MSK: Part 7 Flashcards
How does meningococcal arthritis occur
- Deposition of circulating immune complexes containing meningococcal antigens
How is meningococcal arthritis treated
PENICILLIN
What causes tuberculous arthritis
MYCOBACTERIUM TUBERCULOSIS
What joints are commonly effected in tuberculous arthritis
Hip
Knee
Intervertebral discs
Pathophysiology of tuberculous arthritis
caveating granulomas
Rapid destruction of cartilage and adjacent bone
Clinical presentation of tuberculous arthritis
Fever
Night Sweats
Weight Loss
Pain, swelling and dysfunction
Diagnosis of tuberculous arthritis
- Culture synovial fluid
- Biopsy synovial fluid or intervertebral disc - CT guided
- X-ray may be normal but shows joint-space reduction and bone destruction
4
Treatment for tuberculous arthritis
9 months:
Rest joint and spine immobilised in cute phase
What is osteomyelitis
Bone marrow inflammation localised to one bone
What causes osteomyelitis
Haematogenous spread or due to local infection
What age group is effected by osteomyelitis
Children
How do adults get osteomyelitis
Secondary infection or direct trauma
Main causes of osteomyelitis
- Staph Aureus
- Coagulase negative staphylococci
- Haemophilus influenza
- Salmonella (SSA)
- Pseudomonas aeriguinosa and seratia marcesans in IVDU
Risk factors for osteomyelitis
- Diabetes mellitus
- Peripheral vascular disease
- Malnutrition
- Inflammatory arthritis
- Debilitating disease
- Decreased immunity
- Sickle cell disease
- Immunosuprresive drugs
- Trauma
Two ways bacteria can get into th bone
- Direct inoculation of infection into the bone via trauma
- Contigous spread of infection into the bone (not as easy):
Without breaking skin
Infection of adjacent soft tissue spreading into bone
Haematogenous seeding (hard to do)
What age group usually has osteomyelitis caused by spread of infection into th bone
Elderly: Diabetes mellitus Chronic ulcers Vascular disease Joint replacement Prostheses
What is haematogenous seeding
Infection from skin spreading to the blood then to the bone (Staphylococcus aureus from cannula on skin to blood then into bone)
EXAMPLE
What bones are usually effected in children in haematogenous seeding
Long bones - metaphysics (wide portion of a long bone between the epiphysis and the narrow diaphysis - contains growth plate) of the long bone
Why is the metaphysis most commonly effected in haematogenous seeding
- Here blood flow is slower, endothelial basement membrane is absent and the capillaries lack or have inactive phagocytic lining cells - all these factors predispose to bacteria migrating from blood into bone and the growth of bacteria in the bone
Where is haemotgenous seeding in adults
Vertebra
Why is the vertebra target for haematogenous seeding
With age, vertebra becomes more vascular thereby making bacterial seeding of the vertebral endplate more likely
What condition can cause risk for haematogenous seeding
- IVDU (in younger - clavicle and pelvis)
- Dialysis
- Sickle cell disease
- Urethral catheterisation and UTI
- Endocarditis
What bone does sickle cell disease cause bacteraemia in
Vascular necrosis of the hip
Acute changes to cells in osteomyelitis
- Inflammatory cells
- Oedema
- Vascular congestion
- Small vessel thrombosis
Chronic changes to cells in osteomyelitis
- Necrotic bone ‘sequestra’
- New bone formation - involucrum
- Neutrophil exudates
- Lymphocytes and histiocytes (tissue macrophages)
Pathophysiology of osteomyelitis
- Inflammatory exudates in the marrow leads to increased intramedullary pressure, with extension of exudate into bone cortex
- Causes rupture through periosteum and interruption of periosteal blood supply resulting in necrosis
- This leaves sequestra
- New bone called involucrum forms over it
What is sequestra
Pieces of separated dead bone
Clinical Presentation of osteomyelitis
- Dull pain at site that is aggravated by movement
- Fever, sweats, riggers and malaise
- ACUTE: Tenderness, warmth, erythema and swelling
- CHRONIC: Tenderness, warmth, erythema and swelling
