Helminths - Nematodes (roundworms)

Question 1

Eosinophil

Answer 1

WBC

w/ little pink granules

& bilobed nuclei

Question 2

Enterobius vermicularis (pinworms)

Intestinal nematode (round worms)

source / signs and symptoms

Answer 2

Super Worms!!! (In Nematode City)

Female pinworms migrate to the anus and lay eggs → causes itching → fecal oral transmission can reinfect if touch mouth after scratching anus.

Question 3

Enterobius vermicularis (pinworms)

Intestinal nematode (round worms)

lab tests / tx

Answer 3

Super Worms!!! (In Nematode City)

Scotch tape test on anus → eggs will stick to tape → visible on microscope.

tx with Pyrantel pamoate and Albendazole

Question 4

Ancyclostoma duodenale and Necator americanus (hookworms)

Intestinal nematode (round worms)

source / signs and symptoms

Answer 4

Super Worms!!! (In Nematode City)

• Hookworms found in rural southern US
• Walk barefoot** → Enter _blood_stream** → Larvae go to lungs → ascend bronchiole tree → get coughed up → swallowed, then enter and mature in the intestine. (feet→blood→lungs→GI)
• Pt can develop severe iron deficiency anemia.

Question 5

Ancyclostoma duodenale and Necator americanus (hookworms)

Intestinal nematode (round worms)

lab tests / tx

Answer 5

Super Worms!!! (In Nematode City)

• Look for eggs in stool.
• High eosinophil count (eosinophilia).
• tx with Pyrantel pamoate and Albendazole

Question 6

Ascaris lumbricoides (Giant large worm)

Intestinal nematode (round worms)

source / signs and symptoms

Answer 6

Super Worms!!! (In Nematode City)

• Ingest eggs from contaminated food or water → migrate to lungs through gut wall and bloodstream → come back to gut to become adults → go into feces (GI→blood→lungs→GI)
• Malnutrition and respiratory symptoms (most likely intestinal nematode to cause resp. sympt.)
• Intestinal obstruction at ileocecal valve (major complication!)

Question 7

Ascaris lumbricoides (Giant large worm)

Intestinal nematode (round worms)

lab tests / tx

Answer 7

Super Worms!!! (In Nematode City)

• Look for eggs in stool
• High eosinophil count (eosinophilia).
• tx with Albendazole*

*(Albendazole causes microtubule dysfunction to make worms immobile. Dont give microtubule inhibitors to pregnant women. If pregnant give Pyrantel pamoate)

Question 8

Strondyloides stercoralis (Thread worm)

Intestinal nematode (round worms)

source / signs and symptoms

Answer 8

Super Worms!!! (In Nematode City)

• Penetrate skin on bottom of feet → then goes to lungs → then GI tract → AUTOINFECTION of host by laying eggs** on **intestinal wall! (feet→blood→lungs→GI→GI→GI...)
• If immunocompromised can lead to hyper infection.

Question 9

Strondyloides stercoralis (Thread worm)

Intestinal nematode (round worms)

lab tests / tx

Answer 9

Super Worms!!! (In Nematode City)

• Eggs DONT get passed to stool so only find larvae in stools.
• High eosinophil count (eosinophilia).
• tx with Albendazole* and Ivermectin

*(Albendazole causes microtubule dysfunction to make worms immobile. Dont give microtubule inhibitors to pregnant women. If pregnant give Pyrantel pamoate)

Question 10

Trichinella spiralis (Trichina worm)

Intestinal nematode (round worms)

source / signs and symptoms

Answer 10

Super Worms!!! (In Nematode City)

• Found in undercooked meat, commonly pork or bear.
• Larvae get into blood → go systemic → form cysts in striated muscle cells (GI→blood→systemic→striated muscle cells)
• Periorbital edema
• Vomiting and fever
• Inflammation of muscle → severe myalgia

Question 11

Trichinella spiralis (Trichina worm)

Intestinal nematode (round worms)

lab tests / tx

Answer 11

Super Worms!!! (In Nematode City)

