40 YEAR OLD DIABETIC PATIENT PRESENTED TO ED WITH ACUTELY PAINFUL SWELLING OF THE R. KNEE FOR 2 DAYS DURATION, ON EXAMINATION THERE IS MILD PYREXIA, TENDERNESS OVER THE JOINT AND PASSIVE AND ACTIVE RESTRICTION OF THE JOINT MOVEMENT, WHAT IS YOUR WORK UP ?

Septic ArthritisBy :

Hard H. QaderKirkuk University College Of

Medicine (KUKOM)

• Introduction

• Pathogenesis

• Clinical Features

• Investigations

• Treatment

•SEPTIC ARTHRITIS IS INFLAMMATION OF A SYNOVIAL MEMBRANE WITH PURULENT EFFUSION INTO THE JOINT

CAPSULE, DUE TO INFECTION.

Synovial membrane

Membrane surrounding joint cavityProduce synovial fluidContain rich capillary network for phagocytic and hyaluronate-producing function

ETIOLOGY 1.BACTERIAL

I. STAPH. AUREUS 50%, STREP., E.COLI, AND PROTEUS…

II. GC ARTHRITIS 20%2. VIRAL,MYCOBACTERIAL, AND FUNGAL.

ORGANISMS FOUND IN SEPTIC ARTHRITIS:

1. ARTIFICIAL JOINT IMPLANTS2. BACTERIAL INFECTION ELSEWHERE IN BODY3. CHRONIC ILLNESS OR DISEASE (SUCH AS

DIABETES, RHEUMATOID ARTHRITIS, AND SICKLE CELL DISEASE)

4. INTRAVENOUS (IV) OR INJECTION DRUG USE5. MEDICATIONS THAT SUPPRESS IMMUNE SYSTEM6. RECENT JOINT TRAUMA7. RECENT JOINT ARTHROSCOPY OR OTHER SURGERY

• BACTERIA CAN GAIN ENTRANCE TO A JOINT VIA 3 ROUTES:

Haematogenous

Direct inoculation

Direct spread from adjacent focal infection

Most common form of spreadUsually affect people with underlying medical problem

May result from penetrating traumaIntroduction of organisms during diagnostic and surgicalprocedures. For eg arthroscopy and intra-articular injection

More common in children.Osteomyelitis usually begin in the metaphyseal region, from which it breaks through the periosteum into the joint.

Synovial membrane is highly vascularised.↓

Bacteria can easily enter synovial joint via blood stream.↓

There will be inflammatory reaction with seropurulent exudate and increase in synovial fluid.

↓As pus appear in the joint, the articular cartilage is eroded and destroyed.Partly by the bacterial enzyme, and partly by the enzyme released from

synovium, inflammatory cell and pus

Infant

Destroy the epiphysis, which is

still largely cartilaginous.

Children

Vascular occlusion lead to necrosis of epiphyseal bone

Adult

Effect confined on articular cartilageExtensive erosion can occur due to

synovial proliferation and

ingrowth

a) In the early stage, there is an acute synovitis with a purulent joint effusion

b) Soon the articular cartilage is attacked by bacterial and cellular enzyme.

c) If infection is not arrested , the cartilage may be completely destroyed

d) Healing then leads to ankylosis

If left untreated, it will spread to the underlying bone and out of joint to form

abscess and sinus.

Healing with:1.Complete resolution2.Partial loss of articular cartilage and fibrosis of joint3.Loss of articular cartilage and bony ankylosis4.Bony destruction and permanent deformity

Differ according to age

In new born infants More on septicaemia Rather than joint pain

Baby is irritable & refuse to feed

Tachycardia with fever

Joints are warmth, tenderness, resistance to movement

Umbilical cord and inflamed IV site should be suspicious of source of

infection

In childreno acute pain in single large joint(esp hip)o Pseudoparesiso Child is ill,rapid pulse and swinging fevero Overlying skin looks red & superficial joint swelling may be obvious o Local warmth and marked tenderness

o All movements are restricted by pain or spasm.

o Look for source of infection from septic toe or discharge ear

In adults Monoarticular 85% ,

knee – most common, Other – hip , wrist, shoulder & ankle Sternoclavicular and sacroiliac joint - IVDA

Joints painful, swollen & inflamed.

