MSK Infections Flashcards
Septic Arthritis (aka- infectious arthritis) etiology
- Direct inoculation, contiguous spread from infected tissue, or bloodstream (most common)
- Bacteremia likely to go to a joint with pre-existing arthritis
- If you have more than one of the prior slide risk factors, your risk
increases even more (ie-acute joint pain with prosthetic joint and skin
infection) - > 50% cases by hematogenous spread
Predisposing factors for septic arthritis
- Age >80 years old
- DM
- RA - other irritated joints (check if they are immunosuppressed, e.g. Humira)
- Prosthetic joint
- Recent joint surgery
- Skin infection
- IV drug abuse
- Alcoholism
- Prior intra-articular corticosteroid injection
Nongonococcal arthritis is _____ in 80-90% cases
monoarticular
Infectious monoarthritis typically involves:
- knee (40-50%)
- hip (13-20%)
- shoulder (10-15%)
- wrist (5-8%)
- ankle (6-8%)
- elbow (3-7%)
- small joints of hand and foot (5%)
Pathogenic causes of septic arthritis
- Gonorrhea caused
- Lyme disease
- TB
- Fungal
- Hepatitis
- Other Viral
- Other Bacterial
_____ is the most common source of acute bacterial arthritis in adults and children >2
years, and results in rapid joint destruction
Staph Aureus
Clinical Presentation of Septic Arthritis
- Abrupt onset pain, warmth and swelling in joint - classic!
- Fever, Pain and ROM impaired is classic Triad
- Joint effusion, tender to palpation, marked restriction to passive and active ROM
- Patients with one joint of pain should consider this
- Presents with fever in 60-80%
cases; usually mild - Can have chills, cough, GI sx, GU infection seen as cause
- Bursitis (olecranon and prepatellar mostly) is typically the 1st sign of septic arthritis in
patients with RA
Fever, Pain and ROM impaired is classic Triad for _____
Septic arthritis
Septic arthritis signs in patients with RA
- Bursitis (olecranon and prepatellar mostly) is typically the 1st sign of septic arthritis in
patients with RA.
Slower less painful onset usually with RA and
immunocompromised patients
Clinical Presentation - PE for Septic arthritis
- Decide whether it is articular or periarticular
- warmth
- swelling
- tenderness of involved joint
- Considerable discomfort with any ROM
- Similar Sx to gout
T/F Cellulitis and bursitis cause joint effusions
F
Septic olecranon bursitis distinguished from
elbow septic arthritis by _____
absence of joint pain on extension
Diagnostic Evaluation for septic arthritis
- CBC (with WBC count and diff)
- ESR
- CRP (used to specifically show response to treatment)
- Joint aspiration (WBC >50,000/mm3 is indicative)
- Blood cultures
- Other: Radiographs, MRI, US, Tc-99m scan, etc
Definitive dx of septic arthritis requires:
- Gram stain: +Gram stain is Diagnostic
for Septic arthritis
_______- most common cause of monoarthritis in native joint (60-70%)
S aureus
Importance of radiographs in Septic arthritis
- Used mostly to prove no osteomyelitis, shows tissue swelling and can
show gas formation from E-coli or anaerobic organisms. - Can show bone destruction or formation from infection, joint space
narrowing or osteoporosis
Benefits of CT in septic arthritis
- Shows joints that are harder to palpate- hip, shoulder, SI, sternoclavicular
- Early bone erosions seen and soft tissue extension and effusions
- Helps with arthrocentesis of above joints
MRI use in septic arthritis diagnosis
- Soft tissue edema and abscesses
- Help in detecting septic sacroiliitis
- Early bone erosions
Scintigraphy use for septic arthritis
- Uses labeled WBC’s, technetium colloid, or other to highlight areas
- Many false positives, notes soft tissue infections
- Cannot differentiate septic from aseptic joint inflammation
- False +’s with recent surgery or fracture
Gallium study
- Older test takes 1-3 days,
which renders it low
usefulness for septic arthritis. May use for
osteomyelitis - Accumulates in areas where
extravasation of serum
proteins and leukocytes are - Distinguishes infection from
mechanical damage
Evidence based treatments for septic arthritis
- Drainage: Early arthroscopic lavage, debridement, and drain insertion are replacing
daily joint aspirations - Drain completed to decrease inflammatory cells, decreases joint damage
- Open surgical drainage at times required
- Antibiotics: After diagnostic aspiration, give IV abx immediately!
