Question | Answer |
What aer the following
Nematodes (round worms)
Cestodes (tape worms)
Trematodes (Flukes) | Helminths |
Do adult worms generally multiply in human hosts | NO |
SInce adult worms don't generally multiply in human hosts what can be infered from the number of adult worms living in the host | Implies the number of eggs or larvae that were ingested |
How are the s/sx linked to "worm burden" | patient with only a few adults may be asymptomatic while those with a high infection load will have clinical s/sx |
What are the following
Enterobius vermicularis (Pinworm)
Ascaris lumbricoides (Roundworm)
Necator americanus and Ancylostoma duodenale (Hookworm)
Strongyloides stercoralis (Threadworm)
Trichuris trichiura (Whipworm) | Nematodes |
This organism has
-seperate sexes
-male is smaller than female
-adults are 30-50mm long
tubular alimentary tract which can be 2/3 lenght of worm, mouth is simple lacking lips
-absent excretory sys
-oviparous | Trichuris trichiura (Whipworm) |
how do you get infected with Trichuris trichiura (Whipworm) | ingest fecal contaminated soil or food |
what does Trichuris trichiura (Whipworm) do in the GI tract | burrows into intestinal mucosa w/ ant. end and consumes blood cells. Usually causes negligible loss of blood |
where in the US are you most likely going to see children infected w/ Trichuris trichiura (Whipworm) | Southeastern US infection rate is as high as 20-25% |
what are the s/sx of a light infection vs heavy infection w/ Trichuris trichiura (Whipworm) | Light- asympto
Heavy- epigastric pain, vomiting, distention, flatulence, anorexia, and weight loss may occur
Secere cases may develop blood and mucous in stools |
what are some of the complications associated w/ Trichuris trichiura (Whipworm) | secondary bacterial infections
allergic responses resulting in colitis, proctitis, prolapse of rectum |
how do you dx Trichuris trichiura (Whipworm) | eggs in stool |
What type of immune response do you see to Trichuris trichiura (Whipworm) | induces an IgE response and hypereosinophilia
mast cell activation may lead to increase in allergic responses and symptoms |
what tx would be appropriate for infection w/ Trichuris trichiura (Whipworm) | mebendazole (vermox)- irreversibly blocks glucose uptake and other nutrients in adult intestine where helminths dwell
Albendazole- decreases whipworm ATP production |
What do the s/sx of Trichuris trichiura (Whipworm) look like that may confuse dx | hookworm infections
amebiasis
acute appendicitis
chronic anemia |
This organism has
-seperate sexes
-male is smaller than Female
-adults are 2-13mm long
-Eggs are laid externally in perianal area
- Have a conspicuous muscular bulb on posterior end of esophagus
-have three lips surrounding the mouth | Enterobius vermicularis (Pinworm) |
how do you get infected w/ Enterobius vermicularis (Pinworm) | fecal oral route
person to person transmission is high especially among kids |
Why do you get a high incidence of hand to nail contamination and spreading of Enterobius vermicularis (Pinworm) | female lays eggs perianal causes itiching leading to scratching and people getting poopy infected fingernails and hands |
what are the s/sx of infection w/Enterobius vermicularis (Pinworm) | intense nocturnal perianal itching
insomnia
children too young to talk may show restlessness and irritability at night |
what complications can you see in females w/ Enterobius vermicularis (Pinworm) | can migrate to vagina causing secondary bacterial UTI |
what complication can you see from the scratching associated w/ Enterobius vermicularis (Pinworm) infection | can lead to secondary bacterial infections |
How do you dx Enterobius vermicularis (Pinworm) | tape test from perianal region reveals eggs. |
What immune response is rare to Enterobius Vermicularis ( pinworm) infections | Eosionophilia and elevated IgE are rare |
What is the tx for Enterobius Vermicularis ( pinworm) infections | Mebendazole
Albendazole |
What could be your initial dx in place of Enterobius Vermicularis ( pinworm) infections because they also show perianal itiching as a s/sx but will test negative with tape test | Hemorrhoidal Diseases
Perianal infections
dermatitis |
Organism that has seperate sexes with adults 15-35cm long | Ascaris lumbricoides |
What is the source of infection with Ascaris lumbricoides | Fecal Oral Contamination |
How long can adult Ascaris lumbricoides live i nthe intestines | 6-24 months |
Apart from the colon where else can they be found | they can migrate to appendix, hepatobiliary system, or pancreatic ducts |
What is one complication that Ascaris lumbricoides can cause with a mass infestation | they can cause complete bowel obstruction |
How long does it take from ingestion until they worms hatch and are making new eggs | about 9 weeks. 3 more weeks and eggs start molting and can infect a new host |
