Cestodes Flashcards
What causes hydatid disease?
Larval stage of Echinococcus Granulises
What is the species?
Echinococcus Granulises - note thick neck (differentiates it from T.Solium), double row hooks
What species is this?
Dibothriocephalus latus
What steroid sparing agents can be used for long course steroids in subarachnoid neurocysticercosis?
MTX or TNF inhibitors
What is this and what does it cause?
Calcified lesions of NCC. Taenia Solium. Can still cause seizures.
What causes symptoms in neurocysticercosis?
Parenchymal inflammation
Calcified cysticeri - causes inflammation and scarring
Ventricular cysticerci - causes hydrocephalus
Subarachnoid cysticerci - arachnoiditis
What is this?
Larval stage of T.Solium
Name the species and the structures
Life cycle of T.Solium?
Pigs ingest eggs
Oncospheres hatch and penetrate intestine -> muscle
Cystercirci develop
What species is this?
Dibothricephalus latus adult
What is the Rx for Taeniasis (either species)?
Praziquantel
Name the species
H.Diminunata - thick head, no hooks
What is this?
Echinococcus Granulosus sensu lato
Hooks - double crown of hooks- and 4 suckers
Only 3-4 proglottids
What species is this?
Dibothricephalus latus adult
What species is this?
Taenia species (cannot tell them apart)
What are the names of the stages of dibothrocephalus latus species?
coracidium (larval stage 1) -> procercoid (larval stage 2) -> plerocercoid (advanced larval stage)
What are the treatment options for hydatid disease in liver?
CE1 - simple cyst. <5cm albendazole, 5-10cm PAIR and ABZ, >10cm surgery
CE2 - MOCAT or Surgery +/- albendazole
CE3a - <5cm albendazole, 5-10cm PAIR, >10cm surgery
CE3b - MOCAT or Surgery +/- albendazole
CE4 and CE5 - dead cysts, watch and wait
Rx of subarachnoid neurocysticercosis?
LONG course of anti parasitic drugs (ABZ or both, data emerging on combo therapy)
Steroids key, or alternative
If compression of ventricle - shunt/surgery
Can cause strokes
How do humans become infected with taenia solium/taenia saginata?
Eating uncooked pigs/beef, ingest oncospheres from tissue (larval form)
What are the hosts in hymenolepis nana?
Intermediate: insects
Humans/rodents ingest arthropods containing cystercircoid - embryonated eggs (infective stage)
Definitive: Humans, rodents
How does echinococcosis present?
asymptomatic for years before the cysts grow large enough to cause symptoms in the affected organs.
- Lung - pressure effect
- Liver - pressure effect
- Rupture of cyst: fever, urticaria, eosinophilia, and potentially anaphylactic shock
RARELY
spleen, kidneys, heart, bone, and central nervous system, including the brain and eyes
What species is this?
Taenia Saginata (>12 uterine branches)
What are the intermediate and definitive hosts of dibothricephalus latus?
Intermediate: 1. Crustaceans 2.Fish
Definitive: Mammals (including humans)
NCC you think that all the cysts intraparenchymally are calcified, what to do?
Do MRI to ensure all cysts are calcified to guide further management
What species is this?
Taenia species (striated outer layer and embryo has hooks)
Which is the only tapeworm not to have 4 suckers?
Dibothriocephalus latus
Treatment of choice for H.Diminuta?
Praziquantel
What species is this?
Dibothriocephalus latus
What is this?
H.Diminuta
How do you manage calcified lesions in NCC?
AEDs
Subarachnoid cysts in base of the brain ∆ of NCC. What key clinical concern?
Cause vasculitis of blood vessels - therefore cause stroke.
Can also grow very big, cause mass effect, may cause compression on ventricles causing hydrocephalus.
Rx with ABZ (maybe with PZQ - studies are being done- and long course)
Other symptoms of NC apart from seizures?
Headaches, blurred vision
Name the species
H.Nana head - single row hooks, low rostellum
What is cysticercosis?
Disseminated larval stage of taenia solium from ingestion of eggs
Which cestode does not have 4 suckers?
Dibothriocephalus latus
Neuroimaging criteria for neurocysticercosis
Major: Cystic, enhancing, or calcified lesions suggestive of NCC
Minor: Obstructive hydrocephalus, Meningeal enhancement
Confirmatory: resolution
What does cysts in the subarachnoid space of the spine cause?
Radiculitis, paraparesis
What is the intermediate host for Echinococcus granulises?
Intermediate: sheep
Definitive: Dog
Accidental: humans
Definitive treatment of the T.Solium parasite?
PZQ plus ABZ (if >1 lesion)
PLUS STEROIDS (death of parasite causes increased inflammation and seizures)
How do humans contract T.Solium?
Ingestion of T.Solium eggs (Causes cysticercosis)
Ingestion of larvae would cause Taeniasis (the tapeworm)
Which cestodes are intestinal? Which are tissue?
