What is the workup and treatment for suspected malaria?

Workup and Treatment for Suspected Malaria

The diagnosis of malaria requires urgent blood film examination (thick and thin smears) as the mainstay of diagnosis, followed by immediate treatment with appropriate antimalarials based on species identification and severity assessment. 1

Diagnostic Approach

Initial Assessment

• Consider malaria in any patient with fever who has traveled to an endemic area
• Key symptoms to evaluate:
  • Fever (often cyclical)
  • Headache, malaise, myalgias
  • Gastrointestinal symptoms (nausea, vomiting, diarrhea)
  • Respiratory distress
  • Altered consciousness or seizures
  • Jaundice

Laboratory Diagnosis

1. Blood Films (Gold Standard) 1

   • Thick and thin blood films with Giemsa stain
   • Process from EDTA sample
   • Direct liaison with laboratory to ensure urgent processing
   • Three negative thick blood films taken 12 hours apart generally exclude malaria

2. Rapid Diagnostic Tests (RDTs) 1, 2

   • Complement microscopy, especially in patients with:
     • Low-density parasitemia
     • Those who have taken prophylaxis
   • Reduce time to first malaria test result by approximately 2 hours 2
   • Should be confirmed with microscopy

3. Additional Laboratory Tests 3

   • Complete blood count (look for anemia, thrombocytopenia)
   • Renal and liver function tests
   • Blood glucose (hypoglycemia is common)
   • Arterial blood gas (for metabolic acidosis)

Severity Assessment

High Risk/Severe Malaria (Requires Immediate Treatment) 1, 3

• Depressed conscious level (any degree)
• Active seizure activity
• Respiratory distress or hypoxia (O₂ saturation <95%)
• Shock (SBP <80 mmHg or <70 mmHg in children <1 year)
• Hypoglycemia (<3 mmol/L)
• Metabolic acidosis (base deficit >8 mmol/L)
• Severe anemia (Hb <7 g/dL)
• Hyperparasitemia (>5%)
• Acute kidney injury
• Jaundice

Intermediate Risk 1

• Hemoglobin <100 g/L
• History of convulsions during current illness
• Hyperparasitemia >5%
• Visible jaundice
• P. falciparum in a patient with sickle cell disease

Treatment Protocol

Severe Malaria

1. First-line treatment: Intravenous artesunate 1, 3, 4

   • Administer for 3 doses
   • Monitor parasitemia every 12 hours until decline to <1%, then every 24 hours until negative

2. Alternative: Intravenous quinine 3

   • 20 mg/kg loading dose followed by 10 mg/kg every 8 hours
   • Monitor for QT prolongation and hypoglycemia

3. Switch to oral therapy when:

   • Patient is clinically improved
   • Parasitemia <1%
   • Patient can tolerate oral medication
   • Complete full course of chosen oral ACT (Artemisinin-based Combination Therapy)

Uncomplicated Malaria

1. P. falciparum or unknown species:

   • First choice: Oral ACT 1, 4
   • Alternatives:
     • Atovaquone-proguanil: 4 tablets (adult strength) once daily for 3 days 5, 4
     • Quinine (if ACT unavailable): 648 mg every 8 hours for 7 days with food 6

2. P. vivax, P. ovale, P. malariae, P. knowlesi:

   • Chloroquine (if from chloroquine-sensitive region) or ACT 4
   • For P. vivax and P. ovale: Add primaquine or tafenoquine to eliminate liver hypnozoites 1

Management of Complications

• Seizures: Treat with lorazepam 0.1 mg/kg IV/IO 3
• Shock: Administer 20 ml/kg of colloid or 0.9% saline 3
• Hypoglycemia: Correct with IV glucose
• Severe anemia: Consider blood transfusion
• Fluid management: Restrictive approach to avoid pulmonary or cerebral edema 1
• Renal protection: Consider acetaminophen 1g every 6 hours for 72 hours 1

Monitoring and Follow-up

For Severe Malaria 1

• Continuous monitoring of:
  • Cardiocirculatory parameters
  • Pulmonary function
  • Renal function
  • Metabolic parameters (glycemia, bicarbonate, lactate)
• Monitor for delayed hemolysis (PADH) at days 7,14,21, and 28

For Uncomplicated Malaria 1

• Check parasitemia on day 3 (expect 75% reduction)
• Check parasitemia on day 7 (expect negative result)
• Advise patients from areas with resistant parasites about possibility of recurrent infection

Common Pitfalls to Avoid

1. Delayed diagnosis: Consider malaria in any febrile patient with travel history to endemic areas
2. Inadequate species identification: Different species require different treatment approaches
3. Missing severe malaria: Careful assessment for severity criteria is essential
4. Inadequate monitoring: Frequent reassessment is needed as complications can develop rapidly
5. Overlooking co-infections: Consider bacterial co-infections, especially if not responding to antimalarial therapy

Remember that malaria is a potentially life-threatening but treatable disease, and prompt diagnosis with appropriate treatment is crucial to prevent morbidity and mortality.