PROTOZOAL DISEASES 2( MALARIA ) internal medicine
MALARIA
•
It is caused by Plasmodium vivax, P. ovale, P. malariae and P. falciparum
•
It is transmitted by the bite of female anopheline mosquitoes
LIFE CYCLE:
The female anopheline becomes infected when it feed on human blood containing
gametocytes which develop in the mosquito over 1 – 3 weeks into sporozoites
sporozoites which are transmitted to another persons via mosquito bites and then enter
the liver to form merozoites which leave the liver and invade RBC where multiplication
occurs
forming schizont which rupture to release more merozoites into the blood and causes
fever.
* The periodicity of the fever and rigor depend on the species of the parasite (( Tertian,
Quartian, Aperiodic ))
* P. vivax and P. ovale may persist in the liver as dormant
PATHOGENESIS:
•
The pathology of Malaria is due to hemolysis of the infected red cells and there
adherence to capillaries.
•
Anemia may developed and it worse by spleenomegaly
•
P. Falciparum cause wide spread organ damage.
CLINLCAL FEATURES:
P. vivax & P. ovale
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Continuous fever for several days then classical boats of fever on alternated days (( cold
phase and rigor for ½ - 1 hour, hot phase with flushing for several hours and gives a way
to profuse sweating – wet phase- )) the cycle is repeated every 48 hr.
•
Hepatospleenomegaly
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Anemia
•
Herpes simplex is common
•
Relapses are frequent in the first two years.
P. Malariae
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It is usually associated with mild symptoms
•
boats of fever every third day
•
it may cause GN and nephrotic syndrome
P. Falciparum
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insidious onset with malaise, headache and vomiting ( Flu – like )
•
cough and diarrhea are also common
•
The fever has no particular pattern
•
Jaundice is common
•
Hepatospleenomegaly and anemia developed rapidly
Cerebral Malaria
Cerebral Malaria is a grave complication manifested by coma or confusion, no localizing
sign and death
Other complication
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Hypoglycemia
•
pulmonary oedema
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acute renal failure
•
severe anemia
•
metabolic acidosis
•
aspiration pneumonia
•
shock
DIAGNOSIS:
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Thick blood film for diagnosis to show the blood stage of the parasite.
•
Thin blood film to identify the species of the parasite.
TREATMENT:
P. vivax, P. ovale and P. malarae:
•
Chloroquine 600 mg fallowed by 300 mg in 6 hours then 150 mg 12 hourly for 2 more
days.
TREATMENT
In P. vivax and P. ovale, radical cure and prevention of relapses can be achieved with
primaquine 15 mg daily for 14 days to destroy the hypnozoite phase in the liver.
P. falciparum:
• Because of chloroquine resistance, Quinine is the drug of choice given 600 mg /8 hr.
for 5 days fallowed by single dose of (( sulfadoxine 1.5 gm with pyrimethamin 75 mg
)) 3 tab. Of fansidar.
• In pregnancy, 7days course of quinine should be given alone
• In quinine resistant area, Malarone , 4 tab. Once daily for 3 days
Severe malaria
•
Severe malaria is a medical emergency and cerebral malaria is the most common cause
of death in malaria.
•
Quinine should be given i.v until the patient can take orally, active treatment of
complication with fluid and electrolyte correction.
•
Steroid has no role in treatment
PREVENTION:
1. Avoiding mosquito bites
• Long sleeves and trousers should be worn
• Use of mosquito nets
• Repellent creams and sprays
• Impregnation of bed nets with permethrin.
2. Chemoprophylaxis:
•
Chloroquine sensitive area:
Chloroquine 2 tab./ week & proguanil 1 tab. /day.
•
Moderate Chloroquine resistant areas:
Chloroquine 2 tab./ week & proguanil 2 tab. /day.
•
High chloroquine resistant areas:
Mefloquine I tab. Weekly or
Doxycycline 100 mg daily or
malarone 1 tab. Daily
3. Vaccination: still under trial.