8. Arthritis

Question 1

Although there are over 90 different rheumatic diseases recognized by the American College of Rheumatology, only a few tend to show up on multiple choice tests (and at the view box).

Answer 1

You can broadly categorize arthritis into 3 categories:

1. Degenerative (OA, Neuropathic)
2. Inflammatory (RA and Variants)
3. Metabolic (Gout, CPPD)

Question 2

Degenerative Arthritis

Answer 2

Osteoarthritis
Neuropathic Joint

Question 3

Osteoarthritis

Answer 3

MOST common cause of Degenerative Arthritis

mechanical breakdown (hard work) which leads to cartilage degeneration (fissures, micro-fractures) and fragmentation of subchondral bone (sclerosis and subchondral cysts).

Question 4

Answer 4

Osteoarthritis

You get all the classic stuff, joint space narrowing (NOT svmmetric). subchondral cysts, endplate changes, vacuum phenomenon, etc…

The poster boy is the osteophyte.

Question 5

Charcot Foot

Answer 5

“rocker-bottom deformity”

deformity, with debris, and dislocation, having dense subchondral bone, and destruction o f the articular cortex

Question 6

Erosive Osteoarthritis (Inflammatory Osteoarthritis)

Answer 6

The buzzword is “gull wing”, which describes the central erosions. It is seen in postmenopausal women and favors the DIP joints.

Question 7

Rheumatoid Arthritis

Answer 7

osteoporosis, soft tissue swelling, marginal erosions and uniform joint space narrowing

It’s often bilateral and symmetric. Classically spares the DIP joints (opposite of erosive OA).

The 5th Metatarsal head is the first spot in the foot

Expect the PIP joints to be involved AFTER the MCP joints.

Question 8

RA > 10 years + Splenomegaly + Neutropenia

Answer 8

Felty Syndrome

Question 9

RA + Pneumoconiosis

Answer 9

Caplan Syndrome

Question 10

The distribution of RA vs OA in the hip is a classic teaching point:

Answer 10

Question 11

Rheumatoid Variants:

Answer 11

Psoriatic Arthritis
Reiter’s syndrome (Reactive arthritis)
Ankylosing Spondylitis
Inflammatory Bowel Disease

Question 12

Psoriatic Arthritis:

Answer 12

This is seen in 30% ofpatients with psoriasis. In almost all cases (90%) the skin findings come first, then you get the arthritis.

“erosive change with bone proliferation (IP joints > MCP joints)”

The erosions start in the margins of the joint and progress to involve the central portions (can lead to a “pencil sharpening” effect).

Question 13

Psoriatic Arthritis Buzzwords

Answer 13

Question 14

When I say Ankylosis in the Hand, You Say =

Answer 14

You Say (1) Erosive OA or (2) Psoriasis

Question 15

RA vs Psoriasis

Answer 15

Question 16

Mutilans

Answer 16

Question 17

Reiter’s (Reactive Arthritis)

Answer 17

a very similar situation to Psoriatic arthritis - both have bone proliferation, erosions, and asymmetric SI joint involvement.

The difference is that Reiter’s is RARE in the hands (tends to affect the feet more).

ust remember Reiter’s favors things below the waist (like the penis = urethritis, and the foot).

Question 18

Reiter’s Triad

Answer 18

Urethritis
Conjunctivitis
Arthritis

(Can’t See or Climb a Tree to Pee on a Nazi named Reiter).

Question 19

Psoriatic and Reactive arthritis are both associated

Answer 19

HLA-B27

Question 20

Ankylosing Spondylitis

Answer 20

This disease favors the spine and SI joints

“bamboo spine”

SI joint involvement is usually the first site (symmetric)

Question 21

Answer 21

Ankylosing Spondylitis:

“bamboo spine”

syndesmophytes flowing from adjacent vertebral bodies.

Question 22

Any significant Ank Spon / DISH + Even Minor Trauma =

Answer 22

Whole Spine CT

Question 23

When the peripheral skeleton is involved in patient’s with Ank Spond =

Answer 23

think about the shoulders and hips (hips more common). Hip involvement can be very disabling.