- Mobilization
- Immobilize after treatment initially
- passive ROM to prevent adhesions and clear exudates
- Passive is followed by active strengthening to prevent contractures
Complications of septic arthritis
- Osteomyelitis
- Persistent/recurrent infections
- Decreased joint mobility
- Ankylosis
- Persistent pain
- Sepsis
- Death
- Contractures
Gonococcal Arthritis
Also a common form of septic arthritis in the US…
Rarely associated with Joint destruction
Gonococcal arthritis incidence
- Most common overall in younger/sexually active individuals
- Usually in healthy individuals
- 2-3Xs more common in women, especially during menses and pregnancy
- Rare after age 40
- MSM common
- pharyngitis and proctitis leads to dissemination
Gonococcal Arthritis clinical presentations
- 1 day-3 months migratory polyarthralgias
- Typically asymmetric an usually upper extremities vs lower
- Characteristic asymptomatic small necrotic pustules distributed over the extremities
- DAYS TO WEEKS LATER, can locate into one or many joints, resulting in septic arthritis
Gonococcal Arthritis diagnosis
- Urethral, throat, cervical, and rectal
cultures should be done in ALL
patients - Blood leukocytes, synovial fluid WBC
count and gram stain are not great
detectors of Gonococcal arthritis - Radiographs usually normal
Gonococcal arthritis treatment
- Admit to the hospital
- Test for other STIs (chlamydia, HIV, Syphilis, Mycoplasma Genitalium, HSV)
- Confirm Diagnosis
- Exclude endocarditis
- Start Treatment
- Ceftriaxone 1g IV/IM q24hrs plus single dosage of Azithromycin 1g PO
- *** New Ceftriaxone 500mg IM (or 1 mg depending on size), Doxy 100mg BID
x7days - Joint aspiration required if purulent fluid
Hepatitis B Arthritis incidence
- Self limited polyarthritis is common and usually prior to jaundice
- 25% of patients with HBV develop joint symptoms
- Most infections resolve, but less than 5% in healthy adults stay
around (HBsAg, anti-HBc antibodies, HBeAg, anti-HBs)
Pathogenesis of Hep B arthritis
- Prodromal phase 1-6 months, symptoms fever,
NV, anorexia, RUQ pain, malaise, etc; icterus follows - Viral replication continues and results are variable
- Circulating immune complexes causing rash and polyarthralgias
Hepatitis B Arthritis presentation
- Rash and joint pain present at the same time
usually - Urticarial rash and Maculopapular rash on
lower extremities are typical - Resembles serum sickness
- Joint symptoms can be symmetrical, migratory
or additive- usually in the prodrome stage - Joint pain improves with the onset of jaundice
Hepatitis B Arthritis Diagnosis
- CMP shows elevated transaminase levels
- Chronic Hepatitis panel: Hep B surface antigen positive/reactive (HbsAg +)
- low complement levels in active arthritis
- Increased circulating immune complexes
- Joint fluid may show inflammatory changes, but not much else
PREVENTION of Hep B Arthritis
Education on how it is transmitted (blood and sexual)
Treatment for Hep B Arthritis
- PREVENTION
- Education on how it is transmitted (blood and sexual)
- Vaccination has greatly decreased Hep B associated polyarthritis
- Treatment is limited to symptomatic supportive care
- Joint disease is self limited
Hepatitis C Arthritis Incidence
- Common cause of persistent viral infection
- Arthritis noted in 2-20% of HCV patients
- Chronic polyarthralgia in up to 20% of cases
- Chronic polyarthritis in 3-5% cases
- Frequently misdiagnosed as RA
- Can have Hep C polyarthralgias and RA at the same time
Hepatitis C Arthritis pathogenesis
- Antibody response to viral products
- This forms circulating immune complexes
- Immune complexes deposit into tissues producing clinical
manifestations (arthritis, glomerulonephritis, vasculitis, etc) - Mixed cryoglobulinemia
Hep C arthritis clinical Presentations- extrahepatic
- Lichen planus
- necrolytic acral erythema
- leukocytoclastic vasculitis
- Sjogren’s
- Arthritis noted in 2-20% of patients
- SLE
- RA
- Polyarteritis nodosa
- Antiphospholipid syndrome
Hepatitis C Arthritis diagnostic evaluation
- X-rays
