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Flashcards in Locomotor System Deck (78)
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1
Q

What is the pathophysiology of septic arthritis?

A

Damage occurs within hours from cartilage degradation by enzymes and bone ischaemia from increased pressure

2
Q

What is the cause of septic arthritis?

A

Most commonly is haematogenous spread of s aureus

Also can develop from osteomyelitis (esp neonates) infection spreads from metaphysis via transphyseal vessels

or direct inoculation

3
Q

What are the most common causative organisms in septic arthritis?

A

S aureus (most)

Group B strep
Gram -ve bacilli
Group A step
Strep pneumonia
Neisseria gonorrhoea
4
Q

Give examples of gram -ve bacilli

A
E Coli
Salmonella
Shigella
Leigonella
Pseudomonas
6
Q

What is group A strep?

A

Streptococcus pyogenes

cause strep throat, impetigo

7
Q

What is group B strep?

A

Streptococcus agalactiae

8
Q

How does septic arthritis present in children?

A

Easily missed! Infants characteristically do not appear ill and may be confused with more common conditions eg transient synovitis and trauma

Fever (but 50% do not have)
Joint pain
Unwillingness to move affected join (eg limp / refusal to weight bear)
Hot, warm, swollen joint

9
Q

What age group / sex does septic arthritis most commonly affect in children?

A

Preschool infants
Toddlers

Half present in first 2 years

Twice as common in M

9
Q

Group A and B streptococcus are both beta-haemolytic. What are alpha-haemolytic streptococcus?

A

Streptococcus pneumoniae

Streptococcus viridans

(gamma- haemolytic = enterococcus)

10
Q

What joints are most commonly affected in children with septic arthritis?

A

75% = lower limb

Knee > hip > ankle

Other 25% = upper limb

11
Q

What investigations are performed for septic arthritis?

A

CRP, synovial WCC, and % of polymorphonuclear cells and lactate = best markers

FBC
Synovial fluid examination
Synovial tissue culture
Blood culture
PCR
Tests for Lyme disease
Immunology
Imaging - plain radiographs, US, CT or MRI
12
Q

What is the medical and surgical management of septic arthritis?

A

Surgical drainage and lavage of the joint

High dose IV abx

  • Start before results of cultures are known
  • IV for 2-3 weeks then switch PO for 2-4 weeks

1st line : flucloxicillin (clindamycin if allergy)

If MRSA suspected = vancomycin (or teicoplanan)

13
Q

What would a plain XR show of a septic joint?

A

Usually normal initially

Widened joint spaces suggest effusion

Later signs:

  • Subluxation / dislocation
  • Space narrowing
  • Erosive changes
14
Q

When would an MRI be used in septic arthritis?

A

If diagnosis in doubt to exclude osteomyelitis

15
Q

When would a CT be used in septic arthritis?

A

To image sternoclavicular and sacroiliac joints

16
Q

What other management may improve recovery from septic arthritis?

A

Splintage

  • In position of function
  • Improves pain
  • Allow inflammation to settle

Physiotherapy

17
Q

Which joint has the worst prognosis in septic arthritis?

A

Septic hip - potential complication is complete destruction of femoral head and capsule, dislocation and 30% loss of growth of potential femur

18
Q

What is developmental dysplasia of this hip (DDH)?

A

Previously called congenital dislocation of the hip (CDH)

The acetabulum is shallow and does not adequately cover the femoral head, leading to the hip joint being dislocatable or dislocated

19
Q

What is the spectrum of DDH?

A

Wide spectrum of severity ranging from mild acetabular dysplasia with a stable hip, through more severe forms of dysplasia with neonatal hip instability, to established hip dysplasia with or without later subluxation or dislocation

Not always detectable at birth

20
Q

Which hip is more commonly dislocated in DDH?

A

Left hip

Possibly due to more common left occiput anterior position in utero, limiting abduction of the left hip

21
Q

What % of DDH are bilateral?

A

20%

22
Q

List some RF for DDH (6)

A

1) Breech position (17x inc risk)
2) FH
3) Female sex (80% F)
4) Impaired limb movement eg oligohydraminous or multiple pregnancies
5) Prematurity
6) Neuromuscular disorders eg CP

23
Q

How common is DDH? When is DDH usually picked up?

A

1-3% newborns

6-8 week baby checks

24
Q

What is DDH associated with?

A

Tallipes

25
Q

What is important to include in an examination for DDH?

A

1) Observation of symmetrical skin creases and leg length
2) Ortolani test
3) Barlow test

26
Q

What is the Barlow test?

