A 45 year old man, known case of chronic renal failure develops rugger jersy spine. The probable cause it :

Answer is B (Secondary hyperparathyroidism): Rugger jersey spine results from osteosclerosis, which occurs in the setting of secondary hyperparathyroidism in chronic renal failure. In chronic renal failure, hyperphosphatemia and decreased renal production of active vit. D, initially produce a decrease in ionized calcium. This stimulates the parathyroid glands causing secondary hyperparathyroidism. The bone disease resulting in this setting is known as Renal Osteodystrophy. Patients with renal osteodystrophy may have ectopic calcifications around joints or in soft tissues. They may exhibit X-Ray changes of osteopenia, osteitis fibrosa, or osteosclerosis; alone or in combination. Osteosclerosis of veebral bodies is known as "Rugger jersey spine".