (armed), thin neck
T Solium - 4 suckers, rostellum with double crown of hooks (armed), thin neck
T Solium - <12 uterine branches (range 7 13), lateral genital pore.
T solium life cycle
Cysticercosis Infective vs diagnosic?
Infective stage: embryonated eggs
Diagnostic stage: cysticercus (imaging,
Taenia solium
Cysticercus cellulosae (larval stage)
Taenia solium
Cysticercus cellulosae (larval stage)
Development of a spreading, multilobular cyst that may lack a scolex typically in the subarachnoid region called?
racemose cysticercosis
Echinococcus granulosus Life cycle? Infective stage? Diagnostic stage?
Infective stage : embryonated egg
Diagnostic stage: hydatic cyst
Echinococcus granulosus
4 suckers , rostellum with double crown of hooks (armed), strobila 1 immature proglottid 1 mature proglottid 1 2 gravid proglottid
Echinococcus granulosus
4 suckers , rostellum with double crown of hooks (armed), strobila 1 immature proglottid 1 mature proglottid 1 2 gravid proglottid
3 layers of cyst in echinococcus granulosus
Pericyst
(outer adventitia , host-derived fibrous tissue and blood
Ectocyst
(middle layer): elastic, laminated/cuticular layer, acellular hyaline layer.
Endocyst
(inner layer): germinal layer . Forms the ectocyst , brood capsules, hydatic
echinococcus granulosus
What are A-F
A - host tissue
B - Laminated layer
C - Germinal layer
D - Brood capsule
E - Protoscolites
F - immature hooklets
E Granulosus protoscolex (note hooklets)
Buzz words for CE2 and CE3a in E. granulosus
Hymenolepis nana
Hymenolepis nana
Who am I and what fun facts?
Hymenolepis nana - smallest (2 4cm) and most common cestode infecting humans
Hymenolepis spp.
rectangular (4x wider than longer: trapezoidal, “overlapped”)
Structures : lateral genital pore (not visible), lobulated uterus filled with eggs , 3 testicular follicles.
Hymenolepis spp.
lobulated uterus filled with eggs
Hymenolepis nana
4 suckers , short rostellum with a single row of hooklets (armed), thick neck
Nana puckering for a kiss
Hymenolepis diminuta life cycle? Difference to nana?
Infective vs diagnostic stage?
NO autoinfection
-Infective stage : ingestion of an intermediate
host carrying the cysticercoid larva
-Diagnostic stage : eggs , proglottids (rare)
Hymenolepis Diminuta
2 membranes outer shell and inner embryophore Oncosphere with 6 hooklets
Space between membranes
has a smooth appearance
No polar filaments
no polar thickening
Bile stained
Hymenolepis Diminuta
Hymenolepis Diminuta
4 suckers , rostellum with no hooks.
Hymenolepis Diminuta
4 suckers , rostellum with no hooks.
What disease might I give you?
Intermediate host (H. diminuta
Confused flour beetle - T. confusum 3-6mm long
H diminuta - hookless invaginated scolex, tail .
Dibothriocephalus latus / Adenocephalus pacificus
Look for the
-operculum (Lid bit can be inconspicuous)
- abopercular knob (barely discernible),
Longest tapeworm?
Dibothriocephalus latus / Adenocephalus pacificus 15m long wow nasty
Dibothriocephalus latus / Adenocephalus pacificus
- spoon shaped , two sucking grooves
Dibothriocephalus latus / Adenocephalus pacificus
-centrally located coiled + rosette shaped uterus
Dibothriocephalus latus / Adenocephalus pacificus
Prevention and control taeniasis
Adequate cooking of meat
Vaccinate livestock from t saginata and t solium
How did peru interupt t solium?
Chemo of community - niclosamide
Chemo of pigs - oxfendazole
Korean
46 yo F with 3 d perianal pruritus and passing noodle like material
During year prior, had intermittent colicky abd pain, loose stool, “irritable bowel
Colonoscopy revealed a long, moving tapeworm, in the terminal ileum and extending to the sigmoid colon
Dx?
Get from?
Rx?
Dibothriocephalus ssp.
-consumption raw fish
Praziquantel single dose
Diphyllobothriid species locations?
Key issue?
Cause b12 deficiency - as have a higher affinity b12 receptor than ours
[Learn the europe and south america name]
Ten year old from India with new onset seizures=? rx?
NeuroCysticercosis
Praziquantel + albendazole + steroids + antiepileptics
[if only 1 lesion can use just albendazole]
Why seizures in cysticercosis only after several years
Older cysts lose the ability to suppress inflammation
-> Granuloma and inflammatory reaction around
Symptoms: young person with HA, altered mental status, reduced visual acuity,
Obstructive hydrocephalus - first thing you’re thinking as a Dx? rx?
Ventricular cysticerci
-> mechanical obstruction of CSF
Optimal Rx is neuro endoscopic removal
Subarachnoid cysticercosis key issue?
Stroke
What clinical picture would you expect from NCC cysts in these locations?
1. Calcified
2. Subarachnoid
3. Ventricular
4. Single enhancing
5. Multiple cystic
6. Spinal
- Calcified - Chronic epilepsy
- Subarachnoid - meningitis and stroke
- Ventricular - obstructive hydrocephalus
- Single enhancing - benign
- Multiple cystic - recurrent seizures
- Spinal - paraplegia
Relevance of Ocular Cysticercosis
Make sure surgical removal before giving antiparasitics
-Otherwise risk of inflammation and blindness
Cysticercosis ix?
Neuroimaging
Western blot
Rx of calcified cysts in neurocysticercosis
Antiepileptics only +/- rx of oedema if present
[You need to be sure they’re not viable]
Name 3 worms capable of autoinfection
Strongy
Hypenolepis nana
capillaria philippinensis
Enterobius vermicularis (kind of)
T solium - rarely
Neurocystercircosis
-If it is a SINGLE lesion rx?
-Multiple?
Albendazole + Steroids
+antiepileptics if needed
+ praziquantel for multiple
Multiple round 8-10 cm diameter spherical lesions in the right lung in a kid =? rx?
Echinococcus granulosus
Surgery + post op albendazole
A college student returns from a vacation in Mexico noting passing long-thin noodle-like structures that wiggle as they come out. The structures are 1 cm wide 1-2 mm thick and in chains that vary from 2-12 cm
Dx? Rx? 2nd line?
Tapeworm
Praziquantel
Niclosamide (or nitazoxanide)
Basal Subarachnoid NCC called?
racemose
Neurocystercecosis rx of:
Viable live cysts:
Calcified cysts:
Extra-parenchymal eg ventricular cysts:
Subarachnoid cysts eg racemose:
Hydrocephalus but no viable cyst:
Ophthalmic:
Spinal:
Viable live cysts: Antiparasitic + steroids
Calcified cysts: Steroids
Extra-parenchymal eg ventricular cysts: Neuroendoscopic removal
Subarachnoid cysts eg racemose: Antiparasitic + steroids (+ VP shunt if hydrocephalus)
Hydrocephalus but no viable cyst: VP shunt
Ophthalmic: Surgical
Spinal: Surgical
What stage hydatid am I? Rx?
CE2 - Surgical + albendazole
What stage hydatid am I? Rx?
CE1
<5cm Albendazole
>5 PAIR + albendazole
What stage hydatid am I? Rx?
CE3a - detachment of membranes
<5cm Abz
>5 PAIR + abz
What stage hydatid am I? Rx?
CE3b solid with daughters
Surgery + Abz