Draining sinus tract which is associated with deep/large ulcers that fail to heal despite treatment - SEPTIC ARTHRITIS
Symptoms if osteomyelitis occurs in the hip, vertebrae or pelvis
Pain and that’s it
Why would osteomyelitis result in septic arthritis
- When infection breaks through cortex resulting in discharge of pus into the joint - knee, hip or shoulder
Where is septic arthritis caused by osteomyelitis common
Infants - patent transphyseal blood vessels and immature growth plates
Differential diagnosis of osteomyelitis
- CHARCOT JOINT - damage due to sensory nerves affected by diabetes
- Soft tissue infection (cellulitis and erysipelas)
- Avascular necrosis of the bone causes: steroids, radiation or bisphosphonate use)
- Gout
- Fracture
- Malignancy
Diagnostics of osteomyelitis
- Imagine (X-rays, bone scans and MRI)
- FBC
- Bone biopsy and culture to determine aetiology
What would an x-ray show in osteomyelitis
- Osteopenia
- Cortical erosions
- Sclerosis
- Sequestra
- Soft tissue swelling
When is an MRI for osteomyelitis done
Marrow oedema from 3-5 days
Soft tissue inflammation
AFTER X-ray (takes time for changes to be seen)
FBC results in osteomyelitis
- ESR and CRP raised
- Raised WCC in acute
- Chronic osteomyelitis - normal WCC
How is osteomyelitis treated
- Immobilisation
- IV TECLOPANIN
- IV FLUCOXACILLIN
- ORAL FUSIDIC ACID
- ESR and CRP monitoring
- Removal of dead bone (sequestrium)
How is tuberculous osteomyelitis caused
Haematogenous spread from a reactivated primary focus in lungs or GI tract
Clinical presentation of tuberculous osteomyelitis
- Local Pain
2. Swelling if pus collected
Diagnostics for tuberculous osteomyelitis
- BIOPSY - caveating granuloma
Treatment for tuberculous osteomyelitis
- 12 months with same treatment as for pulmonary tuberculosis
Where does prosthetic joint infection happen
Hips and Knees
Main causes of prosthetic joint infection
Staph A
Coagulase negative staphylococci (most frequent after hip replacement)
Gram-POSITIVES
Risk factors for Prosthetic joint infection
- Poor infection control
- Old age
- Diabetes
- Obesity
How do you prevent infections in prosthetic joints
- Plastic screen that walls off the anaesthetist from joint
- Lamina flow theatres with filtered air blowing out of the theatre to make it difficult for organisms to enter
- Antibiotics placed into bone cement and systemic antibiotics pre-op help minimise infection risk
Clinical presentation of prosthetic joints
- Not acutely infected
- Systemically well
- Tender, hot, swollen joint
Diagnostics for prosthetic joints
- Tissue sample from surgery
- ESR and CRP raised
- Alpha defensive
- Joint aspiration - GOLD STANDARD
Why is joint aspiration the gold standard for prosthetic joints
- Identifies organisms and antibiotic sensitivities
2. MUST BE DONE OFF ANTIBIOTICS FOR 2 WEEKS MINIMUM
Treatment for prosthetic joints
- Antibiotics suppression
- Debridement and retention of prosthesis
- Excision arthroplasty
- One-stage arthroplasty exchange
- Two-stage arthroplasty exchange
6/ A,mutation in severe infection
What are the aims of treatment in prosthetic joint infections
- Eradicate sepsis
- Relieve pain
- Restore function
When is excision arthroplasty done
High risk frail and co-morbidities who have infection that is uncontrolled with antibiotic suppression
- People with low functional demand
- Effectie in removing infection but not good at restoring function
What is one-stage arthroplasty exchange
- Radical debridement
- Implantation of new prosthesis with antibiotic cement
- Systemic and local antibiotics
- Avoid bone graft
- 85% success rate
What is two-stage arthroplasty exchange
- radical debridement
- Local antibiotic spacer +/- systemic antibiotics
- Interval stage (suture up and wait for infection to clear)
- Implantation of new prosthesis with antibiotic cement
- Routine antibiotic prophylaxis
- 90-95% success
Define major trauma
- Serious and often multiple injuries where there is a strong possibility of death or disability with an injury severity score greater than 15
