Soft Tissue & Musculoskeletal

Infections in the Primary Care Setting

Patty W. Wright, MDMarch 2011

Objectives To familiarize participants with some of the most

common soft tissue and musculoskeletal infections in the primary care setting, including their diagnosis and treatment.

Case 1 A 42 yo female who

works as a housekeeper presents with a one year history of swelling and redness along the borders of her nails bilaterally.

What is the diagnosis? How would you treat

her?

http://missinglink.ucsf.edu/lm/DermatologyGlossary/paronychia.html

Paronychia Infection of the skin

(epidermis) bordering the nail

Typically associated with trauma: Manicures Ingrown nails Dishwashing Thumb sucking

http://en.wikipedia.org/wiki/File:Paronychia_argentea_(286232698).jpg

Chronic Paronychia Chronic paronychia typically due to eczema Often have superinfection with yeast

(Candida) Rx with steroid and antifungal creams If no response, trial of oral antifungals with

topical steroids Patient should avoid prolonged water

exposure to the hands Consider alternative diagnoses such as

psoriasis

Acute Paronychia

Commonly due bacteria such to Staph aureus or Group A Strep

Soaks and surgical drainage usually enough

If severe, treat with oral antibiotics

http://en.wikipedia.org/wiki/File:Paronychia.jpg

Case 2 A 26 yo female hair

dresser develops throbbing pain, swelling, redness, & warmth in the distal portion of her index finger. She recalls that she accidentally stuck herself in the finger with her scissors the day before.

What is the diagnosis? How would you treat her?

http://drhem.com/2009/08/16/hand-case-3-1/

Felon Abscess of the pad (or pulp) of the tip of the finger

or toe Significant pain, redness, and swelling in finger tip Most commonly due to S. aureus May spread to bone with resulting infection

(osteomyelitis) Most commonly in thumb and index finger Typically related to trauma: splinters, puncture

wounds, scraps or abrasions

Felon

If early: elevation, soaks, and oral antibiotics If late: rx as above plus surgical drainage Culture the fluid to direct antibiotic therapy Consider x-ray to rule out foreign body or

bone infection Rx for 5-14 days depending on severity

Case 3 A 33 year old female

presents with a red pustular lesion on her left 5th finger. The lesion is tender and has been present for almost a week.

What additional questions would you like to ask this patient?

What pathogens are on your differential diagnosis?

Herpetic Whitlow Autoinoculation of HSV 1 or 2 into non-intact

skin Health care workers at risk if not using

universal precautions Abrupt onset of edema, erythema and

tenderness Clear vessicles may coalesce become cloudy Confirm with Tzanck test, viral culture, DFA,

or HSV PCR

Herpetic Whitlow Typically resolves in 2-3 weeks without rx Treatment with antivirals (acyclovir,

famciclovir, valacyclovir) within 48hrs of onset may lessen severity

Cover with dry dressing to avoid spread to other areas

Recurs in up to 50% of patients, though primary outbreak most severe

Case 4 A 47 yo male construction

worker with a history of “athletes' foot” presents to the ED with redness, pain, and swelling over his ankle and lower leg.

What is the diagnosis? How would you treat him?

http://battlegames.wordpress.com/2008/12/

Cellulitis Infection of the skin (dermis and hypodermis)

with some extension into the fatty, subcutaneous tissues

Local signs: redness, swelling, warmth, and tenderness +/- enlarged lymph nodes

Systemic signs may include low grade fevers, chills, and body aches

Blood cultures rarely positive (2%)

Cellulitis Most common causes are Group A Strep and

S. aureus Rx with iv antibiotics (vancomycin) for

inpatients Rx with oral antibiotics for outpatient therapy

If pt not systemically ill, has a normal immune system, and has reliable follow up and access to antibiotics

Remember that trim-sulfa may not be the best coverage for Strep

Case 5

A 50 yo male carpenter presents to the ER c/o pain in his hand. He reports that a board fell on his hand yesterday with some mild bruising. He awoke today with pain so severe that he was unable to drive himself to the ED.

