Parasites

Question 1

Giardia lamblia

Answer 1

Question 2

Toxoplasma gondii

Answer 2

Question 3

Classic presentation of neonate with Congenital Toxoplasmosis:

Answer 3

1. Chorioretinitis
2. Intracranial calcifications
3. Hydrocephalus

Question 4

Name that propylactic drug: AIDS patient who lives with 3 cats

Answer 4

TMP-SMX
* To prevent Toxoplasma infection in AIDS patients
* May also be used as a 2nd line therapy for other patients (after pyrimethamine + sulfadiazine)

Question 5

How does Toxoplasma present in immunocompetent, healthy patients?

Answer 5

As a “mononucleosis-like” infection
* headache, fever
* pharyngitis
* hepatosplemomegaly
* negative heterophile Ab/monospot test

Question 6

Entamoeba histolytica

Answer 6

Question 7

Cryptosporidium

Answer 7

Question 8

Why does Entamoeba histolytica infection result in a bloody stool?

Answer 8

Trophozoite invasion of the intestinal mucosa

Question 9

Crazy Entamoeba histolytica presentation aspects:

Answer 9

• Liver abscess with anchovy paste
• Colonoscopy with flask-shaped colonic ulcers
• Stoop O&P - trophozoites have engulfed RBCs
• bloody diarrhea

Question 10

Cryptosporidium

Answer 10

Question 11

First-line Rx for cryptosporidium infection?

Answer 11

Nitazoxanide

Question 12

Naegleria fowleri

Answer 12

Question 13

Naegleria fowleri - Dx

Answer 13

Amoebas in CSF
* Rapidly fatal meningoencephalitis

Question 14

Trypanosoma brucei

Answer 14

Question 15

Which parasite causes “African sleeping sickness” (daytime somnolescence)?

Answer 15

Trypanosoma brucei
* Vector = Tsetse fly

Question 16

Plasmodium (overview)

Answer 16

Question 17

Which plasmodium species produce hypnozoites?

Answer 17

• P. vivax
• P. ovale

Primaquine required to treat these types of malaria by killing hypnozoites

Hypnozoites = Dormant form

Question 18

Blood smears with ring-shaped parasites visualized is diagnostic of which infection?

Answer 18

Malaria
* Plasmodium’s ring-shaped trophozoites
* Giemsa staining

Question 19

What causes the cyclical fevers in malaria?

Answer 19

RBC lysis every 2-3 days
* schedule seen in most malarial diseases

Question 20

Plasmodium species with 48 hour life cycles:

Answer 20

1. P. falciparum
2. P. vivax
3. P. ovale

Anopheles mosquito

Question 21

Plasmodium species with 72 hour life cycles:

Answer 21

1. P. malariae

Anopheles mosquito

Question 22

High yield plasmodium presentation:

Answer 22

1. Relapsing fevers
2. Splenomegaly
3. Hemolysis – Anemia, jaundice

Question 23

How to distinguish Babesia and Plasmodium:

Answer 23

Both show ring-shaped inclusions in RBCs on peripheral smear but needs to be differentiated clinically:
* Plasmodium - cyclical fevers
* Babesia - no cyclical fever

Question 24

Malaria (plasmodium disease)

Answer 24

Question 25

Babesia

Answer 25

Question 26

Common **co-infection** spread by the **Ixodes tick** (NE USA):

Answer 26

* Babesia * Borrelia burgdorferi

Question 27

**Name that parasite**: ring-shaped or **maltese cross** inclusions in RBCs

Answer 27

Babesia

Question 28

Babesia Rx combo:

Answer 28

* **Atovaquone** * **Azithromycin** (macrolide)

Question 29

Trypanosoma cruzi ## Footnote Kissing bug disease.

