**Question:** Avascular necrosis of bone is most common in

A. Patients with long-term corticosteroid use
B. Alcoholics
C. Diabetics
D. Patients with sickle cell anemia

**Core Concept:**
Avascular necrosis (AVN), also known as osteonecrosis or necrosis of bone, is a condition characterized by the death of bone tissue due to a sudden or gradual reduction in blood supply. This can lead to severe pain, deformity, and disability if left untreated. The term "avascular" emphasizes the lack of blood supply to the affected bone, while "necrosis" refers to cell death.

**Why the Correct Answer is Right:**
The correct answer, A, highlights the long-term corticosteroid use as a significant risk factor for developing avascular necrosis of bone. Corticosteroids, particularly high-dose and prolonged use, can lead to impaired blood flow to bone tissue, causing damage to bone cells and eventually death.

**Why Each Wrong Option is Incorrect:**

B. Alcoholism: Although excessive alcohol consumption can damage blood vessels and increase the risk of peripheral vascular disease, it is not the primary cause for avascular necrosis of bone. Long-term corticosteroid use is a more direct contributor to this condition.

C. Diabetes: While diabetes can have various complications, including impaired wound healing and increased risk of infections, it is not a primary risk factor for avascular necrosis of bone. The primary cause is typically related to factors that compromise blood flow to the bone, such as corticosteroid use.

D. Sickle cell anemia: Although sickle cell anemia can lead to bone deformities and pain, it is not primarily responsible for avascular necrosis of bone. The condition occurs more frequently in patients receiving high-dose corticosteroid therapy.

**Clinical Pearl:**

Avoiding corticosteroid therapy and monitoring patients for potential side effects, including avascular necrosis, is crucial in primary care. In case of medication administration, discussing the potential risks with patients and monitoring for early signs of avascular necrosis (e.g., pain, deformity, and decreased range of motion) can help identify the condition early and initiate appropriate management, which may include corticosteroid cessation or dose reduction.

**Correct Answer:** A (Long-term corticosteroid use)