the painful limb, knee & back

the painful limb, knee & back

1. growing pains

   • aka nocturnal idiopathic pain
   • =episodes of generalised pain in lower limbs
   • common in preschool & school-aged kids
   • pain often wakes child from sleep
   • pain settles w/ massage or comforting
   • features needed for diagnosis
     • age range 3-12 years
     • pains symmetrical in lower limbs & not limited to joints
     • pains NEVER present @ start of day after waking
     • physical activities not limited; NO LIMP
     • physical exam normal & otherwise
       • except for some w/ joint hypermobility

2. hypermobility

   • older kids or teens
     • MSK pain confined mainly lower limbs
       • worse after exercise
     • joint swelling absent/transient
   • distribution
     • generalised
     • limited to peripheral joints
       • hands & feet
   • upper limb findings
     • symmetrical hyperextension of thumbs
     • fingers that can be hyperextended onto forearms
     • elbows that can be hyperextended beyond 10 deg
     • palms can be placed flat on floor w/ knees straight
   • lower limb finding
     • knees that can be hyperextended beyond 10 deg
     • flat feet w/ normal arches on tip toe
       • feet over-pronated secondary to ankle hypermobility
   • mild degrees are a normal finding in younger female kids
   • many are asyptomatic
     • helps for dancing & gymnastics
   • some experience recurrent mechanical joint & activity-related mm pain
     • specialist assessment needed
     • advice about
       • footwear
       • exercises
       • orthotics
   • a feature of other conditions
     • chromosomal disorders
       • Down syn
     • inherited collagen disorders
       • Marfan syn
       • Ehlers-Danlos syn

3. complex regional pain syndromes

   • aka idiopathic pain syndromes
   • localised or generalised
     • localised
       • clinical features
         • extreme & incapacitating pain
           • trigger= minor trauma, can be w/o clear precipitant
         • foot & ankle involvement
           • often unlit
           • cool to touch
           • swelling & mottling
           • held in flexion w/ minimal (if any) active movement
             • normal range of passive movements possible w/ distraction
           • bizarre posturing
         • hyperaesthesia (increased sensitivity to stimuli)
         • allodynia (pain from a stimulus that doesn't normally cause pain)
       • present in a wheelchair
     • generalised
       • clinical features
         • severe widespread pain
         • disturbed sleep patterns
         • feeling exhausted
         • extreme tenderness over soft tissues
         • absent or fewer tender points like those found in adults with fibromyalgia
   • usually present in teen females
   • otherwise well
     • physical exam otherwise normal
   • unknown cause
     • but pts often have sig stresses in lives
   • need to exclude organic pathology
   • MDT approach needed
     • mostly physical therapy based
       • community or inpt

4. acute-onset limb pain

   • osteomyelitis
     • infection of metaphysis of long bones
     • commonest sites
       • distal femur
       • proximal tibia
     • route
       • usually due to haematogenous spread of pathogen
       • direct spread from infected wound
     • swollen skin directly over affected site
     • can spread to cause septic arthritis
       • in areas where joint capsule is inserted distal to epiphyseal plate- e.g. hip, elbow, shoulder
     • causative pathogens
       • Staph .aureus
         • causes most infections
       • in the unimmunised
         • H. influenzae
         • TB
       • Streptococcus
       • if sickle cell anaemia
         • Staph
         • Salmonella
     • presentation
       • markedly painful immobile limb (pseudoparesis) in child w/ acute febrile illness
       • swelling & exquisite tenderness over infected site
       • erythematous & warm over infected site
       • moving limb causes severe pain
       • possible sterile effusion of adj joint
       • more insidious presentation in infants
         • swelling & reduced limb movement
           • initial sign
       • outside infancy
         • back pain
           • vertebral infection
         • groin pain
           • pelvic infection
         • multiple foci
           • disseminated Staph or H. influenze infection
     • Ix
       • blood cultures usually +ve
       • raised WCC
       • ESR/CRP raised
       • X-rays
         • normal
           • takes 7-10 days for subperiosteal new bone formation & localised bone refraction to be visible
         • may show soft tissue swelling
         • characteristic changes (chronic osteomyelitis)
           • periosteal rxn along lateral shaft of tibia
           • multiple hypodense areas within metaphyseal regions
       • US
         • periosteal elevation @ presentation
       • MRI
         • allow IDn of subperiosteal pus & purulent debris (i.e. infection) in bone
       • radionuclide bone scan
         • helpful if site of infection unclear
     • Rx
       • parental Abx promptly for several weeks
         • prevention of
           • bone necrosis
           • chronic infection w/ discharging sinus
         • iv Abx given until clinical recover & ESR/CRP normal
           • fb oral therapy for several weeks
       • aspiration or surgical decompression of subperiosteal space
         • if atypical px
         • if immunodef kid
       • surgical drainage
         • if not responding quickly to Abx
       • affected limb initially rested in splint
         • then subseq mobilised
   • malignant disease
     • acute lymphoblastic leukaemia
       • bone pain in kids
         • sometimes primarily @ night
       • frank arthritis
     • neuroblastoma
       • usually young kids
       • presentation of mets- sx hard to localise
         • systemic arthritis
         • bone pain
     • bone tumours
       • osteogenic sarcoma
       • Ewing tumour
       • rare
       • present w/ swelling or pathological fracture
   • osteoid sarcoma
     • benign tumour
     • affects teens
       • esp boys
     • involves femur or tibia or spine
     • presentation
       • pain more severe @ night
         • improves w/ NSAIDs
       • involves femur or tibia or spine
       • if near a joint
         • localised tenderness
         • soft tissue swelling
         • joint effusion
       • scoliosis if in spine
     • X-ray
       • usually diag
       • sharply demarcated radiolucent nidus of osteoid tissue w/ sclerotic bone around it
       • if normal, CT or MRI
     • Rx- surgical removal

