Limping Child ✅ Flashcards
What is the most common cause of limp in 0-3 years old?
Trauma
What causes of limp in 0-3 years old require urgent intervention?
- Osteomyelitis
- Septic arthritis
- Non-accidental injury
- Malignancy
- Testicular torsion
- Inguinal hernia
What are the other causes of limp to consider in 0-3 years old?
- Developmental dysplasia of the hip
- JIA
- Metabolic
- Haematological disease
- Reactive arthritis
- Lyme arthritis
Give an example of a malignancy causing limp in 0-3 year olds?
Neuroblastoma
Give an example of a metabolic cause of limp in 0-3 year olds?
Rickets
Give an example of a haematological cause of limp in 0-3 year olds?
- Sickle cell anaemia
What are the most common causes of limp in 4-10 years?
- Trauma
- Transient synovitis
- Perthes disease
Give an example of a malignancy causing limp in 4-10 year olds?
Acute lymphoblastic leukaemia
What other causes of limp should be considered in 4-10 year olds?
JIA
What are the most common causes of limp in 11-16 year olds?
- Trauma
- Osgood-Schlatter disease
What causes of limp in 11-16 year olds require urgent intervention?
- Osteomyelitis
- Septic arthritis
- Slipped upper femoral epiphysis
- Malignancy, e.g. bone tumours
- Testicular torsion
- Appendicitis
- Inguinal hernia
What are the other important causes of limp to consider in 11-16 year olds?
JIA
What is septic arthritis?
Bacterial infection of the joint
At what age is septic arthritis most common?
First 2 years of life
What is osteomyelitis?
Infection of bone
At what age is osteomyelitis most common?
Under 2 years
What are the categories of osteomyelitis?
- Acute
- Subacute
- Chronic
How do most bone infections spread?
Via the haematogenous route
Are organisms always isolated in bone infections?
No
Do septic arthritis and osteomyelitis occur alone or together?
Either
How can infection spread in young children?
Directly from the bony metaphysis to the joint space
Why can infection spread directly from the bony metaphysis to the joint space in young children?
In young children, the synovial membrane of the hip, ankle, shoulder, and radial head inserts distally to the epiphysis
What proportion of neonates with septic arthritis have concomitant osteomyelitis?
Around half
What proportion of infants with septic arthritis have concomitant osteomyelitis?
1/5
In what joint is sepsis from adjacent osteomyelitis particularly common?
Hip
What joint is septic arthritis most common in?
Low limb joins - knee > hip > ankle
What are the common causative organisms of septic arthritis?
- Staph aureus
- Group A strep
- Gram -ve bacilli
When should mycobacterial infection be considered in septic arthritis?
- Immunocompromised
- Endemic areas
How does septic arthritis present?
- Fever and associated constitutional symptoms
- Joint pain, swelling, warmth, and/or redness
- Guarding of the affected area, e.g. refusal to weight bear
Why might the diagnosis of septic arthritis be difficult?
Signs and symptoms may be subtle and non-specific
Why is septic arthritis a medical emergency?
Bone and joint infections can be rapidly destructive
What can delay in diagnosis or treatment lead to in septic arthritis?
Irreversible damage to the joint, with associated long-term pain and functional impairment
How useful are blood tests in septic arthritis?
They are not diagnostic, and can only be used in the context of clinical findings
What factors predict septic arthritis (according to Kocher)?
- Fever >38.5
- Non-weight bearing, or pain with passive motion of the joint
- ESR >40mm/hour
- WBC >12
What investigations are helpful in septic arthritis?
- FBC, ESR, CRP
- Blood cultures
- Joint aspiration
- X-ray
- USS
What might be found on FBC in septic arthritis?
Markedly elevated neutrophil and platelet count
Is ESR or CRP a better predictor of acute infection?
CRP
Are blood cultures always positive in septic arthritis?
No
Are blood cultures always positive in osteomyelitis?
