Sketchy Parasites

Question 1

Protozoa of the Intestinal Tract:
How is Giardia lamblia transmitted?

Answer 1

Cysts via fecal-oral transmission

Question 2

Protozoa of the Intestinal Tract:
What pt population is often affected by Giardia lamblia?

Answer 2

Campers and hikers who drink unfiltered or unpurified water.

Question 3

Protozoa of the Intestinal Tract:
What symptoms does Giardiasis consist of?

Answer 3

Bloating, flatulaence, and foul-smelling diarrhea. Steatorrhea also due to. fat malabsorption

Question 4

Protozoa of the Intestinal Tract:
What do Giardial cysts transform into?

Answer 4

Trophozoites, which have a distinctive pear-shaped appearance under a microscope.

Question 5

Protozoa of the Intestinal Tract:
How do you diagnose Giardiasis?

Answer 5

Trophozoites in the stool.
Stool test for ova and parasites (O and P test) or an enzyme-linked immunosorbent assay (ELISA) stool antigen test

Question 6

Protozoa of the Intestinal Tract:
What is the treatment for Giardiasis?

Answer 6

Metronidazole

Question 7

Protozoa of the Intestinal Tract:
How can Entamoeba histolytica be transmitted?

Answer 7

Cysts can be ingested in contaminated water or can be transmitted via anal-oral sexual contact.

Question 8

Protozoa of the Intestinal Tract:
Where would you expect an amoebic liver abscess?

Answer 8

Right lobe of the liver is most common
*Cause of right upper quadrant pain and is described as anchovy paste”

Question 9

Protozoa of the Intestinal Tract:
How does intestinal amebiasis present?

Answer 9

Ulcers and bloody diarrhea.
Microscopically the ulcers have a flask-shaped appearance.

Question 10

Protozoa of the Intestinal Tract:
How would you diagnose Entamoeba Histolytica?

Answer 10

Stool O and P; would find trophozoites with endocytosed RBCs.
Or Elisa or Serology to detect Entamoeba antibodies.

Question 11

Protozoa of the Intestinal Tract:
What is the treatment for Entamoeba Histolytica?

Answer 11

Metronidazole
Also Luminal Drugs ie Paramycin and Iodoquinol to eliminate cysts.
DO NOT OPERATE ON THE CYST

Question 12

Protozoa of the Intestinal Tract:
How does Cryptosporidium spp present?

Answer 12

Severe water and copious diarrhea in HIV patients.
Mild in immunocompetent.

Question 13

What is the only parasite you need to know that stains acid fast?

Answer 13

Cryptosporidium spp.
*Partially acid-fast

Question 14

Protozoa of the Intestinal Tract:
How does Cryptosporidium spp infect?

Answer 14

Fecal oral transmission. Infectious cysts passed through stool.
Cysts have 4 motile sporozoites then attach to intestinal wall and cause diarrhea.

Question 15

Protozoa of the Intestinal Tract:
How do you treat Cryptosporidium spp.?

Answer 15

• Nitazoxanide for immunocompetent pts
• Spiramycin for immunocompromised
• chlorination and filtration of oocytes of the water supplies

Question 16

Protozoa of the CNS:
Is Toxoplasma gondii intracellular or extracellular?

Answer 16

Intracellular

Question 17

Protozoa of the CNS:
How is Toxo transmitted commonly?

Answer 17

• consumption of raw or undercooked meat containing the cysts
• ingestion of water or veggies contaminated with oocytes shed in the feces of infected animals (particularly cats)
• vertically from mother to fetus if the mom is exposed during pregnancy

Question 18

Protozoa of the CNS:
What pt population is most at risk of toxo infection?

Answer 18

Pregnant and the immunocompromised, specifically those with HIV
*Pregnant women are encouraged not to change the kitty litter while pregnant.

Question 19

Protozoa of the CNS:
What would you see on CT or MRI in the case of Toxo?

Answer 19

Multiple Ring enhancing lesions, these are abscesses
*Encephalitis can show single, if single keep CNS lymphoma in the ddx. Brain biopsy to differentiate.

Question 20

Protozoa of the CNS
What is the triad for Congenital toxoplasmosis?

