Platelet count decreases in

RRB Staff Nurse Jaipur-6th June 2018

Pathology & Genetics

Easy

Appeared in: RRB Staff Nurse Jaipur-6th June 2018

Explanation

Dengue fever is a viral illness where a low platelet count (thrombocytopenia) is a defining characteristic.
The dengue virus leads to thrombocytopenia through two main mechanisms: suppression of platelet production in the bone marrow and increased destruction of platelets in the bloodstream by the immune system.
This rapid drop in platelets is a critical marker for monitoring the severity of the disease and the risk of progressing to Dengue Hemorrhagic Fever (DHF).

Option A: While malaria can cause mild to moderate thrombocytopenia, its primary and most well-known hematological effect is the destruction of red blood cells, leading to anemia.
Option B: Filaria is a parasitic infection that primarily affects the lymphatic system, causing conditions like lymphedema (elephantiasis). It is not characteristically associated with a decrease in platelet count.
Option D: Typhoid fever, caused by Salmonella typhi, is more commonly associated with leukopenia (a decrease in white blood cells). While thrombocytopenia can occur, it is not a hallmark feature as it is in dengue.

Visual 1: Chart: Depicting the typical triphasic pattern of platelet count during Dengue fever (initial decrease, nadir during the critical phase, and subsequent recovery).
Visual 2: Infographic: Comparing the key lab findings in Dengue (thrombocytopenia, leukopenia, rising hematocrit), Malaria (anemia, parasites on smear), and Typhoid (leukopenia, positive culture).
Visual 3: Image: Clinical photograph of petechiae on a patient's skin, a common manifestation of low platelet counts in Dengue.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Hematological manifestations of common infectious diseases as background academic context rather than a clinical decision trigger.
Monitoring the platelet count is a crucial nursing responsibility in managing Dengue patients. A rapid drop below 100,000/μL is a warning sign for potential progression to severe dengue.
Nurses must educate patients to avoid NSAIDs like aspirin or ibuprofen for fever, as these drugs can further impair platelet function and increase bleeding risk.
Patient and family education on recognizing warning signs of bleeding (e.g., gum bleeding, nosebleeds, black stools, skin rashes) is vital for early intervention.

How to Approach the Question

First, understand the question is asking for the disease most characteristically associated with a decreased platelet count.
Recall the primary hematological manifestations of each of the four infectious diseases listed.
Consider Malaria: It's known for causing anemia due to red blood cell destruction.
Consider Filaria: It's a lymphatic system disease, causing lymphedema, not primarily a blood cell disorder.
Consider Typhoid: It's typically associated with a low white blood cell count (leukopenia).
Consider Dengue: Recall that thrombocytopenia is a hallmark of Dengue fever and is used to monitor disease severity and risk of complications.

Concept Tested & Keywords

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