Infectious Arthritis Management Quiz

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Questions and Answers

What is the recommended duration for antibiotic therapy in cases of nongonococcal septic arthritis?

4 to 6 weeks

1 to 2 weeks

2 to 3 weeks

3 to 4 weeks (correct)

In the management of gonococcal arthritis, what should be done if no improvement is seen within 5-6 days?

Switch to a different antibiotic immediately

Re-aspirate the joint and reculture (correct)

Continue with the same antibiotics

Increase the dosage of antibiotics

What is the necessary surgical action for a prosthetic joint infection?

Drainage without any removal

Surgical immobilization of the joint

Aggressive debridement and/or removal of the prosthesis (correct)

Immediate two-stage exchange arthroplasty

Which of the following statements about physical therapy after joint infection treatment is true?

Aggressive physical therapy is required to restore joint function. Signup and view all the answers

When is a two-stage exchange arthroplasty more commonly indicated?

When the hardware associated with osteomyelitis is removed Signup and view all the answers

What is the earliest time frame in which a prosthetic joint infection can occur after implantation?

Within 3 months Signup and view all the answers

What type of bacteria is primarily responsible for most early prosthetic joint infections?

Staphylococci Signup and view all the answers

What is a common characteristic of bacteria in prosthetic joint infections that makes them resistant to treatment?

Quorum sensing and biofilm formation Signup and view all the answers

Which of the following is most likely to be a feature of septic arthritis?

Acute monoarticular joint pain Signup and view all the answers

In delayed prosthetic joint infections, which bacteria are commonly involved?

Coagulase-negative Staphylococcus and Gram-negative bacteria Signup and view all the answers

Which joint is most frequently affected by septic arthritis?

Knee joint Signup and view all the answers

What is the most commonly used imaging technique for evaluating suspected osteomyelitis initially?

Plain radiographs Signup and view all the answers

Which symptom is classically associated with septic arthritis?

Tenderness with passive movement Signup and view all the answers

Which imaging method is noted for having the highest combined sensitivity and specificity for detecting osteomyelitis?

Magnetic resonance imaging (MRI) Signup and view all the answers

What major complication can arise from biofilm formation in prosthetic joints?

Implant failure Signup and view all the answers

After how many days of disease onset can MRI typically detect early bone infection?

3 to 5 days Signup and view all the answers

What is considered insufficient for correlating with bone biopsy results in osteomyelitis diagnosis?

Superficial wound cultures Signup and view all the answers

Which imaging method has very poor specificity despite having high sensitivity for detecting early bone disease?

Nuclear imaging Signup and view all the answers

What is the preferred method of obtaining a bone biopsy when possible?

Open bone biopsy Signup and view all the answers

Which statement best describes the requirement for conducting a bone biopsy in osteomyelitis?

Two samples should be collected for histopathology and culture. Signup and view all the answers

What is typically seen on plain radiographs when evaluating osteomyelitis?

Osteopenia, soft tissue swelling, and periosteal reaction Signup and view all the answers

What is the treatment of choice (TOC) for osteomyelitis caused by Enterobacteriaceae that are quinolone sensitive?

Ciprofloxacin Signup and view all the answers

Which antibiotic is considered an alternative regimen for treating osteomyelitis caused by Pseudomonas aeruginosa?

Imipenem Signup and view all the answers

For Enterococci infections in osteomyelitis, which is an alternative treatment option?

Vancomycin Signup and view all the answers

What is the recommended duration of parenteral antibiotic therapy for adults with osteomyelitis?

4 to 6 weeks Signup and view all the answers

What is the most common organism responsible for septic arthritis in adults?

Staphylococcus aureus Signup and view all the answers

In which special circumstance is Salmonella sp. a common cause of septic arthritis?

In patients with sickle cell disease Signup and view all the answers

Which laboratory technique is commonly used for evaluating septic arthritis?

Joint aspiration and analysis of synovial fluid Signup and view all the answers

What is the treatment of choice (TOC) for anaerobic infections in osteomyelitis?

Clindamycin Signup and view all the answers

Which organism is most commonly responsible for osteomyelitis in pediatric patients?

Staphylococcus aureus Signup and view all the answers

What is a significant finding in a patient with acute vertebral osteomyelitis?

Tenderness to palpation over vertebral bone Signup and view all the answers

In chronic osteomyelitis, which of the following symptoms is less commonly observed?

Constitutional symptoms like fever Signup and view all the answers

What type of infection commonly leads to osteomyelitis in diabetic patients?

Contiguous spread from soft tissues Signup and view all the answers

Which presentation is typically associated with acute osteomyelitis?

Local symptoms appearing within two weeks Signup and view all the answers

What role does radiographic imaging play in osteomyelitis evaluation?

