Rheumatological disease in a child (arthritis; infective, juvenile idiopathic, reactive) Flashcards
What is the most common arthritis in childhood?
Reactive arthritis
What are the causes of reactive arthritis in children?
- Enteric bacteria (Salmonella, Shigella, Campylobacter and Yersinia)
- Viral infections
- STIs in adolescents (chlamydia, gonococcus)
- Mycoplasma
- Lyme disease (Borellia burgdorferi)
- Rheumatic fever and post-streptococcal infection
What are the findings on imaging/bloods in reactive arthritis?
- Mildly elevated acute-phase reactants (CRP, ESR)
- X rays are normal
What is the management of reactive arthritis? What is the prognosis?
No treatment/ NSAIDs - complete recovery, self-limiting.
What is the aetiology of septic arthritis?
- Direct inoculation e.g. trauma or surgery or wound puncture (chickenpox)
- Haematogenous seeding - URTI precedes ~80% of cases
- Extension from bone/osteomyelitis - common in neonates who have transphyseal vessels that allow spread to the joint
What age group in children is septic arthritis most common in?
<2 years old
What is the most common cause of septic arthritis in a neonate?
Group A streptococcus (may be exposed frm vaginal delivery)
What is the most common cause of septic arthritis in an unimmunised infant/child?
Hib unvaccinnated - H. influenzae
What is the most common cause of septic arthritis in children?
staphylococcus aureus
What is the most common cause of septic arthritis in adolescents?
Staphylococcus aureus and neisseria gonorrhoea
What does this posturing signify?
Septic arthritis of the hip in an infant to reduce intracapsular pressure - any leg movement is painful and resisted
How does septic arthritis present in a child/infant?
- Erythematous, warm, tender joint
- Reduced range of movement
- Acutely unwell child
- Febrile
- Effusion may be detectable in peripheral joints
NB: diagnosis in an infant can be difficult as the joint is covered with subcutaneous fat
What % of septic arthritis cases coexist with osteomyelitis?
15% of cases of osteomyelitis also have septic arthritis
What do investigations show in septic arthritis?
Bloods:
- Increased WCC (>12)
- Increased ESR (>40) and CRP (>20)
- Blood culture
Imaging:
- X ray - normal initially but may show soft tissue swelling and increased size of joint space
- USS deep joints - can identify effusion
Invasive:
- Joint aspiration - definitive diagnosis by culture; done immediately unless this would significantly delay antibiotics
What is the management of septic arthritis?
- Antibiotics alone are rarely indicated - usually cephalosporins
- Urgent surgical irrigation and debribement followed by IV antibiotics - standard of care for hips
What is the pathophysiology of septic arthritis and what are the complications?
Pathophysiology: enzymatic destruction and increased joint pressure which may cause osteonecrosis
Complications: femoral head destruction/deformity, growth disturbance.
Prognosis: good unless diagnosis is delayed (>4 days), child is <6 months, hip rather than knee affected and if there is associated osteomyelitis.
What is the Kocher Criteria for septic arthritis?
- WBC >12
- inability to weight bear
- fever >38.5
- ESR >40
What is the most common chronic inflammatory joint disease in children and adolescents in th eUK?
Juvenile idiopathic arthritis (JIA)
Define JIA.
Persistent joint swelling of >6 weeks duration, presenting before 16 years of age in the absence of infection or any other defined cause.
In 95% it is clinically and immunologically distinct from RhA in adults.
How common is JIA?
affects 1 in 1000 children (similar to epilepsy)