Histopathology 15: Bone Pathology Flashcards
What part of long bones encompasses the growth plates ?
Metaphysis
What are some of the main differences between cancellous and cortical bone ?
Cancellous bone is mainly metabolic whereas cortical is for support and protection
Cancellous bone is found as part of the axial skeleton (pelvis, vertebrae) cortical is found in long bones
Cortical bone is more calcified
How do osteoblasts inhibit osteoclast formation ?
Osteoblasts release osteoprotegrin which inhibits RANKL from binding to the RANKL receptor on osteoclast precursors. This blocks differentiation into mature osteoclasts.
List fractures commonly seen in patients with osteoporosis ?
Colle’s fracture of the wrist
NOF and intertrochanteric fractures of the hip
Pelvic
Vertebra
What are the biochemistry findings in a patient with osteoporosis ?
Normal calcium
Normal phosphate
Normal ALP
What are the histological findings in osteoporosis ?
Loss of cancellous bone
List 2 ty typical X-ray findings suggestive of Osteomalacia ?
Bowing of the legs in Rickets
Horizontal pseudofractures in looser’s zones
List signs and symptoms of Rickets in children ?
Bone pain Bowing tibia Rachitic rosary frontal bossing Pigeon chest Delayed walking
What is a histological feature of Osteomalacia ?
Excess unmineralised bone
List symptoms of hyperparathyroidism?
Moans - depression, confusion
Stones- calcium oxalate renal calculi
Bones- bone pain
Groans- constipation, pancreatitis, polyuria
Which metabolic bone disease shows histological bone changes of osteitis fibrosa cystica ?
Hyperparathyroidism
List 3 x-ray findings suggestive of hyperparathyroidism ?
Brown’s tumours (osteitis fibrosa cystica)
Salt and pepper skull
Subperiosteal bone resorption in phalanges
Describe the actions of PTH ?
Acts directly on the bone causing increased calcium and phosphate reabsorption.
Acts on the kidneys causing increased 1 alpha hydroxylase conversion of calcidiol to calcitriol
Calcitriol (activated vit D) then causes increased absorption of dietary calcium and phosphate from the small intestine.
PTH (“phosphate thrashing hormone”) acts directly on the kidneys to cause Increased calcium reabsorption and increased phosphate excretion.
What is renal osteodystrophy ?
A term that describes all skeletal changes associated with chronic renal disease
What are the biochemistry findings in Osteomalacia/rickets ?
Normal/low calcium
Low phosphate
High ALP
Low Vitamin D
What are the biochemical findings in primary Hyperparathyroidism?
High PTH
High Calcium
Low/normal phosphate
High/normal ALP
What are the biochemistry findings in Paget’s disease ?
Normal calcium
Normal phosphate
Super high ALP
What is the most common causative organism for osteomyelitis in adults ?
S.Aureus
List 2 histological findings in Paget’s disease ?
Huge Osteoclasts with >100 nuclei
Mosaic pattern of lamellar bone
List the x-ray features of osteoarthritis ?
L- loss of joint space
O- osteophytes
S- subchondral sclerosis
S- subchondral cysts
List 2 features of osteoarthritis in the hands ?
Heberden’s nodes (DIP joints)
Bouchard’s nodes (PIP joints)
List 6 features of rheumatoid arthritis in the hands and wrist?
Sparring of the DIP joints Radial deviation of the wrist Ulnar deviation of the fingers Swan neck deformity of the fingers Boutonniere’s deformity of the fingers “Z” shaped thumb
List 3 histological features of rheumatoid arthritis ?
Proliferative synovitis
Pannus formation
Grimley sokoloff cells- multinucleate giant cells
Which infectious organism causes osteomyelitis with Langerhans-type giant cells on histology ?
Tuberculosis
Which shape Chrystal are seen in gout and pseudogout?
Gout = needle shaped Pseudogout = rhomboid shaped
Which syndrome has the following features: Blue sclera, hearing loss, miss shaped teeth and recurrent fractures ?
Oesteogenesis imperfecta (autosomal dominant)
Describe the 4 stages of fracture repair ?
1 - Organisation of haematoma
2- fibrocartilaginous callus formation
3- Mineralisation of fibrocartilaginous callus
4- remodelling of bone along weight bearing lines