All intestinal except echinococcus (tissue) and T.Solium which is tissue and intestinal
What is this?
H.Nana (polar filaments, granular space between shells)
What is the dwarf tapeworm?
Hymenolepis species
Name the species
Echinococcus
Which of the cestodes are tissue cestodes?
T.Solium (tissue and intestinal)
Echinococcus (tissue)
What investigations can you do for echinococcus?
Imaging: CXR/CT/US
Serology – Western Blot
Name the species
Cysticercis (larva), Taenia solium
What does a single enhancing lesion of neurocysticercosis usually cause?
Benign prognosis
What are the main cestodes causing human disease?
Tapeworms
Small CE2 small cyst, an option instead of PAIR?
MOCAT - modified catheterisation technique if small
Same for CE3b
PAIR contraindicated for these, and medical therapy doesn’t work
Why does hymenolepis not cause human disease?
Larval stage instantly becomes scolex (hence why doesn’t cause human disease)
Treatment of choice for hymenolepis nana?
Praziquantel
What is the intermediate host for hymenolepis nana and diminuta?
Arthropods - fleas, beetles
How Is hymenolepis diminuta transmitted?
Cystercirci of hymenolepis diminuta ingested from arthropod
Name the species
Taenia Saginata adult
> 100 cysts in neurocysticercosis?
Consensus management - no agreement but probably steroids and antiparasitics
Key principle of treating neurocysticercosis?
Manage the symptoms/effect of the disease is key
Antiepileptics
Hydrocephalus shunting
What is the name for the rat tapeworm?
Hymenolepis Diminuta
Which stage of the life cycle must humans ingest to get echinococcosis?
ingesting eggs
Criteria for diagnosis of neurocysticercosis?
Complex!
One absolute
What is the Rx of echinococcus?
CE1 and CE3a - <5cm Albendazole, 5-10cm PAIR, >10cm Surgery (albendazole after)
CE2 and CE3b <5cm albendazole, >5cm surgery (albendazole after)
CE4 and CE5 - watch and wait
Characteristic features of dibothriocephalus latus?
Fish tapeworm
Proglottids are wide, long tapeworm
B12 deficiency key presenting feature
Multiple intraperitoneal cysts of hydatid disease. Rx?
Surgery to remove as many cysts as possible and then albendazole
Treatment of neurocysticercosis?
Anti epileptics
Steroids
Praziquantel and albendazole (if <3 lesion, just ABZ ok if 1-2 lesion)
Name the species
Hymenolepis diminunata
Prevention of neurocysticercosis?
Mass chemotherapy of humans and pigs
Single lesion parasite Rx?
Albendazole only (do not need combination therapy)
Treatment of dibothriocephalus latus?
Single dose praziquantel
Name the species
Proglottid, adult taenia solium (<12 uterine branches)
Which of the tapeworms can cause auto infection?
Hymenolepis nana
NCC causing aggressive encephalitis. Mx?
Symptomatic - AEDS
Steroids and mannitol
When inflammation resolved, can decide re: antiparasitics.
How does hymenolepsis present?
*Headache, weakness, dizziness, weight loss
* Epigastric or diffuse abdominal pain, nausea,
loose bowel movements or diarrhoea
* Anal pruritus, urticaria
* Sleep and behavioural disturbances
How do you know when to stop antiparasitics in subarachnoid NCC?
CSF antigen test and WCC
Which of the cestodes does not have a genital pore laterally?
Diphyllobothriasis
Treatment of T.Saginata?
Single dose praziquantel
Species in Asia similar to Taenia saginata?
T.Asiatica (pigs are host though)
Diagnosis of neurocysticercosis made how?
Neuroimaging
Hisotpathology (definitive)
Serology
Classic clinical hx of neurocysticercosis?
Young person aged 10-40
Seizures new onset
Single enhancing lesion on CT head - in India and US
Multiple lesions in Latin America
What is the definition of incidental host, intermediate host, definitive host, accidental host, paratenic host?
- Intermediate host: the parasite reproduces asexually and harbours the larval stage
- Incidental host: A host that becomes infected, but is not required for the maintenance of the population of a pathogen
- Paratenic host:?
- dead end host: parasite lives but cannot continue its life cycle
- Definitive: the parasite reproduces sexually or harbours the adult stage
What is the orgnaism and diagnosis?
Neurocysticercosis
T.Solium
What species is this?
Taenia Solium (<12 uterine branches)
Name the species
Echinococcus granulises - similar to taenia but no hooked embryo
How can you diagnose tapeworms?
Eggs in faeces
Adult in intestine
Larvae in tissue causing disease (depending on type)
Difference between CE2 and CE3b?
CE2 more complex septated cysts but no solid component
CE3b - solid component with multiple daughter cysts
What is this?
H.Nana
Hooks and thick neck
Single row hooks
symptoms of Dibothriocephalus latus?
IBS like syndrome
Abdominal pain, colicky, loose stools
Contraindication for anti parasitic meds in neurocysticercosis?
