Sketchy Micro: Entamoeba Histolytica

Question 1

How can you associate this Sketch with Entamoeba histolytica?

Answer 1

The scene takes place at an excavation site with a sign telling passersby “do not ENTer / HISTOrical excavation in progress.”

Question 2

How is Entamoeba histolytica transmitted?

Answer 2

People ingest the cyst form in poop-contaminated water.

Think of the archaeologists drinking the bubbly water.

Question 3

What population is at increased risk for E. histolytica?

Answer 3

MSM –thought to be related to anal-oral contact (like the guys holding hands)

Question 4

E. histolytica can invade the GI tract, and when it does, it frequently _________________.

Answer 4

passes into the right lobe of the liver via the portal circulation and forms liver abscesses (like the dug-out hole in the upper-right portion of the excavation site which is liver-shaped)

Question 5

The pus inside amoebic liver abscesses is often said to have a _____________ consistency.

Answer 5

anchovy-paste

Think of the truck driving by in the background with Anchovy Paste advertised on the side.

Question 6

If you did a colonoscopy of someone with E. histolytica infection, what might you see?

Answer 6

Intestinal amebiasis: flask-shaped ulcerations along the colon

(Think of the haustra-like pipe sticking out of the wall with rust spots along the inside. Also, the diggers are drinking water out of flasks.)

Question 7

_____________ diarrhea is typical of E. histolytica infection.

Answer 7

Bloody (red stools)

Question 8

Ova and parasite stool tests are needed to diagnose E. histolytica. What will you see under microscopy?

Answer 8

Trophozoites with endocytosed RBCs

Think of the puddle with red cups in it.

Question 9

In addition to O&P, ______________ can also be used to diagnose Entamoeba.

Answer 9

stool ELISA and serum antigen tests

Question 10

What three agents can treat E. histolytica infection?

Answer 10

• Metronidazole (subway entering site)
• Paramycin (two mice running out of the subway tunnel)
• Iodoquinol (QUeen IODO’s tomb is being excavated)

Note: the second two are luminal agents that kill the cysts residing in the lumen of the intestine.

Question 11

True or false: surgical drainage is often needed for E. histolytica abscesses.

Answer 11

False. There is another protozoan that does need to be drained, but E. histolytica is usually treatable with the three agents mentioned.