Paediatrics - orthopaedics, rheumatology and dermatology Flashcards
what is osteogenesis imperfecta
Osteogenesis imperfecta is a genetic condition that results in brittle bones that are prone to fractures. It is caused by a range of genetic mutations that affect the formation of collagen (type 1)
what are the features of osteogenesis imperfecta
Hypermobility
Blue / grey sclera (the “whites” of the eyes)
Triangular face
Short stature
Deafness from early adulthood
Dental problems, particularly with formation of teeth
Bone deformities, such as bowed legs and scoliosis
Joint and bone pain
what other conditions is osteogenesis imperfecta associated with
congenital cataracts
what are the four major clinical features which characterises osteogenesis imperfecta
- osteoporosis with abnormal bone fragility
- blue sclera
- dentinogenetic imperfecta
- hearing impairment
what is the pathophysiology of osteogenesis imperfecta
there is a disturbance in the synthesis of type 1 collagen, which is the predominant protein of the extracellular matrix of most tissue
in bone this defect results on osteoporosis which increases the tendency to fracture
type 1 collagen is also a major constituent of dentine, sclarae, ligaments, blood vessels and skin
what are the genetic abnormalities behind osteogenesis imperfecta
mutation in one of two genes that carry instructions for making type 1 collagen
mutations in the COL1A1 and COL1A2 genes are responsible for over 90% of cases
what are the three main types of osteogenesis imperfecta
- mild: type 1
- perinatal lethal: type 2
- progressive deforming: type 3
types 4 and 5 are variable in severity and are uncommon
what features of osteogenesis imperfecta may be seen on antenatal scans
decreased attenuation and abnormally increased visualisation of fetal brain
may show evidence of fractures
may be evidence of polyhydramnios
what is the treatment of osteogenesis imperfecta
Bisphosphonates
vitamin D supplementation
physiotherapy and occupational therapy
paediatricians for follow up
orthopaedic surgeons for managing fractures
specialist workers
social workers
what is rickets
rickets is a condition affecting children where there is defective bone mineralisation causing soft and deformed bones
what are causes of rickets
rickets is caused by a deficiency in vitamin D or calcium
rare form of rickets is caused by genetic defects that results in low blood phosphate
how is vitamin D obtained in the body
produces in response to sunlight
obtained through eating foods such as eggs, oily fish or fortified cereals or supplements
what is hereditary hypophosphataemic rickets
this is a rare form of rickets caused by an X linked dominant disorder, where there is low phosphate in the blood
what is the pathophysiology of rickets
- vitamin D is a hormone created by cholesterol in response to UV
- reduced sun without vitamin D supplementation leads to a deficiency
- malabsorption disorders can also cause vitamin D deficiency, and so can chronic kidney disease
- Vitamin D is essential for calcium and phosphate absorption as well as regulating bone turnover and promoting bone resorption to boost serum calcium
- inadequate vitamin D leads to a lack of calcium and phosphate in the blood, leading to defective bone mineralisation.
- low calcium also causes a secondary hyperparathyroidism
how does rickets present
lethargy
bone pain
swollen wrists
bone deformities
poor growth
dental problems
muscle weakness
pathological or abnormal fractures
what bone deformities can occur in rickets
Bowing of the legs - legs curve outward
knock knees - curve inwards
rachitic rosary - where the ends of the ribs expand and the costochondral junctions causing lumps along the chest
craniotabes - soft skull with delayed closure of the sutures and frontal bossing
delayed teeth - under-developed enamel
what investigations should be done in someone with suspected rickets
Serum 25-hydroxyvitamin D
W ray
serum calcium and phosphate
serum alkaline phosphatase
parathyroid hormone levels
FBC and ferritin
inflammatory markers
kidney function tests
liver function tests
thyroid function tests
malabsorption screen
autoimmune and rheumatoid tests
what level of serum 25-hydroxyvitamin D in the blood would establish a diagnosis of vitamin D deficiency
25 nmol/L or less
what is the management for children with rickets
children with vitamin D deficiency can be treated with vitamin D (ergocalciferol) with doses depending on the age
- dose for children between 6 months and 12 years is 6,000 IU per day for 8-12 weeks
children with features of rickets should be referred and treated with vitamin D and calcium. can also have surgery
how can you prevent rickets from occurring
breastfed babies are at higher risk of vitamin D deficiency than formula fed babies
breastfeeding women and all children should take vitamin D supplementation
NICE recommends 400 IU (10mg) supplement per day
what is transient synovitis
a temporary irritation and inflammation in the synovial membrane of a joint
what is transient synovitis often associated with
a recent viral upper respiratory tract infection
how does transient synovitis present
occurs within a few weeks of viral illness
hip presents in flexion, abduction and external rotation
limp
refusal to weight bear
groin or hip pain
limited range of movement: most commonly hip abduction
mild low grade fever
normal obs and should be systemically well
how is transient synovitis diagnosed
need to rule out septic arthritis
- bed side observations
- bloods: full screen + culture
- imaging: X-ray, USS