Helminthic GI (lec 8) Flashcards
Nematode (roundworm) morphology?
elongated, tapering cylinder,
multiple layers of cuticle,
separate sexes
Nematode Life Cycle?
Eggs in environment
Larvae enviro to host
Adult in host
E. vermicularis (pinworms) epidemiology?
Most common helm dz in US,
P-to-P or environment
(U) kids
E. vermicularis infection causes?
sxs?
enterobiasis
(U) asymp
anal itching
(P) 2º bacterial infection
E. vermicularis Life Cycle?
1) Eggs deposited on perianal (infectious w/i 4 hrs)
2) Eggs ingested and hatch in SI
3) Mature/colonize ~ 2mo
4) GRAVID female deposits eggs on anus at night
Eggs in environment survive 2-3 wks
E. vermicularis diagnostics?
anal eggs
E. vermicularis tx?
DOC: Mebendazole or Albendazole
*treat whole family
Ascaris lumbricoides morph?
Largest intestinal worm in humans
A. lumbricoides epidemiology?
Soil transmission,
(C) warm climates
A. lumbricoides Life Cycle?
1) Eggs ingested -> larva released into duo
2) Larva penetrate mucosa -> blood into lungs
3) Alveoli -> trachea -> orophary
4) Swallowed beck to duo -> mature
Adults live 2 yrs
A. lumbricoides causes?
sxs?
Ascariasis
Asymp - blockage
depends on # of worms
(P) Pulmonary-Leoffler’s synd
A. lumbricoides diagnostics?
Tx?
Eggs in stool
DOC: Mebendazole or Albendazole
Trichuris trichiura (whipworm) morph?
small, whiptail
egg capsules
T. trichiura Life Cycle?
1) Embryonated eggs ingested
2) Larvae released in duo
3) Mature in colon
4) Released eggs can mature in soil
T. trichiura epidemiology?
Soil transmission
(U) kids
T. trichiura causes?
sxs/
trichuriasis
dependent on worm burden
aysmp to painful watery stool w/ mucus/blood
(P) rectal prolapse
T. trichiura diagnostics?
Tx?
Eggs in stool
DOC: Mebendazole or Albendazole
Necator americanus/Ancylostoma duodenale
(hookworms) Life Cycle?
1) Infective eggs in soil
2) Larvae penetrate skin -> blood into lungs
3) Alveoli -> trachea -> orophary
4) Swallowed beck to duo -> mature
5) Feeds on blood in mucosa
N. americanus
A. duodenale epidemiology?
Human feces in soil
N. americanus
A. duodenale sxs?
Depends on worm burden and host’s nutrition
Blood-filled, pruritic lesions at penetration site,
Constant blood loss from GI
N. americanus
A. duodenale diagnostics?
Tx?
Eggs in stool
DOC: Mebendazole
Strongyloides stercoralis (threadworm) Life Cycle?
Two Cycles:
1) Same as hookworm -> larvae into feces
2) Multiply in soil
S. stercoralis epidemiology?
Human feces in soil
(U) tropical
S. stercoralis causes?
sxs?
Dep on worm burden
Visible trail under skin,
Painful D or constipation,
Life-threatening if defective cell-mediated immunity,
Can auto-reinfect for yrs
S. stercoralis diagnostics?
Tx?
Larvae in stool or sputum
DOC: Thiabendazole
Trematodes (flukes) morph?
flat, leaf-like w/ suckers
Clonorchis sinensis (chinese liver fluke) Life Cycle?
1) Ingest encysted larvae
2) Excystation in duo
3) Mature in bile ducts
4) Eggs -> poop
C. sinensis epidemiology?
Poorly cooked fish
(C) far east
C. sinensis causes?
sxs?
Clonorchoriasis
(U) asymp
C. sinensis diagnostics?
tx?
eggs in stool
DOC: Praziquentel
Taenia (tapeworms) morph?
Hosts?
meters long
scolex (suckers/hooks)
Humans
T. solium (pork)
T. saginata (beef)
Life Cycle?
1) Eggs ingested by cows/pigs
2) Hatch in duo -> penetrate wall
3) Cysticerci grow in mm
Humans eat meat:
1) Cysticerci matures in jejun
2) Eggs (proglottids) -> poop
T. solium (pork)
T. saginata (beef) cause?
sxs?
taeniasis
t. solium also causes cysticercosis
(U) asymp and one worm
cysticercosis (P) lead to blindness, seizures
T. solium (pork)
T. saginata (beef) diagnostics?
Tx?
Eggs/proglottis in stool
CT
Histo
DOC: Praziquantel
Diphyllobothrium latum (fish tapeworm) Life Cycle?
1) Eggs hatch in fresh water
* series of host passages until
2) Larvae ingested by fish
Humans/mammals eat fish:
1) Ingest larvae -> duo
2) Adults in jeju
3) Eggs pooped
D. latum causes?
sxs?
diphyllobothriasis
(U) asymp
competes for B12
D. latum diagnostics?
Tx?
Eggs in stool
Anemia + hx of raw fish
DOC: Praziquantel
