Di Imaging I - Exam 2 (PEAR + RA)

Seropositive vs Seronegative arthropathies refer to the presence/absence of

rheumatoid factor (RH)

What is always a differential dx

infection

When the cause of an enthesophyte is degenerative it is known as

osteophyte

When the cause of an enthresophyte is inflammation it is known as

syndesmophyte

Seronegatives (for RF) (PEAR)

psoriatic arthritis

enteropathic arthritis

ankylosing spondylitis

reactive arthritis

The vowels in PEAR are ______ of each other and the consonants in PEAR are ______ of each other

radiographic mimics

AE (vowels) vs PR (consonants) in PEAR locations

AE = axial skeleton

PR = appendicular/peripheral skeleton

PEAR have a positive finding in blood (sero) tests, what is it

HLA-B27

HLA-B27 and seropositive/negative are just tests for

possibility

What is the most common seronegative spondyloarthropathy

ankylosing spondylitis (fusion)

Ankylosing spondylitis (Marie-Strumpell/Bechterew disease) MC occurs in what population

young males (15-35 yo)

(over call males, under call females)

Ankylosing spondylitis characteristics

synovial proliferation → pannus

erosions, bony proliferation/sclerosis, fusion

bilateral and symmetrical

Where is MC the first site of AS

sacroiliac joints (sacroilitis)

AS also likes the ____ joints causing limited chest expansion

costovertebral joints

Serological studies for AS

+HLA-B27 (in 90% of pts)

+ESR

-RF

-ANA

What two things are found on this image

achilles tendon enthesophyte

plantaraponerosis enthesophyte

Normal SI joints

Why is MRI not great for looking at cortical bone

it holds onto its protons

AS Sacroilitis grading

0 - normal SI joint width + sharp joint margins

1 - suspicious

2 - sclerosis, some erosions

3 - severe erosions, pseudo-dilation of joint space, partial ankylosis

4 - complete ankylosis

We can see JSN and subchondral sclerosis in OA, which feature of AS is not seen in OA

erosions!!

With AS, don’t forget to

review prior imaging

(well-defined SI joints, 5yrs later poorly defined SI joints, 10yrs later ankylosis)

AS spinal findings are not enough to dx, what additional information/imaging do you need to be able to diagnosis AS

erosions of SI

What three DDx could you give this patient

OPLL

AH

OA/DDD

AS typical order of events (early to later findings)

corner erosions (Romanus lesions)

reactive sclerosis (shiny corner sign)

loss of anterior concavity (vertebrae squaring)

thin, marginal syndesmophytes (bamboo sign)

interspinous ligament ossification (dagger sign)

z-joint/facet capsular ossification (railroad track sign)

dagger sign + railroad track sign = trolley track sign

ischial enthesopathy (whiskering)

endplate destruction (andersson lesion)

spinal fracture (carrot stick fracture)

What two findings of AS are found in this image

Corner erosions (Romanus lesions)

Reactive sclerosis (shiny corner)

What two findings of AS are found in this image

Loss of anterior concavity (vertebrae squaring)

Reactive sclerosis (shiny corner)

What finding of AS is found in this image

symmetrical, thin, marginal syndesmophytes (bamboo sign)

• gracile/fragile

Where should you be looking every time you think the disease could be AS

SI joints

What finding of AS is found in this image

Interspinous ligament ossification (Dagger sign)

What finding of AS is found in this image

Z-joint/facet capsular ossification (Railroad track sign)

Dagger sign + Railroad track sign =

Trolley track sign

What finding of AS is found in this image

Ischial enthesopathy (Whiskering)

Ischial enthesopathy (Whiskering) could be found in AH as well, how would you ddx

via SI joints

What finding of AS is found in this image

Endplate destruction (Andersson lesion)

• causes loss of mobility and ability to shock absorb

Andersson lesion is also known as

rheumatic spondylodiscitis

What finding of AS is found in this image

Spinal fracture (Carrot/Chalk stick fracture)

• IVDs hold vertebrae together still but can’t withhold forces

Erosive conditions with SI involvement

PEAR (AS 100%)

Osteomyelitis/septic arthritis/infection

Non-erosive conditions with SI involvement

OA

Osteitis Condensans Ilii (OCI)

• compaction/condensation of cortical bone

Osteitis Condensans Ilii (OCI)

sclerosis at inferior SI joint (Iliac side of joint ONLY)

NO erosions

triangular shape

What population is OCI most common in

postpartum females

(joint laxity, add sclerosis to increase stability)

Enteropathic arthritis

inflammatory spondyloarthropathy associated with inflammatory bowel disease (IBD)

In enteropathic arthritis, it is self-limiting but symptoms worsen with

flare-up of bowel disease

Enteropathic arthritis symptoms in the axial skeleton

morning stiffness

independent of GI symptoms

MC in Crohn’s disease

Enteropathic arthritis - when do symptoms show up in appendicular/peripheral skeleton

may precede intestinal involvement but usually at the same time as bowel disease

could show up as late as 10yrs after IBD diagnosis

Two types of peripheral enteropathic arthritis

1 - pauciarticular <5 joints

2 - polyarticular >5 joints

Where does peripheral enteropathic arthritis occur

heel - achilles and plantar fascia

knee - tibial tuberosity and patella

ischial tuberosities

Bowel resection for treatment of enteropathic arthritis may halt the peripheral arthropathy, but not the

axial arthropathy

Psoriatic arthritis

chronic disease of the joints and entheses

Upper extremity = hand

Erosive!!!!