• Most often diagnosed by a Trichinella antibody test. In some cases a muscle biopsy may be performed.
• High eosinophil count (eosinophilia).
• tx with Albendazole*

*(Albendazole causes microtubule dysfunction to make worms immobile. Dont give microtubule inhibitors to pregnant women. If pregnant give Pyrantel pamoate)

Question 12

Dracunculus medinesis (Guinea worm)

Tissue nematode (round worms)

source / signs and symptoms

Answer 12

Screamatodes III: Return of the flesh eaters

• Transmitted by ingesting water contaminated with copepods (small crustaceans) containing larvae
• Painful skin ulcer
• Worms (adult female) coming out of the skin!

Question 13

Dracunculus medinesis (Guinea worm)

Tissue nematode (round worms)

lab tests / tx

Answer 13

Screamatodes III: Return of the flesh eaters

• Diagnosed via worms (adult female) coming out of the skin!
• Peripheral eosinophilia
• Pull out by spinning matchsticks or pencil slowly over several days.
• Metronidazole will help speed up the process (but not cure it)

Question 14

Onchocerca volvulus (Filaria worm)

Tissue nematode (round worms)

source / signs and symptoms

Answer 14

Screamatodes III: Return of the flesh eaters

• Found around rivers in Africa, C. america and S. America
• Black fly bites human host → larvae burrow down into the hosts skin → make micro filarial that come back out, starting as scattered puritic papules → making hyper and hypo pigmented spots. (Hypo usually on shins of older patients)
• River blindness!!! 2nd leading cause of blindness after Trachoma (Chlamydia)

Question 15

Onchocerca volvulus (Filaria worm)

Tissue nematode (round worms)

lab tests / tx

Answer 15

Screamatodes III: Return of the flesh eaters

• Eosinophilia
• Microfilaria on skin biopsy under microscope.
• Tx with Ivermectin

Question 16

Wucheria bancrofti (Thread worm)

Tissue nematode (round worms)

source / signs and symptoms

Answer 16

Screamatodes III: Return of the flesh eaters

• Mosquitos are intermediate host → bite human and deposit larvae on skin → which enter the lymph system → lymphadenopathy
• Elephantiasis (From long standing lower extremity lymphodema)
• Microfilaria travel to the lungs and cause hypersensitivity rxn

Question 17

Wucheria bancrofti (Thread worm)

Tissue nematode (round worms)

lab tests / tx

Answer 17

Screamatodes III: Return of the flesh eaters

• Organisms can be seen on thick blood smear
• Eosinophilia
• Tx with Diethylcarbamazine

Question 18

Toxicara canis (Dog roundworm)

Tissue nematode (round worms)

source / signs and symptoms

Answer 18

Screamatodes III: Return of the flesh eaters

• Transmitted by ingestion of food contaminated with dog or cat feces containing the eggs.
• Parasitic larvae never mature out of larvae stage.
• AKA Visceral larvae migrans
• AKA Ocular larvae migrans if it gets into the eye → can cause blindness

Question 19

Toxicara canis (Dog roundworm)

Tissue nematode (round worms)

lab tests / tx

Answer 19

Screamatodes III: Return of the flesh eaters

• Blood tests to detect antibodies to toxocara
• Eosinophilia
• Tx with Albendozole

Question 20

Loa Loa (Filaria worm)

Tissue nematode (round worms)

source / signs and symptoms

Answer 20

Screamatodes III: Return of the flesh eaters

• Bite from deer fly → adult Loa Loa worm migrates throughout the subcutaneous tissues of humans
• Transient angioedema, localized subcutaneous swellings (AKA Calabar swellings; red and itchy)
• AKA “African Eye Worm“ (occasionally crosses into subconjunctival tissues of the eye where it can be easily observed!)

Question 21

Loa Loa (Filaria worm)

Tissue nematode (round worms)

lab tests / tx

Answer 21

Screamatodes III: Return of the flesh eaters

• Diagnosed with a blood smear.
• Eosinophilia
• Tx with diethylcarbamazine and albendozole