Infections Flashcards
(33 cards)
What is osteomyelitis?
Infection of the bone including compact, spongy bone and bone marrow
Name two ways that you can get osteomylelitis
- Organisms directly infecting the bone by trauma.
2. Indirectly by haemoatogenous spread from an infection at a distant site.
Describe what happens one infective organisms reach the bone
Enzymes from white blood cells cause osteolysis and pus which then eradicates local blood flow.
What is a dead fragment of bone called?
A sequestreum
What is it called when new bone forms around a sequestreum?
Involucrum
What are children more likely to get osteomyelitis?
The metaphysis of long bones have a more complex system of vessels and a more sluggish flow meaning it is easier for bacteria to accumulate.
Children can develop a subacute osteomyelitis where the bone reacts by walling off the abscess with a thin rim of sclerotic bone. What is this called?
Brodie’s abscess
What two infections are most likely to spread haematogenously and cause a chronic osteomyelitis in adults?
Pulmonary
Urinary
What are the three most common infecting organisms in osteomyelitis of the newborn?
Staph aureus, enterobacter and group a & b strep
What are the three most common infecting organisms in osteomyelitis of children?
Staph aureus, group A strep, haemophilus influenzae and enterobactor
What are the three most common infecting organisms in osteomyelitis of adolescents?
Staph aureus, group A strep, haemophilus influenzae and enterobactor
What is the most common infecting organism for osteomyelitis in an adult?
Staph aureus
What type of bacteria usually only causes osteomyelitis in sickle cell amemia patients?
Salmonella
What tests would you do to confirm a diagnosis of osteomyelitis?
MRI
Blood cultures
Bone biopsy and culture
How do you treat osteomyeltitis?
IV flucloxacillin and oral fusidic acid.
Switch to oral antibiotics after 2 weeks and continue for a further 4 weeks.
What would you do if there was a bone abcess?
Surgery to drain
A man presents to your clinic with constant, unremitting lower back pain. He also describes spasm of the muscles in his back and feels generally unwell and feverish. He suffers from diabetes and has poor control.
Osteomyeltis of the spine
How do you assess whether a patient is responding to antibiotics you have prescribed for an osteomyeltits of the spine?
Regular measuring of CRP
What is potts disease?
Bones become infected with myobacterium tuberculosis
What makes acute osteomyelitis difficult to eradicate?
The fact that pus formation impairs local blood flow, meaning that it is more difficult for the antibiotics to reach the site of infection
What is the most common causitive organism in septic arthritis? Name three other organisms that are also seen.
Staph aureus
Streptococci
Haemophilus influenzae
Neisseria gonorrhoeae
Who is at a greater risk of getting septic arthritis?
People with rheumatoid arthritis Immumosupressed patients Artificial joints Infants Elderly Alcoholics
A teenage girl presents to you with an extremely painful, hot, swollen joint that she cannot move at all.
Septic arthritis
What investigations would you perform if you suspected a septic arthritis?
Joint aspirate and send for gram staining and culture. Fluid aspirated may be frank pus.
Bood cultures
Look for raised white cell count
May want to do investigations to look for causes (eg urine sample, skin wound swab)
