Malaria

Notes
  • Malaria is a parasitic disease that is caused by Plasmodium falciparum (≥ 90% in most parts of Kenya), malarie, P.ovale and P.vivax (40-50% in Northern Kenya).
  • The malarial parasites are transmitted by the female anopheles mosquito.
  • Malaria kills about 655,000 people globally (mainly children below 5 years) of which 90% are in Africa.
  • Transmission of plasmodium ssp:

_A female anopheles mosquito feeds on an infected person and ingests blood containing gametocytes.

_After 1-2 wk(s) gametocytes produce sporozoites sexually.

_Sporozoite-infected mosquito feeds on another person

_Sporozoites infect hepatocytes and mature into tissue schizonts

_Each schizont produces 10,000 to 30,000 merozoites

_The merozoite-infected hepatocyte rupture releasing merozoites into blood stream

_The released merozoites invade the Red Blood Cells

_They are transformed into trophozoites which grow and develop into erythrocyte schizonts that in turn produce more merozoites.

_The merozoites then  rupture the RBC and are released in plasma after 48-72hrs.

_The released merozoites invade new RBCs, repeating the cycle.

_Some of the trophozoites develop into gametocytes.

_In the gut of the mosquito gametocytes which develop into oocysts and later released as sporozoites that migrate to the salivary glands.

Symptoms

Uncomplicated Malaria

  • Paroxysms of fever, chills, rigor and sweating.
  • Abdonminal discomfort, nausea, vomiting and diarrhea.
  • Headache
  • Joint pains and myalgia

Severe Malaria

  • As described under “uncomplicated malaria”
  • Parasitemia (200,000 parasites /uL in high endemic areas and 100,000 parasites /uL in low endemic areas)
  • High fevers (temperature above 39 0C)
  • Oliguria
  • Cerebral malaria (manifested as confusion, stupor, coma and convulsions)
  • Jaundice
  • Hypovoleamic shock.
  •  
  • Pulmonary edema.
  • Hypoglycaemia, where blood glucose can be lower than 2.2mmol/L
  • Complications of Malaria
  • Anemia with HB of less that 5gm/dL
  • Electrolyte imbalance.
Diagnosis
  • Thick blood smear (more sensitive but cannot identify the type of plasmodium better)
  • Thin blood smear (less sensitive but can identify the type of plasmodium better; also better for parasitic count and determination of morphology of RBC).
  • Malaria Rapid Diagnostic Tests (RDTs)
  • HB
  • Blood sugar
  • Urinalysis

**Do NOT assume absence of malaria in BS negative cases.

**Consider possibility of other diseases with similar presentations to severe malaria e.g.meningitis).  

Differential
  • African Trypanosomiasis
  • Amoebic liver abscess
  • Bacteremia
  • Babesiosis
  • Brucellosis
  • Dengue
  • HIV seroconversion
  • Infective Endocarditis
  • Infectious mononucleosis
  • Influenza
  • Leptospirosis
  • Meningitis
  • Other viral infections
  • Pulmonary TB
  • Schistosomiasis
  • Toxic Shock Syndrome
  • Typhoid Fever
  • Yellow fever
Prevention
  • Use of long lasting insecticide-treated nets (LLINS)
  • Indoor residual spraying (IRS)
  • Advise the community to be covering their exposed skin in the evenings
  • Advise the community to be seeking early treatment of fevers.
Management

Therapeutics guided by Essential Drug List consideration

Antimalarials in the Essential Drug List:

  • Artemether oily injection 80mg/mL
  • Artemether-Lumefantrine (20mg/120mg)
  • Quinine 300mg (bisulphate or sulphate)
  • Doxycycline 100mg caps
  • Dihydroartemesinin 40mg / piperaquine 320mg (complementary list).
  • Sulphadoxine / Pyrimethamine (for prophylaxis)

Uncomplicated Malaria

  • Artemether-lumefantrine [AL]
  • For the Artemether 20mg/Lumefantrine 120mg tablets:

*Adults: 4 tablets stat, then 4 after 8hrs, then 4BD x 2/7 [24 tablets].

*5-15kg: 1 tablet stat, then 1 after 8 hrs, then 1 BD x 2/7 [total = 6 tablets].

*15- 25kg: 2 tablet stat, then 2 after 8hrs, then 2 BD x 2/7 [to-tal = 12 tablets].

*5- 15kg: 3 tablet stat, then 3 after 8hrs, then 3 BD x 2/7 [total = 18 tablets].

