What are the clinical features of severe malaria?

Features of Severe Malaria

Severe malaria is characterized by depressed consciousness of any degree, active seizure activity, respiratory distress, and evidence of shock, representing a medical emergency requiring immediate intervention. 1

High-Risk Clinical Features

Neurological Manifestations

• Depressed conscious level (any degree) 1
• Active seizure activity 1
• Multiple convulsions (>2 seizures within 24h) 1
• Cerebral malaria with drowsiness, mental confusion, coma 1
• Prostration (inability to sit, stand, or walk without assistance) 1

Respiratory Manifestations

• Irregular respirations or obstructed airway (pooling saliva or vomit) 1
• Hypoxia (oxygen saturations <95%) 1
• Respiratory distress 1
• Acute respiratory distress syndrome (ARDS) 2
• Tachypnea or increased work of breathing 1

Cardiovascular Manifestations

• Evidence of shock: systolic blood pressure <80 mm Hg (<70 mm Hg in children <1 year) 1
• Associated signs of shock: tachycardia, cool peripheries, capillary refill time ≥3 seconds, temperature gradient 1
• Hypotension 1

Hematological Manifestations

• Severe anemia (hemoglobin <7 g/dL or hematocrit <20%) 1
• Hemorrhagic diatheses (bleeding from nose, gums, venipuncture sites) 1
• Thrombocytopenia 1

Metabolic Abnormalities

• Hypoglycemia (<3 mmol/L) 1
• Metabolic acidosis (base deficit >8 mmol/L) 1
• Hyperlactatemia (venous plasma lactate >5 mmol/L) 1
• Acidosis (pH <7.35 or plasma bicarbonate <15 mmol/L) 1

Renal Manifestations

• Hemoglobinuria, oliguria, or anuria 1
• Acute renal failure 1
• Elevated creatinine 1

Hepatic Manifestations

• Jaundice 1
• Visible jaundice with bilirubin >3 mg/dL (>50 μmol/L) 1
• Hepatic impairment 3

Parasitological Criteria

• Hyperparasitemia >5% (in non-immune subjects) 1
• Hyperparasitemia >10% (in semi-immune subjects) 1

Risk Stratification

High Risk (Immediate Risk of Death)

• Any of the above high-risk features 1
• Multi-organ failure 3

Intermediate Risk (Need for High Dependency Care)

• Hemoglobin <100 g/L 1
• History of convulsions during current illness 1
• Hyperparasitemia >5% 1
• Visible jaundice 1
• P. falciparum in a child with sickle cell disease 1

Diagnostic Approach

1. Blood Films: Thick and thin blood films remain the mainstay of diagnosis 1
2. Rapid Diagnostic Tests: Useful but can have false negatives with low parasitemia or non-falciparum species 1
3. Laboratory Tests: Complete blood count, renal function, liver function, blood glucose, arterial blood gas 1
4. Consider Lumbar Puncture: In patients with altered consciousness or repeated convulsions to rule out meningitis 1

Common Pitfalls and Caveats

• Severe malaria can develop 3-7 days after onset of fever, even after starting treatment 4
• Respiratory distress may develop in up to 25% of adults and 40% of children with severe falciparum malaria 2
• ARDS can develop several days after antimalarial treatment has begun 2
• Bacterial co-infections are common and should be considered, especially in patients not responding to antimalarial therapy 1
• Malaria should be considered in any patient with "flu-like symptoms" who has traveled to malarious areas within the past year 1
• Oral quinine and chloroquine should never be prescribed to treat falciparum malaria in children 1

Early recognition of these features and prompt initiation of appropriate treatment are crucial for reducing mortality in severe malaria.