Kembara Xtra - Medicine - Septic Arthritis

Kembara Xtra - Medicine - Septic Arthritis 
​DESCRIPTION Bacterial invasion of the joint space results in infection; musculoskeletal systems are affected
Synonyms include bacterial arthritis, suppurative arthritis, infections arthritis, pyarthrosis, and pyogenic arthritis.

EPIDEMIOLOGY

Gonococcal: females over males; Nongonococcal: males over females
Bimodal incidence, with maxima in youth and age 55+, may occur at any age.
among general, there are 40 to 60 instances per 100,000 people per year. However, there are 70 cases per 100,000 people per year among immunocompromised people and people who have prosthetic joints. Prevalence
Nongonococcal septic arthritis affects 27% of patients with monoarticular arthritis.
Infected hardware is now the most prevalent type of septic arthritis (between 1 and 10% of all joint recipients), due to the increased use of prosthetic joints.

PATHOPHYSIOLOGY AND ETIOLOGY Numerous pathogens
Not gonorrheic:
- Staphylococcus aureus, which affects adults the most MRSA risk is higher in the elderly, IV medication users, and postsurgical patients. - Streptococcus species (second most prevalent among adults). Gram-negative rods (GNR): immunosuppressed, IVDU, trauma, severe ages 
Neisseria gonorrhoeae, which affects young, sexually active adults the most 
Other: rickettsial (such as Lyme), fungal, and mycobacterial infections Polymicrobial infections: Pantoea agglomerans, Nocardia asteroides; generally develop after penetrating trauma such as bite wounds or organic foreign body penetration 
Risk by particular age:
From 1 month to 4 years: S. aureus, Streptococcus pneumoniae, Neisseria meningitidis; from 16 to 40 years: N. meningitidis, S. aureus; from >40 years: S. aureus
Patients with native joint infections are more likely to get an infection from a prosthesis (if the original joint needs to be replaced).
Particular high-risk groups
- S. aureus with rheumatoid arthritis (RA)
- IVDU: GNR, opportunistic pathogens, S. aureus - Newborns: GBS
- Gram-negative bacteria and fungi that are immune-compromised
- Mixed flora in trauma patients with exposed wounds
. Pathogenesis
Hematogenous spread is the most prevalent.
- Adjacent spread (e.g., osteomyelitis) - Direct injection by microorganisms as a result of trauma or iatrogenesis (e.g., joint surgery)
• Pathophysiology
- The synovial membrane is the first point of entry for microorganisms, which then spread to the synovial fluid. - The ensuing inflammatory response releases cytokines and damaging proteases, which cause systemic symptoms and joint damage.

RISK FACTORS Joint capsule violation - prior orthopedic surgery Age >80 years Low socioeconomic situation, drinking Cellulitis and skin ulcers 
- Trauma - Intra-articular injection
Previous joint disease history
- Arthritis that is inflammatory (RA: 10-fold greater risk)
- Crystal arthritides - Osteoarthritis
Risks for hematogenous spread include IVDU and severe sepsis/systemic infection. Systemic illnesses include diabetes mellitus, liver disease, HIV, cancer, end-stage renal failure/hemodialysis, immunosuppression, and sickle cell anemia.


DURATIONAL PREVENTION
Control risk factors. Quick treatment of skin and soft tissue infections. Immunizations (S. pneumoniae, N. meningitidis).

CONDITIONS OFTEN Associated with

current joint issues, past joint damage or surgery, and artificial joints

DISEASE HISTORY
Common symptoms include joint discomfort, edema, warmth, and a reduction in range of motion. 
80% of nongonococcal arthritis cases are monoarticular. - Commonly big joints are the shoulder (8%), ankle (7%), hip (50%), and hip (20%). The majority of patients express fever.
– An infection in axial joints, such as the sternoclavicular joint, can occur in IV drug users.
– Prosthetic joints may have only minor symptoms and a sinus draining above the joint.
– Patients using long-term immunosuppressive medications or getting articular corticosteroid injections may present in an unusual way (without fever or joint discomfort, for example).
Child safety considerations:
- Babies may avoid moving a limb (which is frequently interpreted as a neurologic issue).
- Knee and/or thigh discomfort may also be referred to as hip pain.
Bacteremic phase of gonococcal arthritis
 Tenosynovitis, dermatitis-arthritis syndrome, high fever, chills, and migratory polyarthritis - Regional phase
 Fewer symptoms, frequently monoarticular, low-grade fever
No risk factors or underlying joint illness were present in about 22% of the patients with culture-proven septic arthritis.

