The patient presented with sudden onset severe low back pain from 2 weeks. There was no direct trauma but the pain started when she tried to lift her baby. Now the patient is wheelchair-bound and not able to bear weight due to pain. 

X-rays of the pelvis and lumbar spine were normal. An acute disc prolapse was suspected clinically and an MRI of the lumbar spine was obtained. MRI of the spine was normal. However, the coronal STIR screening of the sacroiliac joints showed features of a sacral insufficiency fracture on the left side. A complimentary CT scan was obtained which clearly shows a fracture line surrounded by a zone of sclerosis. 

Lab results showed evidence of vitamin D deficiency with a serum vitamin D level of 17.35 ng/mL.

DEXA scan of the lumbar spine, as well as femoral necks, showed osteopenia.