MSK Flashcards
What is the genetic pattern of the genetic mutations that are associated with osteogenesis imperfecta (and what % have this)?
90%
Type 1 collagen genes - COL1A1 and COL1A2
Dominant mutation
What is osteogenesis imperfecta?
Brittle bone syndrome where the brittle bones are prone to fractures
What is the key sign to look out for in a child with suspected osteogenesis imperfecta?
Recurrent unexplained fractures (where you are considering safeguarding) and have GREY/BLUE sclera
Other than blue sclera how may a child with osteogenesis imperfecta present?
Hypermobility
Triangular face and short stature
Bone deformities with bowed legs and scoliosis
How may the most severe present during pregnancy?
Most severe forms prenatal diagnosis: 2nd trimester by USS
How may osteogenesis imperfecta present after birth?
X-Ray, bone densitometry and genetic testing after birth.
How may osteogenesis imperfecta be managed (two medication given)?
Bisphosphates: increase bone density
Vitamin D supplements: prevent deficiency
What is transient synovitis?
Irritable hip caused by transient irritation and inflammation in the synovial joint membrane (associated with recent viral URTI)
How does transient synovitis tend to present?
Within few weeks of viral illness.
Acute/more gradual onset of limb, refusal to weight bear, groin/hip pain, mild-low grade fever
The presence of what will prompt transient synovitis to be treated as septic arthritis?
The presence of a fever
How should transient synovitis be managed?
Treat symptoms with simple analgesia prior to symptom resolution which should take 1-2 wks. If fever then treat like septic arthritis
What is the recurrence rate of transient synovitis?
Around 20%
What is rickets?
Defective bone mineralization causing soft and deformed bones
What can rickets progress to in adults if left untreated?
Can progress to causing osteomalacia in adults
What is rickets a deficiency in?
Vitamin D or Calcium
What is rickets secondary to?
- Gastrointestinal malabsorption - consider causes
- Liver disease
- Renal disease
- Drugs: anticonvulsants, rifampicin, HAART
- Severe dietary calcium deficiency
What can cause GI malabsorption which can contribute to rickets in a paediatric patient?
- Surgery
- Cystic fibrosis
- Chronic pancreatic disease
- Crohn’s
- Biliary disease
- Coeliac disease
What is the genetic pattern of hereditary hypophosphatemia rickets?
X-linked dominant disorder
Describe the pathophysiological mechanism causing rickets to be worsened?
- Inadequate vit D
- Lack of calcium and phosphate in blood
- Low levels result in defective bone mineralization
- Secondary hyper-PTH as parathyroid gland secretes PTH to raise calcium levels
- Stimulates increased reabsorption of calcium from bones
- Further bone mineralization problems
How will rickets present?
Bone deformity
Lethargy
Bone pain, swollen wrist
Poor growth and muscle weakness
Dental problems
Patho and abnormal fractures
What level of serum 25-hydroxyvitamin D in rickets patients is required to diagnose vitamin D deficiency?
<25 nmol/L
What will be observed on blood serum in a rickets patient?
Low serum calcium, phosphate
High PTH, serum alkaline phosphate
What is required for rickets diagnosis?
X-ray
What is given as a management for rickets?
Supplement 10 micrograms per day of calcium
Ergocalciferol vitamin D for vitamin deficiency
Which age of children is septic arthritis seen most often in?
<4 years old
What are the symptoms of paediatric septic arthritis?
Hot, red, swollen, painful joint
Hip and knee = third of cases
Refusal to weight bear
Stiffness and reduced range of motion
Systemic symptoms - fever, lethargy, sepsis
Name bacterial causes of septic arthritis?
Staphylococcus aureus
Neisseria gonorrhoea (especially sexually active teens)
GAS
HiB
Escherichia coli
What are the key differential diagnoses to consider?
- Transient synovitis
- Perthes disease
- Slipped upper femoral epiphysis
- Juvenile idiopathic arthritis
What is the gold standard of septic arthritis?
Joint aspiration
What medication is given to patients with septic arthritis?
Flucloxacillin and vancomycin (MRSA)
What is given as an alternative to flucloxacillin should one have a penicillin allergy?
Clindamycin
What is the cause of Perthes disease and location?
Epiphysis of femur
Disruption of blood flow to the femoral head causing avascular necrosis of bone
What age range will Perthes disease effect predominantly?
Children ages 4-12 and is more common in boys
How does the pathological process of Perthes disease present and worsen?
- Revascularization or neovascularization of femoral head over time
- Bone remodeling as it heals
- Complication: soft and deformed femoral head