What investigations should be ordered for a 60-year-old patient with frequent rib fractures secondary to cough, who is only taking steroid inhalers (corticosteroids)?

Investigations for a 60-Year-Old Patient with Frequent Rib Fractures Secondary to Cough Who Takes Steroid Inhalers

A 60-year-old patient with frequent rib fractures secondary to cough who is taking steroid inhalers should undergo dual-energy x-ray absorptiometry (DXA) of the spine and hip as the primary investigation, along with vertebral fracture assessment (VFA) or spinal radiography to identify potential subclinical vertebral fractures. 1, 2

Primary Investigations

1. Bone Mineral Density Testing

   • DXA scan of the lumbar spine and hip 1
   • This is the gold standard for diagnosing osteoporosis and should be completed as soon as possible

2. Vertebral Fracture Assessment

   • VFA or spinal radiography to detect subclinical vertebral fractures 1
   • Presence of vertebral fractures significantly increases future fracture risk independent of BMD

3. Basic Laboratory Testing 1, 2

   • Complete blood count
   • Serum calcium and albumin
   • Serum creatinine
   • Thyroid-stimulating hormone
   • 25-hydroxyvitamin D level
   • Consider testosterone level (for male patients)

Risk Assessment

The patient has multiple significant risk factors for osteoporosis and fragility fractures:

1. Chronic inhaled corticosteroid use - Even inhaled corticosteroids increase fracture risk, particularly at the hip and spine 3

2. Recurrent rib fractures from minimal trauma (cough) - Fractures from minimal trauma are diagnostic of osteoporosis regardless of BMD 1

3. Age (60 years) - Age is an independent risk factor for osteoporosis 1

Fracture Risk Calculation

• Calculate 10-year fracture risk using FRAX tool (https://www.shef.ac.uk/FRAX/tool.jsp) 1
• For patients on corticosteroids, the FRAX calculation should be adjusted:
  • If using inhaled corticosteroids at moderate-to-high doses, select "secondary osteoporosis" in the FRAX tool 1
  • For patients on oral corticosteroids, increase hip fracture risk by 1.2 and major osteoporotic fracture risk by 1.15 1

Additional Investigations to Consider

1. Chest radiography 1

   • To document current rib fractures and rule out underlying pulmonary pathology
   • Note: Standard chest radiography may miss up to 90% of rib fractures 1

2. CT scan of the chest 1

   • Consider if multiple fractures are suspected but not visible on plain radiographs
   • More sensitive than radiography for detecting rib fractures and complications

3. Bone turnover markers 2

   • May help assess bone metabolism and monitor treatment response

Clinical Pitfalls to Avoid

1. Underestimating inhaled corticosteroid risk - Even inhaled corticosteroids can increase fracture risk, especially at higher doses and with long-term use 4, 3

2. Missing secondary causes of osteoporosis - Don't assume inhaled corticosteroids are the only cause; investigate for other potential contributors 1, 2

3. Delaying treatment - Patients with fragility fractures have high imminent fracture risk and require prompt intervention 1, 2

4. Focusing only on BMD - Remember that fracture risk is determined by multiple factors beyond BMD, including falls risk and prior fractures 1, 2

By following this systematic approach to investigation, you can properly assess fracture risk and determine appropriate treatment to prevent future fractures in this patient with recurrent rib fractures while on inhaled corticosteroids.