Final answer:
Edema is swelling caused by the accumulation of excess fluid in the body's tissues and is the correct answer to the student's question. This condition can stem from various factors such as underlying illness, drug use, and physiological changes, and it often requires addressing the root cause for treatment.
Step-by-step explanation:
Edema is the correct answer to the description of a patient's arm being swollen with excessive fluid. Edema typically involves the accumulation of excessive fluid in the tissues, most commonly in the soft tissues of the extremities such as arms and legs. This condition can arise due to a variety of causes, including water leakage from blood capillaries due to underlying medical conditions, the use of certain therapeutic drugs, pregnancy, localized injuries, allergic reactions, or increased permeability caused by pro-inflammatory molecules released during bacterial infections.
A hallmark of edema is the swelling of the subcutaneous tissues, leading to an enlargement of the affected limb, and skin that appears stretched and tight. A simple clinical test to diagnose edema is the "pitting" test, where persistent indentation after pressing a finger into the swollen area suggests edema. Additionally, systemic factors such as hypervolemia can contribute to edema, seen in conditions like heart failure, liver cirrhosis, certain kidney diseases, hyperaldosteronism, and treatment with some glucocorticoid steroids. Treatments aim to tackle the underlying cause and restore homeostasis by reducing fluid retention.
Systemic edema can occur in more extensive body areas, mostly the lower extremities, where gravity encourages pooling of blood and fluids, exacerbating the swelling. Damage to blood vessels, a decrease in osmotic pressure in the blood due to a lack of plasma proteins as seen in liver diseases, can also lead to edema due to water loss from the capillaries into the tissues.