Infectious Arthritis and Osteomyelitis Flashcards
SEE TABLE FOR TREATMENT - patients without implants
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Classification -> According to mechanisms of spread:
- hematogenous spread
- spread from contiguous site following surgery
- secondary infection in the setting ofvascular insufficiency or concomitant neuropathy (e.g. in diabetes)
Classification -> According to the duration of infection:
- acute: can be treated with antibiotics alone
- chronic: antibiotics should be combined with debridement surgery
Classification -> According to location:
- in the long bones
- the vertebral column
- periarticular bones
What is the most common manifestation of hematogenous bone infection in adults?
vertebral osteomyelitis
What is the most common cause of acute vertebral osteomyelitis?
- 40-50% s. aureus
- 20% gram negative bacilli (mainly e.coli and p. aeruginosa)
- 12% streptococci
What is the most common cause of subacute vertebral osteomyelitis?
- mycobacterium tuberculosis or brucella
- and in patients with endocarditis by s. viridans
Is implant-associated spinal osteomyelitis usually acute or chronic?
chronic
What causes implant-associated spinal osteomyelitis?
- coagulase-negative staph and P. acnes
What is the most common cause of spinal osteomyelitis in cases of prolonged bacteremia (e.g in patients with infected pacemaker)?
- coagulase-negative staph
Candida species in…..
IV drug users (vertebral osteomyelitis)
What is the most leading initial symptom in vertebral osteomyelitis?
back pain
What are the clinical manifestation in vertebral osteomyelitis?
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- back pain
- fever >38 (degrees celcius)
- neurologic deficits (radiculopathy, weakness or sensory loss)
What is the diagnosis for vertebral osteomyelitis?
- ↑ Erythrocyte sedimentation rate
- ↑ CRP lever
- blood culture
- *plain radiography can be useful in patients with subacute or chronic vertebral osteomyelitis WITHOUT neurologic symptoms
- *MRI is the gold standard in patients with neurologic impairment
When it comes to the diagnosis of vertebral osteomyelitis, what should we do if the blood culture is negative?
- in patients with negative blood cultures, CT-guided or open biopsy is needed.
- bone samples should be cultures for aerobic, anaerobic and fungal agents with a portion if the sample sent to histopathologic study.
What is the gold standard in patients with neurologic impairment?
MRI is the gold standard in patients with neurologic impairment
When is plain radiography can be useful in diagnosis of vertebral osteomyelitis?
plain radiography can be useful in patients with subacute or chronic vertebral osteomyelitis WITHOUT neurologic symptom
What is the treatment of vertebral osteomyelitis in patients without sepsis syndrome?
in patients without sepsis syndrome, antibiotics should not be administered until the pathogen is identified in a blood culture, a bone biopsy or aspirated pus collection
What is the treatment of vertebral osteomyelitis for those with bone infection?
bone infections are least initially treated by the IV route
Other things to take notice from when it comes to duration of the treatment of vertebral osteomyelitis?
- no data on the optimal duration of therapy
- most suggest 6 weeks for patients who have acute osteomyelitis without an impairment
When is prolonged antibiotic therapy recommended in vertebral osteomyelitis?
prolonged antibiotic therapy recommended for patients with abscesses that have not been drained and patients with spinal implants
What is the treatment necessary in implant-associated spinal infection?
surgical treatment
SEE TABLE FOR TREATMENT
slide 11-15, 19
What is the osteomyelitis in long bones a consequence of?
- hematogenous seeding
- contamination during trauma (open fracture)
- perioperative contamination during orthopedic repairs
Who developed chronic osteomyelitis in long bones in the preantibiotic era?
more common in elderly patients
What is the most common cause of osteomyelitis in long bones in adults?
- posttrauma
- postsurgery
Which organism is most commonly isolated from adult patients?
- s.aureus.
- after open fracture, infection is typically caused by gram-negative bacilli or mixed bacteria
What are the clinical manifestation of hematogenous osteomyelitis?