No, frequently negative
What tests are done on joint aspirate in septic arthritis?
Gram stain microscopy and culture
What is the limitation of x-ray in septic arthritis?
May be normal in early stages of infection, and bony changes can take up to 21 days to evolve
Why might USS be useful in septic arthritis? §
To demonstrate joint effusion and guide aspiration
When is MRI useful in septic arthritis?
If diagnosis is unclear
What is an alternative to MRI in septic arthritis?
Radionucleotide bone scanning
What is often the first-line antibiotic in septic arthritis?
Cefuroxime
Why is cefuroxime often the first line antibiotic in septic arthritis?
Broad spectrum with good bone penetration
How long should antibiotics be continued for in septic arthritis?
10-14 days IV, then switch to oral if adequate response
What is the most common cause of hip pain between 3-10 years?
Transient synovitis
Which gender is transient synovitis more common in?
Boys
What kind of diagnosis is transient synovitis?
Diagnosis of exclusion
What is the aetiology of transient synovitis?
Unclear, but viral, autoimmune, and allergic associations have been suggested
What proportion of children with transient synovitis report a viral infection during the preceding week?
Around half
How does transient synovitis most commonly present?
Painless limp in relatively well child
What features suggest an alternative diagnosis when considering transient synovitis?
- High fever
- Markedly elevated inflammatory markers
- Severe pain
- Functional impairment
What is found on hip x-ray in transient synovitis?
Normal
What is found on USS in transient synovitis?
May be small effusion
What happens in most cases of transient synovitis?
Settle quickly
When is review necessary in transient synovitis?
If limp persists
Why is review needed if the limp persists in transient synovitis?
To exclude Perthe’s disease or evolving JIA
What is rickets?
Defective ossification of the bony matrix
What can cause rickets?
- Deficiency of active form of vitamin D
- Deficiency of phosphate
- (Rarely) deficiency of calcium
What is the active form of vitamin D?
1,25-dihydroxyvitamin D, or 1,25-vitamin D
What conditions causing limp in 4-10 year olds require urgent intervention?
- Osteomyelitis
- Septic arthritis
- Non-accidental injury
- Malignant disease
- Testicular torsion
- Appendicitis
- Inguinal hernia
How does rickets present?
- Bone tenderness
- Joint pain
- Proximal muscle weakness
- Delayed dentition
- Increased frequency of fractures
- Growth delay
- Skeletal deformities
What skeletal deformities may be present in rickets?
- Bowing of long bones
- Persistent genu varum
- Splaying of rib cabe
- Costochondroal swelling (rachitic rosary)
What is the most common cause of rickets?
Vitamin D deficiency
What is the normal source of 1,25-vitamin D?
The skin
What % of bioavailable vitamin D is produced by the skin?
90%
How is vitamin D produced in the skin?
UV light converts 7-dehydroxycholesterol into vitamin D prohormone, which is then converted to 25-hydroxyvitamin D (calcidiol) in the liver, and then 1,25-dihydroxyvitamin D in the kidneys
Is cutaneous vitamin D production higher in lighter skin or darker skin individuals?
Lighter
What can deficiency of 1,25-dihydroxyvitamin D result from?
- Low exposure to UV light rays
- Nutritional deficiency
- Liver or kidney disease
Who is at higher risk of vitamin D deficiency?
Breastfed infants whose mothers are not exposed to sunlight, or themselves are not exposed to sunlight
What has happened to the incidence of vitamin D deficiency in the UK over the last few years?
Increased
What has potentially caused the increased incidence of vitamin D deficiency in the past few years?
Increased use of sunblock, preventing UV light from reaching the surface of the skin
How is vitamin D deficiency treated?
Between 3000-10,000 units daily (depending on age) for 4-8 weeks
What is found on x-rays in rickets?
- Impaired mineralisation of growth plates
- Cupping and fraying of margins of metaphyses