Question 24

If they show you normal SI joints then show you anything in the spine =

Answer 24

it’s not Ankylosisng spondylitis

It has to hit the SI joints first (especially on multiple choice).

Question 25

inflammatory Bowel Disease (Enteropathic)

Answer 25

Allegedly 20% of patient’s with Crohns & UC have a chronic inflammatory arthritis. The imaging findings occurs in two distinct flavors.

(A): Axial Arthritis (favors SI joints and spine) - often unrelated to bowel disease
(B): Peripheral Arthritis - this one varies depending on the severity of the bowel disease.

Question 26

SI Joint Involvement Patterns (Rheumatoid Variants)

Answer 26

Question 27

Metabolic arthtritis =

Answer 27

Gout
CPPD
Hemochromatosis
Hyperparathyroidism

Question 28

Answer 28

Gouty Arthritis

Earliest Sign = Joint Effusion

Spares the Joint Space (until late in the disease); Juxta- articular Erosions - away from the joint.

“Punched out lytic lesions”

“Overhanging Edges”

Soft tissue tophi

Question 29

Gout Mimickers:

Answer 29

There are 5 entities that can give a similar appearance to a gouty arthritis, although they are much less common. This is the mnemonic I was taught in training:

“American Roentgen Ray Society Hooray”
Amyloid
RA (cystic)
Reticular Histocytosis (the most rare)
Sarcoid
Hyperlipidemia

Question 30

CPPD

Answer 30

Calcium Pyrophosphate Dihydrate Disease

is super common in old people

It often causes chondocalcinosis (although there are other causes)

Question 31

Answer 31

CPPD loves the triangular fibrocartilage of the wrist, the peri-odontoid tissue, and intervertebral disks.

“degenerative change in an uncommon joint”

Hooked MCP Osteophytes with chondrocalcinosis in the TFCC is a classic look (although hemochromatosis can also look that way).

Question 32

Synovitis + CPPD =

Answer 32

Pseudogout

Question 33

pyrophosphate arthropathy is most common at the?

Answer 33

knee

Question 34

Ifyou see isolateddisease in thepatellofemoral, radiocarpal, or talonavicularjoint, think

Answer 34

CPPD

Question 35

OA vs CPPD ?

Answer 35

There are many overlapping features including joint space narrowing, subchondral sclerosis, subchondral cyst, and osteophyte formation

CPPD has some unique features such as =
“atypical joint distribution”

favoring compartments like the patellofemoral or radiocarpal. Subchondral cyst formation can be bigger than expected.

Question 36

Hemochromatosis

Answer 36

iron overload disease also is known for calcium pyrophosphate deposition and resulting chondrocalcinosis.

It has a similar distribution to CPPD (MCP joints). Both CPPD and Hemochromatosis will have “hooked osteophytes” at the MCP joint.

Question 37

CPPD vs Hemochromatosis:

Answer 37

Hemochromatosis has uniform joint space loss at ALL the MCP joints.

CPPD favors the index and middle finger MCPs.

As a point of trivia, therapy for the systemic disease does NOT affect the arthritis.

Question 38

Answer 38

‘‘Milwaukee Shoulder”

This is an apocalyptic destruction of the shoulder (almost looks neuropathic) secondary to the demon mineral hydroxyapatite.

Classic History: Old women with a history of trauma to that joint.

Question 39

Hyperparathyroidism

Answer 39

this can be primary or secondary, and its effects on calcium metabolism typically manifest in the bones.

Question 40

“Subperiosteal bone resorption”

Answer 40

Hyperparathyroidism

Question 41

Answer 41

Hyperparathyroidism

The classic ways this can be shown:

Superior and inferior rib notching - bone resorption
Resorption along the radial aspect o f thefingers with brown tumors
Tuft Resorption
Rugger Jersey Spine
Pelvis with Narrowing or “Constricting”ofthefemoral necks, and wide SI joints.

Fuckery: They can show you any of these classic pictures and then want you to say “Phosphate Retention” is the cause (Hyper PTH causes phosphate retention)