A patient of nephrotic syndrome taking steroids for 6 years presented with a limp gait and limitation of abduction and internal rotation. He MOST probably has:
**Core Concept**
Steroid-induced osteonecrosis of the femoral head is a well-known complication of prolonged steroid use, particularly in patients with nephrotic syndrome. This condition is characterized by the death of bone tissue due to inadequate blood supply, leading to joint pain and limited mobility.
**Why the Correct Answer is Right**
The patient's symptoms of limp gait, limitation of abduction, and internal rotation are classic signs of femoral head osteonecrosis. This condition occurs due to the disruption of blood supply to the femoral head, which is exacerbated by long-term steroid use. The steroids have a negative effect on bone metabolism, reducing the production of osteoblasts and increasing the activity of osteoclasts, leading to bone resorption and decreased blood flow to the femoral head.
**Why Each Wrong Option is Incorrect**
**Option A:** Other causes of hip pain in patients with nephrotic syndrome, such as septic arthritis or avascular necrosis of the femoral head, are less likely given the patient's prolonged steroid use and specific symptoms.
**Option B:** Avascular necrosis of the femoral head is the correct diagnosis in this scenario, making option B incorrect as it is a synonymous term for the correct answer.
**Option D:** While osteoporosis is a potential side effect of long-term steroid use, it does not typically present with the specific symptoms of limp gait and limitation of abduction and internal rotation.
**Clinical Pearl / High-Yield Fact**
It is essential to consider the patient's history of prolonged steroid use when evaluating hip pain, as it is a known risk factor for osteonecrosis of the femoral head.
**Correct Answer:** C. Avascular necrosis of the femoral head.