Malaria Flashcards
Malaria
5 species
- Plasmodium vivax
- Pl falciparum
- Pl ovale
- Pl malariae
- Pl knowlesi
Malaria
Definitive host?
Host where the sexula phase of the parasite takes place
* Female anopheles culicifacies mosquito
Malaria
Intermediate host
Human
Malaria
Which species have hypnozoites
- Pl vivax
- Pl ovale
Malaria
Hypnozoites
Live stage of the parasite in the human. Cause relapses of fever
Malaria
Life cycle stages
- Human- Sporozoite stage, Pre- erythrocytic stage, erythrocytic stage, Gametocyte formation
- Mosquito - Sporogonic stage
Malaria
Sporozoite stage
Infected mosquito bites humans and inject sporozoites.
Malaria
Sporozoites
infectious form of the parasite
Malaria
Pre- erythocytic stage
- Sporozoites enter the liver within minutes from the bite
- Invade hepatocytes and multiply
- 1-2 weeks after they become merozoites
- Liver cells rupture and release merozoites into blood
- Hypnozoites in Pl. Ovale and vivax stay dormant and cause relapses months or years later.
Malaria
Erythrocytic stage
- Merozoites infect RBCs
- Inside RBCs they become trophozoites and feed on Hb.
- Trophozoites»»> schizonts»» divide and form merozoites»» continue infecting RBCs.
- This infecting RBCs stage gives Sx
Malaria
Gametocyte formation stage
- Merozoites become gametocytes inside humans
- Gametocytes circulate in blood stream
Malaria
Sporogonic stage
- Mosquito bites infected humans
- gametocytes enter the mosquito
- Gametocytes develop into male and female gametes in the female mosquito stomach
- Gametes fuse and form zygotes
- zygotes»> ookinete»> form sporozoites
Malaria
Incubation period of Pl. falciparum
around a week ( 7-10 days)
Malaria
Incubation period of Pl. vivax
around 1- 2 weeks ( 10- 12 days)
Malaria
Incubation period of Pl. malariae
18- 40 days ( around a month)
Malaria
Clinical manifestations of malaria is due to….. stage of the plasmodium life cycle
erythrocytic stage - infect RBCs
Malaria
Febrile paroxysms stages
- Cold stage
- Hot stage
- Sweating stage
Malaria
Cold stage
- 15- 60 mins
- Intense cold and uncontrollable shivering
Malaria
Hot stage
- 2-6 hrs
- intense high fever, severe headache, Nausea, Vomiting
Malaria
Sweating stage
- Drenched in severe profuse sweating
- temp drops rapidly
Malaria
Fever periodicity
Synchronous rupture of mature schizonts
Malaria
Fever periodicity is not seen in
falciparum
Malaria
Sx
- Headache
- Anorexia
- lethargy
- myalgia
- diarrhea
- Abd pain
- cough
* fever w chills and rigors - Nausea
- Vomiting
Malaria
Signs
- Fever
- Anemia
- jaundice ( mild)
- Hepatosplenomegaly
- NO RASH OR LYMPHADENOPATHY
Malaria
CLINICAL CLUES FOR MALARIA!!
- Fever w chills and rigors
- Recent travel Hx to India, Africa
- Pallor + Jaundice
Malaria
DDs for chills and rigors
- Acute pyelonephritis
- Cholangitis
- Abscess
Malaria
Complications of falciparum
- Cerebral malaria
- Confusion
- Coma +/- fits
- Unusual focal signs
- Variable tone, extensor posturing, upgoing plantar, dysconjugate gaze
- Metabolic acidosis
- Hypoglycemia
- ARF - ATN, hemoglobinuria
- Pulm edema
- ARDS
Malaria
Hemoglobinuria is due to
intravascular hemolysis
Malaria
Black water fever
malaria due to hemoglobinuria ( dark urine)
Malaria
Dx to confirm the parasite
Thick film of blood
Malaria
Dx to identify the species
thin film of blood
Malaria
Rapid stick test ?
to detect the malaria Ag
Malaria
Ix
- serial thick and thin film
- Rapid stick test
- FBC- reduced Hb, Plts
- BU and SE for falciparum renal failure
- Urinalysis - hemoglobinuria, proteinuria, cells
Malaria
Mx for P. vivax
- Chloroquine for 3d»» Primaquine for 14 d ( to destroy hypnozoites and gametocytes)
Malaria
Mx for P falciparum ( uncomplicated)
- Artemisinin based combo therapy (ACT)»_space;» single dose of primaquine ( to get rid of gametocytes)
Malaria
Mx of P falciparum ( severe and complicated)
- IV artesunate ( more effective than IV quinine)
- Once improving and can take oral meds , except children < 5 years should be given ACT ( weight appropriate)
- Followed by a single dose of primaquine
Malaria
primaquine ADRS
can cause hemolysis in pts w G6PD deficiency
Malaria
What should be done ideally before giving primaquine
check G6PD levels
Malaria
Differences between P falciparum and vivax
Pl. vivax
* Entry into reticulocytes
* Single parasite in one RBC
* Enlarged RBCs
* hypnozoites +
* Round gametocytes
Pl. falciparum
* Can enter into any stage of the RBC
* Multiple parasites in one RBC
* Not enlarged
* No hypnozoites
* Crescenteric shaped gametocytes