Physical examination has a low sensitivity and specificity for diagnosing septic arthritis, however typical findings include: - Joint effusion and soreness - Fever - Limited range of motion
- Warmth and erythema around the afflicted joint - Pain during passive range of motion
Infants with septic hip arthritis maintain the joint in flexion and external rotation as a posture of comfort. Hip and shoulder involvement may display considerable pain with range of motion and less visible edema.
Purpura linked to widespread gonococcal infection

DIFFERENTIAL DIAGNOSIS Gout, pseudogout, calcium oxalate, and cholesterol cause crystal arthritis. Fungi, spirochetes, rheumatic fever, HIV, and viral agents cause infectious arthritis. 
Osteoarthritis, inflammatory arthritis, systemic lupus erythematosus, sarcoidosis, spondyloarthropathy, trauma, meniscal tears, fractures, hemarthrosis, and other conditions such bursitis, cellulitis, and tendonitis 

Initial tests (lab, imaging) Diagnostic tests and interpretation
The most reliable method of diagnosis is synovial fluid analysis.
- Whenever feasible, obtain before starting antibiotic medication.
- Incorporate crystal analysis, cell count/differential, culture, and Gram stain.
Use blood culture bottles to boost production.
- >50,000 WBCs/HPF with >90% polymorphonuclear leukocytes is indicative. - Gram stain (sensitivity 29-65%); culture (positive in 80%).
 The synovial WBC (sWBC) count by itself cannot confirm or exclude septic arthritis (1).
As sWBC climbs >100,000/HPF, the risk of septic arthritis increases (1).
The negative predictive value (NPV) of synovial fluid leukocyte esterase analysis is high (2). - The presence of crystals (such as calcium pyrophosphate or urate) does not rule out concomitant infectious arthritis.
WBC counts for prosthetic joints are inaccurate; a decreased level of sWBCs may signify infection.
WBC count alone is not sensitive nor specific in serum assays.
- ESR >15 mm/hr has low specificity but up to 94% sensitivity (3)[B].
- Sensitivity of CRP >20 mg/L is 92% (3)[B].
When 250 U/L, synovial lactate is a promising biomarker to rule out septic arthritis, but more research is required.
- About 50% of those with positive blood cultures
Additional tests:
- Disseminated gonococcus: culture joint fluid, blood, cervix, urine, urethra, and - Borrelia IgM and IgG serum titers suggest exposure; suspect Lyme arthritis.
Pediatrics: Septic arthritis and transitory synovitis cannot be distinguished by a single lab test. Fever, not being able to bear weight, and increased ESR/CRP all point to a potentially dangerous condition; whenever feasible, get synovial fluid for testing.

Imaging: - Can aid in identifying effusion, but does not further distinguish arthritic etiology - Plain films
 Useful for osteoarthritis, osteopenia, soft tissue edema, and septic arthritis but nondiagnostic for septic arthritis  Could manifest non-specific inflammatory arthritic changes, such as erosions, joint degeneration, or loss of joint space. – Ultrasound
MRI is highly sensitive for effusion and may assist distinguish between transitory synovitis and septic arthritis in children. It is recommended for aspiration of deep joints, such as the hip.
CT is not always necessary.
If osteomyelitis is suspected concurrently, bone scans are not conducted.
Arthrocentesis is performed during diagnostic procedures in all suspected instances before the administration of antibiotics. 
When performing arthrocentesis, keep contaminated tissue (such as cellulitis that is overlaying) to a minimum.
Interpretation of Tests
Polymorphonuclear leukocytes and (perhaps) the pathogen are seen in synovial biopsies.

