Makindo Medical Notes.com

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Always consider falciparum malaria in anyone with a flu-like illness recently in an endemic area in the past 3 months and speak to the lab and specialists and send thick and thin films. Take expert Tropical disease or Infectious diseases help early. A patient with a flu-like illness and Falciparum malaria can die before the post take ward round so it will be on the first contact to take a history and consider the diagnosis.

About: See BNF for Current Treatment

• Falciparum malaria can kill within hours and the presentation can be vague and it should be suspected in all coming from an endemic area within the past 3 months.
• Red cell involved > 2% is severe

Anopheles female blood feeding and Plasmodium falciparum eggs in Anopheles mosquito midguts.

Aetiology

• Infection by a protozoan parasite found in tropics and subtropics
• Malaria in the UK is an imported disease but there is evidence that it was once indigenous
• Spread is from the female Anopheles mosquito or sometimes from infected blood or imported mosquitos e.g. near airports
• Rosetting is another finding where infected cells adhere to uninfected RBC's.

Cytoadherence

• Lethal form is plasmodium falciparum
• Mechanism is possibly through the process of cytoadherence
• Infected red cells adhere to the walls and block post capillary venules
• Formation of P. falciparum erythrocyte membrane protein (PfEMP)-1.

Epidemiology

• Kills 1 million humans year after year
• Mostly in Africa but also SE Asia and South America Amazon region

Steps

• Sporozoites enter via skin from feeding mosquito enter the liver and become merozoites
• Multiply in the liver and then hepatocyte ruptures releasing merozoites which enter RBCs
• Further steps until erythrocytes ruptures and/or adhere to vascular endothelium with organ damage brain, gut, liver, kidney

Clinical

• Flu like - malaise fever and headache, Rigors
• Severe cerebral malaria - coma, fits, paralysis - hemiparesis, blindness
• Mild hepatosplenomegaly may be found

Complications

• Reduced GCS and seizures and coma
• Acute renal failure: dialysis in 10%
• Metabolic acidosis
• Parasitaemia = 10%
• Hypoglycaemia
• Intravascular haemolysis, Jaundice
• Oliguria, Haemoglobinuria "Blackwater fever"
• DIC: D-Dimers, low platelets and FDP's elevated
• Non cardiogenic pulmonary oedema and ARDS
• Anaemia Hb =8g/dl

Investigations

• FBC, U&E, CRP, LFT, Glucose, Lactate
• Blood culture, Urine culture, Stool culture
• CXR: pneumonia
• COVID test may be indicated
• Blood films ask for 3-5 thick and thin blood film examinations over 48 hours to exclude malaria
  • Thick films x3 to identify parasite infection repeated
  • Thin Giemsa-stained blood films x 3 show the number of red cells infected and type
  • A high parasite count >5 % indicates an increased risk of cerebral malaria. Determine the species of Plasmodium
  • Pre-schizont forms indicate an increased risk of cerebral malaria.
• Raised IgM and marked splenomegaly and anaemia with chronic infection
• Rapid Antigen detection tests

Differentials: NB patients can have more than one infection

• Dengue
• Schistosomiasis
• Tick typhus
• Typhoid
• Tuberculosis
• Dysentery
• Influenza
• Viral Pneumonia
• Bacterial Pneumonia
• HIV infection
• Bacterial sepsis - chest and urine
• Bacterial meningitis

Management: See BNF for Current Treatment

• Uncomplicated Falciparum Malaria (Oral treatment)
  • Quinine given by mouth for 5-7 days, together with or followed by either doxycycline for 7 days or clindamycin for 7 days
  • Malarone (atovaquone with proguanil hydrochloride)
  • Riamet (artemether with lumefantrine)
• Complicated Falciparum Malaria
  • ABCDE, Support in HDU/ITU
  • Watch out for hypoglycaemia and give IV glucose if needed
  • Strict fluid balance must be kept and monitor with urine output
  • If the patient is seriously ill or unable to take tablets, or if more than 2% of red blood cell are parasitized then either
    • IV Artesunate 2.4 mg/kg at 0,12,24 hours may be available for named-patient use. Especially difficult cases (e.g. very high parasite count, deterioration on optimal doses of quinine, infection acquired in quinine-resistant areas of south-east Asia)
    • Quinine Sulfate 20 mg/kg IV loading over 4 hours then reduce to 10 mg/kg every 8 hours for 7 days. Given in IV Dextrose. Continue until oral therapy can be started. Can then start Quinine 600 mg TDS to give a full 7-day course. In total, one needs to complete a 7-day course together with or followed by either Doxycycline 200 mg PO for 7 days or Clindamycin.
  • Beware hypoglycaemia induced by the infection and quinine
  • Treat any suspected bacterial super infection
• Pregnancy
  • Falciparum malaria is particularly dangerous in pregnancy
  • Most dangerous in the last trimester.
  • Can use Oral and intravenous quinine
  • Clindamycin should be given after quinine. Do not give Doxycycline if pregnant.
  • Specialist advice in difficult cases as Artesunate may be considered
• Advice
  • PHE (Public Health England) Malaria Reference Laboratory (020) 7637 0248 (fax) (prophylaxis only) www.malaria-reference.co.uk
  • National Travel Health Network and Centre 0845 602 6712
  • Monday - Friday (closed Wednesday afternoons and Bank Holidays): 09:00 to 11:45 and 13:00 to 15:45
  • Travel Medicine Team, Health Protection Scotland (registered users of Travax only) www.travax.nhs.uk (for registered users of the NHS Travax website only) (0141) 300 1100 (weekdays 2 to 4 p.m. only)
  • Birmingham (0121) 424 2358, Liverpool (0151) 705 3100
  • London 0845 155 5000 (treatment), Oxford (01865) 225 430