Malaria assessment and treatment algorithm

Assessment

• Undertake a risk assessment for High Consequence Infectious Diseases (co-infection can occur) - see step 2 of Fever in Returning Traveller guidance.
• Treatment of malaria depends on species and severity of disease.
• All cases of malaria should be treated promptly including out of hours (OOH)
• Review for any signs of severe malaria (see table below). Severe malaria is a medical emergency.
• Discuss all cases with Infectious Diseases oncall (ID Oncall), including OOH.
• Positive malaria results are automatically reported to Public Health by the Laboratory.

Investigations for suspected or confirmed malaria

• Urgent blood film for malaria speciation & parasite count - including OOH. Notify site haematology biomedical scientist (BMS) of request.
• FBC, Coagulation screen, U&Es, LFTs, CRP, Venous blood gas, blood glucose, lactate.
• Blood cultures (ideally 2 sets adequately filled) to check for secondary bacteraemia.
• CXR (looking for signs of Acute Respiratory Distress Syndrome (ARDS)/Pulmonary oedema).
• Urinalysis (looking for haemoglobinuria).
• Pregnancy test (if relevant).
• G6PD levels (if vivax or ovale malaria confirmed).
• Consider Lumbar Puncture (LP) in patients with impaired consciousness or repeated seizures (to exclude meningitis).

Severe malaria criteria 

This is a medical emergency - treat immediately (see table below) and discuss early with Critical Care

• Impaired consciousness or seizures
• Renal impairment (oliguria <0.4 ml/kg bodyweight per hour or creatinine >265 mmol/l)
• Acidosis (pH < 7.3)
• Hypoglycaemia (<2.2 mmol/l)
• Pulmonary oedema or ARDS
• Haemoglobin ≤80 g/L
• Spontaneous bleeding / Disseminated Intravascular Coagulation (DIC)
• Shock (BP <90/60 mmHg)
• Haemoglobinuria (without G6PD deficiency)
• Parasitaemia >10% 

Other indications for intravenous therapy:

• Parasitaemia >2% 
• Pregnant (discuss with ID)
• Unable to swallow 

➡️ If any one of above present, process to severe malarial treatment.

➡️ If nil of these present proceed to non-severe malaria treatment guidance.

Treatment of severe malaria (all species)

* If IV Artesunate not immediately available, discuss urgently again with on call pharmacist and Infectious Diseases.

⁺See artesunate monograph in Medusa for details.

Review results of malaria blood film and RDT. Blood film shows: 

1. Falciparum malaria (Falciparum, mixed species, or species not characterised)

1. 1. If no criteria for severe disease present, go to Table 1.
   2. If vivax/ovale co-infection confirmed, go to Table 1 + Table 3.
   3. If treatment failure (recrudescence) go to Table 4.

2. Non-falciparum malaria (vivax, ovale, malariae, knowlesi).

1. 1. If no criteria for severe disease present, go to Table 2.
   2. If vivax or ovale, go to Table 2 + Table 3.

3. No evidence of malaria (a single negative film does not exclude malaria).

1. 1. Blood film daily for 2 more days.
   2. Malaria is unlikely with 3 negative films.
   3. See Fever in the returning traveller guidance.

Table 1: Treatment of uncomplicated falciparum malaria (oral)

* All pregnant and breast-feeding patients should be discussed with the ID consultant oncall and pharmacist.  

Table 2: Treatment of uncomplicated non-falciparum malaria (vivax, ovale, malariae, knowlesi)

* All pregnant and breast-feeding patients should be discussed with the ID consultant oncall and pharmacist. 

Table 3: Treatment to eradicate liver stage of vivax/ovale (hypnozoites)

Table 4: Management of treatment failure (recrudescence) in Falciparum malaria

Additional guidance for the ID team is available here.