Bone and Joint Infection Osteomyelitis/Septic Arthritis

Question 1

What is the name of bone infection?

Answer 1

Osteomyelitis

Question 2

What is the difference on x-ray between acute and chronic osteomyelitis?

Answer 2

Acute- no bone damage seen on x-ray
Chronic- bone damage seen on x-ray

Question 3

Septic arthritis?

Answer 3

Infection of the joint

Question 4

In which age group in acute osteomyelitis more common in?

Answer 4

Children
Boys > girls

->often in more deprived areas

Question 5

Acute osteomyelitis can occur in adults, usually in those with underlying causes such as?

Answer 5

Usually some type of immunocompromise
e.g. diabetes, rheumatoid arthritis, steroids, sickle cell disease

Question 6

What is usually the source of infection in acute osteomyelitis?

Answer 6

Usually haematogenous spread e.g. child scraping knee and entering through skin

Question 7

Okay lets break this down a bit

In infants, what is the most common cause of infection which leads to acute osteomyelitis?

Answer 7

Infected umbilical cord

Question 8

Okay lets break this down a bit

In children, what is the most common cause of infection which leads to acute osteomyelitis?

Answer 8

Boils, tonsillitis, skin abrasions

Question 9

Okay lets break this down a bit

In adults, what is the most common cause of infection which leads to acute osteomyelitis?

Answer 9

UTI, arterial line, chest infection, gall bladder infection

Question 10

What is the most common causative microorganism of acute osteomyelitis?

Answer 10

Staph. Aureus

Question 11

What is the most common causative microorganism of acute osteomyelitis in infants <1yr?

Answer 11

Staph Aureus-most common
Group B streptococci- common in childbirth etc
E.Coli

Question 12

What is the most common causative microorganism of acute osteomyelitis in older children?

Answer 12

Staph Aureus- most common
Strep pyogenes
Haemophilus influenzae

Question 13

What is the most common causative microorganism of acute osteomyelitis in adults?

Answer 13

Staph Aureus- most common
Pseudomonas aeruginosa- often of foot

Question 14

What would be the causative microorganism of patients with acute osteomyelitis and diabetic foot and pressure sores?

Answer 14

Mixed infection including anaerobes

Question 15

Which microorganisms tend to cause vertebral osteomyelitis?

Answer 15

S.Aureus
TB

Question 16

Which microorganisms tend to cause osteomyelitis related to sickle cell disease?

Answer 16

Salmonella

Question 17

Which bones does acute osteomyelitis tend to affect more?

Answer 17

Long bones in the metaphysis- distal femur, proximal tibia/humerus

Question 18

Which joints does acute osteomyelitis tend to affect more?

Answer 18

Joints with intra-articular metaphysis e.g. hip and elbow

Question 19

How can a patient get septicaemia from osteomyelitis?

Answer 19

Build up of pus within bone- usually after trauma- which can burst out into the joint and cause infection of blood or septic arthritis

Question 20

What is the treatment prognosis like for acute osteomyelitis?

Answer 20

As acute, can treat aggressively before bone destruction

Question 21

Sequestrum?

Answer 21

Necrosis of bone, no blood supply

Question 22

Involucrum?

Answer 22

Formation of new bone around the dead bone

Question 23

No matter how much antibiotic is given, it cannot get into the sequestrum, why is this?

Answer 23

It’s dead bone with no blood supply
The extra involucrum around it isolates the dead bone even more

->these factors are seen in chronic osteomyelitis

Question 24

What are the clinical features of acute osteomyelitis in infants?

Answer 24

Redness and infection around umbilicus
Failure to thrive
Not feeding
Pseudo-paralysis

Question 25

What are the clinical features of acute osteomyelitis in children?

Answer 25

Severe pain Reluctant to move Swinging pyrexia Malaise; vomiting, nausea ->classical presentation is injury a few days ago but then fine shortly after, sore the next day, fever the day after, and progresses like that

Question 26

What are the clinical features of acute osteomyelitis in adults?

Answer 26

Backache- unremitting and at rest History of UTI or urological procedure ->primary osteomyelitis most commonly seen in thoracolumbar spine hence backache

Question 27

Who is secondary osteomyelitis more common in?

Answer 27

Adults Often after an open fracture or surgery

Question 28

Diagnosis of acute osteomyelitis and investigations?

