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)
How are the different sybtypes of JIA classified?
- According to:
- Number of joints involved in the first 6 months
- Systemic involvement e.g. rash and fever
- Presentce of rheumatoid factor and HLA B27 tissue type
- Psoriatic arthritis and enthesitis are also subtypes
How does JIA present?
- Gelling (stiffness after periods of rest)
- Morning joint stiffness
- Swelling of joint due to fluid within
- Limp
- Deterioration in behaviour/mood and avoidance of previously enjoyed activities rather than pain
What are the later signs of JIA?
- Joint swelling due to fluir
- Inflammation
- Chronic arthritis
- Proliferation (thickening) of the synovium and swelling of periarticular soft tissues
What do investigations show in JIA?
Normal initiallly therefore diagnosis may be difficult i.e. normal FBC, CRP, ESR, -ve RhF, normal radiographs
- ANA - but may be present in healthy children too
- RF- two results required to diagnose; +ve associated with more aggressive disease
- ESR - highest in systemic-onset and polyarticular JIA; mildly elevated in oligoarticular JIA
- FBC - may show anaemia of chronic disease (microcytic or normocytic with low reticulocyte count)
What should you consider in a child with multi joint involvement, widespread pain and fatigue?
- Connective tissue disorder
- Sepsis
- Malignancy
What is the management of JIA?
Early referral to paediatric rheumatology; early treatment significantly improves outcome
MDT management
Medications
- NSAIDs and analgesics
- Joint injections - for oligoarticular JIA
- Methotrexate
- Systemic corticosteroids
- Cytokine modulators (‘biologics’) and immunotherapies e.g. anti TNA-alpha, IL-1, CTLA-4, IL-6.
What are the complications of JIA?
- Chronic anterior uveitis - regular ophthalmologic testing should be done to detect this
- Flexion contractures of the joints - joint held in most comfortable position
- Growth failure - anorexia, chronic disease and systemic corticosteroid therapy; can affect one limb; premature fusion of epiphyses may occur
- Anaemia of chronic disease
- Delayed puberty
- Osteoporosis - multifactorial causes
- Amyloidosis - causing renal failure due to proteinuria; rare now
What is the benefit of methotrexate? What is its side effect? What must be monitored?
- Early use reduces joint damage
- SE include nausea and it is less effective in systemic JIA
- Abnormal LFTs and bone marrow suppression
Why should systemic corticosteroids be avoided if possible in JIA?
Can cause growth suppression and osteoporosis but may be life saving in severe systemic arthritis or macrophage activation syndrome
When are biologic therapies given in JIA?
When refractory to methotrexate
BUT these are costly and given under strict national guidance
What % of children with JIA will require treatment into adulthood to maintain remission?
1 in 3 (33%)
What is the most common type of JIA? How many joints are invovled?
Oligoarthritis (49% of JIA cases)- 1-4 joints invovled; knee, ankle or wrist are most common
What is the gender ratio in JIA? What is the age of onset in most cases?
Most are more common in females (5:1 F:M ratio), except systemic arthritis and psoriatic arthritis which are 1:1.
Usual onset at 1-6 years (oligoarthritis persistent and extended, RF -ve polyarthritis). RF +ve polyarthritis onset is at 10-16 years; systemic arthritis at 1-10 years; psoriattic arthritis at 1-16 years; enthesitis-related at 6-16 years and undifferentiated at 1-16 years.
What anaesthetic is used during joint injections in children?
Sedation or inhaled anaesthesia (Entonox)
What is JIA also known as?
Still’s disease
Which autoimmune conditions are related to arthritis?
- IBD - erythema nodosum present
- Hypothyroidism
- SLE - butterfly rasg, hair loss
- Psoriasis
etc
What is genu varum?
Bow legs - normal in toddlers, pathological in rickets and Bluont disease in Black children
What is genu valgum?
Feet wide apart when standing with knees held together. Intermalleolar distance should be <8cm. Normal in many young children but should resolve.
What is pes planus? When is it normal? When is it pathological?
Flat feet - normal in children as they have no medial longitudinal arch and have fat pads. But arch should be demonstarted when standing on tip toes.
Pathological if absence of arch when tip-toeing; may indicate tendo-Achilles contracture, tarsal coalition or JIA and should be referred.
If symptomatic, advise arch support.
What are these musculoskeletal variations? When should they disappear?
- Metatarsus adductus
- Medial tibial torsion
- Femoral anteversion
3 different types of in toeing; shown below and resolve by 5-8 years.
Give the normal age ranges for these and the differential diagnoses that should be considered.
- Bow lgs
- Knock knees
- Flat feet
- In-toeing
- Toe walking
What is talipes equinovarus? What is the mild form called?
Clubfoot - should be distinguished from positional talipes which is normal from intrauterine compression and can bbe corrected with passive maniutaion.
What condition is clubfoot also associated with? What is the management?
Check for neuromuscular disorders (e.g. spina bifida) , spinal lesions or DDH.
Management: plaster casting and bracing (‘Ponsetti method’). Surgery in severe cases.
What is pes cavus and what is it associated with?
High arched foot
Neuromuscular disorders e.g. Friedreich ataxia and type I hereditary motor sensory neuropathy (peroneal muscular atrophy).
What is talipes calcaneovalgus? What is it associated with?
- Foot is dorsiflexed and everted
- Caused by intrauterine moulding and self-corrects
- Associated with DDH
What is a pathological cause of toe walking?
- Mild cerebral palsy
- Tightness of the Achilles tendon
- Inflammatory arthritis in the foot or ankle (JIA)
- Duchenne muscular dystrophy (in boys)
What are the ‘rules of growing pains’?
- Age range 3-12 years
- Symmetrical pain in lower limbs not limited to joints
- Pain never presents at the start of the day or after waking
- No limp, no activity limitation
- Normal pGALS, except for hypermobility in some
Further assessment required if presentation does not fit the rules.
Which chromosomal syndrome can cause joint hypermobility?
Down syndrome
Collagen disorders e.g. Marfan and Ehlers-Danlos syndrome
Name 3 bone tumours and their typical features
Malignant: osteoid sarcoma and Ewig tumour - pain and swelling or pathological fracture; usually in distal femur or proximal tibia.
Benign: osteoid osteoma - in adolescents in femur, tibia or spine; severe pain at night that improves with NSAIDs; x-ray shows demarcated radioluscent osteoid tissue. Surgical removeal with good prognosis.
What is the diagnosis…?
- Nocturnal wakening with leg pain?
- ‘Clink’ on hip movement on neonatal and early infant screening, limp in an older infant
- Febrile toxic-looking infant with irritability on nappy changing
- Sudden linp in an otherwise well young child
- Fever, erythematous rash, red eyes, irritability in infant or young child
What is the diagnosis…?
- Irritability, fever, resultance to move in an infant or young child
- Joint pain, stiffness, and restriction. Loss of joint function
- Hip pain in an obese adolescent boy
- Lethargy, unwillingness to do physical activities, irritability and rash
- Constitutional symptoms, lethargy, arthralgia in an adolescent female
