Parasitology Flashcards Preview

Neuro > Parasitology > Flashcards

Flashcards in Parasitology Deck (10)
Loading flashcards...
1
Q

Trypanosoma brucei

A
  • Life cycle: Tsetse fly injects into bloodstream, binary fission. Key point: extracellular
  • Causes African Sleeping Sickness (African Trypanosomiasis) characterized by somnolence and demyelination
  • Time scale to CNS system infection (stage 2): Gambiense (1-2 yrs); Rhodesiense (few weeks). Treat in stage 1 (lymphatics). *Waves of parasitemia
2
Q

Trypanocidal drugs

A

Stage 1:

  • Pentamidine: does not penetrate CNS, IM delivery, mild toxicity
  • Suramin: slow IV admin (not practical), loss of consciousness, nephrotoxic, etc. Don’t take unless have to.
  • Nitroaromatics (Nifurtimox & Benznidazole): no BBB, but GI absorption. Pretty Toxic.

Stage 2:

  • Arsenicals (Melarsoprol): The nasty one, extremely toxic; 5-10% encephalopathy and 1/2 of those die
  • Eflornithine: trypanostatic, need long IV infusion. Not as bad toxicity as Melarsoprol. Need functional immune system. Inhibits ornithine decarboxylase

*Eflornithine + Nifurtimox is best option for late stage African trypanosomiasias.

3
Q

Trypanosoma cruzi

A

Endemic to Latin America or Mexico (kissing bug transmission). Causes Chagas’ disease. Intracellular and extracellular bloodstream stages.

4
Q

Chagas’ Disease

A
  • Acute stage is mild, asymptomatic. Drugs effective
  • Chronic stage (20-40%) can cause myocarditis. Can happen decades after initial infection. US transmission could occur through blood supply.
5
Q

Leishmania spp.

A
  • Req. uptake by phagocytic cell
  • Transmitted by sand fly
  • Causes Leishmaniasis (skin lesions, splenomegaly, mucocutaneous leishmaniasis)
6
Q

Antileishmanial Drugs

A

Organic antimonials Sodium stibogluconate & Meglumine antimoniate

  • interferes with glycolysis and fatty acid beta oxidation
  • toxicity increases over time
7
Q

Toxoplasma gondii

A
  • Ingest cysts, litterbox, cats usually pick it up by eating rats and birds, cats poop. Unwashed produce and animals that we eat that ingest cysts.
  • Opportunistic: the T in TORCH infections.
  • Causes toxoplamosis: often occurs in basal ganglia (tremors, chorea, hemiballism)
8
Q

Toxoplamosis

A

Caused by toxoplasma gondii.
-basal ganglia
-Ocular toxoplasmosis- headlight in the fog lesion in fund. exam
-Perinatal toxoplasmosis: prego dont change litter box. Abnormal head size and neuro deficits
*Pregnant women and immunocomprompised get drugs, most don’t
Treat with atovaquone and folate antagonist combo
-Spiramycin is macrolide used, need to obtain FDA if prego

9
Q

Naegleria fowleri

A
  • Thermophilic freshwater amoeba
  • Normally eats bacteria
  • Rarely, can consume neural tissue and penetrate to CNS
  • Penetrates via the olfactory epithelium if mucosal surface fails; into the olfactory bulbs and to the meninges
10
Q

What are the diagnostic hints of Primary Amebic Meningoencephalitis ?

A

Symptoms being about 5 days post-infection:
Initially: Headache, nausea, fever, vomiting
Later:
-Stiff neck
-Confusion
-Lack of attention to people and surroundings
-Loss of balance, seizures
-Hallucinations
Rapid disease progression, death usually occurs within about 5 days