Septic Bursitis and Community Acquired MRSA

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Septic Bursitis and Community Acquired MRSA

• AM Report
• 9/21/07
• Laura Patel, M.D.

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Septic Bursitis Defined

• Small fluid-filled sac located at the point where
  a muscle or tendon slides across bone.
• Bursae serve to reduce friction between the two
  moving surfaces. There are 150 bursae in the
  body.
• Superficial subcutaneous and separate skin from
  deeper tissues
• Deep reduce friction between fibrous structures
  such as tendons from adjacent bone.

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Common locations for Septic bursitis

• Superficial bursa predisposed to infection from
  skin trauma. Direct inoculation vs spread from
  cellulitus
• Olecranon bursitis often from repetitive trauma.
  Plumbers, carpenters, COPD, chronic HD via access
  in arm.
• Prepatellar bursitis often seen in people who
  kneel a lot- housemaids, gardners, clergy.
• Ischiogluteal bursitis often in spinal cord
  injured patients.
• Deep Bursa more often associated with septic
  arthritis from hematogenous seeding

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Anatomy
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Host Factors

• RA or gout increase bursal fluid
• Loss of skin integrity
• Impaired response to infection e.g DM, etoh

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Clinical Presentation

• History and Physical
• pain and peribursal erythema, edema
• Majority have fever
• Joint motion is relatively preserved vs septic
  joint where motion is usually severely limited.

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Diagnosis

• Labs Elevated wbc with neutrophilic
  predominance. Usually are not bacteremic.
• Aspiration of bursal fluid
• cell count usually 2000 wbc
• Gram stain and culture
• Send for crystals
• Micro Usually staph aureus 80 or Beta
  hemolytic strep. Subacute bursitis more often
  brucella, mycobacteria or fungal.
• Plain film to evaluate for foreign body if trauma
• If septic bursitis of deep bursa is suspected
  then ultrasound, CT or MRI.

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Differential diagnosis

• Cellulitus
• Crystal induced bursitus
• Acute monoarthritis
• Hemobursa
• Nonseptic bursitis

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Treatment

• Drain infected bursa either by serial needle
  aspiration, ID, or in extreme cases bursectomy
• Antibiotics
• Mild inflammation and not immunosuppressed
  dicloxicillin or clindamycin, /- bactrim if high
  rates of MRSA (multiple contacts with hospital,
  long term care, IVDA, community with prevalence
  15)
• Severe inflammation Vancomycin
• Immunosuppressed broad spectrum including
  pseudomonal coverage

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Duration of Therapy

• Based on clinical response, culture results and
  health of host
• Most treated 2-3 weeks

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Community Acquired MRSA

• MRSA- initially described in the 1960s in
  association with nosocomial infections
• CA-MRSA- first reported in 1980s. Increasing in
  incidence and prevalence
• NEJM 2006 Prospective study examined adults with
  skin and soft tissue infections who presented to
  1 of 11 university affiliated ED in US. S. Aureus
  isolated from 320 of 422 (76). Of these, 59
  were MRSA and 98 of these were CaMRSA
• Some closed communities thought to have higher
  prevalence, up to 40 Native Americans, daycare,
  MSM, prison inmates, competitive athletes.

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So whats the difference between HA-MRSA and
CA-MRSA?
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Clinical Characteristics of CA-MRSA

• Diagnosis made in outpatient setting
• No medical history of MRSA infection or
  colonization
• No recent history of hospitalization, surgery,
  dialysis or SNF
• No permanent indwelling catheter
• Often associated with skin and soft tissue
  infections
• CA-MRSA often sensitive to clindamycin, bactrim,
  doxycycline etc.

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CA-MRSA is crossing borders

• More CA-MRSA strains found in hospitalized
  patients
• 2003 metaanalysis found to account for 37 of
  MRSA isolates in hospitalized patients. But
  majority of these patients had 1 healthcare
  associated risk
• Migration of resistant strains from community
  into hospitals may lead to failure of traditional
  control measures

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Conclusion

• Septic bursitis- more common in superficial bursa
• Associated with erythema, edema and pain, but
  joint motion preserved
• Confirm diagnosis with aspiration and culture of
  fluid
• Majority caused by S.Aureus
• CA-MRSA is on the rise- think about this when
  choosing antibiotics
• Treatment involves debridement and antibiotics

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References

• File, TM. Impact of community-acquired
  methicillin-resistant Staphylococcus aureus in
  the hospital setting. Cleveland Clinic Journal of
  Medicine. Vol 74, Supplement 4. Aug 2007 S6-11.
• Kluytmans-Vandenberg MF. Community-acquired
  methicillin-resistant Staphylococcus aureus
  current perspectives. Clinical Microbiology and
  Infection, Vol 12. Supplement 1, 2006, 9-15.
• Salgado CD, Farr BM, Clafee DP.
  Community-acquired methicillin-resistant
  Staphylococcus aureus a meta-analysis of
  prevalence and risk factors. Clin Infect Dis
  2003 36 131-139.
• Shorr, AF. Epidemiology and Economic Impact of
  Meticillin-Resistant Staphylococcus Aureus.
  Pharmacoeconomics 2007 25 (9) 751-768.
• Uptodate septic bursitis
• Uptodate Epidemiology and clinical
  manifestations of methicillin-resistant
  Staphylococcus aureus infection in adults.