A 45 year old was given steroids after renal transplant. After 2 years he had difficulty in walking and pain in both hips. Which one of the following is most likely cause –
**Core Concept**
The patient's symptoms of difficulty walking and hip pain after long-term steroid use are suggestive of steroid-induced osteonecrosis of the femoral head, a well-known complication of prolonged corticosteroid therapy.
**Why the Correct Answer is Right**
Steroid-induced osteonecrosis occurs due to the disruption of the blood supply to the bone, particularly the femoral head. Long-term steroid use can lead to increased intracellular lipids, which accumulate in the bone marrow, causing fat embolism and subsequent thrombosis of the small blood vessels. This results in aseptic necrosis of the bone. The femoral head is a common site for this condition due to its high metabolic activity and limited blood supply.
**Why Each Wrong Option is Incorrect**
**Option A:** Osteoporosis is a possible complication of long-term steroid use, but it does not typically present with hip pain and difficulty walking in the early stages.
**Option B:** Avascular necrosis of the femoral head is a correct term, but the question specifically asks for the cause of the patient's symptoms, which is the disruption of blood supply due to steroid use.
**Option C:** Osteoarthritis is a possible cause of hip pain, but it is not directly related to long-term steroid use.
**Option D:** Osteomyelitis is an infection of the bone and is not a direct complication of steroid use.
**Clinical Pearl / High-Yield Fact**
Steroid-induced osteonecrosis is a well-known complication of long-term corticosteroid therapy, particularly in patients with autoimmune diseases or those undergoing organ transplantation. It is essential to monitor patients on long-term steroids for early signs of bone necrosis.
**Correct Answer:** C. Avascular necrosis of the femoral head due to disruption of blood supply.