Parasites & Fungi Infecting CNS

Question 1

What are the major parasitic infections of the central nervous system (CNS)?

Answer 1

• Free-living amoebae
• Toxoplasmosis
• Neurocysticercosis
• Cerebral malaria

Question 2

What is the major fungal infection of the CNS?

Answer 2

Cryptococcal Meningitis

Question 3

What is the causative agent of primary amoebic meningoencephalitis (PAM)?

Answer 3

Naegleria fowleri

Question 4

Which amoeba causes granulomatous amoebic encephalitis (GAE)?

Answer 4

• Acanthamoeba species
• Balamuthia mandrillaris

Question 5

What is the infective form of Toxoplasma gondii?

Answer 5

• Tachyzoites
• Tissue cysts containing bradyzoites
• Oocysts

Question 6

What is the definitive host for Toxoplasma gondii?

Answer 6

Cats and other feline animals

Question 7

What is the most common transmission route for Toxoplasmosis?

Answer 7

Ingestion of tissue cyst from undercooked meat

Question 8

What are the clinical manifestations of Toxoplasma encephalitis in HIV-infected patients?

Answer 8

• Encephalitis
• Pulmonary infections
• Chorioretinitis

Question 9

What is the treatment of choice for Toxoplasmosis in HIV-infected patients?

Answer 9

Cotrimoxazole

Question 10

What is the pathogenesis of cerebral malaria caused by Plasmodium falciparum?

Answer 10

Sequestration of parasitized RBCs in brain capillaries, leading to vascular occlusion and cerebral anoxia

Question 11

What are the common clinical manifestations of cerebral malaria?

Answer 11

• Seizures
• Diffuse symmetric encephalopathy
• Retinal hemorrhages
• Neurologic sequelae

Question 12

What is the gold standard method for diagnosing P. falciparum?

Answer 12

Peripheral blood smear examination

Question 13

What is the etiological agent of neurocysticercosis?

Answer 13

Taenia solium

Question 14

What are the common symptoms of neurocysticercosis?

Answer 14

• Seizures
• Headache
• Vomiting
• Vertigo

Question 15

What is the treatment for neurocysticercosis?

Answer 15

• Albendazole
• Praziquantel
• Surgery

Question 16

What is the principal virulence factor of Cryptococcus neoformans?

Answer 16

Polysaccharide capsule

Question 17

What are the common clinical manifestations of cryptococcosis?

Answer 17

• Pulmonary cryptococcosis
• Cryptococcal meningitis
• Skin lesions
• Osteolytic bone lesions

Question 18

What are the laboratory diagnosis methods for cryptococcosis?

Answer 18

• India ink stain
• Culture on SDA
• Capsular antigen detection
• Direct detection methods

Question 19

What is the drug of choice for cryptococcosis without CNS involvement?

Answer 19

Fluconazole

Question 20

What is the recommended treatment regimen for HIV-infected patients with CNS involvement from cryptococcosis?

Answer 20

• Induction phase: Amphotericin B ± flucytosine
• Maintenance therapy: Fluconazole

Question 21

Fill in the blank: The infective form of Toxoplasma gondii is _______.

Answer 21

Tachyzoites

Question 22

True or False: Cryptococcus neoformans can cross the blood-brain barrier.

Answer 22

True

Question 23

What diagnostic test is used to demonstrate the capsule of Cryptococcus neoformans?

Answer 23

Negative staining by modified India ink stain

Question 24

What is the recommended induction phase regimen for treating Cryptococcus neoformans?

Answer 24

Induction phase for 2 weeks with Amphotericin B ± flucytosine

This is followed by lifelong maintenance therapy with fluconazole.

Question 25

What does India ink staining reveal in the context of Cryptococcus neoformans?

Answer 25

Clear refractile capsules surrounding round budding yeast cells ## Footnote The arrow in the image indicates the budding yeast cells.

Question 26

What type of colonies does Cryptococcus neoformans produce when grown on SDA at 370C?

Answer 26

Creamy white mucoid colonies ## Footnote This growth characteristic is significant for identification.

Question 27

What is the lifelong maintenance therapy used after the induction phase for Cryptococcus neoformans?

Answer 27

Fluconazole ## Footnote This therapy is essential for preventing relapse.