DXA Bone Scan — DXA Screening Guidelines, Cystic Fibrosis (CF) — Clinical Pathway: Inpatient, Outpatient Specialty Care and Primary Care

Bone Density Scan (DXA) Clinical Pathway — Outpatient Specialty Care and Primary Care

DXA Screening Guidelines for Children with Cystic Fibrosis (CF)

Indications

  • All children should receive a DXA scan by age 17-18 yrs.
  • Children may receive DXA earlier at 8-10 yrs if they have 1 absolute indication (see tables below).
  • Relative indications are listed to provide clinical guidance. If 2 or more relative indications are present, consider ordering a DXA.
  • Use clinical judgment in screening children with CF for DXA scan.
CF Specific
Absolute Indications Relative Indications
  • Moderate or severe malnutrition
    • BMI Z-score ≤ -2 or
    • Height Z-score ≤ -2.5
 Well-controlled CF-related diabetes
  • > 90 days of systemic glucocorticoid therapy
    • At suppressive doses and/or
    • Evidence of glucocorticoid excess
  • Mild malnutrition
    • BMI Z-score ≤ -1 despite nutritional interventions
  • Poor/declining lung function
    • FEV1 < 50% or
    • FEV1 50-75% with multiple hospitalizations or deteriorating lung function
  • Poor adherence to Pancreatic enzyme replacement therapy (PERT)
    • Less than 50% adherence to prescribed PERT dose with fat-containing food
  • Persistent vitamin D deficiency < 20
    • 2 consecutive measurements at least 2-3 mos apart
  • Vitamin K deficiency
    • As measured by low PIVKA 2 assay or
    • Prolonged persistently abnormal prothrombin time
Poorly controlled CF-related diabetes
Pre-organ transplant
Non-CF Specific
Absolute Indications Relative Indications
  • Fracture history
    • Long bone fracture of lower extremity
    • Vertebral compression fracture
    • 2 or more upper extremity fractures
    • Low trauma or atraumatic fractures
  • Delayed puberty
  • Secondary amenorrhea
  • Other hypogonadism
Short bowel syndrome Below genetic height potential (stunting)
Cirrhosis of the liver Family history of early osteoporosis
  • Celiac disease
    • Once Anti-TTG antibody normalizes
 X-ray findings consistent with low bone
mineral density
  • Poorly controlled autoimmune disease
    • e.g., rheumatoid arthritis, inflammatory
      bowel disease

What DXA Scan to Order

  • Every child receiving a DXA will get a lumbar spine and whole body scan unless there are interfering factors, such as a spinal rod
  • Please order a hip scan for all children 15 yrs and older to screen for hip fractures

Recommendations for Follow-up DXA Scans

DXA Result Recommendation
BMD Z-score is between +2 to -1 Repeat scan every 5 yrs or sooner if clinical status deteriorates
BMD Z-score is between -1 and -2 Repeat scan every 2 yrs
BMD Z-score is < -2 Repeat scan every year

References