CONTROL / GENERAL MEASURES
Accept admission for monitoring and parenteral antibiotics.
- Start taking antibiotics right away following arthrocentesis.
If the hip is involved, surgical drainage and irrigation are advised due to the increased risk of avascular necrosis, and drainage of purulent material is necessary.
- Antibiotics and a consultation with an orthopedic surgeon to discuss revision, resection, or débridement arthroplasty for the prosthetic joint 
In most situations, antibiotic treatment lasts for a total of 4 to 6 weeks. - Prosthetics require longer treatment times for native joint infections than 2 weeks.
– Every case should be assessed uniquely and contextually, with the assistance of infectious disease experts as needed.
Intra-articular antibiotics are rarely advised or utilized, with the exception of gonococcal arthritis, which is routinely treated for 2–3 weeks.

First Line: MEDICATION
Based on age, clinical history, and risk factors, the most likely organism or Gram stain is used to determine the first antibiotic to use.
Nongonococcal (1, 2) [C] - Vancomycin 15 to 20 mg/kg 2 to 3 times per day or linezolid 600 mg twice per day for gram-positive cocci. Cefepime 2 g twice daily, ceftriaxone 2 g daily, ceftazidime 2 g three times daily, or cefotaxime 2 g three times daily are the recommended dosages for Gram-negative bacilli.  If you have a cephalosporin allergy, you should think about taking ciprofloxacin 400 mg three times a day.
- Vancomycin 15 to 20 mg/kg twice daily or three times per day plus a third-generation cephalosporin until cultures and susceptibilities are restored – Therapy lasts for an average of 2 weeks, with an additional 2 to 4 weeks administered orally while continuously monitoring the treatment response. 
Ceftriaxone 1 g IV/IM daily for 7 to 14 days for gonococcal infections
 Keep going for at least 24 to 48 hours after the symptom has subsided.
Concurrent draining of the afflicted joint may be necessary. Concurrent Chlamydia treatment (doxycycline 100 mg twice daily or azithromycin 1 g once).
Salmonella should be taken into consideration in pediatric patients with a history of sickle cell illness. - Narrow antibiotic therapy based on culture results.
In this case, third-generation cephalosporins are used to treat Lyme arthritis.
If there is no neurologic involvement, take doxycycline 100 mg PO twice daily or amoxicillin 500 mg PO three times daily for 28 days; if there is, take ceftriaxone 2 g IV daily.

Issues for referral include orthopedic and infectious disease consultations, as well as ID specialist consultations for IVDU and immunosuppressed patients and orthopedic consultations for infections of prosthetic joints.

SURGICAL AND OTHER PROCEDURE

Consider drainage in all situations, especially with regard to the shoulder, hip, and prosthetic joints. Arthrotomy, arthroscopy, and repeated needle aspiration are other therapy possibilities.

CONSIDERATIONS FOR ADMISSION, THE INPATIENT, AND NURSING
 
The average hospital stay lasts 12 days.

RECOMMENDATIONS, FOLLOW-UP, AND CONTINUING CARE
patient observation

After initial treatment, synovial fluid can be monitored to confirm decreased WBC and sterile fluid. If there is no improvement after 24 hours, review and consider arthroscopy.
Follow up to rule out relapse at 1 week and 1 month after stopping antibiotics.


PROGNOSIS Delay in diagnosis or treatment is linked to increased morbidity and mortality. Early intervention improves functional result.

 The likelihood of a bad result is further increased by old age, concomitant RA, S. aureus infections, and hip and shoulder infections.

COMPROMISES Mortality rates ranging from 3% to 25% 
Sinus formation Osteomyelitis Postinfectious Synovitis Limb length discrepancy (most often in cases before skeletal maturity) Limited joint range of motion, ankylosis, osteomyelitis, and post infectious synovitis Secondary osteoarthritis; flail, fused, or dislocated joint; sepsis, septic necrosis