Rheumatology II Flashcards
1. Identify and recognise signs and symptoms of common non-autoimmune rheumatological conditions 2. Understand the role of imaging and blood investigations at arriving at a diagnosis 3. Explain dental relevance of non-autoimmune rheumatological conditions and their clinical management
List inherited non-autoimmune bone disorders
- Osteogenesis imperfecta (brittle bone syndrome)
- Cleidocranial dysplasia
- Osteoporosis (marble bone disease)
List acquired non-autoimmune bone disorders
- Osteomalacia and rickets
- Osteoporosis
- Osteomyelitis
- Paget’s disease of bone
- Osteoarthritis
- Fibrous dysplasia
What is osteogenesis imperfecta
A rare autosomal dominant inherited condition closely related to the gene for dentinogenesis imperfecta, and it is characterised by brittle bones susceptible to fracture due to defective type I collagen formation and small osteoblasts - this means mainly woven bone is formed (this is more fibrous than cortico-lamellar bone which is stronger)
Outline the clinical features of osteogenesis imperfecta
- Multiple fractures on minimal impact (less post puberty)
- Gross deformity and dwarfism due to bone distortion on healing from fractures
- Parietal bossing causing eversion of upper ear
- Deafness, blue sclera, easy bruising
- Loose/weak tendons and ligaments
- Hernias
How is osteogenesis imperfecta diagnosed
- positive family history
- clinical presentation (multiple fractures, ear eversion due to parietal bossing, deformed bone healing)
- radiography
- skin biopsy
- DNA based sequencing
How is osteogenesis imperfecta managed
- No cure
- Supportive therapy to decrease fractures
- Bisphosphonates to prevent bone loss
What is the dental relevance of osteogenesis imperfects
- Handle patients carefully due to bone fragility
- Do not confuse with physical abuse
- Minimal force, support jaws and ensure haemostasis
- Chest deformity can contraindicate surgery (kyphoidosis)
- Dentinogenesis imperfecta (so weak teeth due to dentine not being strong - this predisposes to caries)
- Bisphosphonates can cause MRONJ
What is cleidocranial dysplasia
A rare autosomal dominant trait on chromosome 6 causing defects of membrane bone formation (bone formed directly from CT not from cartilage) e.g. skull and clavicles
Describe the clinical features of cleidocranial dysplasia and how is it diagnosed
- Absent/ defective clavicle
- Prognathic mandible due to maxillary hypoplasia (looks like mandible protrudes out and causes a reverse overbite)
- Depressed nasal bridge
- Frontal, parietal and occipital bossing
- Kyphoscoliosis and pelvic abnormalities
Diagnosis is based on these clinical features and radiography
What is the dental relevance of cleidocranial dysplasia
- Facial abnormalities
- Deciduous teeth retention causing delayed/failure of eruption of permanent dentition
- Hyperdontia, supernumerary teeth
- Twisted roots (complicate extractions)
- Malformed crowns
- Dentigerous cysts (form when teeth are retained in the bone as they cannot erupt)
What is osteopetrosis
Marble bone disease = rare genetic disorder characterised by excessive bone density, defective osteoclastic activity and remodelling to give dense but weak fragile bone which can heal normally
What are the clinical features of osteopetrosis and the findings on investigation
- Bone pain, fractures, osteomyelitis
- Infection and anaemia
- Cranial neuropathies (XS bone can compress nerves)
- Epilepsy and learning disabilities (rare)
- Dense appearance on radiographs
Normal Ca2+ and PO43- on testing as there is no issue with osteoclastic activity
Radiographs show dense marble-like bone appearance
What is the dental relevance of osteopetrosis
- Frontal bossing and hypertelorism (increased distance e.g. between orbit and eye)
- Trigeminal/ facial neuropathies can be a complication
- Jaw fractures
- Anaemia
- Delayed tooth eruption
- Osteomyelitis is a complication of osteopetrosis
How is PTH involved in calcium metabolism
It is released from the parathyroid gland when there is low serum calcium levels and this acts on the bone and kidneys
In bone this causes the release of calcium to increase serum calcium levels
In kidney this increases calcitriol formation (active vitamin D3) and decreases the excretion of calcium
How is vitamin D involved in calcium metabolism
Vitamin D is hydroxylated in the liver to calcidiol and then in the kidneys to calcitriol - this increases the absorption of dietary calcium in the small intestine and acts on the bone to release calcium - In turn both of these increase the serum calcium levels
What is osteomalacia and rickets
Osteomalacia (adults) = failure of mineralisation of replacement bone
Rickets (children) = inadequate mineralisation of bone framework
What are the risk factors for osteomalacia and rickets
- Vit D deficiency
- Pigmented skin, sunscreen, elderly, institutionalised
- Calcium malabsorption
- Renal diseases
- Drugs
- Pregnancy and lactation (increased demands for calcium)
What are the clinical features of osteomalacia and rickets
- Weak, hypotonic muscles due to low Ca2+
- Bone pain
- Fractures as bone is weak (not mineralised)
- Bone deformity and impaired growth in children
- Hypocalcemia, tetany and seizures
- Swelling at costochondral joints ‘Rachitic rosary’
How is osteomalacia and rickets diagnosed
- radiographically
- low/normal PO43- and Ca2+
- high ALP
- high PTH
- low vitamin D
How is osteomalacia and rickets managed
Treating underlying causes thus vitamin D and calcium supplements
What is the dental relevance of osteomalacia and rickets
- Delayed eruption in severe cases
2. If associated with malabsorption can cause vitamin K deficiency and secondary hyperparathyroidism
What is osteoporosis
When the bone mass is diminished leading to fragility and increased risk of fracture affecting the spine, forearms and hips (increase in porosity)
What are the modifiable risk factors for osteoporosis