Answer 20

Chorioretinitis, hydrocephalus (seizures), and intracranial calcifications.
Also deafness can present

Question 21

Protozoa of the CNS:
How is Toxo diagnosed?

Answer 21

Serology or biopsy

Question 22

Protozoa of the CNS:
How is Toxo treated?
What is the prophylaxis and what is the prophylaxis?

Answer 22

Sulfadiazine and Pyrimethamine
*Prophylaxis with TMP-SMX is recommended for HIV patients with CD4 counts less than 100 and positive for IgG.

Question 23

Protozoa of the CNS:
Name the three main members of Trypanosoma brucei:

Answer 23

Trypanosoma b. gambiense, Trypanosoma b. rhodesiense, and Trypanosoma b. brucei

Question 24

Protozoa of the CNS:
What is the vector of Trypanosoma brucei?

Answer 24

Tsetse fly

Question 25

Protozoa of the CNS: Where is Trypanosoma b. gambiense found? What is the reservoir?

Answer 25

Streams along Western and Central Africa Humans

Question 26

Protozoa of the CNS: Where is Trypanosoma b. rhodesiense found? What is the reservoir?

Answer 26

Eastern and Southeastern African savannas and woodlands. Antelopes

Question 27

Protozoa of the CNS: What does Trypanosoma b. gambiense and Trypanosoma b. rhodesiense cause? What is the difference between the two?

Answer 27

Sleeping Sickness Two stages of infection: Tsetse fly bites and develops a Trypanosomal chancre. - hemolymphatic phases, which affects blood and lymphatics - follows is a neurological or meningoencephalitis phase, here you would see neuropsychiatric symptoms and *DAYTIME SLEEPINESS* CSF can be analyzed to determine the stage: 1st stage there are few WBCs and no detectable organisms, whereas the 2nd stage shows an elevated WBC count and organisms present. Difference is TBG is slow onset and chronic, TBR is more rapid and fatal, but rare.

Question 28

Protozoa of the CNS: What kind of fever does Trypanosoma present with?

Answer 28

Intermittent spiking fever, intervals can vary from a few days to a few months.

Question 29

Protozoa of the CNS: What kind of lymphadenopathy would you expect with Trypanosoma?

Answer 29

Cervical and axillary

Question 30

Protozoa of the CNS: How is Trypanosoma diagnosed?

Answer 30

Trypomastigotes seen on blood smear For TBG also seen lymph bx with light microscopy.

Question 31

Protozoa of the CNS: How would you treat Trypanosoma? Prophylaxis?

Answer 31

Prophylaxis is Aerial insecticides Tx: - Pentamidine for First stage TBG - Suramin works on both TBG and TBR 1st stage but should be used for TBR. - Nifurtimox-eflornithine combination therapy (NECT) for 2nd stage TBG - Melarsoprol for 2nd stage TBR (highly toxic) *Prognosis: monitor for 2 years!

Question 32

Protozoa of the CNS: How to Trypanosoma species evade the immune response?

Answer 32

Altering surface glycoproteins

Question 33

Protozoa of the CNS: What kind of parasites is Naegleria fowleri?

Answer 33

Amoeba

Question 34

Protozoa of the CNS: Where is Naegleria Fowleri found?

Answer 34

Freshwater lakes *look for a history with water sports *Rarely, OTC nasal irrigation systems and contact lens solutions can be potential sources of infection

Question 35

Protozoa of the CNS: How does Naegleria fowleri travel into the CNS?

Answer 35

Trophozoites enter CNS via cribriform plate

Question 36

Protozoa of the CNS: How Naegleria fowleri present?

Answer 36

Symptoms of Meningitis and Encephalitis *if NF is the perpetrator, the disease is termed Primary Amebic Meningoencephalitis, which is rapidly fatal and has a poor prognosis

Question 37

Protozoa of the CNS: How can we diagnose Naegleria fowleri?

Answer 37

Spinal tap (Lumbar puncture)

Question 38

Protozoa of the CNS: What is the treatment for Naegleria Fowleri?

Answer 38

If detected early give Amphotericin B