Ascaris lumbricoides

Question 1

Ascaris lumbricoides - parasite

Answer 1

GI nematode - giant roundworm

Question 2

Ascaris lumbricoides - adult size

Answer 2

20-35cm

Question 3

Ascaris lumbricoides - lifecycle

Answer 3

Larvae develop to infectivity with fertile eggs up to 1-2 weeks
After infective eggs are swallowed, the larvae hatch and invade the intestinal mucosa - carried via portal, then systemic circulation to lungs
Larvae mature further in lungs 10-14 days - penetrate alveolar walls, ascend bronchial tree and are swallowed
Upon reaching small intestine, they develop into adult worms - can live 1-2 years

Question 4

Ascaris lumbricoides - clinical presentation

Answer 4

Early:
Lung migration - cough, wheeze, Loeffler’s, Charcot-Leyden crystals in tissue histology

Late:
GI worm burden - asymptomatic if low
Adults pass spontaneously
Nausea, abdominal pain, obstruction in heavy infectionA

Question 5

Ascaris lumbricoides - diagnosis

Answer 5

Suspect diagnosis
Eggs in stool OCP

Question 6

Ascaris lumbricoides - management

Answer 6

Medications:
Albendazole, mebenadazole or pyrantel pamoate

Surgery - obstruction