Histopathology - Non-neoplastic Bone Disease

Question 1

What is the epidemiology of Gout?

Answer 1

• Obese
• Middle-aged man

Question 2

What is the aetiology of Gout?

Answer 2

Hyperuricaemia
- Increased intake = increased dietary purine intake, alcohol excess
- Increased production = tumour lysis syndrome, inherited metabollic abnormalities
- Decreased excretion = diuretics

Question 3

What joints are affected in gout?

Answer 3

Acute monoarthritis:
- Classically 1st MTP (big toe)
- Precipitated by trauma/infection

Chronic tophaceous gout:
- Polyarticular arthritis
- Tophi deposits in ear lobes, fingers + elbows
- Urate kidney stones

Question 4

Whatt are the clinical features of gout?

Answer 4

• Hot, swollen, red, exquisitely painful joint
• Tophus (s/c deposits of urate) = pathognomonic lesion (e.g. on pinna + hands)

Question 5

What are the crystals seen in Gout?

Answer 5

• Urate crystals
• NEEDLE SHAPED

Question 6

What are the investigations for Gout?

Answer 6

• Polarised light = NEGATIVELY bifringent crystals (orange)
• XR = Rat-bite erosions

Question 7

What is the management of Gout?

Answer 7

Acute attack:
- Colchicine

Long-term:
- Allopurinol

Conservative:
- Decrease alcohol intake
- Decrease purine intake (e.g. sardines + liver)

Question 8

What is the epidemiology of psuedogout?

Answer 8

• > 50yr Women

Question 9

What is the aetiology of Pseudogout?

Answer 9

• Idiopathic
• Electrolytes = HyperPTH, HypoPO4. HypoMg
• Metabolic = DM, Hypothyroid, Wilsons, Haemochromatosis

Question 10

What joints are affected in Pseudogout?

Answer 10

Acute Monoarthritis:
- Knee + shoulder
- Precipitated by trauma/infection

Chronic:
- Polyarticular arthritis

Question 11

What are the clinical features of Pseudogout?

Answer 11

• Hot swollen joint with effusion

Question 12

What are the crystals seen in Pseudogout?

Answer 12

• Calcium pyrophosphate crystals
• RHOMBOID SHAPED

Question 13

What are the investigations for Pseudogout?

Answer 13

• Polarised light = POSITIVELY birefringent
• XR: White lines of Chondrocalcinosis

Question 14

What is the management for Pseudogout?

Answer 14

• NSAIDs
• Intra-articular steroids

Question 15

What are the different types of fractures?

Answer 15

• Simple (straight)
• Compound (slant)
• Greenstick (vertical)
• Comminuted (Multiple/smashed)
• Impacted

Question 16

What is the process for fracture repair?

Answer 16

1. Organisation of haematoma (pro-callus)
2. Formation of fibrocartilaginous callus
3. Mineralisation of fibrocartilaginous callus
4. Remodelling of bone along weight bearing lines

Question 17

What factors influence how a fracture heals?

Answer 17

• Fracture type
• Neoplasm
• Metabolic disorder
• Drugs
• Vitamin deficiency
• Infection

Question 18

What is osteomyelitis?

Answer 18

Haematogenous spread or local infection
- Post-trauna
- Bacterial
- Rarely fungal

Question 19

What is the presentation of osteomyelitis?

Answer 19

• Pain
• Swelling
• Tenderness
• General features: Malaise, fever, chills, leukocytosis

Question 20

What are the XR changes seen in Osteomyelitis?

Answer 20

• Early changes = SUB-PERIOSTEAL NEW BONE FORMATION
• ~10days post-onset = LYTIC DESTRUCTION OF BONE
• 3-6wks: DETACHMENT OF NECROTIC CORTEX (sequestra)

Question 21

What is the causative organism and most likely locations of Osteomyelitis in Adults?

Answer 21

Cause: Staphylococcus. aureus

Location:
- Vertebrae
- Jaw (secondary to dental abscess)
- Toes (secondary to diabetic skin ulcer)

Question 22

What are the causative organisms + most likely location of Osteomyelitis in Children?

Answer 22

Cause:
- Haemophilus influenzae
- GBS

Location:
- Long bones

Question 23

What are the causative organisms of Osteomyelitis in sickle cell, immunocompromised and congenital patients?

Answer 23

Sickle cell:
- Salmonella

Immunocompromised:
- TB

Congenital:
- Syphilis

Question 24

What is osteoarthrits?

Answer 24

A degenerative joint disease of the articular cartilage mainly affecting vertebrae, hips + knees

Question 25

What are some clinical signs of Osteoarthritis?

Answer 25

• Heberden’s nodes (DIPJ)
• Bouchard’s nodes (PIPJ)

Question 26

What are the XR features of osteoarthritis?

Answer 26

LOSS
- Loss of joint space
- Osteophytes
- Sunchondral sclerosis
- Subchondral cysts

Question 27

What is rheumatoid arthritis?

Answer 27

Inflammation of the synovium

Question 28

What are the clinical features of Rheumatoid arthritis?

Answer 28

• Slowly progressing course
• Symmetrical
• Small joints of hands + feet (sparing DIPJ), wrists, elbows, ankles + knees

Question 29

What is the serology of Rheumatoid arthritis?

Answer 29

• RF +ve (60-70%)
• Anti-CCP (more sens + spec)

Question 30

What are the characteristic deformities of Rheumatoid arthritis?

Answer 30

• Radial deviation of wrist + ulnar deviation of fingers
• SWAN NECK deformity of fingers = hyperextension of PIPJ + flexion of DIPJ
• BOUTONNIERE deformity of fingers = flexion of PIPJ + hyperextension of DIPJ
• Z-shaped thumb
• Synovial swelling

Question 31

What are some extra-articular features of Rheumatoid arthritis?

Answer 31

• Pulmonary fibrosis
• Vasculitis
• Amyloidosis
• Pericarditis
• Subcutaneous nodules
• DVT

Question 32

What is the histopathology of Rheumatoid arthritis?

Answer 32

• Thickening of synovial membrane
• Hyperplasia of surface synoviocytes
• Intense inflammatory cell infiltrate + fibrin deposition + necrosis

Question 33

What are the genetic predispositions of Rheumatoid arthritis?

Answer 33

• HLA DR-4
• PADI 2 + 4 (increase citrullination of proteins)
• PTPN 2 (suppresses T cell activation)