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41 Cards in this Set
- Front
- Back
What is essential to diagnose Malaria?
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History of travel to endemic area
Periodic attacks of chills, fever and sweating Headache, myalgia, splenomegaly, anemia, leukopenia Characteristic parasites in erythrocytes: I.D. via thick or thin film Giemsa Stain |
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What are the relapsing Malarias?
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Vivax
Ovale hide in liver |
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which malaria is the most deadly?
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falciparum
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When do you take the blood smear?
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take it during fever phase: fever due to cell rupture
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Transmission via:
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1. human to human anopheles mosquito
2. Transplacental Transmission 3. Infected blood transfusion |
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Stages of Plasmodium Life Cycle
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Tissue Phase
1. carrier mosquito injects the sporozoite into a human 2. Sporozite is transformed into merozoite in the liver 3. The merozoites enter into the blood stream adn parasitizes the RBC; organism is called a blood schizont 4. Erythrocyte lysis occurs with release of gametocytes 5. Non-carrier mosquito ingests the gametocytes by biting an infected man |
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2 Life cycles of malaria
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1. asexual in humans
2. sexual in mosquito |
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What phase do you take prophylactics?
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Preexoerythrocytic Phase: when the sporozoite is in the liver or in the mosquito
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Primary Erythrocytic Phase
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common to all malaria
use Chloroquine (quinolenes) in this phase |
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Secondary Exoerythrocytic Phase
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Vivax and Ovale
reinvade liver need to treat with/2 varieties 1. tissue---> primoquine 2. blood----> chloroquine |
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Fevers in Ovale, Malaria, Falciparum, Vivax
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Every other day
Vivax Falciparum Ovale Every 3rd Day Malaria Due to rupture of blood cells and pyrogenes being released |
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Complications of Falciparum Malaria
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Cerebral Malaria
Hyperpyrexia Hemolytic anemia Convulsions Dysenteric or Cholera like stools Dark Urine and Anuria Hypoglycemia |
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Chloroquine
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4-aminoquinoline
drug of choice for all forms of malaria except chloroquine resistant forms of falciparum decreased accumulation of the drug in the parasite well absorbed and concentrated in the liver, kidney, lungs, RBCs and brain kidney excretion acts on erythrocytic stage |
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Chloroquine MOA
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enters parasite by energy dependent mechanism
accumulates in food vacuole of plasmodium prevents polymerization of hemoglobin; break down product heme is toxic to the parasite |
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What happens in Chloroquine resistance?
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parasites expel drug via a membrane P-glycoprotein pump.
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Chloroquine USE
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used in acute cases
prophylaxis: chloroquine + primaquine amebic liver abscess: chloroquine + emetine collagen disorder: anti-inflammatory: SLE, R.A. can be used in pregnancy |
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What do you use with persistent stage malaria or relapse
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Primaquine
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Chloroquine Toxicity
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dizziness, blurred vision, retinal damage, headache, diarrhea, GI-irritation, epigastric pain, exfoliative dermatitis, neuropathy, and auditory impairment
Myocardial depression c/i: psoriasis and porphyria |
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Primaquine
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8-aminoquinoline
used in exoerythrocytic phase (liver) (vivax or ovale-dormant) called a tissue schizonticidal agent no effect in acute attacks |
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What effect does primaquine have on a G6PD deficient individual?
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primaquine is a cellular oxidant (the drug forms quinoline-quinone metabolite) and causes hemolysis
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Primaquine AE
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GI, nausea, vomiting, epigastric pain, abdominal cramps. Headache, agranulocytosis, pruritis, methemoglobinemia
prophylaxis in endemic areas of ovale and vivax |
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Antifolates
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Pyrimethamine and Proguanil
Sulfadoxine and Dapsone: oral route and urinary elimination inhibits dihydrofolate reductase |
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Proguanil + Atovaquone (Malarone)
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used in the prophylaxis of resistant falciparum sp.
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Pyrimethamine + Sulfadoxine
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synergistic sequential blockade in folate pathway
used as prophylaxis in chloroquine sensitive regions used in toxoplasmosis MOA similar to smz+tmp |
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Antifolates: AE
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high doses of pyrimethamine can result in megaloblastic anemia
sulfas-crystalluria, hemolysis, Steven-Johnson syndrome |
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Quinine
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alkaloid derivative from bark of cinchona tree
i.v. admin in severe infections also absorbed well via oral |
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Quinine MOA
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complexes with double stranded DNA and prevents separation of strands, thus preventing DNA replication and transcription
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What is quinine used with to shorten therapy and limit toxicity?
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doxycycline
clindamycin pyrimethamine used in CRPF |
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What can be used instead of quinine? and What kind of medicine is it primarily?
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Quinidine
antiarrythmatic |
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Quinine Use
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1. resistant form of p. falciparum
2. nocturnal leg cramps associated with arthritis, diabetes, atherosclerosis and thrombophlebitis 3.Myotonia Congenita: reducing response to Ach and as a sclerosing agent: relaxes muscles |
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Quinine AE
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Cinchosim: headache, vertigo, tinnitus, blurred vision, GI distress---> dose dependent
Cardiac conduction abnormalities Black water fever: intravascular hemolysis occurs in quinine sensitized patients hypoglycemia---> pancreas is stimulating to produce insulin c/i in pregnancy: categorized as X |
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Drugs in Category X
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Thalidomide
Clomiphene Ergot Ethionamide HMG-CoA reductase inhibitors isotrentinoin mebendazole halofantrine ribavarin misoprostol |
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Category D drugs:
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potential benefit to harm is greater in Pregnancy and may outweigh the risk: used with caution
aminoglycosides tetracyclines fluroquinolones |
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Mefloquine
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first line drug for prophylaxis
synthetic 4-quinoline MOA: not known long half life (6 days) due to enterohepatic circulation well absorbed from GI tract and 20% excreted unchanged |
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Mefloquine AE
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toxicity: cardiac conduction abnormalities, pyschiatric abnormalities, neurological abnormalities, seizures
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Halofantrine
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MOA not known
effective against all 4 malarial species including CRPF species. effective in erythrocytic phase |
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Halofantrine AE
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cardiotoxicity: QT prolongation
embryotoxicity |
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Doxycycline
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good prophylactic agent in areas with chloroquine resistant and mefloquine resistant P falciparum
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Artemether
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ginghaosu or wormwood
effective in chloriquine-resistant p. falciparum metabolized in the food vacuole of parasite forming toxic reactive free radicals blood schizonticidal agent short half life so no prophylaxis Artesunate is similar |
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Atovaquone
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inhibits electron transport system-ATP synthesis
complex-3 of electron transport system resistance is not seen active against PCP, trophozites and cyst forms of T.Gondii |
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Pregnancy and Antimalarials
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advised not to travel to endemic areas
Mefloquine recommended in pregnancy if traveling to chloroquine resistant areas Chloroquine or hydroxychloroquine are safe in pregnancy, if traveling to endemic active against P. Falciparum |