What is the diagnosis? How would you treat him?

Fasciitis / Myositis Fasciitis

Infection of the fascia (thick layer of connective tissue that surrounds the muscles, bones, nerves and blood vessels)

Myositis Infection of the muscles

Rare: 500-1500 cases/year in the US Clinical Presentation

Fever, elevated heart rate, & low blood pressure Local signs and symptoms such as swelling, large

blisters, crepitus, and pain out of proportion to the exam

Fasciitis Imaging studies

such as CT or MRI scans helpful if gas present in the soft tissues

Negative imaging does not rule out fasciitis

Fasciitis Type 1

Mixed infection of aerobic and anaerobic bacteria Seen in post surgical patients, diabetics and

patients with PVD Type 2

Monomicrobial infection caused by GAS or MRSA in previously healthy patients

Fasciitis Surgery, Surgery, Surgery

Re-exploration after 24 hours with repeat debridement, if necessary

Blood pressure support and ICU care, if indicated

Antibiotic therapy

Fasciitis Empiric Antibiotics

1. Core antibiotic: Imipenem, Meropenem, Pip-tazo

2. Secondary antibiotic: Vancomycin, Linezolid, Daptomycin

3. Clindamycin and IVIG

Target1. Sensitive Gram

positives, Gram negatives & anerobes

2. MRSA

3. Group A Streptococcus toxin

Case 6 An 28 yo male

landscaper presents with pain and swelling along the length of his middle finger. He reports that his pain is most severe when he tries to move the finger.

What is the diagnosis? How would you treat

him?

Infectious Tenosynovitis

Infection of the fluid-filled sheath that surrounds the tendon

Leads to swelling and pain of the finger (or toe) especially with movement

http://www.sportnetdoc.com/injury/07-06.htm

Acute Infectious Tenosynovitis Kanavel signs for pyogenic flexor

tenosynovitis: Uniform symmetric swelling of the digit Digit held in partial flexion at rest Excessive tenderness along the entire

tendon sheath Pain along the sheath with passive digit

extension Most clinically reproducible sign

Acute Infectious Flexor Tenosynovitis Most commonly related to trauma, particularly

at the flexor crease Most common pathogens are Staph and

Strep Polymicrobial infections possible in DM or

immunocompromised May occur following hematogenous spread,

particularly with N. gonorrhoeae Early stage may respond to elevation,

splinting, and iv abx

Acute Infectious Tenosynovitis I&D if…

DM Immunocompromised No improvement within 12-24 hrs of abx

therapy Gram stain and culture to direct abx therapy Rx empirically with vancomycin and

quinolone (ciprofloxacin, levofloxacin) then tailor regimen to cx results

Chronic Infectious Tenosynovitis Often due to atypical mycobacterial or fungal

infections Empiric therapy is difficult given wide

spectrum of etiologies Cultures for AFB and fungi essential to

diagnosis and treatment Pathology with special stains may be helpful,

but cultures best

Case 7 A 44 yo former roofer is

paralyzed following a fall with spinal cord injury 5 years ago. Recently he developed a small ulceration on his lower back which has progressed despite local care. On exam, the wound probes to the bone.

What is the diagnosis? How would you treat him?

http://boneandspine.com/orthopaedic-images/clinical-photograph-of-stage-iv-sacral-bed-sore-in-a-patient-of-cervical-spine-injury/

Osteomyelitis

May be acute (progressing over days) or chronic (progressing over weeks to months)

May occur from direct spread of infection or spread of infection through the blood stream Hematogenous (20%)

Children Contiguous with vascular insufficiency (30%)

Diabetic neuropathy Contiguous without vascular insufficiency (50%)

Trauma (natural or iatrogenic)