What are the s/sx of infection w/ Ascaris lumbricoides | Usually asymptomatic but may develop
General Symptoms
-Fever
-Jaundice (in biliary obstruction)
-Chachexia (due to malnutrition)
-Mental Retardation (due to malnutrition) |
What s/sx may be seen during larval maturation | Pulmonary symptoms
-wheezing
-rales
-diminished breath sounds
-dyspnea
-hemoptysis |
What abdominal symptoms may be present with Ascaris lumbricoides infection | abdominal tenderness
appendicitis
or right upper quadrant tenderness with hepatobiliary infections
peritoneal signs in cases of bowel perforation |
What is Loeffler's syndrome | Bening acute eosinophilic pneumonia of unknown cause characterizied by migrating pulmonary infiltrates and minimal clinical manifestations |
What is larva migrans | infection with dog or cat species of Ascarid larvae since they can't mature in host they migrate through the tissue and encyst as second stage larvae leaving hemorrhagic necrosis and eosinophilic and lymphocityic infiltration |
How do you dx Ascaris lumbricoides infections | eggs in stool
eosinophilia at early infection
sputum may show larva at early infection |
what is the tx for Ascaris lumbricoides infections | albendazole
mebendazole
pyrantel pamoate- depolarizing neuromuscular blocking agent inhibits cholinesterases, resulting in spastic paralysis of worm
piperazine citrate- block ACH response in worm flaccid paralysis |
What can Ascaris lumbricoides infections appear as | acute appendicitis
allergic asthma
cholangitis
cholecystitis or biliary cholic
hookworm infection
bowel obstruction
pancreatitis
strongyloides Stercoralis infection |
These organisms have seperate sexes 6-12mm long and can be divided into two groups based on morphology of oral cavity | Necator americanus- has dorsal and ventral cutting plates
and Ancylostoma duodenale- has four sharp tooth like structures
(Hookworm) |
what is the source of infection with Necator americanus and Ancylostoma duodenale (Hookworm) | direct contact by walking barefoot through contaminated soil or ingestion of human fecal matter |
What are the s/sx of Necator americanus and Ancylostoma duodenale (Hookworm) | most asymptomatic
ground itch- induce pruritic maculopapular dermatitis at site of entry
-transient pneumonitis may develop while larvae migrate through lungs
Early intestinal phase- may have epigastric pain, inflammatory diarrhea and eosinophilia |
what is the progression of infection of Necator americanus and Ancylostoma duodenale (Hookworm) | 1 eggs are passed in stool
2 larvae hatch grow in soil
3 5-10 days are infective
4 on contact w/ human penetrate skin and use veins to heart and lungs. they penetrate alveoli and climb bronchial tree to pharynx then are swallowed get to GI tract to fe |
what is the primary syndrome associated w/ Necator americanus and Ancylostoma duodenale (Hookworm) infections | iron deficiency anemia
extreme weakness, SOB, skin depigmentation
Cardiac Complications can also occur during INTERCURRENT infections
impaired physical, mental, and sexual dev. in children
occult blood in stool |
What is Cutaneous Larva Migrans | Dog or cat hookworms enter skin and are unable to complete life cycle they encyst in tissue and may cause serpiginous erythematous tracts in tissue. |
How do you dx Necator americanus and Ancylostoma duodenale (Hookworm) infections | eggs in fresh stool. larvae in old stool |
What can occur immuninity wise while larvae of hookworm is migrating through the body | eosinophilia |
What is the tx for Necator americanus and Ancylostoma duodenale (Hookworm) infections | albendazole
mebendazole
pyrantel pamoate |
What may be necessary tx for hookworm infections because of the anemia that can develop | may need blood transfusion and long term treatment with ferrous sulfate until hemoglobin levels become normal |
What other differential diagnosis could you come up with to explain the anemia caused by Necator americanus and Ancylostoma duodenale (Hookworm) infections | parvovirus B19
Chronic Malaria
Genetic Causes
etc. |
This organism has free-living and parasitic life cycles can cause auto infection
has separate sexes and are about 2mm long | Strongyloides stercoralis (Threadworm) |
What is the source of infection of Strongyloides stercoralis (Threadworm) | direct contact with contaminated soil or eating contaminated soil |
What is the progression of infection of Strongyloides stercoralis (Threadworm) | infection through feet or ingestion
colonization of bowel and maturation
can spread to lymphatics, blood stream and other organs (causing tissue abscessess, granulomas, or sepsis from normal GI flora escaping with worms) |
What are s/sx of Strongyloides stercoralis (Threadworm) infections | Often asymptomatic
Ground Itch, petechial hemorrhages and edema at site of entry
