A 28-year-old woman from Assam with malaria develops severe headache, altered mental status, and seizures. Which is the most common organ system affected in severe malaria?

Explanation

## Severe Malaria Complications: Organ System Involvement **Key Point:** Cerebral malaria (CNS involvement) is the most common and most severe complication of malaria, occurring in 1–3% of P. falciparum infections. It carries a mortality rate of 15–20% even with treatment. ### Frequency of Severe Malaria Complications | Complication | Frequency | Mortality (%) | Mechanism | |--------------|-----------|---------------|----------| | **Cerebral malaria** | Most common | 15–20% | Sequestration, RBC rosetting, cytokine storm | | **Acute kidney injury** | Common | 5–10% | Acute tubular necrosis, hypovolemia | | **Pulmonary edema/ARDS** | Moderate | 10–15% | Increased vascular permeability | | **Severe anemia** | Common | 2–5% | Hemolysis, RBC destruction | | **Hepatic dysfunction** | Less common | 1–3% | Hepatocellular injury | **High-Yield:** Cerebral malaria is defined by: 1. **Unrousable coma** (Glasgow Coma Scale ≤9) in the presence of P. falciparum parasitemia 2. **No other cause** of coma (hypoglycemia, electrolyte abnormality, post-ictal state must be excluded) 3. **Rapid progression** from fever to altered consciousness ### Pathophysiology of Cerebral Malaria ```mermaid flowchart TD A[P. falciparum infection]:::outcome --> B[Infected RBC sequestration in brain microvasculature]:::action B --> C[Rosetting & cytoadherence]:::action C --> D[Endothelial activation & BBB disruption]:::action D --> E[Cytokine release TNF-α, IL-1, IL-6]:::action E --> F[Cerebral edema & increased ICP]:::action F --> G[Altered mental status, seizures, coma]:::outcome G --> H{Treatment initiated?}:::decision H -->|Yes| I[Artesunate IV/IM]:::action H -->|No| J[Neurological sequelae or death]:::urgent ``` **Clinical Pearl:** Cerebral malaria can present with: - Prodromal fever followed by sudden altered consciousness - Generalized seizures (common in children) - Posturing, pupillary abnormalities - Retinal hemorrhages (pathognomonic but not required for diagnosis) **Mnemonic:** **SEVERE MALARIA** complications: - **S**eizures, **S**evere anemia - **E**ncephalopathy (cerebral malaria) - **V**ascular collapse (shock) - **E**dema (pulmonary) - **R**enal failure - **E**lectrolyte disturbance ### Why Cerebral Malaria is Most Common 1. P. falciparum-infected RBCs preferentially sequester in brain microvasculature 2. Occurs early in severe malaria (often within 24–48 hours of symptom onset) 3. Affects 1–3% of P. falciparum cases but is the leading cause of death in severe malaria [cite:Harrison 21e Ch 219]