Edema is due to EXCEPT?

Appeared in: AIIMS Rishikesh & Jodhpur NO - 2017

Explanation

The question asks to identify the factor that does NOT cause edema.
Edema is the accumulation of excess fluid in the interstitial space.
Hydrostatic pressure is the force that pushes fluid OUT of the capillaries.
A decrease in hydrostatic pressure would reduce the filtration of fluid into the tissues.
Therefore, decreased hydrostatic pressure would counteract or prevent edema, not cause it.

Option A: This is a primary cause of edema. Increased hydrostatic pressure (e.g., from heart failure or venous blockage) forces excess fluid out of the blood vessels into the surrounding tissues.
Option C: This is a direct cause of edema. When capillary walls become more permeable (e.g., during inflammation or allergic reactions), plasma proteins and fluid leak into the interstitial space, leading to swelling.
Option D: This is a major cause of generalized edema. Oncotic pressure, maintained by plasma proteins like albumin, pulls fluid back into the capillaries. When this pressure is reduced (e.g., in liver disease or nephrotic syndrome), fluid remains in the interstitial space.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pathophysiology of edema formation as background academic context rather than a clinical decision trigger.
Nurses frequently assess for edema, especially in patients with cardiac, renal, or liver conditions. Understanding the underlying cause helps in implementing appropriate interventions, such as administering diuretics to reduce hydrostatic pressure or monitoring albumin levels.
Assessment of pitting edema (grading from 1+ to 4+) is a key nursing skill to quantify the severity of interstitial fluid accumulation and track the effectiveness of treatment.
What if the patient had severe burns? In this case, the primary cause of edema would be a massive increase in capillary permeability, leading to significant fluid and protein loss into the interstitial space, requiring aggressive fluid resuscitation.

How to Approach the Question

First, identify the keyword "EXCEPT". This signals that you are looking for the option that is NOT a cause of edema.
Recall the basic principles of fluid exchange in capillaries (Starling's forces).
Evaluate each option: Does it promote or prevent fluid from moving into the interstitial tissue?
Option A (Increased hydrostatic pressure) pushes fluid out, causing edema.
Option C (Increased permeability) lets fluid leak out, causing edema.
Option D (Reduced oncotic pressure) weakens the force pulling fluid in, causing edema.

Concept Tested & Keywords

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E6 Pathology-Textbook of PATHOLOGYHarsh Mohan Part 1 (1-214) p. 184-186

E6 Medicine Harrison 22e Part 1 p. 320-322

Practise the full AIIMS Rishikesh & Jodhpur NO - 2017

Attempt every question from this paper in a timed mock, then review the full solution for each one.