Malaria Flashcards
Various species associated with
malarial infection in humans and their characteristics
Phenotype carried by West Africans which are generally resistant to P. vivax malaria
Duffy-negative FyFy phenotype
Pathogenesis of malarial infection
Period of asexual reproduction
Intrahepatic or preerythrocytic schizogony
Dormant forms, causes of relapses
hypnozoites
when the parasite has consumed two-thirds of the RBC’s hemoglobin and has grown to occupy most of the cell
schizont
morphologically distinct, longer-lived sexual forms, can transmit malaria
gametocytes
Vector of malaria
Anopheles mosquito
Principal determinants of the epidemiology of malaria
- Number (density)
- Human-biting habits
- Longevity of the anopheline mosquito vectors
Central to the pathogenesis of falciparum malaria
- Cytoadherence
- Rosetting
- Agglutination
Genetic disorders that confer protection against death from falciparum malaria
- Thalassemia
- Sickle cell disease
- Hemoglobin C and E
- Hereditary ovalocytosis
- G6PD deficiency
defined in terms of rates of microscopy-detected parasitemia or palpable spleens in children 2-9 years of age
Endemicity
Classifications of endemicity
- Hypoendemic (<10%)
- Mesoendemic (11-50%)
- Hyperendemic (51-75%)
- Holoendemic (>75%)
Initial constitutional symptoms
Lack of a sense of well-being, headache, fatigue, abdominal discomfort, and muscle aches followed by fever
Manifestations of severe falciparum malaria
characteristic and ominous feature of falciparum malaria, and even with treatment, has been associated with death rates of ~20% among adults and 15% among children
Coma
Manifestation of cerebral malaria
Diffuse symmetric encephalopathy, focal neurologic signs are unusual
Clinical features indicating a poor prognosis in severe falciparum malaria
Laboratory features indicating a poor prognosis
Pregnant women with malaria
-fetal loss in early pregnancy
-more severe in areas with unstable transmission
-high parasetemia with anemia
-hypoglycemia
-acute pulmonary edema
Common results of pregnancy in people with malaria
fetal distress
premature labor
stillbirth
low birthweight
transfusion malaria
-transmitted by BT, needlestick injury or organ transplantation
-short incubation period
-no preerythrocytic stage of development
-primaquine unnecessary for transfusion transmitted P. vivax and P. ovale
Chronic complications of malaria
-Hyperreactive malarial splenomegaly
-Quartan malarial nephropathy
-Burkitt’s lymphoma and EBV infection
Approach to diagnosis of malaria
thick and thin smears should be prepared and examined immediately to confirm the diagnosis and identify the species of infecting parasite
diagnosis of malaria
demonstration of asexual forms of the parasite in stained peripheral blood smears
Treatment for uncomplicated malaria
Treatment for severe malaria
Treatment for severe malaria
Firstline treatment for uncomplicated falciparum malaria in malaria-endemic areas
Artemisinin-based combination therapy (ACT)
Drug of choice for all patients with severe malaria
Artesunate
Indications to stop quinidine infusion
-total plasma levels exceed 8 ug/ml
-QT interval exceeds 0.6s
-QRS complex widens more than 25% overbaseline
Cannot be given to pregnant women
Primaquine
Tetracycline
Doxycycline
Complications of severe malaria
Acute renal failure
Acute pulmonary edema
Hypoglycemia
Sepsis
Bleeding
Convulsions
Only drug advised for pregnant women travelling to areas with drug-resistant malaria
Mefloquine
Duration of chemoprophylaxis for travelers
2 days to 2 weeks before departure and continued until 4 weeks after the traveler has left
Should not be given to patients with G6PD deficiency, as it causes serious hemolysis
Primaquine