Haematogenous Osteomyelitis PAIN is primary symptom

Frequently progressive over several months Constitutional symptoms or local edema/erythema

less common Long bones most common site in children Vertebrae most common site in adults Single pathogen most likely

S. aureus most common P. aeruginosa with injection drug use

Osteomyelitis Definitive diagnosis requires

bone biopsy Often diagnosed clinically

based on exam, labs, and imaging

WBC count rarely elevated Sedimentation rate (ESR)

and C-reactive protein (CRP) measures of inflammation are useful for serial monitoring

www4.path.utah.edu

“Probe Test” of Osteomyelitis

Obtain sterile probe Gently insert into

deepest portion of ulcer Sens = 66% Spec = 85% PPV = 89% NPV = 56%

Exposed bone is infected bone

Osteomyelitis Imaging – Xrays

Cheap and easy Able to evaluate for

foreign body Not useful for acute

osteomyelitis Radiolucent areas do not

appear until 50-75% bone loss

Osteomyelitis Imaging – Technetium Bone Scan

More sensitive than plain radiography Taken up in areas with

Increased blood flow New bone formation

May be positive as early as 48 hours after infection

Gallium and indium scans less sensitive

Osteomyelitis Imaging – CT and MRI scans Excellent bone

resolution Hindered by presence

of prosthetic material MRI preferred for

small bones of hands/feet

flickr.com/photos/69918874@N00/2208251162/

Osteomyelitis Treatment typically involves…

Surgical debridement followed by aggressive wound care

Prolonged antibiotic therapy6 weeks minimum, may extend for months

depending on clinical course IV antibiotics needed for acute osteomyelitisOral antibiotics alone may be indicated for

some chronic osteomyelitisUnless definitive pathogen identified by bone

biopsy, broad spectrum coverage indicated

Case 8 An 82 year old woman

presents with swelling and pain in her left knee. She underwent a total knee arthroplasty 10 years ago for OA with a revision 3 years ago for loosening of the hardware.

What is the diagnosis? How would you treat her?

Epidemiology of Prosthetic Joint Infections1-3% of primary joint replacements

Knee = 1-2% Hip = 0.3 – 1.3% Shoulder - <1%

3-6% of revision procedures Knee = 6% Hip = 3%

Prosthetic Joint Infections-Timing of Infection

Classification Characteristic

Early (<3 months) Typically acquired at surgery and associated more virulent organismse.g. Staphylococcus aureus, Gram-negative bacilli

Delayed (3 – 24 months) Typically acquired at surgery and associated with less virulent organismse.g. coagulase-negative Staphylococci, Proprionibacterium acnes

Late (>24 months) Usually associated with haematogenous spread from distant infection

Prosthetic Joint Infections-Clinical Presentation

PAIN Present in >90% casesNight pain more concerning for

infectionStart-up pain appears more

consistent with aseptic loosening

Prosthetic Joint Infections- Diagnosis Primary differentiation is between infection

and aseptic loosening Rely on “totality of circumstances”

Clinical exam Laboratory data

ESR/CRPCulture of joint fluid

Imaging

Prosthetic Joint Infections-Treatment Approach

Acute infection (<4 wks) AND stable implant AND no sinus tract… Consider debridement

with retention followed by IV antibiotics +/- additional PO antibiotics

Chronic PJI… Joint removal is

necessary for cure Debridement with

retention followed by IV antibiotics then suppressive PO antibiotics may be considered in debilitated patients who cannot tolerate joint removal

Summary Paronychia & felons are infections of the

fingers/toes which often improve with simple I&D and/or po abx

Treatment for cellulitis should include coverage of Staph and Strep

Fasciitis is a surgical emergency & should be treated with very broad-spectrum antibiotics

Acute infectious tenosynovitis is typically due to bacteria; chronic is often due to mycobacteria or fungi

Exposed bone is infected bone Osteomyelitis and PJI’s typically require surgery

and long-term abx therapy