It helps identify the extent of bone involvement Signup and view all the answers

Which condition should raise suspicion for native vertebral osteomyelitis?

Diagnosis of bacteremia or endocarditis Signup and view all the answers

Which organism is most likely to cause osteomyelitis after a cat or dog bite?

Pasteurella multocida Signup and view all the answers

What is the primary consideration in the management of hematogenous osteomyelitis?

Prolonged antibiotic therapy Signup and view all the answers

Which organism is treated with IV nafcillin as the treatment of choice?

Staphylococcus aureus penicillin-resistant (MSSA) Signup and view all the answers

When is surgical debridement necessary in osteomyelitis cases?

When necrotic bone is present and when associated with spinal implants Signup and view all the answers

What type of osteomyelitis is usually polymicrobial?

Osteomyelitis due to contiguous spread or direct inoculation Signup and view all the answers

What should guide the choice of antibiotic treatment for osteomyelitis?

Results of culture and sensitivity Signup and view all the answers

Study Notes

Bone and Joint Infections

Bone and joint infections are a significant concern in infectious diseases.
Osteomyelitis is a specific type of bone infection.

Learning Objectives

Identify the causes of osteomyelitis.
Describe the presentation of patients with osteomyelitis.
Understand the role of imaging in evaluating osteomyelitis.
Outline the diagnostic and management approach for osteomyelitis.

Microbiology

Staphylococcus aureus is the most common cause of osteomyelitis overall.
Mycobacterium tuberculosis is a cause in vertebral involvement (Pott disease).
This bacteria can spread to the spine from the lungs.
Pasteurella multocida can cause osteomyelitis; it results from cat or dog bites.
Pseudomonas and Candida species may cause osteomyelitis in intravenous drug users.

Pathogenesis

Hematogenous seeding of bone is more common in children than adults.
In children, long bones are typically affected.
In adults, the vertebrae are commonly affected.
Usually affects two adjacent vertebral endplates, as segmental arteries bifurcate to supply them.
Contiguous spread of infection from adjacent tissues such as joints or soft tissues.
Diabetic foot infections can lead to osteomyelitis due to vascular insufficiency.
Pressure-related decubitus ulcers may also be a factor.
Open fractures, and surgical hardware implantation frequently induce osteomyelitis.

Clinical Presentation

Acute osteomyelitis usually manifests within two weeks.
Local symptoms include erythema, swelling, and warmth at the infection site.
Patients may experience dull pain with or without motion.
Fever is present in approximately 40% of cases.
Acute vertebral osteomyelitis (OM) can cause new or worsening neck or back pain with fever.
Recent diagnoses of bacteremia or endocarditis should raise suspicion of native vertebral osteomyelitis (NVO).
Tenderness to palpation over the vertebral bone may be a key sign of osteomyelitis.
In chronic osteomyelitis, symptoms persist for more than two weeks.
Swelling, pain, and erythema are at the infection site; constitutional symptoms like fever are less common.
Extensive ulcers that don't heal despite treatment, especially in patients with diabetes or other weaknesses, may indicate chronic OM.
The ability to probe to the bone from an ulcer with a blunt instrument signifies osteomyelitis.

Diagnostic Approach

Radiographic imaging is crucial for evaluating suspected osteomyelitis.
Plain radiographs often show soft tissue swelling, osteopenia, osteolysis, bony destruction and nonspecific periosteal reaction.
Lytic lesions are evident on radiographs after substantial bone loss (usually 50-75%).
Magnetic resonance imaging (MRI) is the most sensitive and specific imaging method for detecting osteomyelitis, particularly in the first 3-5 days after infection onset, except when dealing with surgical implants
Nuclear imaging is highly sensitive for early bone disease but has poor specificity
This is especially useful when implants preclude MRI
Three-phase technetium-99m bone scan, and tagged white blood cell scans are common.
Bone biopsy (open or percutaneous) is essential for diagnosis. It determines the cause.
Superficial wound cultures are insufficient. Performing open biopsies are preferred if possible
Percutaneous is done through intact skin, using fluoroscopy or CT guidance.
Collect two samples: one for histology, and one for culture and gram stain
Biopsy can be avoided if blood cultures and imaging confirm osteomyelitis

Bone Biopsy/Histopathology

Acute osteomyelitis shows congested or thrombosed blood vessels; neutrophils are prominent.
Chronic osteomyelitis presents with necrotic bone, significant mononuclear cells, and fibrous tissue leading to bone loss and sinus tracts.

