bone infection Flashcards
Who is more susceptible to bone and/or bone marrow infection?
It is more common in children but can also occur in adults.
What are the usual causes of bone and/or bone marrow infection?
It’s usually caused by bacteria, occasionally by fungi.
Name some of the risk factors associated with bone and/or bone marrow infection.
Immunocompromised patients, individuals with chronic diseases, the elderly, and even the young are at risk.
What are the common causative organisms in newborns (<4 months) with bone infections?
S. aureus, Enterobacter sp., and group A and B Strep are common in this age group.
In adults, what is the most common causative organism for bone and/or bone marrow infection?
In adults, S. aureus is the most common, occasionally followed by Enterobacter or Streptococcus sp.
What are the primary routes of bone infection?
The two primary routes are haematogenous and exogenous.
Describe the difference between haematogenous and exogenous routes of infection for bone infections.
Haematogenous infections travel through the blood from another infected site, while exogenous infections result from trauma or contiguous spread.
How does the immune system respond once a bone is infected?
Enzymes from leucocytes cause local osteolysis, leading to pus formation and impairing local blood flow, making the infection challenging to eradicate.
What is the formation known as a sequestrum in the context of bone infection?
A sequestrum is a dead fragment of bone that forms and, once present, antibiotics alone will not cure the infection.
Define involucrum in the context of bone infections.
It’s the new bone formed around the area of necrosis in response to bone infection.
Who primarily experiences acute osteomyelitis in the absence of recent surgery?
Acute osteomyelitis usually occurs in children in the absence of recent surgery.
What anatomical features in children’s long bones contribute to the occurrence of acute osteomyelitis?
Children’s long bones contain abundant tortuous vessels with sluggish flow, promoting bacterial accumulation and spread towards the epiphysis.
What is the potential consequence of certain metaphyses being intra-articular in neonates and infants?
In neonates and infants, intra-articular metaphyses can cause infection to spread into the joint, resulting in co-existent septic arthritis.
How does the periosteum in infants contribute to the spread of abscesses in acute osteomyelitis?
In infants, the loosely applied periosteum allows abscesses to extend widely along the subperiosteal space.
What is Brodie’s abscess, and in what way does it differ from typical acute osteomyelitis?
Brodie’s abscess is a form of subacute osteomyelitis where the bone reacts by walling off the abscess with a thin rim of sclerotic bone.
How does chronic osteomyelitis typically develop?
Chronic osteomyelitis typically develops from untreated acute osteomyelitis and may involve a sequestrum and/or involucrum.
Where is the infection primarily found in adults with chronic osteomyelitis, and how does it often spread?
In adults, the infection tends to occur in the axial skeleton, primarily the spine or pelvis, often spreading hematogenously.
Other than typical bacterial causes, what other condition can cause chronic osteomyelitis, and how does it predominantly affect the body?
Tuberculosis can cause chronic osteomyelitis, particularly in the spine, through hematogenous spread from primary lung infection.
In what circumstances does sickle cell osteomyelitis commonly occur?
Sickle cell osteomyelitis commonly occurs during sickle cell crisis.
What is Gaucher’s disease, and how can it resemble osteomyelitis?
Gaucher’s disease, a lysosomal storage disorder, can mimic osteomyelitis.
Which disorders—SAPHO and CRMO—commonly affect specific anatomical areas?
SAPHO and CRMO predominantly affect the chest wall.
What are the common symptoms associated with acute osteomyelitis?
Acute osteomyelitis presents with gradual onset pain at the site of infection, point tenderness, swelling, redness, warmth, and systemic findings such as malaise, fever, and chills.
What distinguishable symptoms are observed in chronic osteomyelitis?
Chronic osteomyelitis exhibits recurrent pain following a prior episode, with swelling and redness. Spinal osteomyelitis presents with constant, unremitting back pain.
How do patients typically present when experiencing spinal osteomyelitis?
In spinal OM, patients present with insidious onset of back pain which is constant and unremitting (see notes)
What types of areas should be probed for investigations related to osteomyelitis?
Probe areas include bone or visible bone, non-healing ulcers, and sinuses.
Why is CRP useful in the investigation of osteomyelitis, and what other blood test is commonly recommended?
CRP is useful for monitoring response, and blood cultures are commonly recommended.
List different imaging techniques used in diagnosing osteomyelitis.
Imaging techniques include X-rays, MRI, CT scans, PET scans, and bone scans.
What is the gold standard for confirming osteomyelitis, and why are wound swabs or blood cultures not always diagnostic?
The gold standard for confirming osteomyelitis is a bone biopsy; wound swabs or blood cultures might not always provide a diagnostic result.
In case the first biopsy is negative, what should be considered?
If the first biopsy is negative, considering another biopsy is advisable.
When is microbiological diagnosis awaited in osteomyelitis management?
Microbiological diagnosis is awaited unless the patient is septic or has soft tissue infection.
What is the initial treatment approach for acute osteomyelitis?
The initial treatment approach for acute osteomyelitis involves ‘best guess’ antibiotics given intravenously, unless there’s an abscess requiring drainage.
What actions might be taken if the infection fails to resolve in acute osteomyelitis?
If the infection fails to resolve in acute osteomyelitis, second-line antibiotics might be considered, along with surgery to obtain a sample for culture and removal of infected bone or tissue.
Can chronic osteomyelitis be entirely cured by antibiotics alone?
Chronic osteomyelitis cannot be entirely cured by antibiotics alone.
What surgical interventions are typically recommended for chronic osteomyelitis?
Surgical interventions for chronic osteomyelitis include gaining deep bone tissue cultures, removing sequestrum, and debridement of infected or non-viable bone.
If bone debridement causes instability, what further action might be necessary?
If bone debridement causes instability, bone stabilization through internal or external fixation might be necessary.
Besides surgical intervention, what other strategies are used in managing chronic osteomyelitis?
Other strategies in managing chronic osteomyelitis include local antibiotic delivery systems, bone grafting, and possibly requiring plastic surgery for skin and soft tissue coverage over the bone.
How long are IV antibiotics continued after surgery in chronic osteomyelitis cases?
IV antibiotics are continued for several weeks after surgery in chronic osteomyelitis cases.
What is osteomyelitis, and what is the most common mode of infection?
Osteomyelitis refers to bone and bone marrow inflammation caused mainly by bacterial infection. The most common mode of infection is haematogenous osteomyelitis.
How does haematogenous osteomyelitis differ from direct contamination in causing bone infection?
Haematogenous osteomyelitis involves pathogens seeded in the bone via the bloodstream, whereas direct contamination occurs at the bone due to factors such as fractures or orthopedic operations.
Which bacterium is responsible for most cases of osteomyelitis?
Staphylococcus aureus is responsible for most osteomyelitis cases.