5. the painful knee

   • hip pain often referred to knee
   • Osgood-Schlatter disease
     • osteochondritis of the patellar tendon insertion @ knee
     • often affects physically active teen males
       • esp football or basketball
     • presentation
       • knee pain after exercise
       • localised tenderness over knee
       • swelling over tibial tuberosity
     • Mx
       • reduced activity
       • physiotherapy for quadriceps mm strengthening
       • hamstring stretches
       • orthotics
       • knee immobiliser splint
   • chondromalacia patellae
     • softening of articular cartilage
     • often teen females
     • causes pain when patella tightly apposed to femoral condyles i.e.
       • standing up from sitting
       • on walking up stairs
     • assoc w/ hypermobility & flat feet
       • suggests biomechanical component to aetiology
     • Rx
       • rest
       • physiotherapy for quadriceps mm strengthening
   • osteochondritis dissecans (segmental avascular necrosis of subchondrial bone)
     • presents as knee pain in physically active teen
       • w/ localised tenderness over femoral condyles
       • pain caused by separation of bone & cartilage from medial femoral condyle ff avascular necrosis
         • complete separation of articular fragments may -> loose body formation & sx of knee locking or giving way
     • Rx
       • rest & quadriceps exercises
       • arthroscopic surgery
   • subluxation & dislocation of patella
     • subluxation
       • produces feeling of instability/giving way of knee
       • often assoc w/ general hypermobility
     • dislocation
       • usually laterally
       • sudden
       • rare
       • severe pain
       • reduction occurs spontaneously or on gentle extension of knee
       • Rx
         • quadriceps exercises
         • surgery to realign pull of quadriceps on patellar tendon
   • injuries
     • contact sports -> acute knee inj
       • inj to menisci & ligaments common in teens
         • MRI to determine extent of damage
         • conservative mx
         • these inj in infants & young kids-> fractures
           • cos ligaments stronger than their bone
     • non-contact sports w/ sustained activity-> chronic inj &over syndromes

6. back pain

   • concerning in very young & pre-teen girls
     • cause can often be IDed (unlike adults)
       • mechanical causes
         • muscle spasm or soft tissue pain
           • from sports-rel in
           • poor posture
           • abnormal loading
       • tumours: benign or malignant
         • spine is common site for osteoid osteoma
         • spine can be primary site for many tumours
       • vertebral osteomyelitis or discitis
         • localised tenderness
         • infants
           • reluctance to walk or bear weight
           • pain on spine flexion
         • fever
         • systemic upset
         • plain x-ray +/- MRI
         • Rx= iv Abx
       • spinal cord or nerve root entrapment
         • from tumour
         • or prolapsed iv disc
         • often assoc w/ trauma or heavy lifting
       • Scheuermann disease
         • osteochondrosis of vertebral body
         • may present w/ fixed thoracic kyphosis +/- back pain
         • diag on X-ray
           • radiographic changes often incidental finding & pt often asymptomatic
       • complex regional pain syn
         • diagnosed when no physical cause found
         • exacerbated by psychological stress
       • spondylolysis/spondylolisthesis
         • stress fracture of pars interarticularis of vertebra
         • increased risk w/ certain sports
           • bowling in cricket
           • gymnastics
         • if bilat-> spondylolisthesis
           • forward slip of vertebral body
             • & potential cord or nerve root compression
         • X-ray + CT
   • red flag clinical features
     • young age
       • pathology more likely
     • high fever
       • infections
     • night waking, persistent pain
       • osteoid sarcoma
       • tumours
     • painful scoliosis- infection or malignancy
     • focal neuro signs- suggest nerve root/spinal cord compression
       • nerve root irritation
       • loss of bladder/bowel control
     • assoc weight, systemic malaise- malignancy