- RA - causes objective arthritis (not just arthralgias) and can be erosive
- Hep C associated arthritis is non-erosive
- Chronic Hepatitis panel: Hepatitis B Core Antibody Total, Hepatitis B Surface Antigen, Hepatitis B Surface Antibody, Hepatitis C Antibody (+)
Evidence Based Treatment Options in
addition to treatment directed
against Hepatitis C Virus:
- NSAIDS and hydroxychloroquine may
be helpful - TNF-a inhibitors are relatively safe to
use in RA like disorders - AVOID glucocorticoids
- Antiviral Treatment mixed with
biologics is the most effective
treatment potentially***
HIV Arthritis pathogenesis
- Issues from the disease and from the medications used
- Painful articular syndrome- lasts <24 hours
- HIV associated arthritis- self limited and lasts <6 weeks
- Reactive Arthritis- (primary for spondyloarthritis seen in HIV patients)
- HLA-B27 antigen is usually positive in 70%
- Septic Arthritis - Similar bacteria to non HIV patients with some opportunistic infections
- Psoriatic arthritis - most affected are feet and ankles
- Diffuse Infiltrative Lymphocytosis Syndrome - resembles Sjogren’s… Parotid enlargement
- New onset SLE and RA (Rare)
- Vasculitis- Polyarteritis nodosa commonly
reported and all vessel sizes are seen - Immune reconstitution inflammatory
syndromes- (IRIS)
HIV Arthritis clinic presentation
- Most common sign is arthralgias and arthritis
- HIV painful articular syndrome- oligoarticular/asymmetric pattern that resolves in 24 hours
- Joint exam is WNL
- HIV associated arthritis
- Severe psoriatic and reactive arthritis happen in HIV patients
- Muscle weakness-
- Inflammatory myositis
- Diffuse infiltrative lymphocytosis syndrome with
parotid gland enlargement (resembles Sjogren’s) - Various vasculitis forms
Diagnostic Evaluation of HIV arthritis
- labs: HIV +/-, CD4 count, etc.
- Include all other labs discussed prior initially!
Treatment of HIV Arthritis
- Some of the spondyloarthropathies respond to NSAIDs though many are
unresponsive - Antiretroviral therapies
- Immunosuppressives meds
- Antiviral intro has decreased articular syndromes
- Methotrexate or Sulfasalazine can be used if refractory to NSAIDs
Lyme Disease Arthritis clinical history
- Rely on history and location/trips
- Only 25% have known tick bite
- Lyme disease involving the knee is less acute,
does not show positive cultures, and may be
preceded by known tick exposure and
characteristic rash (Erythema Migrans). - NE USA, parts of Asia and Europe as well
Clinical Presentation of lyme disease arthritis
- Early localized (within a month after bite)
- Erythema Migrans, viral syndrome
- Early disseminated (weeks to months after bite)
- Cardiac and neurological involvement
- Bell’s Palsy and pericarditis are most common
- Late Disease (months to years after bite)
- Arthritis (60% of untreated patients) and neurologic Sx
- Arthritis: knee most commonly affected, 2nd most frequent manifestation
- Encephalopathy, neuropathies
Diagnostic Evaluation of lyme disease arthritis
- Can cause false(+) with history of syphilis
- Can do separate IgM and IgG Borrelia antibodies and usually positive if early disseminated phase
- 2 tiered test recommended for serological testing to support Dx
- If ELISA or IFA negative- testing can be stopped
- If (+)ELISA or IFA, do Western blot
Lyme Disease Arthritis distinguishing features
- Erythema Migrans rash
- Timeline as discussed prior
- History of travel
Can be misdiagnosed as fibromyalgia
Lyme Disease Arthritis
Lyme Disease Arthritis management
- Prevention is key**
- Erythema Migrans- Doxycycline 10 days
- Late disease - Longer duration
- Typical treatment of diagnosed Lyme Disease:
- Doxycycline 100mg BID X 21 daysOR
- Amoxicillin 500 mg TID X 21 days
- others require IV treatment
- Anti-inflammatory therapy or arthroscopic synovectomy
- Avoid reinfection
Osteomyelitis antibiotics
– Likely staph
* Vancomycin
– Consider pseudomonas coverage?
Diagnosis of osteomyelitis
X-rays and Labs- CBC, CRP, ESR
* Cultures
– Blood cultures
– Bone cultures
– Need susceptibility