A

Pushing backwards to try and dislocate the hip

Feeling a clink as dislocatable hip slips out of the acetabulum

27
Q

What is the Ortolani test?

A

Abduct the hips to try to relocate hip

Fingers push femur forwards into acetabulum

A dislocated hip will not abduct fully, and ‘clunks’ as it relocates into the acetabulu

28
Q

What investigations may be performed in DDH?

A

Dynamic USS to assess hip stability and acetabular development in infants

US used in <4.5 months but pelvic X-rays used more in older infants and children - once femoral head ossification centre as developed

+/- CT / MRI

Athrography used peri-operatively when deciding between open and closed reduction

29
Q

What is the Galeazzi sign?

A

Child lies supine with hips and knees flexed to 90 degrees and the height of each knee compared

30
Q

How may DDH present in an older child?

A

Limited abduction when fully flexed

May walk on toes on affected side or present with a painless limp

31
Q

How may bilateral DDH present?

A

Often a waddling gait with hyperlordosis

Difficult to diagnosis as:

  • Absent Galeazzi sign
  • Absent asymmetrical thigh and skin folds
  • Absent asymmetrical decreased abduction
32
Q

What is the management of DDH?

A

Early diagnosis important for good prognosis

Most unstable hips stabilise spontaneously by 2-6 weeks of age and any hip that remains dislocatable or pathologically unstable after this time requires prompt treatment

1st line = bracing

Surgery for those where bracing fails or in children diagnosed >6 months

33
Q

What bracing is used for DDH?

A

A dynamic flexion-abduction orthosis (Pavlik harness) and splinting - used to maintain hip reduction

Start ASAP

Adjust harness as child grows and hip stabilises

34
Q

How successful is bracing for DDH?

A

Very effective

If started within 90 days of age, only approx 5% need any further treatment

35
Q

What are some risks of bracing for DDH?

A

Avascular necrosis
Temporary femoral nerve palsy

Pavlik harness contraindicated if child >4.5-6 months and when hip irreducible

36
Q

What is the surgical management of DDH?

A

Closed reduction with adductor or psoas tenotomy (to decrease adduction contracture)

Followed by 3-4 months in a plaster cast or abduction brace

37
Q

What are potential long term complications of DDH?

A

Premature degenerative joint disease and low back pain

DDH accounts for 9% of all primary hip replacements and 29% of those 60yr or over

Follow up required until hip clinically stable and normal imaging

38
Q

List some causes of leg pain and limp in children

A

Organic:

  • Transient synovitis
  • Septic arthritis
  • Legg-Calvé-Perthes disease
  • Slipped capital femoral epipysis
  • Trauma
  • Osteomyelitis
  • Neoplastic disease
  • Systemic disease

Non-organic:
- Growing pains

39
Q

What is the most common cause of a limp?

A

Transient synovitis

Important to distinguish from septic arthritis which can lead to obstruction of joint

40
Q

What is transient synovitis?

A

Self-limiting condition in which there is inflammation in the synovial of the capsule of the hip joint

41
Q

What age group / sex is transient synovitis more common in?

A

Boys aged 2-8 years

42
Q

How does transient synovitis present?

A

Sudden onset of limp

No systemic symptoms

Single joint pain

No pain on passive movement

Often preceded by URTI

43
Q

What do investigations show in transient synovitis?

A

Diagnosis of exclusion

Normal investigations and radiographs

Infection screen and joint aspiration performed to exclude bacterial infection

May show signs of preceding infection eg raised WCC, CRP, pyrexia

44
Q

What does fever, swelling, erythema and tenderness in a child presenting with a limp?

A

Osteomyelitis

45
Q

What may investigations show in osteomyelitis?

A

High CRP and WCC

Diagnosis using radiography, bone scan or MRI

46
Q

What is Legg-Perthes disease?

A

Osteochondritis leading to avascular necrosis of femoral head

47
Q

In which population is Legg-Perthes disease more common?

A

4:1 M:F

Ages 4-11 years, peak 4-7 years

48
Q

What can Legg-Perthes disease follow?

A

Transient synovitis

49
Q

How does Legg-Perthes disease present?

A

Initially painless

Pain and limp when feature occurs

50
Q

How is Legg-Perthes disease diagnosed?

A

Radiography or MRI

51
Q

In which population do slipped capital femoral epiphysis tend to occur?

A

Overweight teenage boys

52
Q

How do slipped capital femoral epiphysis present?

