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ARTHRITIS

- Disease that affects bones on both sides ofthe joint space and Narrows the space in

between them

Classification

Hypertrophic Hallmarks

Bone production Sclerosis

Infectious Hallmark

Destruction of articularcortex

Erosive Hallmark

ErosionsHypertrophic Arthritis (Osteoarthritis)

Degenerative arthritis Charcot arthropathy x-ray changes :

- Sclerosis- Osteophyte formation- Decreased joint space

Hypertrophic Arthritis Classification

Degenerative arthritis Charcot arthropathy

Charcots Arthropathy

General Disturbance in sensation leads to multiple

microfractures

Pain sensation intact from muscles and softtissue

Causes Shoulders syrinx, spinal tumor Hips tertiary syphilis, diabetes Feet diabetes Charcot arthropathy is a

progressivemusculoskeletal

condition characterized byjoint

dislocation,fracturesand

deformities. It results in

progressive destruction ofbone

andsoft tissueof weight-bearing

joints, most commonly in thefoot

andankle. It is most commonly

due todiabetes.

Findings

X-ray findings Fractures

Soft tissue swelling Destruction and/or dislocation of

joint

Sclerosis Osteophytosis

Infectious Arthritis More common in adult

Usually from local trauma-surgeryor accident

Children may can be affected withosteomyelitis

Destruction of articular cartilage & cortex Tends to affect one joint (DDx from gout)

Infectious ArthritisCauses

Usually staph - early destruction ofarticular cortex

Rapid course (unlike mostarthritides)

TB spreads via bloodstream from lung More protracted course In children, spine most common; in

adults, knee

Severe osteoporosis Healing with ankylosis common in both

(ankylosis - Stiffness or, more often, fusion of a joint)

Septic Arthritis

- A plain X-ray is not so useful to diagnose theearly stages of septic arthritis.

- However, it may be a useful test to rule outother medical conditions that share similar

symptoms with septic arthritis.

- Septic arthritis usually has to go untreatedfor at least two weeks before the damage it

causes can be detected on an x-ray.

- X-ray finding: Destruction of articularcartilage & cortex

- A scan of the joint may help to confirm thediagnosis.

Radiographic Findings y of TB of the Bones (Other

than the Vertebral Column)

1. bony rarefaction- at first merely show asosteoporosis, ie. Loss of trabecular pattern

and reactive hyperemia, decalcification

2. bony destuction- is present in epiphysis andmetaphysis and the cortex outline of the

articular surface is lost

3. heavy overcalcification ring calcificationmay be seen with abscess

http://en.wikipedia.org/wiki/Progressive_illnesshttp://en.wikipedia.org/wiki/Musculoskeletalhttp://en.wikipedia.org/wiki/Musculoskeletalhttp://en.wikipedia.org/wiki/Musculoskeletalhttp://en.wikipedia.org/wiki/Jointhttp://en.wikipedia.org/wiki/Jointhttp://en.wikipedia.org/wiki/Jointhttp://en.wikipedia.org/wiki/Dislocationhttp://en.wikipedia.org/wiki/Dislocationhttp://en.wikipedia.org/wiki/Fractureshttp://en.wikipedia.org/wiki/Fractureshttp://en.wikipedia.org/wiki/Fractureshttp://en.wikipedia.org/wiki/Deformitieshttp://en.wikipedia.org/wiki/Deformitieshttp://en.wikipedia.org/wiki/Bonehttp://en.wikipedia.org/wiki/Bonehttp://en.wikipedia.org/wiki/Bonehttp://en.wikipedia.org/wiki/Soft_tissuehttp://en.wikipedia.org/wiki/Soft_tissuehttp://en.wikipedia.org/wiki/Soft_tissuehttp://en.wikipedia.org/wiki/Foothttp://en.wikipedia.org/wiki/Foothttp://en.wikipedia.org/wiki/Foothttp://en.wikipedia.org/wiki/Anklehttp://en.wikipedia.org/wiki/Anklehttp://en.wikipedia.org/wiki/Anklehttp://en.wikipedia.org/wiki/Diabeteshttp://en.wikipedia.org/wiki/Diabeteshttp://en.wikipedia.org/wiki/Diabeteshttp://en.wikipedia.org/wiki/Diabeteshttp://en.wikipedia.org/wiki/Anklehttp://en.wikipedia.org/wiki/Foothttp://en.wikipedia.org/wiki/Soft_tissuehttp://en.wikipedia.org/wiki/Bonehttp://en.wikipedia.org/wiki/Deformitieshttp://en.wikipedia.org/wiki/Fractureshttp://en.wikipedia.org/wiki/Dislocationhttp://en.wikipedia.org/wiki/Jointhttp://en.wikipedia.org/wiki/Musculoskeletalhttp://en.wikipedia.org/wiki/Progressive_illness

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- Juxta-articular erosionso Sharply marginated with sclerotic

rims

o Overhanging edges (rat-bites)- No joint space narrowing until later- Little or no osteoporosis- Soft tissue swelling- Tophi rarely calcified

Gout: Bony erosions are typically punched out with

sclerotic margins and overhanging edges "rat bite

erosions".

