Protozoa of the CNS

Question 1

Toxoplasma gondii

lab tests

Answer 1

Oh Hi, IZ makin sum Toxo

• Ring enhancing lesions on MRI (usually many lesions vs. CNS lymphomas with a single lesion).
• Biopsy will dx from CNS lymphoma.
• (+) for IgG for toxo

Question 2

Toxoplasma gondii

Sources

Answer 2

Oh Hi, IZ makin sum Toxo

1. Consuming raw or undercooked meat containing tissue cysts.
2. Ingestion of water or vegetables contaminated with oocysts shed from the feces of infected animals*.
3. Through placenta from mother to fetus in utero.

* (T. gondii is an intracellular parasitic protozoa that infects almost any warm blooded animal.)

Question 3

Toxoplasma gondii

Most susceptible

Answer 3

Oh Hi, IZ makin sum Toxo

• Pregnant women & fetus (TORCHeS infection!)

Congenital toxo due to transplacental transfer.

*(Pregnant women should NOT change kitty litter!)

• Immunocompromised

(HIV/AID’s pt. with CD4 < 100)

Question 4

Toxoplasma gondii

signs and symptoms if healthy

Answer 4

Oh Hi, IZ makin sum Toxo

Flu-like symptoms

Question 5

Toxoplasma gondii

signs and symptoms if immunocompromised

Answer 5

Oh Hi, IZ makin sum Toxo

• Ring enhancing lesions on MRI (usually many lesions vs. CNS lymphomas with a single lesion).
• Toxoplasma encephalitis
• Chorioretinitis

Question 6

Toxoplasma gondii

signs and symptoms of congenital toxo

Answer 6

Oh Hi, IZ makin sum Toxo

Classic Triad:

1. Brain and intracranial calcifications
2. hydrocephalous
3. Chorioretinitis

Also seen: seizures and deafness

Question 7

Toxoplasma gondii

Treatment

Answer 7

Oh Hi, IZ makin sum Toxo

For active infections:

Sulfadiazine and Pyramethamine

For prophylaxis when CD4 counts < 100 AND (+) for toxo IgG:

TMP/SMX

Question 8

TORCHeS Infections

Answer 8

TORCHeS Infections:

Toxoplasmosis

Other (HIV, VZV, Parvovirus B19, enteroviruses, others)

Rubella

Cytomegalovirus

Herpes

Syphilis

Question 9

Trypansoma brucei gambiense and rhodesiense

lab tests

Answer 9

Prince Bruce to the Rescue

Trypomastogotes on blood smear (finger tip prick etc).

Motile with single flagella.

Question 10

Trypansoma brucei gambiense and rhodesiense

Source

Answer 10

Prince Bruce to the Rescue

painful bite from Tsetse fly (vector)

W & SE Africa: Gambia and Rodesia (old name for Zimbabwe)

Question 11

Trypansoma brucei gambiense and rhodesiense

signs and symptoms

Answer 11

Prince Bruce to the Rescue

• Sleeping sickness! (a problem of CNS and spinal fluid)
• Cervical and axillary lymphadenopathy (after being bit the parasites move from the blood to the lymph nodes)
• Recurrent fevers (from blood infection; Caused by variable surface glycoprotein coats undergoing constant antigenic variation)

Question 12

Trypansoma brucei gambiense and rhodesiense

Treatment

Answer 12

Prince Bruce to the Rescue

For CNS infection: Melarsoprol

For peripheral blood infections: Suramin*

(think suramin for serum!)

Question 13

Naegleria fowleri

lab tests

Answer 13

Naegleria Falls

Lumbar puncture to diagnose

Question 14

Naegleria fowleri

Source

Answer 14

Naegleria Falls

Fresh water (especially warm stagnant water)

• Water sports or lakes
• Nasal irrigation (OTC)
• Contact lens solutions

Question 15

Naegleria fowleri

signs and symptoms

Answer 15

Naegleria Falls

• Causes Primary amoebic meningoencephalitis.

(nucal rigidity, fevers, altered mental status)

• High mortality (that’s rapidly fatal) due to entry through the cribiform plate!

Question 16

Naegleria fowleri

Treatment

Answer 16

Naegleria Falls

AMP B