Psoriatic arthritis (PsA) characteristics

soft tissue edema

asymmetrical JSN (MC DIP)

peripheral erosions w/periostitis (mouse ears)

central erosions (pencil in cup)

ankylosis and deformity

NORMAL bone density

unilateral/bilateral asymmetrical SI erosions

asymmetrical, thick, bulky, non-marginal syndesmophytes

Psoriasis (derm) _____ the onset of psoriatic arthritis

precedes (before)

Psoriatic arthritis occurs in what population

no sex discrimination

30-50 onset

may be linked to: HTN, T2DM, cardiovascular events

Why is RA a differential diagnosis for PsA

b/c they both have inflammatory markers

Psoriatic arthritis commonly starts as dramatic effects in

one joint

• i.e. erosions that shorten digits (Dactylitis/ Sausage digits)

Differentials of OA, PsA and RH

Proliferative synovitis results in

pannus

Psoriatic arthritis mimics of RA (rheumatoid)

JSN

soft tissue edema

marginal erosions at bare areas

ankylosis and deformity

Bare area

are in synovial capsule that is not covered by hyaline cartilage

Psoriatic arthritis distinctions from RA

AIP (acro-osteolysis)

Normal bone density

central erosions (pencil in cup)

asymmetrical - usually involves all joints of ONE digit (ray pattern)

New bone formation (sclerosis) is a key bone change that can be seen in Psa but NOT

RA

The surface of the bone erosion and proliferation in PsA may have a _______ appearance

fluffy (calcium may go into soft tissue)

What two findings of PsA are found in this image

periostitis (mouse ears) - lifts periosteum

soft tissue edema - leaves bone density alone

How are the erosions mentioned in the question beforehand different from RA

In RA… don’t lift periosteum, decrease bone density, goes wherever it wants

What finding of PsA is found in this image

central lesions (pencil in cup)

What finding of PsA is found in this image

Shortened digit (erosions)

Erosive OA (gull-wing erosions) typically occurs in what population

post-menopause females

What type of characterisitcs of PsA are found in this image

soft tissue edema

nail pitting

JSN + central erosions (pencil in cup)

periostitis (lifted periosteum - mouse ears)

Psoriatic arthritis mimics of Enteropathic arthritis

erosions, sclerosis, possible anylosis, syndesmophytes

Psoriatic arthritis distinctions from Enteropathic arthritis

unilateral or bilateral

asymmetrical

thick, bulky nonmarginal syndesmophytes

AS and Enteropathic arthritis syndesmophyte characteristics

symmetrical, thin, gracile/fragile marginal

PsA and Reactive arthritis syndesmophyte characteristics

asymmetrical, thick, bulky nonmarginal (above and below endplates)

Why is this image’s dx NOT Osteitis Condensans Ilii (OCI)

b/c erosions

What are the two dx of these images (left vs right)

Left = PsA

Right = AS

Reactive Arthritis (ReA)

autoimmune condition caused by GI or GU infection (2-4 wks after)

• shigella, salmonella, campylobacter

asymmetric oligoarthritis

dactylitis (sausage digit)

lower extremity = Achilles insertion (weight bearing)

Classic triad of Reactive arthritis

Noninfectious urethritis, Arthrtits, Conjunctivits

(can’t see, can’t pee, can’t climb a tree)

What population does ReA occur in

males

What two diseases are primarily associated with weight bearing joints

OA + Reactive arthritis

Reactive arthritis looks like PsA, but just not

as extreme

Reactive arthritis mimics of PsA

JSN

soft tissue edema

normal bone density

periostitis (mouse ears)

asymmetrical, thick, bulky nonmarginal syndesmophytes

Reactive arthritis distinctions from PsA

MC in lower extremity

no nail pitting

central erosions (pencil in cup) not common

Lover’s heel (ReA)

describes predominance of the plantar and calcaneal insertions

Spondyloarthritis often beging in young people with symptoms starting

before age 45

Rheumatoid arthritis is primarily a

bone density ROBBING disease (don’t even need erosions present to dx)

RA symptoms

stiffness in morning (jelling phenomenon) - OA mimic!

in PIP and MCP (Haygarth) joints

osteopenia!!!

Rheumatoid Arthritis Diagnosis checklist

morning stiffness for at least 6 wks

pain on joint motion for at least 6 wks

swelling of at least 1 joint for at least 6 wks

swelling in at lest 1 other joint for more than 6 wks

bilateral symmetrical joint swelling

subcutaneous nodules

DDx from RA and OA

OA - asymmetrical JSN in weight bearing

RA - symmetrical JSN in non-weight bearing

Distribution of RA in hand joints

MCP = Haygarth, IF nodes

PIP = Bouchard, IF nodes

Ulnar aspect of wrist

All soft tissue hand nodes

MCP = Haygarth nodes (CPPD + RA)

DIP = Heberden nodes (OA)

PIP = Bouchard nodes (OA + RA)

RA likes to first impact synovial joints at bare areas causing

pannus and decreased bone density

OA or RA (left vs right)

Left - OA

Right - RA

OA or RA (left vs right)

Left - OA

Right - RA

Rheumatoid arthritis

multisystem (systemic) disease

pts with higher RF levels tend to have a more severe disease

inflammatory hyperplastic synovitis (pannus)

Rheumatoid arthritis occurs in what population

20-60 females

>60 no sex discrimination

Proliferating pannus in RA erodes cartilage and releases ______ and can cause

chondrolytic collagenase enzymes

subchondral cysts (pannus intrusion)

Associated terms with RA

arthritis mutilans - severe joint deformity

Baker’s cyst - enlargement of gastrognemius bursa (trauma → inflam)

Felty’s syndrome - leukopenia, splenomegaly, RA

Rheumatoid arthritis finger deformit