What is an injury severity score
- Each injury is scored depending on the abbreviated injury scale
- Assigned to one of six body regions:
Head + Neck
Face
Chest
Abdo
Extremity - pelvic skeleton
external
What is the Abbreviated injury scale
- Minor - Superficial Laceration
- Moderate - Fractured sternum
- Serious - Open fracture humerus
- Severe - Perforated trachea
- Critical - Ruptured Liver
- Unsurvivable - Total aortic transection
How is an ISS score made
Only the highest score in each region is counted
The 3 highest scores are counted and then squared and then x3 to generate ISS
Score of 6 in any region gets automatic ISS of 75
What is Juvenile Idiopathic Arthritis
Joint swelling/Stiffness/limitation in those older than 6 weeks but under 16 with not other causes
7 subtypes according to presentation
What doctor would a child age 15 see
Paediatrician
Normal doctor over 16
What usually causes idiopathic arthritis
Autoimmune
Gene combinations
- infection
- Reactive
- Trauma
- Malignancy
- Connective tissue disease
What pathologies can be seen in Juvenile Idiopathic Arthritis
- Synovitis
- Persistent oligoarthritis
- Extended oligoarthritis
- Rheumatoid factor negative polyarthritis
- Rheumatoid factor positive polyarthritis
- Enthesitis
- Stills disease
What are children with JIA at high risk of
UVEITIS - membrane lining the eyes is similar to that of joint and suffer from CHRONIC ANTERIOR UVEITIS
They can go blind
How do we prevent uveitis in juvenile idiopathic arthritis
OPTHALMIC SCREENING EVERY 3 Months
In what individuals is persistent oligoarthritis found in
Less than 6
What joint is effected in persistent oligoarthritis
Knee
Diagnosis for JIA with persistent oligoarthritis
ANA negative
HIGH RISK UVEITIS
Treatment for persistent oligoarthritis in JIA
Grow out of it so leave
What gender is extended oligoarthritis usually effecting
Girls
Peak age of extended oligoarthritis
2-4
What has a worse prognosis extended or persistent
Extended
What risk is associated with extended oligoarthritis
UVEITIS
What defines rheumatoid factor negative polyarthritis in JIA
Acute or insidious onset in more than 5 joints
Clinical features of rheumatoid factor negative polyarthritis
SYMMETRICAL
malaise, fever and anaemia
UVEITIS
When does rheumatoid factor positive polyarthritis manifest
Late adolescent in girls
What condition is rheumatoid factor positive polyarthritis similar to
RA
FBC in rheumatoid factor positive polyarthritis
CCRP antibody is negative
Risk in RFPP
UVEITIS
related to smoking
When does enthsitsis related JIA occur
HLA-B27 positive - spondyloarthritis in young people
What age does enthesitis related JIA occur
MALES OVER 6
HIGH RISK UVEITIS
IBD associated
Symptoms of enthesitis related JIA
IBD
Inflammatory back pain or sacroiliac pain
When does Stills disease occur
4-6 years
What is stills disease
Systemic illness with daily fever - fever spikes daily at same time
Evanscent rash and artritis
Anaemic, raised platelets and high ferritin
Lymphadenopathy , hepatosplenomegaly and serositis
Non-medical Treatment for JIA
- Information and education
- Support and liaison with school
- Physiotherapy
- Occupational therapy
- Psychology
Medical treatment for JIA
- Steroid joint injections - ENTONOX (laughing gas) for general anaesthetic
- IBUPROFEN
- METHOTREXATE
- Systemic steroids
- IV INFLIXIMAB
Where is osteomyelitis seen in children
Arms + Feet
Where is osteomyelitis seen in adults
Feet
Spine
Hips
How does TB spread from ling to bone
HAEMATOGENOUS SPREAD
Pathophysiology of osteomyelitis
Leukocytes invade bone to try engulf pathogens
However produces pus which spreads into blood vessels and blocks blood = sequestra
Bone trys producing now bone to replace necrosed bone = involucrum
Complication of osetomyelitis in children
Subperiosteal abscesses
What two types of osteomyelitis is there
Sclerotic (increased bone density)
Suppurative (pus filled)
What is involucrum
Layer of new bone outside existing bone
Bone biopsy in osteomyelitis
- 16sRNA PCR
2. Inflammation and osteonecrosis