STEP 1 Protozoa 1

Question 1

Name 3 protozoa GI infections STEP 1 cares about

Answer 1

1. Giardia lamblia
2. Entamoeba histolytica
3. Cryptosporidium

Question 2

Giardia causes giardiasis…how does that look exactly? Think poop

Answer 2

Bloating and flatulence.

Foul-smelling, fatty diarrhea…I love my life right now

Question 3

Who gets Giardia?

How to remember the poop associated with Giardia?

Answer 3

Hikers and campers who do not clean their water.

“Ghirardelli chocolates for fatty poops”

Question 4

Transmission of giardia?

Answer 4

Cysts in water

Question 5

How to diagnose giardiasis?

Answer 5

Trophozoites or cysts in stool

Question 6

How to treat giardiasis?

Answer 6

Metronidazole

Question 7

What does Entamoeba histolytica cause?

Answer 7

Amebiasis

Question 8

Clinical presentation of Amebiasis?

1. stool
2. does an abscess occur? where?
3. Pain? location?

Answer 8

1. Bloody stool (dysentery)
2. Liver and colon abscess…“anchovy paste” exudate for the liver bit
3. RUQ pain

Question 9

What does histology show with amebiasis?

Answer 9

**“Flask-shaped ulcer” if submucosal abscess of colon ruptures

Question 10

How is amebiasis transmitted?

Answer 10

Cysts in water

Question 11

Diagnosis of amebiasis? 2

Answer 11

1. Serology and/or trophozites (with RBCs in the cytoplasm)

2. Cysts in the stool

Question 12

Treatment of amebiasis:

Symptomatic and asymptomatic

Answer 12

Symptomatic: Metronidazole

Asymptomatic cyst passer: Iodoquinol

Question 13

What does cryptosporidium cause in immunocompromised patients? In immunocompetent patients?

Answer 13

Severe diarrhea in AIDS patients…Milwaukee

Mild, watery diarrhea in immunocompetent patients

Question 14

How is cryptosporidium transmitted?

How is cryptosporidium diagnosed?

Answer 14

Oocysts in water.

Oocysts on acid-fast stain

Question 15

How to treat cryptosporidium?

Answer 15

Nitazoxanide in immunocompetent (or immunocompromised) hosts

Question 16

Toxoplasma gondii causes two types of infection:

Answer 16

Acquired or congenital

Question 17

What does acquired Toxoplasmosis look like on CT/MRI? In which patient population is Toxo prevalent?

Answer 17

Brain abscess in HIV patients.

Looks like “ring-enhancing brain lesions”

Question 18

What is the classic triad of congenital toxo?

Answer 18

1. Chorioretinitis*
2. Hydrocephalus
3. Diffuse intracranial calcifications

*The chorioretinitis may present as blurry vision, detached retina, or glaucoma

Question 19

Transmission of toxo? 3

Answer 19

1. Cysts in meat
2. Oocysts in cat feces
3. Transplacental transmission

Question 20

For fear of toxo, pregnant women should avoid which animal and their poop?

Answer 20

Cats and cat poop

Question 21

Diagnosis of toxo? 3

Answer 21

1. Serology
2. Biopsy (looking for tachyzoites–crescent shaped (they mean trophozoite)
3. Toxo PCR via LP

Question 22

How to treat Toxo? 3

Answer 22

1. Sulfadiazine
2. Pyrimethamine (which cause bone marrow suppression)
3. Leucovorin** (not in STEP 1 but used to treat the bone marrow suppression)

Question 23

Naegleria fowleri causes what?

Answer 23

Rapidly fatal meningoencephalitis

Question 24

Naegleria transmission

Answer 24

Swimming in FRESHWATER lakes and streams.

Enters via the CRIBRIFORM plate

Question 25

Naegleria diagnosis?

Answer 25

Ameobas in the spinal fluid

Question 26

Treatment for naegleria? Prognosis?

Answer 26

Prognosis is not good. Very few reported survivors of a naegleria infection. Best treatment at the moment is Amphotericin B

Question 27

Trypanosoma brucei is the causative agent of…?

Answer 27

African sleeping sickness

Question 28

Clinical presentation of Trypanosoma infection

Answer 28

1. Enlarged lymph nodes
2. Recurring fever–due to antigenic variation (**differentiate from malaria)
3. Somnolence
4. Coma

Question 29

Trypanosoma transmission

Answer 29

Tsetse fly…painful bite

Question 30

Trypanosoma diagnosis

Answer 30

Blood smear

Question 31

Trypanosoma treatment: 2
Which for blood-borne
*Which for CNS penetration

*If you miss #2 go slap your face

Answer 31

1. Suramin–blood borne

2. Melarsoprol–CNS

Question 32

Two types of Trypanosoma brucei?

**How to treat them? not on STEP 1

Answer 32

1. T. b. rhodesiense (suramin, melarsoprol)
2. T. b. gambiense (pentamidine, eflornithine)
   * *My point here is to show that suramin and melarsoprol only work on rhodesiense