Bone and Skin Infection :Osteomyelitis & Prosthetic Joint Infection

Name: Nur A’isyah Binti Idris

Matric No.: 082012100068

Serial No.: 61

Objectives

• We should able to know:

Definition

Etiological Agent

Clinical Manifestation

Lab diagnosis

Treatment

Osteomyelitis

• Definition: It is a suppurative process of bone caused

by:

Pyogenic organisms;

Pyogenic infection of the cancellous portion the

bone

• Causes : bacterias, fungi, virus, parasites

Etiological Agent

Agent (causative Microorganism)

Host Environment

(the patient) ( general / local /both)

“S” series organism

• Staphylococcus aureus (60-85%)

• Streptococcus hemolyticus (8-10%)

• salmonella

“P” series organism

• Pseudomonas

• Pneumococcus

“H” series organism

• Hemophilus influenza

Agent

“C” series organism

• Clostridium Welchii

• Coliforms (E.Coli)

“B” series organism

• Brucella bacillus

“T” series organism

• Treponema pallidum (syphilitic osteomyelitis)

• Tubercle bacillus (Myobacterium)

FUNGAL OSTEOMYELITIS (ABC)

• Actinomycosis

• Blastomycosis

• Crytptococcosis and Coccidiodomycosis (Chronic osteomyelitis)

• Children: 88% (prone for injury and fall)

• Adults: 12% ( predominantly a disease of childhood)

Age

• Male preponderancesex

• Low socioeconomic groupsEconomic

status

Host Factor

• bring down the resistance of the patient making them susceptible for infection.

General factors

• important in localizing the infection to the metaphysis.

Local factors

General Factor

• Anemia

• Debility

• Infection

• Poor nutrition

• Poor immune status

Local Factor

• Hairpin bend vessels

• Metaphyseal hemorrhage

• Defective phagocytosis

• Rapid growth at metaphysis

• Necrotic tissue

• Vasospasm

• Anoxia

Pathogenesis

Focus of infection through blood reaches

metaphysis

Slow capillary flow flavoring lodgement of

bacteria

Acute inflammatory reaction, exudate, build

up pressure

Inflammation spread in medulla, penetrate

endosteum

Through haversiancanal, form abscess below periosteum

Abscess trek between periosteum & cortical

surface of shaft –rupturing of blood

supply to cortex

Form sequestrum

Pus rupture through periosteum into muscular & SC compartment

Sinus tract formation

Clinical manifestation

Acute osteomyelitis

• Fever- high fever associated with profused sweating, chills & rigors.

• Swelling- acutely painful & skin appear red

• Limitation of movement-movement of joint near the affected bone limited.

Chronic osteomyelitis

• Symptoms : exarcebation of fever, pain, swelling

• Signs :

Irregular thickening of bone

Multiple sinuses

Scar & muscle contractures

Discharge of bony spicules & pus

Deformities & decreased movement

Pathological fractures

Lab Diagnosis

• Hemoglobin – normal or decreased

• ESR - normal or increased

• WBCs- neutrophils increased

Blood test:

•<48 hours

• loss of demarcation of line between subcutaneous shadows & muscles

•appearance of transverse lines of increased densities outward from the muscles

•>2 weeks

•Periosteal of new bone formation is seen

X-rays:

•Aspirate from affected bone

•Help to choose the appropriate

Gram’s Staining

•Technetium 99m, GA-67, Indium-111-labeled leucocytes

• to create images to determine areas of infection and bone remodeling

•The sensitivity of bone scans is often helpful

•valuable in monitoring the efficacy of treatment.

Bone scan

Treatment

General management (RESTS)

• Rest in bed : protect affected part with splints to alleviated pain & spasm

• Elevation of the part, warm & moist packs to reduce the swelling

• Systemic treatment : blood transfusion, iv fluid to correct shock.

• Treatment with antibiotics help to reduce pain & toxicity.

• Surgery : properly indicated & timed to prevent complication.

Cont..