Erosive osteoarthritis is typically bilateral and

symmetrical, and it occurs in the interphalangeal,

particularly distal interphalangeal, joints of the

hands. The disease most commonly occurs in

postmenopausal women, and it may be hereditary.

The erosions are centrally located in contrast to the

marginal erosions in rheumatoid arthritis. Joints

assume a gull-wing configuration, with central

erosions flanked by raised lips of bone.

Rheumatoid Variants

Psoriatic Arthritis Ankylosing Spondylitis

Psoriatic Arthritis

Almost always accompanies skindisease, especially nail changes

Involves DIP joints of hands > feet Cup-in-pencil deformity

Resorption of terminal phalanges No osteoporosis

Psoriatic Arthritis X-ray Findings

Psoriatic arthritis patients often haveosteolysisloss of boneon their x-rays.

The pencil-in-cup deformity at the DIP jointis classic for psoriatic arthritis.

Other x-ray findings seen in psoriatic arthritis

include:

swelling of non-bony structures, joint space narrowing joint erosions and/or spontaneous joint fusions.

These findings can also occur with:

erosive osteoarthritis and rheumatoid arthritis as well

Sausage finger with swelling of middle joint (PIP)

X-ray of the hand with diffuse fusiform soft-tissue swelling of the entire 3rd digit. This

sign refers to fusiform soft-tissue swelling

involving an entire, single digit within the

hand. The appearance of a sausage digit

(cocktail sausage) is classically associated

with the single x-ray pattern of involvement

seen in some patients with psoriatic

arthritis, and may be the initial

manifestation of the disease.

Ankylosing Spondylitis

Ankylosing spondylitis (AS) refers toinflammation of the joints in the spine.

AS is also known as rheumatoid spondylitisor Marie-Strmpells disease (among other

names).

Squaring of vertebral bodies Bamboo-spine from continuous

syndesmophytes

Peripheral large joint erosive arthritisImaging of Infectious Arthritis

- Conventional Radiography- Arthrography- Ultrasound- Nuclear Medicine Studies- CT- MRI

Arthrography

Used only in conjunction with jointaspiration

Joint aspiration is the most effectiveprocedure for diagnosis of infectiousarthritis

- Provides synovial fluid fordiagnosis

- Relieves joint pressure cause byaccumulation of fluid/ pus

Injection of contrast into the joint confirmsneedle placement

Radiographs obtained after contrast mayreveal:

- Destruction of the articularcartilage

- Hypertrophic alterations to thesynovium

Irregular or contracted joint capsule inchronic infection

Ultrasound for Infectious Arthritis

Alone, US is unable to confirm the diagnosisof septic arthritis

However, US is a very sensitive modality fordemonstrating joint effusion

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May be effective in guiding needleaspiration of joint

Nuclear Medicine Studies for Infectious Arthritis

Most rapid method for determination ofthe site and distribution of joint infection

Scintigraphy studies are sensitive indicatorsof altered osteoblastic activity Limited by:

Poor specificity Inability to accurately delineate

complex anatomy

Local disturbances in vascularperfusion, clearance rate,

permeability and chemical binding

3- or 4- phase bone scan with T99m MDP isthe most commonly used nuc med study

Bone Scan for Infectious Arthritis

3-phase T99 MDP Bone Scan findings Increased blood flow adjacent to

the joint

Prominent activity on blood poolimages on both sides of the

affected area

A fourth phase (delayed 24 hour imaging)shows:

Diminution of activity This is in contrast to osteomyelitis

which invariably has increased

activity on delayed images

CT for Infectious Arthritis

Not standard for evaluation of jointinfections but can be used to guide complex

joint aspirations

When used, CT findings include: Water density fluid in the joint

space and associated irregularity

and narrowing of the joint

Soft tissue swelling Articular erosion and subchondral

bone destruction

Effective in dx early infectious arthritis: Synovial thickening Small joint effusion

Can identify air bubbles in infections causedby gas forming organisms

Caution b/c air bubbles can alsorepresent a degenerative process

in SI and facet joints and are also

common after hip dislocation

MRI for Infectious Arthritis

Not commonly used for imaging suspectedseptic arthritis as dx can readily be

confirmed with less expensive modalities

Advantages: Extremely sensitive for detection

of infectiousarthritis

More specific for infectiousarthritis than

conventional

radiography or

CT

Can provide images in any place Disadvantages

Expensive Not needed to establish diagnosis

MR Findings in Infectious Arthritis

Early Stages of Infection: T2 images reveal distention of joint

capsule by

nonspecific high-

intensity fluid

Later Stages of Infection: Can detect joint effusion, cartilage

destruction, narrowing of joint and

cellulitis around joint

MRI can readily detect extension of theinfectious process into adjacent bone

marrow and the transition to

osteomyelitis T2 images reveal infected fluid and

blood in the joint of inhomogeneous

intermediate signal intensity

T2 images also reveal an area of signalhyperintensity in the soft tissue around

the affected joint

Infectious Arthritis Summary

Conventional radiography and jointaspiration are the mainstays of infectious

arthritis diagnosis

Arthrography and less commonly CT orUltrasound may play a role in guiding joint

aspiration

MRI has little role in the dx of infectionarthritis but may be used to evaluate for

complications, particularly osteomyelitis