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Malaria in children : Summarized


Malaria

Dr Nimrah Shehzadi

It is a mosquito born infectious disease affecting human and other animals caused by parasite protozoan belonging to plasmodium type.
Etiology:
Caused by intracellular plasmodium protozoan transmitted to humans by female anopheles mosquitoes .
5 species of plasmodium cause malaria in humans:
·         P.falciparum(most fatal )
·         P.ovale (least common)
·         P.malariae(mildest and most chronic)
·         P.vivax
·         P.knowlesi
Mode of transmission :
·         Mosquito bites
·         Blood transfusions
·         Contaminated needles
·         Transplacentally from mother to fetus
Pathogenesis:
2 phased of life cycle for plasmodium species:
·         Asexual phase (in humans)
·         Sexual phase (in mosquito)
1. Asexual phase :
·         Exoerythrocytic phase : involves
    Sporozoite
    Shizont
    Merozoites
·         Erythrocytic phase   :  involves
    Ring form
    Trophozoites
(Both these forms are identified by GIEMSA STAIN)
 4 pathologic processes are identified:
·         Fever :rupture of Rbcs
·         Anemia:hemolysis and bone marrow suppression
·         Immunopathologic events :(production of TNF)
·         Tissue anoxia: cytoadherence of infected erythrocytes to vascular endothelium ,obstruction of blood flow, vascular leakage of blood ,proteins )
Recurrence :
  It occurs due to immune evasive strategies of parasite :
·         Intracellular replication
·         Vascular cytoadherence
·         Rapid antigenic variance
·         Alteration of host immune response
Human blood resistant to malarial growth:
·         HbS
·         Rbcs lacking duffy blood group antigen
·         HbF
·         Newborns born in hyperendemic areas due to passive maternal antibody and high levels of maternal hemoglobin
Clinical menifestations:
·       Asymptomatic during incubation period
9-14 days for p.falciparum
12-17 days for  p.vivax
16-18 days for p.ovale
18-40 days for p.Malariae
·       Symptomatic:
·          Paroxysms of high grade fever (coinciding with rupture of                               
     Schizont, every 48 hrs for p.vivax and p.ovale ,   
    Every 72 hrs for P.Malariae)
·         Fatigue
·         Sweats
·         Headache
·         Drowsiness
·         Anorexia
·         Nausea
·         Vomiting
·         Diarrhea
Signs :
·       Splenomegaly
·       Hepatomegaly
·       Pallor
Congenital malaria :
Common in endemic areas, causes
·         Abortions
·         Miscarriages
·         Stillbirths
·         Premature births
·         IUGR
·         Neonatal deaths
Symptoms in neonates appear typically btw 10 and 30 days of age. These  include
·         Fever
·         Restlessness
·         Drowsiness
·         Pallor
·         Jaundice
·         Poor feeding
·         Vomiting
·         Diarrhea
·         Cyanosis
·         Hepatosplenomegaly
Diagnosis:
Clinical : fever or unexplained systemic illness in a child who has travelled to endemic area in within previous year should be considered life threatening malaria until proved otherwise.
Laboratory :
·         CBC ( anemia,thrombocytopenia, normal or low leukocyte count )
·         ESR ( raised )
·         Giemsa staining (thick smear :confirmation of malaria, thin smear : identification of species ,Smears should be taken several times a day over 3 successive days, with the spike of fever as it releases parasite into blood with RBC rupture)
·         PCR
BINAXNOW malarial rapid diagnostic test
Differential diagnosis:
·        Enteric fever (the patient of enteric fever looks toxic throughout, while the patient of malaria looks toxic only when there is fever and looks well as fever subsides during episodes)
·       Influenza
·       Hepatitis
·       Sepsis
·       Pneumonia
·       Meningitis
·       Encephalitis
·       Endocarditis
·       Gastroenteritis
·       Pyelonephritis
·       Babesiosis
·       Brucellosis
·       Letospirosis
·       Tuberculosis
·       Relapsing fever
·       Yellow fever
·       Viral hemorrhagic fever
·       Amebic liver abscess
·       Hodgkin disease
·       Collagen vascular disease
Treatment :
Uncomplicated cases :
For P.falciparum
·         Artemether -lumefantrine 1.6 /kg twice daily for 3 days
For chloroquine sensitive P. Vivax, malariae, ovale, knowlesi:
·         Chloroquine 10 mg base /kg stat followed by 10 mg /kg at 24hr and 5mg/kg at 48 hr
 Severe malaria:
·        Artesunate 2.4mg/kg IV or IM followed by 2.4 mg/kg at 12 hr and 24 hr ..then OD daily if needed.
·        Artemether 3.2mg/kg IM stat followed by 1.6 mg/kg daily for 3 days
Complications:
·         Severe malarial anemia (hb<5 g/dl)
·         Cerebral malaria
·         Respiratory distress(poor prognostic)
·         Seizures
·         Algid malaria (circulatory collapse)
·         Long term cognitive impairment
·         Tropical splenomegaly syndrome
·         Jaundice
·         Prostration


Chemoprophylaxis/ Prevention while travelling to Malaria endemic areas:
>>If the destination  is Chloroquine sensitive,
Start prophylaxis with Chloroquine phosphate 2 weeks prior to travelling, in the dose of 5mg/kg once weekly (max 300mg).

>> if the destination is Chloroquine resistant :
   Give Doxycycline 2mg/kg/day (max 100mg) ( do not give to children  <8yrs , consider Mefloquine in these cases)

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