• Antibiotics therapy:

Penicillin

B-lactamase inhibitor

Cephalosporin

Ciprofloxacin

• Parenteral iv- (4-6 weeks)

• Oral- (2-4 weeks)

• Local management

The focus is on well-timed surgery

Nade’s indication for surgery:

Abscess formation

Severely ill and moribund child

Failure to respond to iv antibiotics for more than 48 hours.

SURGICAL METHODS

• Aspiration Helps in decompression and used to identify

organism and check for antibiotic sensitivity

• Incision and drainage Drain the subcutaneous abscess

• Multiple drill holes Drain abscess in subperiosteal by

making holes in the cortex

• Small bone window If MDH failed, small window of

bone is removed from the cortex and

pus is evacuated

Prosthetic Joint Infection

Prosthetic Joint Infection

• Definition : infection associated with joint

replacement.

• Etiological agents :

Staphylococci remains

coagulase-negative staphylococci

Gram-negative organisms (10%)

fungal species :Propionibacteriumacnes (prosthetic shoulder joint infections, 40% )

pathogenesis

• two main mechanisms of PJI:

1. direct inoculation at the time of surgery

2. haematogenous seeding of the prosthesis at a later time.

pathogenesis

microorganisms attach to the

prosthesis

they undergo a phenotypic change to

become the sessile bacteria

form

These sessile bacteria secrete an extracellular

matrix

Cause infection

Clinical manifestation

• classification systems for PJI

• classified as :-

Early- (developing in the first 3 months after surgery),

delayed- (occurring 3–24 months after surgery)

late- (greater than 24 months)

Clinical presentation• wound complications from close to

the time of their original joint surgery.

Early PJI

• associated with history of slowly increasing pain involving the prosthetic joint

Delayed and late presentations

• associated with a history of a joint that was free of any problems for several years before an acute episode of sepsis suddenly occurs

Haematogenous PJIs-

• acute onset with swelling, erythema, discharge, warmth, and tenderness seen in the acute postoperative and hematogenoussettings

• chronic infections show pain and more subtle symptoms

– function deteriorates over time

– pain worsens over time

Lab diagnosis• Culture media

• Identify causative organismsJOINT ASPIRATION

• Elevated WBC

• Elevated ESR

• Elevated C-Reactive ProteinLABORATORY TESTING

• X rays

• Bone scanIMAGING STUDIES

• Gram StainingHistology

• polymerase chain reaction (PCR) of the aspirate

• amplifies bacterial DNA to detect itMolecular testing

treatment• suppressive antibiotic therapy

– indications• patients unfit for surgery and patients who refuse

surgery

– outcomes• goal is to prevent systemic spread and maintain joint

motion with symptomatic relief

• one-stage replacement arthroplasty– indications

• no sinus tract, healthy patient and soft tissue, prolonged antibiotic use, no bone graft

• low-virulence organism with good antibiotic sensitivity

– technique• use antibiotic-impregnated cement

• two-stage replacement arthroplasty

– indications

• gold standard for an infected joint >4 weeks after arthroplasty

• must be medically fit for multiple surgeries

• requires adequate bone stock

– Techniques

• prosthesis removal, antibiotic spacer, IV antibiotics for 4-6 weeks and delayed reconstruction

• resection arthroplasty

– indications

• poor bone and soft tissue quality

• recurrent infections with multi-drug resistant organisms

– technique

• remove all infected tissue and components with no subsequent reimplantation

summary

• Osteomyelitis is inflammation of bone and bone marrow.

• Prosthetic joint infection is infection associated with joint replacement

• Causes : bacterias, fungi, virus,

References

TEXTBOOK OF ORTHOPAEDICS, 4th

EDITION, JOHN EBNEZAR

ATLAS OF PATHOLOGY, 2nd

EDITION, KLATT

• http://www.orthobullets.com/recon/5004/prosthetic-joint-infection

• http://www.uphs.upenn.edu/bugdrug/antibiotic_manual/idsaprostheticjoint2013.pdf

• http://www.medscape.com/viewarticle/777837

Thank you