A

Gradual onset of pain in groin or knee

53
Q

How is slipped capital femoral epiphysis diagnosed?

A

Frog leg Radiography

54
Q

What characteristics of pain suggest organic and inorganic causes of leg pain?

A

Organic:

  • Day and night
  • Interrupts play
  • Unilateral
  • Located in joint
  • Limp or refusal to walk

Non-organic:

  • Only at night
  • Primarily school days
  • No interference with normal activities
  • Located between joints
  • Bilateral
  • Normal gait
55
Q

What features of a history suggest organic and inorganic causes of leg pain?

A

Organic:

  • Weight loss
  • Fever
  • Night sweats
  • Rash
  • Diarrhoea

Inorganic:
- Otherwise healthy child

56
Q

What features on examination suggest organic and inorganic causes of leg pain?

A

Organic:

  • Point tenderness
  • Redness
  • Swelling
  • Limitation of movement
  • Muscle weakness or atrophy
  • Fever, rash, pallor, LN, organomegaly

Inorganic:
- Normal examination or minor changes such as coolness or mottling of leg

57
Q

Where does pain in the hip refer to?

A

The knee - so must do full examination of leg and groin

58
Q

What may children with transient synovitis go on to develop?

A

Reactive arthritis aka post-infectious arthritis

Form of arthritis that occurs during or shortly after extra-articular infection

59
Q

How is irritable hip / reactive arthritis / transient synovitis managed?

A

Symptomatic - paracetamol and NSAIDs

Improvement occurs within days

60
Q

What does reactive arthritis have a genetic association with?

A

HLA-B27

61
Q

When does reactive arthritis occur and is it common in children?

A

Secondary to a GI or genitourinary infection

Not common in children

62
Q

What is juvenile idiopathic arthritis (JIA)?

A

A group of conditions that present in childhood with joint inflammation lasting 6 weeks r which no other cause is found aged <16yr

63
Q

How common is JIA?

A

One of the most common rheumatic diseases of children and is a major cause of chronic disability

64
Q

How is JIA characterised?

A

Synovitis or peripheral joints with soft tissue swelling and effusion

65
Q

What are the 3 main patterns of presentation of JIA?

A

1) Systemic
2) Polyarticular
3) Pauciarticular

66
Q

How common is systemic JIA?

A

= Still’s disease

Rarest form of JIA

67
Q

How may systemic JIA present?

A

Diagnostic puzzle as may not have joint symptoms initially

Child looks ill with:

  • Remitting fever
  • Variable rash
  • Hepatosplenomegaly
  • Anaemia
  • Weight loss
  • Abdo pain
68
Q

How is systemic JIA confirmed?

A

Difficult

No characteristic laboratory findings, RF negative

Sepsis and malignant are often considered as ddx

69
Q

How do children with polyarticular JIA present?

A

Painful swelling and restricted movement of both large and small joints

Commonly symmetrically distributed

Systemic features not prominent but poor weight gain and mild anaemia may occur

Morning stiffness common and young children may be irritable

70
Q

What may be found on bloods of polyarticular JIA?

A

RF negative

Antinuclear antibodies may be positive

71
Q

What is the prognosis of polyarticular JIA?

A

Good

72
Q

Who does pauciarticular JIA usually affect?

A

Girls under the age of 4

73
Q

What joints does pauciarticular JIA involve?

A

Fewer than 5 joints

Commonly knees, ankles and elbows

74
Q

How does pauciarticular JIA present?

A

Joints identical to those in polyarticular JIA

Systemic symptoms minimal

75
Q

How are polyarticular and pauciarticular JIA distinguished from eachother?

A

1) Number of joint affected :
- Pauciarticular = <5

2) Risk of chronic iridocyclitis:
- In pauciarticular arthritis, inflammation of the inner structures of the eye can lead to loss of vision and potentially permanent blindness
- Changes are only detectable by slit lamp examination this regular ophthalmological exams necessary

76
Q

What are the main aims of JIA management? (3)

A

1) Reduce joint inflammation
2) Maintain funciton
3) Prevent deformity

77
Q

How is joint inflammation reduced in JIA?

A

NSAIDs

Corticoseteroids in severe systemic disease unresponsive to other therapies

Steroid injection into selected joints (but should not be routine)

Hydroxychloroquine, penicillamine, gold injections, MTX and immune regulatory drugs in severe disease

78
Q

How is joint function maintained in JIA?

A

Physical and occupational therapy

Daily exercises, hydrotherapy, day and night splints