- pain
- low-grade fever
- occasionally sepsis and local signs of inflammation (erythema and swelling)
SLIDE 17
Diagnosis in osteomyelitis in long bones:
- similar to that of vertebral osteomyelitis
- CT is required in order to estimate the extent of inflamed tissue and to detect bone necrosis (sequestres)
- the three-phase bone scan does not differentiate bone remodeling from infection and is not useful during at least the first year after implantatio
What is the treatment from acute hematogenous infection in long bones?
- identical to that for acute vertebral osteomyelitis
- it should last 4-6 weeks
What are the causes of PJI (periprosthetic joint infection)?
- 70% staph (s.aureus and coagulase-negative staph)
- 10% strep
- 10% gram-negative bacilli
PJI =
periprosthetic joint infection
What are the clinical manifestations of exogenous PJI (periprosthetic joint infection)?
exogenous PIJ with local signs of infections
What are the clinical manifestations of acute hematogenous PJI (periprosthetic joint infection)?
acute hematogenous PJI causes new-onset pain that initially is not accompanied by local inflammatory signs
What are the clinical manifestations of chronic PJI (periprosthetic joint infection)?
chronic PJI presents with join effusion, local pain, implant loosening, occasionally sinus tract
Diagnosis of PJI:
- blood tests (CRP, erythrocyte sedimentation)
- during debridement surgery (at least 3 samples obtained)
- CT or MRI
What is the treatment of PJI?
- antimicrobial treatment should be accompanied with surgical intervention (go back to the slide: “treatment - patient with orthopedic device”)
When does sternal osteomyelitis occur?
sternal osteomyelitis occurs primarily after sternal surgery with the entry of exogenous organisms
What is poststernotomy osteomyelitis caused by?
- s. aureus (40-50%)
- gram-negative bacilli (15-25%)
- enterococci (5-12%)
- sometimes fungi (candida ssp)
- M. tuberculosis in patients from endemic areas (as reactivation)
What is the clinical manifestation of sternal osteomyelitis?
- fever, increased local pain, erythema, wound idscharge
- sternal instability
- contiguous mediastinitis may occur as a complication of sternal osteomyelitis (in 10-30% of cases)
Diagnosis - sternal osteomyelitis:
- in secondary sternal osteomyelitis, leukocyte counts may be normal but the CRP level is >100mg/l in most cases
- samples from at least three deep biopsies should be taken for microbiologic examination
Treatment - sternal osteomyelitis:
- antibiotic treatment right after the samples have been obtained
- primary sternal osteomyelitis can be treated without surgical intervension
- secondary sternal osteomyelitis debridement is required
Who usually gets osteomyelitis of the foot?
- patients with DIABETES
- peripheral arterial insufficiency
- peripheral neuropathy
- after foot surgery
What is the incidence of diabetic foot infection?
incidence of diabetic foot infection is 30-40cases/1000 persons with diabetes per year. It increases the risk of amputation.
Pathogens - foot osteomyelitis:
- s. aureus (30-40%)
- gram-negative bacilli (30-40%)
- anaerobes (10-20%)
pretreatment selects for P.aeruginosa or enterococci
Diagnosis - foot osteomyelitis:
- in many cases foot osteomyelitis can be diagnosed clinically with the “probe-to-bone” test: diagnosis is highly probable if bone can be directly touched with a metal instrument
- in a patient with lower pretest probability, MRI should be performed
Treatment - foot osteomyelitis:
- correlation between cultures of bone and those of wound swabs is poor so antimicrobial therapy should be based on bone culture
- treatment consists of wound debridement combined with a 4-6 weeks course of antibiotics
Acute bacterial arthritis:
- bacteria enter the joint:
- from the blood stream
- from a contiguous site of infection in bone or soft tissue
- by direct inoculation during surgery, injection, animal or human bite, or trauma
What is the most common route of infection in acute bacterial arthritis?
the hematogenous route of infection is the most common route in all age groups
Microbiology - acute bacterial arthritis:
- NEISSERIA GONORRHEA is the most common pathogen of bacterial arthritis
- S. AUREUS is the most common nongonococcal pathogen of bacterial arthritis
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