Answer 28

History and clinical examination Bloods: FBC, WBC, ESR, CRP Blood cultures- repeated U&E indicative of illness and dehydration Bone biopsy occasionally to get organism and confirm diagnosis but not the common way of doing this Bone scans ->some of these flashcards are a bit wordy but really recommend rewatching this lecture, really good

Question 29

What are ESR and CRP markers of?

Answer 29

Markers of inflammation

Question 30

X-ray can be done for acute osteomyelitis but what needs to be bared in mind?

Answer 30

Normal in first 10-14 days after injury

Question 31

What is seen in x-ray in acute osteomyelitis after 10-20 days?

Answer 31

Early periosteal changes and medullary changes

Question 32

What can be shown by x-rays later into osteomyelitis, when it is potentially reaching the chronic phases?

Answer 32

Sequestrum- bone necrosis Involucrum - new bone

Question 33

If giving a child an MRI, what may they need?

Answer 33

If less than six, a general anaesthetic so they stay still!!

Question 34

What is done for a microbiological diagnosis of acute osteomyelitis?

Answer 34

Blood cultures Potential bone biopsy if not sure of primary source of culture

Question 35

Treatment of acute osteomyelitis?

Answer 35

Supportive- pain and hydration Rest and splintage of limb Antibiotics ->tends to be overtreated just to really reduce risks of chronic osteomyelitis which is a lifelong condition

Question 36

Acute osteomyelitis is very rarely treated using surgery but what are some of the surgical indications?

Answer 36

If required to collect aspiration of pus for diagnosis and culture For abscess draining if fever not responding to treatment Debridement of dead or infected tissue

Question 37

Complications of acute osteomyelitis?

Answer 37

Metastatic infection Pathological fracture Septic arthritis Septicaemia, death Altered bone growth Chronic osteomyelitis

Question 38

Chronic osteomyelitis is a lot rarer, especially in children, but can follow acute osteomyelitis. However, why else may it occur?

Answer 38

Following operation Following open fracture Immunosuppressed, diabetics, drug abusers

Question 39

Treatment of chronic osteomyelitis?

Answer 39

Long term antibiotics Eradication of infected bone- often massive surgery Amputation?

Question 40

Complications of chronic osteomyelitis?

Answer 40

Chronically discharging sinus and flare-ups Ongoing metastatic infection Pathological fracture Marjolin's ulcer- very rare but a type of squamous cell carcinoma due to chronic discharge of bone and irritation of local tissues

Question 41

What are some of the routes of infection of septic arthritis?

Answer 41

Haematogenous Eruption of bone abscess Direct invasion e.g. penetrating wounds

Question 42

Most common causative microorganisms of septic arthritis?

Answer 42

Staph.Aureus Haemophilus influenzae Streptococcus pyogenes E.Coli

Question 43

Pathology behind septic arthritis?

Answer 43

Acute synovitis with purulent joint effusion Articular cartilage attacked by toxins leading to destruction of the cartilage

Question 44

Outcomes of acute septic arthritis?

Answer 44

Complete recovery or Partial loss of articular cartilage or Fibrous or bony ankylosis

Question 45

How does septic arthritis present in neonates?

Answer 45

Irritability Resistant of joint movement Septicaemia

Question 46

How does septic arthritis present in children?

Answer 46

Acute pain in single large joint Tachycardia Pyrexia Tenderness

Question 47

What is the difference between a child with a skin infection and a child with acute septic arthritis?

Answer 47

Acute septic arthritis has such severe pain that child will not let you touch the joint

Question 48

Treatment of acute septic arthritis?

Answer 48

General supportive measures Urgent surgical drainage Antibiotics Infected joint replacements

Question 49

TB can affect bones and joins and is known as being the 'great mimic'. Where can TB impact?

Answer 49

Extra-articular Intra-articular Vertebral bodies- multiple lesions in 1/3 of patients

Question 50

Clinical features of TB?

Answer 50

Insidious onset and general ill health Contact with TB Pain, esp at night Sweating Weight loss Joint swelling Low grade pyrexia Progressive deformity

Question 51

Where is commonly the primary TB infection found in the body?

Answer 51

Lung or gut ->this then spreads e.g. vertebral joints

Question 52

Which investigations are used to diagnose TB?

Answer 52

Bloods; FBC, ESR Sputum/urine culture X-rays Joint aspiration and biopsy

Question 53

Treatment of TB?

Answer 53

Mostly antibiotics, combination of them