MCQ – 10905

Which organ is NOT typically affected by Plasmodium falciparum infection?

Correct Answer » A Explanation

linical Reasoning for the Correct Answer:
– *Plasmodium falciparum* primarily targets organs with high microvascular flow and where sequestration of parasitized red blood cells (RBCs) occurs.
– Commonly affected organs include the liver, kidneys, and lungs, which show typical pathological changes and complications in severe malaria.
– The heart is notably spared from significant direct involvement during falciparum malaria.

Why Option A (Heart) is Correct:
– Myocardial involvement is extremely rare in malaria; the heart is not a common site for sequestration of infected RBCs.
– No classic clinical syndrome of malaria involves direct cardiac injury or failure attributable to *P. falciparum*.
– If cardiac failure occurs, it is indirect (e.g., due to metabolic derangement or volume overload), not from primary heart pathology.

Why Option B (Liver) is Incorrect:
– The liver is involved in both the exoerythrocytic (hepatic) and erythrocytic cycles of *Plasmodium* species.
– Hepatosplenomegaly and liver dysfunction (mild jaundice, elevated transaminases) are common in falciparum malaria.

Why Option C (Lungs) is Incorrect:
– Pulmonary complications (e.g., acute respiratory distress syndrome—ARDS, pulmonary edema) are recognized in severe falciparum malaria.
– Lung involvement results from sequestration of parasitized RBCs and increased vascular permeability.

Why Option D (Kidney) is Incorrect:
– Renal involvement is well-documented, often manifesting as acute kidney injury (AKI), acute tubular necrosis, or “blackwater fever.”
– Kidneys are frequent sites of microvascular obstruction by parasitized red blood cells.

High‑Yield Synopsis:

Pathogenesis & Affected Organs
– *Plasmodium falciparum*: most severe form of malaria due to cytoadherence, causing microvascular obstruction.
– Key organs affected:
– Brain (cerebral malaria: altered mental status, seizures)
– Kidneys (AKI, hemoglobinuria)
– Liver (jaundice, hepatomegaly)
– Lungs (ARDS, pulmonary edema)

Organs Typically Spared
– Heart: rarely affected, no significant myocarditis or failure directly caused by malaria.

Differential Organ Involvement
– Most visceral organs with microcirculatory beds can be affected, except the heart.
– Cardiac complications are uncommon and not a feature of the disease’s primary pathology.

Diagnostic Clues
– Combination of fever, anemia, thrombocytopenia, multi-organ dysfunction in endemic areas.
– Evidence of multiple organs affected seen in severe cases (particularly P. falciparum).

Management & Prognosis
– Prompt recognition and management of complications in affected organs is critical.
– Cardiac support is rarely required; focus remains on renal, hepatic, and respiratory complications.