Smoking, alcohol abuse, low dietary calcium intake, vitamin D deficiency, lack of physical activity, immobility, drugs (steroids, anticoagulants, anticonvulsants)
What are the non-modifiable risk factors for osetoporosis
- old age
- sex: female
- race: caucasian and asian
- family history
What are the clinical features of osteoporosis
- Fractures at - thoracic and lumbar vertebrae, head of femur, distal radius (Colles fracture)
- Kyphosis
- Height shrinkage (widow’s stoop)
What investigations are done for osteoporosis
- Bone density DEXA scan (
Why is calcium, phosphate and alkaline phosphate are normal in patients with osteoporosis
Because it is to do with the bone density and matrix
How is osteoporosis managed
- Avoid modifiable risk factors
- Increase dietary calcium and vitamin D
- Bisphosphonates prevent fractures and slow the reduction in density
What is the dental relevance of osteoporosis
- GA can be contraindicated in deformed chest and vertebral collapse
- Jaw osteoporosis can cause XS alveolar loss (esp. women)
- Bisphosphonates - MRONJ
What is osteomyelitis
Infection of the bone mainly by staphylococcus (can be haemophilia influenza, salmonella in sickle cell anaemia) And the source can be haematogenous or direct/contiguous spread
What are characteristics of the haematogenous source of osteomyelitis
- Bacteria seeding from the blood
- Involves a single specie of bacteria
- Occurs in children
- Common site is rapidly growing and highly vascular metaphysic of growing bones
What are characteristics of the direct/contiguous source of osteomyelitis
- Usually due to local infection caused by trauma/ surgery
- Tends to involve multiple bacterium
What are the clinical features of osteomyelitis
Fever, localised pain and erythema
If in jaw:
- deep seated boring pain with swelling, truisms and regional lymphadenopathy
- lower lip paraesthesia
- teeth are tender and may be mobile
- pus discharges from gingival crevices/ several sinuses if cortical plate is penetrated
How is osteomyelitis diagnosed
From the history of clinical findings and radiographs show marked bony destruction in late stage
Blood tests show leukocytosis with neutrophilia and raised ESR
How is osteomyelitis treated
Antibiotics: Flucloxacillin and fusidic acid for 4-6 weeks starting with IV route
What is the dental relevance of osteomyelitis
- Can affect jaw (acute = adults, mandible/chronic = secondary to inadequate treatment of acute type or de novo from low virulent bacteria)
- Delay all dental treatment until complete resolution
What is Paget disease of bone (osteitis deformans)
Progressive bone enlargement and deformity from osteoclastic and osteoblastic over activity - the increased abnormal bone resorption is followed by weaker new bone formation due to chaotic repair and renewal
There is increased local bone blood flow and fibrous tissue and the commonly affected sites are the pelvis, lumbar spine, femur, thoracic spine, skull and tibia
Incidence increases with age and is male dominating
Describe the clinical features of Paget disease of bone (osteitis deformans)
- Asymptomatic in early stage, spared hands and feet
- Pain around hips, knees
- Deformities: skull enlargement, bowed tibia
- Pathological fractures (esp. in elderly)
- Cranial nerve compression
- High output cardiac failure due to bone hypervascularity (if disease is widespread)
- Osteosarcoma is a rare complication
How can Paget disease of bone (osteitis deformans) be diagnosed
- radiographs
- radionuclide bone scans
- raised alkaline phosphatase
- normal calcium and phosphate
How is Paget disease of bones (osteitis deformans) treated
Bisphosphonates
What is the dental relevance of Paget disease of bone (osteitis deformans)
- Patients can develop heart failure
- Avoid GA
- Hypercementosis can complicate extractions
- Gross symmetrical widening of alveolar ridges
- Poor blood supply may predispose to chronic osteomyelitis
- Senses of hearing, sight and smell deteriorate
- Osteosarcoma in the jaw
What is osteoarthritis and what is it characterised by
This is the most common form of arthritis (>45 yrs) and is characterised by
- degeneration of the articular cartilage
- thickening of the exposed underlying bone
- development of peri-articular cysts
- joint deformation
What are the risk factors of osteoarthritis
Age, gender, genetics, obesity, occupation, fracture through a joint, congenital joint dysplasia, Paget’s disease and gout
Describe the clinical features of osteoarthritis
- Joint pain which is worse on movement and relieved by rest
- Stiff joints
- Deformity
- Loss of function
- Herberden’s nodes = hard bony lumps in the DIP joints of fingers
How is osteoarthritis managed
Regular exercise, weight control, good footwear, using a walking stick, NSAIDs, antidepressants intra-articular injections and surgery
Outline the dental relevance of osteoarthritis
- Dental care access is complicated by age and motility
- Bleeding tendency due to aspirin so ensure haemostasis
- Reduced manual dexterity
- TMJ involvement
What is fibrous dysplasia
Replacement of an area of bone by fibrous tissue which causes localised swelling affecting a single bone (monostotic) or several bones (polyostotic): lesions start in childhood and stabilise
What is mostotic fibrous dysplasia
This is the more common form and occurs more in females involving the jaw especially the maxilla
What is polystotic fibrous dysplasia
Less common and can be unilateral and involve 50% of skeleton and cause abnormal skin hyperpigmentation Café-au-lait spots and Albright syndrome
How is fibrous dysplasia diagnosed and mannaged
Ground glass appearance on radiograph with normal serum calcium, phosphate with raised alkaline phosphatase
- It is self-limiting and stops progressing after adolescence
- Bisphosphonate treatment can cause MRONJ
- Surgery to correct cosmetic defects
- Endocrine conditions can complicate treatment
What is the dental relevance of fibrous dysplasia
- Facial bones are involved in monostotic type
2. Hyperthyroidism and diabetes may be associated with the polyostotic type