Answer 29

Question 30

**Name that parasite**: Patient presenting with **cardiac abnormalities** (arrhythmias, heart failure), **achalasia** (trouble swallowing), and **megacolon**

Answer 30

T. cruzi - **Chagas disease** 1. Dilated cardiomyopathy (**DCM**) 2. **Megaesophagus** - difficulty swallowing 3. Megacolon Rx * **Benznidazole** * Nifurtimox ## Footnote All patients with Chagas Disease are screened for cardiac abnormalities, even if they appear to be asymptomatic

Question 31

Leishmania ## Footnote * Vector = the sandfly * Kala azar * Infects **macrophages**

Answer 31

Question 32

**Name that parasite**: Patient who returned from the Middle East, presenting with **suddenly darkened skin**, **splenomegaly**, **hepatomegaly**, and **pancytopenia** (bone marrow failure), and **painless ulcers**:

Answer 32

**Leishmania** * (Disease = Leishmaniasis) * **Visceral** & **cutaneous** disease presentations

Question 33

**Amastigotes** - blood smear ## Footnote **Leishmania** infecting **macrophages**

Answer 33

Question 34

Main **Rx** for **Leishmania**

Answer 34

* **Amphotericin B** * Stibogluconate

Question 35

Trichomonas vaginalis

Answer 35

Question 36

**Enterobius vermicularis** (pinworm) ## Footnote * **Scotch-tape** test * Stool **O&P is not** effective

Answer 36

Question 37

**Ascaris lumbricoides** (giant roundworm)

Answer 37

Question 38

**Stronglyoides stercoralis** (threadworm)

Answer 38

Question 39

Where in the GI tract does **Ascaris lumbricoides** famously **obstruct**?

Answer 39

At the **ileocecal valve**.

Question 40

**Name that parasite**: Patient that walks **barefoot** in Thailand parks who is **coughing with bloody sputum**, experiencing **GI symptoms**, has raised **pruritic skin streaks** along the lower extremities, and shows **rhabditiform larvae** on **O&P stool microscopy**:

Answer 40

**Strongyloides stercoralis** (threadworm)

Question 41

**Rx** for **Strongyloides stercoralis** (threadworm)

Answer 41

Ivermectin

Question 42

**Ancylostoma** & **Necator** (Hookworm) ## Footnote * Serpiginous tracks * Anemia * Barefoot walkers

Answer 42

Question 43

**Rx** for **hookworm** infections (ancylostoma & necator):

Answer 43

1. **Bendazoles** 2. **Pyrantel pamoate** (pregnant patients)

Question 44

Trichinella spiralis ## Footnote * **Muscle biopsy** can be diagnostic (larvae detected)

Answer 44

Question 45

**Name that bug**: Young woman presenting with **yellow-green discharge** and **strawberry cervix**:

Answer 45

Trichomonas vaginalis

Question 46

Name that bug: Patient who just ingested **undercooked pork roast** and is experiencing **GI symptoms**, **myositis** (muscle pain), and **periorbital edema** (swelling around the eyes):

Answer 46

**Trichinella spiralis** * **Larvae** can bet detected upon **muscle** biopsy * Rx = **Bendazoles**

Question 47

**Trichuris trichiura** (whipworm)

Answer 47

Question 48

**Name that bug**: Child with **rectal prolapse**, impaired **growth/cognition**, & **diarrhea** with a resulting **microcytic anemia**:

Answer 48

**Trichuris trichiura** (whipworm)

Question 49

Toxocara canis

Answer 49

Question 50

Onchocerca volvulus ## Footnote * One of the leading causes of blindness **worldwide** -- uveitis, optic atrophy, & keratitis * "**River blindness**"

Answer 50

Question 51

Loa loa ## Footnote * Eye worm * Rx = DEC

Answer 51

Question 52

Wuchereria bancrofti ## Footnote **Lymphatic filariasis** (elephantitis)

Answer 52

Question 53

Taenia solium

Answer 53

Question 54

Diphyllobothrium latum

Question 55

Echinococcus granulosus ## Footnote * The "dog tapeworm" * Liver: hydatid cyst decades after initial infection

Answer 55

Question 56

Schistosoma

Question 57

Clonorchis sinensis

Question 58

**Scabies** (Sarcoptes scabei)

Question 59

Rx for **neurocysticercosis**:

Answer 59

* Praziquantel * **Albendazole**