Raised ICP (inflammation following death of parasite will raise ICP further)
What is a paratenic host?
A host not needed in the life cycle, but act as reservoirs in which different larval stages of the parasite can persist but not develop further
Which species of Echinococcus is found in Northern hemisphere more?
E. multilocularis
central and northern Europe, Central Asia, northern Russia, northern Japan, north-central United States, northwestern Alaska, and northwestern Canada.
Name the species
Echinococcus Granulises
Which species is this?
dibothriocephalus latus
How do you diagnose dibothriocephalus latus?
Ova or tapeworm segments in stool
What is the Rx of choice for ocular neurocysticercosis?
Surgical removal - Rx will cause inflammation (which causes blindness)
How do you contract Taenia saginata?
Ingestion of uncooked beef
Treatment of single enhancing lesion in neurocysticercosis?
Single therapy with albendazole
Steroids and Prazi
Which hydatid cysts can be rx with PAIR?
Liver cysts only
What must you do during PAIR for hydatid disease?
Test for bilirubin (before inject the alcohol) as would cause biliary sclerosis
What should you test for before starting Rx for neurocysticercosis?
Screen for TB and strongyloides
Name the species
Hymenolepis Nana
What is the organism for fish tapeworm?
dibothriocephalus latus
What is water Lilly sign? How would you manage?
Echinococcus - hydatid disease
Specifically in keeping with ruptured cyst
ABZ and PZQ
May also need surgery
What should you do if a hydatid cyst ruptures?
Give ABZ and PZQ (prevent seeding) for a few months
Which group of patients usually present with lung hydatid disease?
Paediatric population
Splenic cyst of hydatid disease?
Surgical removal unless very small, and consider medical Rx or PAIR
What is this?
Echinococcus Granulosus sensu lato
What is the pork tapeworm?
Taenia solium
What is the infective stage of Taenia solium?
Cysticercis - ingestion of larva from autoinfection
Which species of adult tapeworm is this?
Taenia Solium
2 rows of hooks
Name the species
Taenia solium - 2 rows of hooks on rostellum. 4 suckers
Diagnostic stage of taenia solium?
Proglottids and eggs in faeces
How do humans get infected with hymenolepis nana?
Ingest the cysticercoid infected arthropods or eggs (either)
What causes of neurocysticercosis?
Larval stage of T.Solium
Host response - parenchymal inflammation
What are the absolute criteria for neurocysticercosis
Biopsy of brain or spinal cord histology confirmation
Subretinal cysticercus
Scolex with cystic lesion on neuroimaging
If non of this need neuroimaging criteria
What is a cestode/nematode/trematode?
Tapeworm/round worm/fluke
What is this?
H.Diminuta
Which species of adult tapeworm is this?
Taenia Saginata
No hooks
Thin neck
Hydatid cysts in spine, brain and heart, abdominal cavity, bronchi, urinary tract?
Surgery
Name some anatomical features of cestodes?
No GI tract, flat in shape, proglottids and scolex.
What is this?
H.Diminuta
Management of intraventricular neurocysticercosis?
Endoscopic removal used for cysticerci in the 3rd and lateral ventricles
What is the beef tapeworm?
Taenia saginata
Name the species.
Taenia Saginata
WHO Grading of Echinococcus?
Water lily sign - CE3a
Neurocysticercosis with ring enhancement around cysts but not calcification, how would you manage?
Steroids and ABZ/PQL - even though the ring enhancement means that immune system -> inflammation and likely to calcify, this process is faster with antiparasitics
Exposure and clinical criteria for neurocysticercosis
Specific antibody or antigen-detected
Cysticercosis outside of the CNS (biopsy, calcified lesions on xray)
Household contact with T solium infection
Seizures or obstructive hydrocephalus
Prior residence in an endemic village
What do you need to do on long term albendazole?
Monitor transaminases and WCC
What is this and what does it cause?
Calcified lesions of neurocysticercosis
Chronic epilepsy
Hydatid cyst with detached membranes in lung. How would you manage?
Remove it surgically as risk of infection very high
What is the definitive hosts for dibotriocephalus latus?
Humans
Fish eating mammals
Birds
Fish - paratenic host
Subarachnoid neurocysticercosis causes?
Meningits, stroke
How do you know when to stop Rx for NCC in subarachnoid space which needs long term Rx?
Antigen testing and PCR
What is the species for the dwarf tape worm?
Hymenolepis Nana
What species is this?
Dibothriocephalus latus
New onset seizures in the tropics?
Neurocysticercosis (30% due to this!!!)
What is the transmission of dibothriocephalus latus?
Fish tapeworm
Ingestion of uncooked fish
What is the definitive/intermediate host of echinococcus? What is the organism?
echinococcus granulosus
Intermediate: sheep
Definitive: Dog
Most common human Cestode?
H.Nana
Which of the cestodes cause auto infection?
H.Nana
T.Solium
Tribolium fly - intermediate host for?
H.Diminuta