CNS pathogens/Disease

Question 1

Prions

Answer 1

• Cause misfolding of proteins that lead to amyloids (beta-pleated sheets)
• Cause subacute spongiform encephalopathies.

Question 2

What are the types of prion disease spongiform encephalopathies?

Answer 2

• Consist of PrPc being mutated to PrPsc
• Kuru: via human cannabalism
• Creutzfeldt Jakob disease: blood or tissue contact with infected.
• Bovine spongiform encephalopathy: Infection from ingesting infected cattle.
• Scrapie: occurs within sheep/goats.

Question 3

Bacterial Meningitis (Neisseria meningitides)

Answer 3

• Common with MAC complex deficiency.
• Begins as petechial rash, headache, fever; via the LPS toxin.
• Diagnosis:
  
  • CSF culture on Thayer-Martin VCN stain
  • Gram(-) diplococci
  • PCR
• Contain antiphagocytic capsule

Question 4

Treponema pallidum

Answer 4

• spirochete, gram (-) motile. unable to grow in vitro.
• Forms lympoplasmacytic vasculitis and granulomas.

Question 5

Syphilis (Treponema pallidum pallidum)

Answer 5

• 10-90 day incubation with painless contagious hard chancre.
• 2-24 weeks later disseminated disease with 2-6week long rash.
• years later develop tertiary syphilis with gummas and cardiac or neuro syphilis will be most likely cause of death.

Question 6

Congenital syphilis

Answer 6

• 1/2 die in utero.
• Infantile form: symptoms present in 1st two year of life.
• Tardive form: appear AFTER 2 y/o.
  
  • Hutchinson Triad: interstitial keratitis, notched incisors, sensorineural heaing loss.

Question 7

Treponematosis

Answer 7

Non-sexually transmitted form of syphilis similar to yaws and pinta.

Question 8

Common causes of granulomatous encephalitis

Answer 8

• Acanthamoeba castellanii
• Balamuthia mandrillaris

Question 9

Cause of meningoencephalitis associated with a cribrifrom plate fracture.

Answer 9

Naegleria fowleri

Question 10

Eosinophilic meningitis (Angiostrongylus cantonensis)

Answer 10

• Eosinophilic meningitis: mimics bacterial meningitis via the rat lungworm.
• Rat: definitive host (primary)
• Humans: Incidental host with undercoooked intermediate hosts
  
  • snail or slugs.

Question 11

Cysticercosis (Taenia solium)

Answer 11

• Cysticercosis: tissue infection with inflammation, edema, and fibrosis.
• Ingestion of undercooked pork or beef.
• Ingest from intermediate host= mild GI symptoms
• Ingestion from eggs in human fecal material =cysticercosis

Question 12

Coccidiomycosis (Coccidiodes immitis)

Answer 12

• Infection by thermally dimorphic fungi
  
  • yeast in the heat
  • Mold in the Cold
    
    • Candida is the opposite
• Most common in california.
  
  • Has angioinvasion, thrombosis, septic infarcts.

Question 13

Cryptococcus neoformans/ C. gattii

Answer 13

• Form “soap bubble” lesion in brain of immunocompromised.
  
  • encapsulated
• Detected with Mucicarmine/PAS stain
• produce solitary pulmonary granuloma.

Question 14

Hantavirus

Answer 14

• Hemorrhagic fever with renal failure.
• Pulmonary Syndrome: spreading via aerosolized rodent excrement leading to pulmonary edema.
• Carrier is deer mice.

Question 15

Dengue virus

Answer 15

• Dengue fever: virus replicates in skin and travels to lymphoid. Causing viremia with rash of 3-9 days.
• Dengue hemorrhagic fever: immunopathological process with massive permeability, causing shock and death.

Question 16

Powassan virus

Answer 16

• 1wk-1mo incubation period, ranging from asymptomatic to encephalitis
  
  • 50% develop permanent neurologic defect.
  • 10% die

Question 17

St Louis encephalitis virus

Answer 17

Viremia that can lead to neuronal degeneration.

Question 18

Zika virus

Answer 18

Acute onset with fever, rash, joint pain, muscle pain, conjunctivitis, headache. Can lead to microcephaly, lissencephaly in utero during 2nd trimester. Transferred sexually or in utero.

Question 19

What are the Encephalitis viruses?

Answer 19

1. Hantavirus
2. Dengue virus
3. Powasssan virus
4. St Louis encephalitis virus
5. West Nile virus
6. Yellow fever virus
7. Zika virus.

Question 20

Cytomegalovirus

Answer 20

• Owl-eye basophilic intranuclear inclusions.
• CMV mononucleosis syndrome: fever, fatigue and atypical lymphocytes.
• Congenital CMV: jaundice, purpura, hepatosplenomegaly, CNS development disorder
• Transmission
  
  • Transplacental: primary infection from pregnant mother
  • Neonatal: cervical/vaginal infection via birth
  • Perinatal: breast milk from active infected.
  • Saliva: preschool cause.

Question 21

Epstein-Barr virus

Answer 21

• Attach via CD21 (complement receptor 2)
• produces infectious mononucleosis:
  
  • fever, fatigue, malaise, pharyngitis
  • Downey cells (t cell)
  • Hodgkin lymphoma, burkitt lymphoma, CNS lymphoma, nasopharyngeal carcinoma.
• Treat with monospot.