Osteopetrosis

• AKA Marble bone disease
• AKA Albers-Schonberg disease

Definition

• Abnormally dense bones due disorder of osteoclasis
  • Failure of osteoclastic resorption
  • Dense bones
  • Decreased marrow space

Classification

Tarda

• AD
• Adult form
• Relatively benign
• Common form is the Tarda form

Congenita

• AR
• Infantile form
• More severe

Infantile	autosomal recessive
Intermediate	autosomal recessive
Autosomal dominant	Albers Schonberg Disease

Pathology

• Consists of generalised osteosclerosis, bone fragility & failure of remodelling
• Diminished bone resorption due to osteoclast defect
• May be due to immune thymic defect

• Bones exceedingly dense
• Marrow spaces & foraminae encroached upon by bone
• Bone fragile & brittle
• Tongues of cartilage persist at sites of enchondral bone formation
• May project into metaphysis
• Are calcified (cf. Rickets)

Clinical Features

Tarda

• May be unaffected
• Often chance diagnosis
• May see
  • Mild anaemia
  • Facial palsy
  • Deafness due to Otosclerosis
  • Fractures due to brittleness
    • Fracture more common
    • Heals slowly with ↑ non union (absence of vascular bone marrow)
  • Prone to osteomyelitis after tooth extraction
• Beware IM nailing as no canal
  • Drill out rather than Ream
  • Use Delta nail

Congenita

• Presents in infancy
• Failure to thrive
• Marrow failure
  • Pancytopaenia
  • Easy bruising & bleeding
• Hepatosplenomegaly
• Multiple fracture
• Cranial nerve palsies (optic & facial)
• Death from repeated haemorrhage or overwhelming infection

Investigations

Xray

• Increased density of all bones
• Widened cortices & narrow medullary cavity
• Bone within bone appearance
  • “Picture-frame” bone
  • Especially. spine
• Sclerotic end plates produce striped appearance (Rugger Jersey Spine)
• Flask-shaped metaphyses (Erlenmeyer Flask)
• Skull thickened & sclerotic

Treatment

• Treatment aimed at introduction of bone marrow with competent osteoclasts
  • Need to do this before 12 months of age