cough and loeffler's syndrome during larva migration through lungs
Chronic Diarrhea- watery mucousy stool but may contain blood
Alternate between diarrhea and constipati |
When do you most often see dissemination of Strongyloides stercoralis (Threadworm) into tissue other than the bowel | in immune compromised or debilitation by concurrent disease or malnutrition. |
What is larva currens | Occurs on trunk or near anus where a linear eruption shows up where larvae are migrating under skin near the surface. Causing a non indurated wheal with red flare to appear moves rapidly and DISAPPEARS IN A FEW HOURS |
how do you dx Strongyloides stercoralis (Threadworm) | larva in stool or bowel fluids |
Blood eosinophilia is usually present during acute and chronic stages, but may be absent during dissemination and levels may fluctuate constantly | Immunity rxn associated with Strongyloides stercoralis (Threadworm) infections |
What is the tx for Strongyloides stercoralis (Threadworm) infections | Ivermectin- causes tonic paralysis of helminth musculature
Albendazole
Thiabendzaole |
What else can Strongyloides stercoralis (Threadworm) be dx as because of similar s/sx | hookworm infections
amebiasis
enteric viral infection
other diarrhea or rash inducing agents |
What is a Proglottids | One segment of a tapeworm body |
What is a cystercerci | tissue cysts of larva |
What type of organism are Taeniasis
T. solium (pig tapeworm)
T. saginata (beef tapeworm) | Cestodes (segmented worms) |
How long can T. Saginata get | 3-8m long |
How long can T. Soluim grown | up to 3m |
How can you get T. Solium | Eating undercooked PORK |
How can you get T. Saginata | Eating undercooked BEEF |
How do Taeniasis infections progress | Ingestion of cystercerci in meat
-worm matures in intestines and releases proglottids filled with eggs
Eating eggs can lead to tissue invasion and cystercerci formation most common in brain |
where is the most common place that cystercerci form from Taeniasis infections | the brain |
What are the s/sx of Taeniasis infections | LIKELY TO BE ASYMPTOMATIC
epigastric discomfort
nausea
sensation of hunger
diarrhea |
How do you dx Taeniasis infections | detection of eggs or proglottids in stool
Cystercerci, Plain films reveal calcified puffed rice lessions in tissue |
What is the tx fro taneiasis infections | Albendazole
Praziquantel- incites damage to parasite's skin internally to make it disintegrate |
What can Taeniasis infections appear as in differnetial dx | tuberculoma
brain absces
arachnoid cyst
tumor
toxoplasmic encephalitis |
what are the following
Clonorchis sinensis
Opisthorchis viverrini
Opisthorchis felineus | Biliary duct dwelling trematodes |
what is fasciola hepatica | Liver dwelling trematode |
Infection of this organism is humans is limited to digenetic trematode
-reproduces sexually in humans
Eggs reach water they can
-infective definitive host
-seek out secondary host
-encyst on vvegitation
Has 2 grasping suckers
are hermaphrodites | Trematode (Fluke) |
What is the source of infection w/ biliary infections | ingest poorly cooked, pickled or smoked fish
may infect entire populations in endemic areas may be infected |
What is the source of infection w/ liver infections | ingestion of metacercariae encysted on aquatic plants (watercress) |
What is the progression of infection w/ biliary Trematode (Fluke) | Excyst in small intestine, migrate through ampulla of Vater into biliary ducts
-worm lead to adenomatous hyperplasia, inflammation and duct obstruction |
What is the progression of infection w/ liver Trematode (Fluke) | Excyst in duodenum, pass through intestines into peritoneum, invade liver through glisson's capsule
Granulomatous rxns, duct obstruction etc may occur |
What are the s/sx with biliary fluke infection | acute infections noted by fever, eosinophilia, and hepatomegaly
-heavy worm burden may lead to constitutional complaints and symptoms associated w/ cholelithiasis and pancreatitis |
HOw can you dx biliary Trematode (Fluke) infections | Ova can be identified in stools, dilation of ducts by imaging |
What are the s/sx of liver Trematode (Fluke) infection | fever, hepatomegaly, and/or abdominal pain
Nausea, cough, diarrhea, and urticaria are also common
Periods of Jaundice |
How would you dx infection with liver Trematode (Fluke) | Fever, hepatomegaly or liver pain with proper clinicaal setting
-serology as ova may not be detected in stool |
What are the common immune profile of Trematode (Fluke) infections w. heavy worm load | Eosinophilia and fever |
What is the tx for biliary Trematode (Fluke) | Praziquantel |
what is the tx for liver Trematode (Fluke) | Bithionol- inhibits phosphorylation in the parasite leading to blockade of ATP synthesis. |
What could you confuse Trematode (Fluke) infection w/ | hepatitis
cholelithiasis
pancreatitis
amebiasis |
Review slide 83 | really review it |