Makindo Medical Notes

Related Subjects: |Calcium Physiology |Hypercalcaemia |Bisphosphonates

Pathological Fractures 🦴 are fractures occurring in abnormal bone due to underlying malignancy, metabolic bone disease, or other pathology. Most neoplastic cases are due to metastatic disease rather than primary bone tumours. Always suspect if a fracture occurs after minimal trauma, spontaneously, or in a patient with known malignancy.

📖 About

• Fractures through weakened bone.
• Causes: malignancy (most common), metabolic bone disease, infection, inherited bone disorders.

⚙️ Pathophysiology

• Osteolytic lesions 🔥: tumour → ↑RANKL → osteoclast activation → bone resorption.
• Osteoblastic lesions 🧱: tumour secretes endothelin-1 → abnormal bone deposition.
• Results in fragile, structurally compromised bone susceptible to fracture.

🧬 Cancer Associations

📝 Other Causes

• Infection: Osteomyelitis
• Inherited bone disorders: bone cysts, achondroplasia, multiple exostoses (diaphysealaclasis), Ollier’s disease (dyschondroplasia)
• Metabolic bone disease: Paget’s, osteoporosis (senile/disuse), osteomalacia, rickets, scurvy, hyperparathyroidism, Cushing’s
• Iatrogenic: long-term steroids → osteoporosis
• Endocrine syndromes: hypopituitarism (Frohlich’s syndrome)

🩺 Clinical Suspicion

• Fracture occurs:
  • After minor trauma or spontaneously 🚩
  • Unusual pattern or location
  • History of recent multiple fractures
• Bone pain or limb swelling preceding fracture.
• Older patient with unexplained fracture.
• History of known malignancy or B-symptoms (weight loss, fevers, night sweats).
• Paget’s disease patient who develops new pain → concern for malignant transformation.

🔬 Investigations

• Bloods:
  • FBC (anaemia, raised ESR in myeloma/malignancy)
  • Calcium (↑ in bone resorption / malignancy)
  • Protein electrophoresis, urinary light chains (myeloma)
  • Tumour markers: PSA, CA125, CA19.9, CEA
• Imaging:
  • X-ray: lytic/blastic lesions, cortical thinning, cystic changes
  • Bone scan: hot lesions (increased uptake), cold in myeloma
  • MRI: marrow infiltration, cord compression
  • CT chest/abdomen/pelvis: primary tumour search
  • DEXA: fragility fracture if osteoporosis suspected
• Special:
  • Myeloma screen: Bence-Jones proteins, skeletal survey (skull, spine, pelvis)
  • Breast exam + mammogram; prostate exam + PSA
  • Urinalysis (haematuria in RCC/bladder Ca)
  • Bone marrow biopsy if myeloma suspected
• Biopsy: If uncertain diagnosis, always after full staging scans.

🆚 Differentials

• Stress fracture: repetitive microtrauma
• Paget’s disease: mixed lytic/blastic lesions
• Avascular necrosis: ischaemic bone necrosis
• Benign fracture: mechanical failure without underlying pathology
• Osteomyelitis: infection eroding bone

💊 Management

• General: Pain control, immobilisation, fracture stabilisation.
• Systemic therapy:
  • Hormonal therapy (breast/prostate Ca)
  • Chemotherapy for primary cancer
  • Bisphosphonates (zoledronic acid) → reduce skeletal-related events
  • Denosumab (RANKL inhibitor) → prevents osteoclast activation
• Radiotherapy:
  • External beam for bone pain
  • Stereotactic Body Radiotherapy (SBRT)
  • Radiopharmaceuticals (radionuclides)
• Surgical: Internal fixation (nail/plate), joint replacement if needed. Indications: impending or actual fracture, pain, instability.
• Referral: MDT approach → oncology, orthopaedics, geriatrics, palliative care.

📌 OSCE / Exam Pearls

• Fracture with minimal trauma in elderly = pathological until proven otherwise.
• Prostate → sclerotic/blastic, Kidney/Lung/Thyroid → lytic, Breast → mixed.
• In suspected myeloma: do NOT order bone scan (lesions can be cold) → skeletal survey is gold standard.
• Always document pain before fracture (clue to pathological cause).

📚 References

• NCBI – Pathological Bone Fractures
• Rockwood & Green’s Fractures in Adults, 9th ed.
• NICE: Myeloma and Metastatic Bone Disease guidelines.