Histopathology - Non-neoplastic Bone Disease Flashcards
What is the epidemiology of Gout?
- Obese
- Middle-aged man
What is the aetiology of Gout?
Hyperuricaemia
- Increased intake = increased dietary purine intake, alcohol excess
- Increased production = tumour lysis syndrome, inherited metabollic abnormalities
- Decreased excretion = diuretics
What joints are affected in gout?
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
Whatt are the clinical features of gout?
- Hot, swollen, red, exquisitely painful joint
- Tophus (s/c deposits of urate) = pathognomonic lesion (e.g. on pinna + hands)
What are the crystals seen in Gout?
- Urate crystals
- NEEDLE SHAPED
What are the investigations for Gout?
- Polarised light = NEGATIVELY bifringent crystals (orange)
- XR = Rat-bite erosions
What is the management of Gout?
Acute attack:
- Colchicine
Long-term:
- Allopurinol
Conservative:
- Decrease alcohol intake
- Decrease purine intake (e.g. sardines + liver)
What is the epidemiology of psuedogout?
- > 50yr Women
What is the aetiology of Pseudogout?
- Idiopathic
- Electrolytes = HyperPTH, HypoPO4. HypoMg
- Metabolic = DM, Hypothyroid, Wilsons, Haemochromatosis
What joints are affected in Pseudogout?
Acute Monoarthritis:
- Knee + shoulder
- Precipitated by trauma/infection
Chronic:
- Polyarticular arthritis
What are the clinical features of Pseudogout?
- Hot swollen joint with effusion
What are the crystals seen in Pseudogout?
- Calcium pyrophosphate crystals
- RHOMBOID SHAPED
What are the investigations for Pseudogout?
- Polarised light = POSITIVELY birefringent
- XR: White lines of Chondrocalcinosis
What is the management for Pseudogout?
- NSAIDs
- Intra-articular steroids
What are the different types of fractures?
- Simple (straight)
- Compound (slant)
- Greenstick (vertical)
- Comminuted (Multiple/smashed)
- Impacted
What is the process for fracture repair?
- Organisation of haematoma (pro-callus)
- Formation of fibrocartilaginous callus
- Mineralisation of fibrocartilaginous callus
- Remodelling of bone along weight bearing lines
What factors influence how a fracture heals?
- Fracture type
- Neoplasm
- Metabolic disorder
- Drugs
- Vitamin deficiency
- Infection
What is osteomyelitis?
Haematogenous spread or local infection
- Post-trauna
- Bacterial
- Rarely fungal
What is the presentation of osteomyelitis?
- Pain
- Swelling
- Tenderness
- General features: Malaise, fever, chills, leukocytosis
What are the XR changes seen in Osteomyelitis?
- Early changes = SUB-PERIOSTEAL NEW BONE FORMATION
- ~10days post-onset = LYTIC DESTRUCTION OF BONE
- 3-6wks: DETACHMENT OF NECROTIC CORTEX (sequestra)
What is the causative organism and most likely locations of Osteomyelitis in Adults?
Cause: Staphylococcus. aureus
Location:
- Vertebrae
- Jaw (secondary to dental abscess)
- Toes (secondary to diabetic skin ulcer)
What are the causative organisms + most likely location of Osteomyelitis in Children?
Cause:
- Haemophilus influenzae
- GBS
Location:
- Long bones
What are the causative organisms of Osteomyelitis in sickle cell, immunocompromised and congenital patients?
Sickle cell:
- Salmonella
Immunocompromised:
- TB
Congenital:
- Syphilis
What is osteoarthrits?
A degenerative joint disease of the articular cartilage mainly affecting vertebrae, hips + knees
What are some clinical signs of Osteoarthritis?
- Heberden’s nodes (DIPJ)
- Bouchard’s nodes (PIPJ)
What are the XR features of osteoarthritis?
LOSS
- Loss of joint space
- Osteophytes
- Sunchondral sclerosis
- Subchondral cysts
What is rheumatoid arthritis?
Inflammation of the synovium
What are the clinical features of Rheumatoid arthritis?
- Slowly progressing course
- Symmetrical
- Small joints of hands + feet (sparing DIPJ), wrists, elbows, ankles + knees
What is the serology of Rheumatoid arthritis?
- RF +ve (60-70%)
- Anti-CCP (more sens + spec)
What are the characteristic deformities of Rheumatoid arthritis?
- 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
What are some extra-articular features of Rheumatoid arthritis?
- Pulmonary fibrosis
- Vasculitis
- Amyloidosis
- Pericarditis
- Subcutaneous nodules
- DVT
What is the histopathology of Rheumatoid arthritis?
- Thickening of synovial membrane
- Hyperplasia of surface synoviocytes
- Intense inflammatory cell infiltrate + fibrin deposition + necrosis
What are the genetic predispositions of Rheumatoid arthritis?
- HLA DR-4
- PADI 2 + 4 (increase citrullination of proteins)
- PTPN 2 (suppresses T cell activation)
