Which of the following is most severely affected in Kala-azar?

RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Pathology & Genetics

Easy

Appeared in: RUHS, Jaipur, PB B.Sc Nursing Entrance-2020

Explanation

Kala-azar, or Visceral Leishmaniasis, is caused by parasites that target the reticuloendothelial system.
The spleen is the most heavily infiltrated organ, leading to massive splenomegaly, which is the most prominent and defining clinical feature of the disease.
The parasite, Leishmania donovani, multiplies extensively within the macrophages of the spleen, causing it to become hugely enlarged.
While other organs like the liver and bone marrow are also affected, the spleen shows the most severe gross pathological changes.

Option A: The liver is affected in Kala-azar, resulting in hepatomegaly. However, the enlargement is typically described as moderate and is less pronounced than the massive splenomegaly observed.
Option C: The adrenal glands are not a primary target for the Leishmania parasite and are not significantly affected in Kala-azar.
Option D: The bone marrow is significantly affected, leading to the replacement of hematopoietic tissue with parasitized macrophages. This causes pancytopenia (anemia, leukopenia, thrombocytopenia), a major cause of morbidity and mortality. However, in terms of gross anatomical change and parasitic load, the spleen is considered the most severely affected organ.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Organ involvement in Kala-azar (Visceral Leishmaniasis) as background academic context rather than a clinical decision trigger.
Abdominal palpation to assess for splenomegaly is a crucial part of the physical examination for a patient suspected of having Kala-azar, especially in endemic areas.
The massive enlargement of the spleen makes it fragile and susceptible to rupture, which can be a life-threatening complication. Nurses must handle patients with care and educate them to avoid abdominal trauma.
What if? If a patient presents with fever and pancytopenia but only moderate splenomegaly, the differential diagnosis would broaden significantly to include other conditions like malaria, typhoid fever, lymphoma, or leukemia, requiring further specific diagnostic tests to differentiate from Kala-azar.

How to Approach the Question

First, identify the key terms in the question: 'Kala-azar' and 'most severely affected'.
Recall the pathophysiology of Kala-azar (Visceral Leishmaniasis). The disease is characterized by the invasion of the reticuloendothelial system by the Leishmania parasite.
Consider the primary organs of the reticuloendothelial system: spleen, liver, and bone marrow.
Compare the typical extent of involvement for each organ. Remember that massive splenomegaly is the hallmark clinical sign of Kala-azar.
Based on this key feature, conclude that the spleen is the most severely affected organ in terms of gross pathological change and parasitic burden.

Concept Tested & Keywords

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E6 Medicine Davidson Principles Practice 24e p. 302-304

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