Final answer:
The cause of abnormal accumulation of fluid in the intercellular spaces can be poor lymph drainage, heart failure, or increased capillary permeability. These factors can disrupt the normal fluid balance in the body and lead to fluid buildup in the tissues.
Step-by-step explanation:
The cause of abnormal accumulation of fluid in the intercellular spaces is usually due to poor lymph drainage, heart failure, or increased capillary permeability. Poor lymph drainage can occur when the lymphatic system is blocked or damaged, preventing the excess fluid from being drained properly. Heart failure can lead to fluid accumulation because the heart is unable to pump blood effectively, resulting in increased pressure in the blood vessels. Increased capillary permeability can be caused by inflammation or damage to the blood vessels, allowing more fluid to leak into the intercellular spaces.