Warmth and marked local tenderness & movement restricted.

look for STD. Patient with RA and

those on corticosteroid may develop “silent” joint infection.

PHYSICAL EXAMINATION:• LOWER LIMB ANTALGIC LIMP / CANNOT WALK• UPPER LIMB AFFECTED PART IS CLOSELY GUARDED• MARKED TENDERNESS, ACTIVE AND PASSIVE RANGE OF

MOTION ARE LIMITED• EXAMINE FOR SYNOVIAL EFFUSION, ERYTHEMA, HEAT AND

TENDERNESS.• SPASM OF MUSCLES AROUND THE JOINT MAY BE MARKED.• PATIENT MAY HOLD THE JOINT IN A POSITION TO REDUCE

THE INTRA-ARTICULAR PRESSURE TO MINIMIZE PAIN.

Investigations ExplainationFull blood count Elevated white blood cell count

ESR >40 mm/hrCRP >20 mg/dL

Blood culture May be positive

Synovial fluid analysisAseptic technique.Avoid taken from infected site of skin.The fluid is then analyzed by gross and microscopic examination and culture.

Gross examinations include appearance, volume, viscosity.

Microscopic examinations include leucocyte count, staining of smears, serum glucose ratio, protein.

Finally, culture and sensitivity for definitive diagnosis and treatment.

Suspected

condition

Appearance

Viscosity

White cells

Crystals

Biochemistry

Bacteriology

Normal Clear yellow

High Few - As for plasma

-

Septic arthritis

Purulent Low + - Glucose low

+

Tuberculous

arthritis

Turbid Low + - Glucose low

+

Rheumatoid arthritis

Cloudy Low + + - - -

Gout Cloudy Normal ++ Urate - - Pseudogo

utCloudy Normal + Pyrop

hosphate

- -

Osteoarthritis

Clear yellow

High few Often +

- -

X ray Early Stage – Normal

Late stage – Narrowing and irregularity of joint space (destruction of articular cartilage, followed by destruction of subchondral bone)

Plain film findings of superimposed osteomyelitis may develop (periosteal reaction, bone destruction, sequestrum formation).

Narrowing of joint space and irregularity of subchondral bone.

Joint space loss

subchondral erosions and sclerosis of the

femoral head

osteonecrosis and complete collapse

of the femoral head

ULTRASONOGRAPHY• MORE RELIABLE IN REVEALING A JOINT EFFUSION IN EARLY

CASES.• WIDENING OF SPACE BETWEEN CAPSULE AND BONE OF > 2MM

INDICATES EFFUSION.• ECHO-FREE TRANSIENT SYNOVITIS• POSITIVELY ECHOGENIC SEPTIC ARTHRITIS

CT, MRI, AND BONE SCANS

• CT SCANS – SOFT TISSUE SWELLING, JOINT EFFUSIONS, ABSCESS FORMATION, GUIDE JOINT ASPIRATION, MONITOR THERAPY AND PLANNING OPERATIVE APPROACHES.

• MRI – EXTENT OF INFECTION, DIAGNOSING INFECTIONS THAT ARE DIFFICULT TO ACCESS, BETTER ANATOMICAL DETAIL.

• BONE SCANS- DETECT LOCALIZED AREAS OF INFLAMMATION.

• GENERAL SUPPORTIVE CARE- ANALGESICS- IV FLUIDS• SPLINTAGE• ANTIBIOTICS• SURGICAL DRAINAGE

• ARTHROSCOPIC DEBRIDEMENT AND COPIOUS IRRIGATION WITH NORMAL SALINE – MORE FREQUENTLY IN KNEE JOINT SEPTIC ARTHRITIS

• BONE DESTRUCTION AND DISLOCATION OF THE JOINT (ESP HIP)

• CARTILAGE DESTRUCTION - MAY LEAD TO EITHER FIBROSIS OR BONY

ANKYLOSIS• - IN ADULT PARTIAL DESTRUCTION OF THE JOINT

WILL RESULT IN SECONDARY OSTEOARTHRITIS

• GROWTH DISTURBANCE • - PRESENTING AS EITHER LOCALISED

DEFORMITY OR SHORTENING OF THE BONE