Treatment/Management

Hematogenous osteomyelitis is mainly monomicrobial.
Contiguous or inoculated spreads are usually polymicrobial or monomicrobial
Combined medical and surgical approaches are the standard.
Surgical debridement of all the infected bone is standard procedure to improve antibiotic penetration in bone tissue and remove necrosis.
- This can be needed in NVO, if neurological involvement exists, for compression or abscess drainage, or if related to spinal implants.
Revascularization of affected limbs is important in the presence of significant peripheral vascular disease.
Diabetes control improves wound healing.
Culture and sensitivity results guide antibiotic choice in osteomyelitis.
Duration in adults is typically 4-6 weeks (or 2 weeks in fully debrided bone cases).
Vacuum-assisted wound closure is used for extensive wounds.
Hyperbaric oxygen therapy isn't usually recommended.

Differential Diagnosis

Conditions such as Charcot arthropathy (in diabetes), SAPHO syndrome, rheumatoid arthritis, metastatic bone disease, fractures, gout, avascular necrosis, bursitis and sickle cell crises need consideration.

Septic Arthritis

Etiology in adults commonly involves Staphylococcus aureus.
Other etiologies are; Salmonella in sickle cell disease; Pseudomonas in trauma or puncture wounds; and Neisseria gonorrhoeae in sexually active young adults.
Special situations include IV drug use (polymicrobial infections like Serratia marcescens and Pseudomonas aeruginosa. ) and hematological malignancies (like Aeromonas species).

Pathophysiology of Native Joint

Hematogenous seeding: systemic infections reach the joint space due to high vascularization and lack of basement membrane.
Direct inoculation: from injury, puncture wounds, and intra-articular injections.
Contiguous spread: from adjacent osteomyelitis.

Pathophysiology of Prosthetic Joint

Prosthetic joint infections are categorized as early (3 months or less), delayed (3-24 months), and late (>24 months).
Early infections commonly involve Staphylococci due to direct inoculation.
Delayed infections often involve gram-negative and coagulase-negative Staphylococcus epidermidis species
Late infections result from hematogenous spread from other sites.
Biofilm formation is a common factor in prosthetic joint infections.

History and Physical

Septic arthritis typically causes acute monoarticular joint pain, fever, swelling, and limited joint movement.
Knee is commonly affected but other lower extremities, sacroiliac or sterno-clavicular joints can also be involved in injection drug users.
Dermatitis, tenosynovitis, and migratory polyarthralgia are potential signs, especially in young, healthy individuals.

Physical Exam

Effusions (fluid in the joint) are common.
Limited Range-of-motion and pain with palpation could be present.
Most staph infections are monoarticular. Neisseria can involve multiple joints.
Prosthetic joint infections usually present with a draining sinus (opening).

Laboratory Studies

Synovial fluid analysis is crucial: Gram stain, culture, crystal analysis, and white blood cell count (WBC) differential are performed.
High WBC count (>50,000) with neutrophils (>90%) in native joints suggests bacterial infection.
In prosthetic joints, a WBC count of 1000 with >60% neutrophils suggests septic arthritis
Culture growth from the synovial fluid confirms the diagnosis.
Other tests include ESR, and C-reactive protein (CRP) to support the diagnosis.
Blood cultures (two sets) to assess bacteremia.

Imaging Studies

Plain radiographs: may show widened joint spaces, periosteal reaction, soft tissue swelling, or joint abnormalities.
Ultrasonography: used to identify and quantify the effusion and guide needle aspiration.
MRI: sensitive to early joint fluid and reveals surrounding tissue/bony abnormalities and the cartilage involvement.

Treatment/ Management

Combination of antimicrobial therapy and joint drainage (arthrotomy, arthroscopy, or needle aspiration) is critical
Empiric intravenous antimicrobial therapy is initiated immediately after aspiration.
Antistaphylococcal coverage (nafcillin, oxacillin, or vancomycin) is standard.
Third-generation cephalosporins (ceftriaxone, ceftazidime, or cefotaxime) might need to be added in case of immunocompromised patients
Duration in non-gonococcal arthritis is usually 2 weeks IV antibiotics followed by 1-2 weeks of oral antibiotics.
Pseudomonas infections may need longer (4-6 weeks) treatments.
In Gonococcal arthritis, initial IV ceftriaxone for 24-48 hours are followed by oral therapy, If improvement is absent in 5-6 days, the joint is re-aspirated and recultured to rule out other causes including fungi, mycobacteria, and Lyme disease.
Prosthetic joint infections may need removal of the prosthesis and/or aggressive debridement, followed by a two-stage exchange arthroplasty.
Immobilization isn't generally necessary after a few days in most cases but aggressive physical therapy helps restore joint function.

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Description

Test your knowledge on the management and treatment of infectious arthritis, including both nongonococcal and gonococcal septic arthritis. This quiz covers antibiotic therapy durations, surgical interventions for prosthetic joint infections, and characteristics of bacteria involved in joint infections.