In the event of vomiting within I hr of administration a repeat dose should be taken.

For the Artemether 80mg/Lumefantrine 480mg tablets:

*Adults: One tablet BD x 3/7.

Supportive Rx with NSAIDs.

Management of treatment failure (defined as deterioration of clinical conditions or symptoms persisting for more than 3-14 days).

Either,

Quinine tablets: 10mg/kg body weight TID x 1/52

Or

Dihydroartemesinin 40mg / piperaquine 320mg  [DHQ-PPQ].

Patient above 16yrs: day 1(3 tabs); day 2 (3 tabs); day 3 (2 tabs). 11-16yrs: day 1(2 tabs); day 2 (2 tabs); day 3 (2 tabs). 6-11yrs: day 1(1.5 tabs); day 2 (1.5 tabs); day 3 (1 tab)

Failure to complete 1st treatment: repeat full dose of AL.

Treatment of uncomplicated P.vivax infection: AL and primaquine 15mg daily for 14 - 21 days

Rx of severe malaria in patients who  cannot tolerate oral Rx:

In situations where  quinine IV infusion cannot be given

Either,

Quinine, loading dose of 20mg/kg IM  followed by the maintenance dose of  10mg/kg 8hrly IM.

Or,

Artemether, loading dose of 3.2mg/kg IM  followed by the maintenance dose of  1.2mg/kg OD IM until the patient can take oral therapy when  a full dose of ALis given.

**Nasal Gastric tube can be used as well to administer oral doses of quinine.

In situations where quinine IV infusion can be given

Quinine, loading dose of 20mg/kg IV infusion in 500mL 5% dextrose for 4hrs  followed by the maintenance dose of  10mg/kg 8hrly in 500mL 5% dextrose for 4hrs until the patient can take oral therapy when  a full dose of ALis given or quinine tablets, 10mg/kg body weight TID,  to complete the remaining days to ensure a total of 7 day treatment with quinine.

Management of conditions associated with severe malaria

Hypoglycemia: 50% dextrose (1mL/kg)

Oliguria: Monitor urinary output (it should be above  30mL/hr. Otherwise, give frusemide 40-80mg IV STAT.

Convulsion: diazepam 0.3mg/kg IM or IV or rectally 0.5mg/kg

Malaria chemoprophylaxis

Situations where chemoprophylaxis is required include:

Pregnancy: Intermittent preventive therapy (IPTp) using Sulfadoxine / pyrimethamine (SP): It is given during antenatal visits at curative dose of 3 tabs at least twice during pregnancy, once at the second trimester and once at least 1 month after the first treatment.

Non-immune visitors  to malaria endemic areas: Mefloquine tablets 250mg (not in the Essential Drug List) weekly from 2 week before travelling and for at least 4 weeks after travelling.

Children with impaired immunity such as leukemia and HIV.

Sickle cell disease or Thalassemia. (Malaria is known to be the most common precipitating cause of crises in sickle cell disease in malaria-endemic areas): weekly pyrimethamine dose (not in the Essential Drug List).

Therapeutics using drugs that are NOT in the Essential Drug List

Antimalarials that are NOT in the Essential Drug List

  • artesunate / amodiaquine tablets
  • Primaquine for elimination of the liver stage of Vivax and P. Ovale at a dose of 15mg daily for 14 - 21 days (used together with AL)
  • Proguanil for chemoprophylaxis of malaria at the following doses: Adults: 2 tabs daily. Under 1yr: ¼ tab, 1-4yrs: ½ tab, 5-8yrs: 1 tab, 9-14yrs: 1½ tabs [1 week before travelling and for at least 4 weeks after travelling]
  • Proguanil/Atovaquone for acute uncomplicated falciparum malaria and prophylaxis of falciparum malaria especially when resistance to classical anti-malarials is suspected but its use is limited by its high price. It is used in the following dose: Treatment, 11-20kg: 1 tab OD, 21-30kg: 2 tabs OD, 31-40kg: 3 tabs OD, over 41kg: 4 tabs OD. All are taken for 3 days.
  • Doxycycline and clindamycin are the antibiotics .of choice. They are normally administered in full dosage as that of bacterial infections when used as adjuncts in the treatment of malaria. In prophylaxis against malaria, doxycycline is administered at the dose of 100mg OD
  1. Monitoring of patients
    • Daily monitor of parasiteamia (to show the decline)
    • Blood sugar

HB (if below 5gm/dL and there are signs of cardiorespiratory distress transfuse blood)

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