Plasmodium falciparum Malaria

Introduction

• Malaria: Mosquito-borne disease caused by protozoa (Plasmodium falciparum, P. vivax, P. malariae, P. ovale, P. knowlesi).
• P. falciparum responsible for over 90% of malaria mortality globally.
• WHO estimated 228 million cases globally in 2018 with 405,000 deaths.

Etiology

• Transmitted by female Anopheles mosquitoes, which inject sporozoites into the bloodstream.
• Sporozoites infect liver cells, develop into merozoites, which then infect red blood cells, causing symptomatic infection.
• P. falciparum modifies infected RBCs to avoid spleen’s immune response, leading to complications.

Epidemiology

• Global: Concentrated in sub-Saharan Africa and parts of Asia.
• USA: Most cases are imported; rising trend due to increased travel.
• Risk Groups: Children under 5, pregnant women, travelers to endemic areas.

Pathophysiology

• Symptoms arise from the asexual reproduction of parasites in blood.
• Key virulence factor: P. falciparum erythrocyte membrane protein 1 (PfEMP1) causing RBC adhesion and sequestration.

Clinical Features

History and Physical Examination

• Incubation of 12 days; symptoms can range from mild to severe.
• Uncomplicated Malaria: Fever, chills, myalgia, headache, anorexia.
• Severe Malaria: Impaired consciousness, respiratory distress, convulsions, jaundice, acidosis.

Children and Pregnant Women

• Children: Gastrointestinal symptoms, hepatosplenomegaly, seizures.
• Pregnant women: Severe cases can lead to anemia, low birth weight, pulmonary edema.

Evaluation

• Immediate laboratory testing; microscopy is the golden standard.
• Thick and thin blood smears for parasitemia quantification.
• Rapid diagnostic tests (RDTs) and PCR also used.

Treatment and Management

• Uncomplicated Malaria: Artemisinin-based combination therapies (ACT) are preferred.
• Severe Malaria: Intravenous artesunate; intensive monitoring is needed.
• Supportive therapy includes fluid management, glucose, and seizure control.

Differential Diagnosis

• Needs differentiation from other travel-related infections like typhoid, dengue, viral infections.

Prognosis

• Uncomplicated cases have low mortality.
• Severe malaria has higher mortality, especially in children and pregnant women.

Complications

• Cerebral malaria, acute kidney injury, pulmonary edema, hypoglycemia.

Prevention and Education

• Personal protective measures and chemoprophylaxis are key.
• Education on mosquito avoidance and travel precautions.
• Compliance with antimalarial prophylaxis is crucial.

Advances and Future Directions

• Vaccine development ongoing; RTS,S/ASO1 is a promising candidate.
• Addressing insecticide resistance in mosquito populations.

Interprofessional Collaboration

• Importance of prevention and education in healthcare settings.
• Early recognition and treatment are crucial for patient outcomes.

These notes cover the essential aspects of Plasmodium falciparum malaria including its transmission, pathology, clinical presentation, treatment, and prevention strategies, providing a comprehensive overview for educational purposes.