Helminths

Question 1

Which parasitic infection requires its larval form to migrate from duodenum to bronchus(!) so that it can be caughed up and then swallowed?

Answer 1

• Ascaris lumbricoides

Question 2

A 6 year old has cough, fever, rales, and infiltrates on CXR. After treating for pneumonia, he has not improved. He has persistent rales and shifting infiltrates on serial CXR. He has hemoptysis at times. He has eosinophilia on peripheral smear. What infection do you suspect?

Answer 2

Eosinophilia suggests parasite. Cough, hemotptysis, and shifting infiltrates suggest worms: Ascaris lumbricoides

Question 3

This was recovered from the stool of a patient with eosinophilia. You suspect a worm infection. What organism is this likely to be?

Answer 3

Ascaris lumbricoides

You might think pinworm (Enterobius vermicularis) but these will be sort of football shaped.)

Question 4

These worm eggs are recovered from a patient. Was his illness most likely experienced as cough/fever/rales or as “pruritus ani?”

Answer 4

These are pinworm eggs, so the symptoms were likely itchy anus.

Question 5

Which anti-helminthic drug is no longer available in the US?

Answer 5

Mebendazole

Question 6

What is the treatment for pinworms?

Answer 6

Two choices:

• Albendazole
• Pyrantel pamoate

Question 7

What is the treatment for Ascaris lumbricoides (roundworm?)

Answer 7

Two choices:

• Ivermectin
• Albendazole

Remember, mebendazole is no longer available in the US.

Question 8

A mother brings two children into office complaining of itchy anus. Pinworms are identified in both. What should you advise her regarding home hygiene?

Answer 8

Be sure to wash bedding thoroughly in very hot water.

Question 9

A 6 year has slowed growth, anemia, fatigue. He also has this rash.

• What is the name of this rash?
• Causative organism?
• Treatment?

Answer 9

• Cutaneous larva migrans
• Hookworm (Necator americanus)
• Albendazole or pyrantel pamoate

Question 10

Rectal prolapse is a complication associated with what helminthic infection?

Answer 10

Whipworm (Trichuris trichiura)

Question 11

Mebendazole is the drug of choice to treat trichuriasis but it is no longer available in the US. What are the alternatives?

Answer 11

Ivermectin or albendazole x 3 days

Question 12

What helminthic infection is associated with eating wild game meat including bear, venison, horse, boar, seal, walrus? Is treatement similar or different than treating other helminthic infections?

Answer 12

• Trichinosis (Trichinella spiralis)
• Same… treat with albendazole. However, for severe disease you can add steroids.

This is quite rare in the use but more common globally.

Question 13

True or False: Filariasis (Wuchereria bancrofti) is transmitted by bites from worms after walking barefoot.

Answer 13

FALSE. It is actually transmitted by mosquito bites.

Question 14

Wuchereria bancrofti is the organism associated with which infection?

Answer 14

Filariasis (worm, lymphatic filariasis, elephantitis)

Question 15

True or False: Roundworms such as Ascaris lumbricoides replicate in the human body.

Answer 15

False: With the exception of Strongyloides, melminths don’t multiply within the body.

Question 16

What is the treatment for filariasis?

Answer 16

Albendazole or ivermectin PLUS diethylcarbamazine citrate (DEC)

Question 17

True or False: Elephantitis due to Wuchereria bancrofti can be treated with ivermectin or albendazole alone.

Answer 17

False. You need one or the other PLUS DEC (diethylcarbamazine citrate)

Question 18

True or False: Strongyloides infection is diagnosed by finding eggs in stool.

Answer 18

FALSE: Eggs are within the body since this is the only worm that reproduces within humans. Larvae can be found in stool, however.

Question 19

What drug is used to treat Strongyloides?

Answer 19

Ivermectin

Question 20

A child has fever, migratory pneumonia, and eosinophilia. There is a history of pica. Which drug is likely to work for this infection?

• Metronidazole
• Ivermectin
• Diethylcarbamazine citrate
• Albendazole
• Ampho B

Answer 20

This is probably Toxocara canis or cati, a worm infection.

Albendazole

Question 21

Cestodes (flat worms) can cause one of two clinical entities based on what stage of life cycle the organism is ingested. What are these clinical entities called?

Answer 21

• Taeniasis develops if cysticerci are ingested.
• Cysticercosis develops if the eggs are ingested.
  
  • The larvae hatch into oncospheres and then migrate in blood.

Question 22

Oncospheres are a life stage in what type of organism? When found, should they be treated?

Answer 22

• Tape worms
• NO! Treating will cause the organisms to die and the inflammatory reaction will cause irreperable damage, especially concerning if they are found in brain or eye.

Question 23

A 7 year old who is an immigrant from central america presents with new-onset seizures. CT head shows multiple cysts and rare granulomas. What infection do you suspect?

Answer 23

Neurocysticercosis (infection with Taenia species (tape worm) when it was in the egg phase.)

Do not treat if cysts are found in eyes or spine as this can cause irreperable damage.

Question 24

True or False? Albendazole is the treatment of choice for intestinal tapeworm.

Answer 24

False. It is used in neurocysticercosis but not intestinal. Use praziquantel or niclosamide instead.

Question 25

Children infected with Schistosoma haematobium are at risk of developing what type of cancer as adults?

Answer 25

Bladder cancer. This organism infects bladder.

Question 26

A 21 year old with chronic eosinophilia develops fever, lymphadenopathy, diarrhea, hepatosplenomegaly, and he has elevated bilirubin (all direct). He has history of frequent travel to China and frequently eats raw fish there.

• What organism do you suspect?
• What is the treatment?
• Will he have stigmata of liver disease as with alcoholic cirrhosis?

Answer 26

• Schistosomiosis (but this organism is probably Chlonorchis sinensis.)
• A single dose of praziquantel, then repeat in 1-2 months.
• No, he won’t have spider hemangiomata, gynecomastia, or ascites. He could develop esophageal varices, though.