Incorrect Spine Analysis

Case Description:

This is a 32-year-old premenopausal female sent for a determination of whether Prolia should be started. The history was remarkable for past low 25-OH vitamin D and inadequate calcium intake. She is G3P3 with normal menstrual periods. There is no fracture history, and she does not smoke or consume alcohol. The accompanying report said “osteoporosis – treated with denosumab for at least 4 doses”. Her current primary care practitioner was not willing to order the denosumab and sent her to Osteoporosis Clinic for the denosumab to be ordered and administered.
Her lab work=up showed:
25-OH vitamin D = 22.6 ng/ml
Calcium, albumin, creatinine, alkaline phosphatase – wnl
iPTH/T4.TSH all wnl
CBC shows a microcytic anemia
Negative IFE/UIFE/FLC
TTG <5
24-hour urine calcium negative
Therefore, she had a normal secondary cause work-up, except for the iron deficiency anemia and the low 25-OH vitamin D level.

The Hologic right hip scan was technically adequate: Femoral neck Z-score = -0.1, total hip Z-score = -0.4.

The top panel shows the lumbar spine scan. The referring physician was concerned about Z = -3.8 in L4.

There are 2 vertebral bodies in the level marked L3. What is designated at L4 is sacrum.

The bottom panel shows the repeat spine scan done at our clinic (also Hologic). The bone mineral density is within the expected range for age, and denosumab was not ordered.

Adequate calcium intake was discussed and her 25-OH vitamin D status was boosted.

Credit:

Sarah L Morgan, MD, RD, CCD, The University of Alabama at Birmingham

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