Rheumatology: Crystal Arthropathies

Question 1

The _____ are a group of diseases characterized by tissue deposition of monosodium urate (MSU) crystals due to hyperuricemia.

Answer 1

crystal arthropathies

Question 2

Name the 4 manifestations of crystal arthopathies.

Answer 2

1. gouty arthritis
2. tophi (deposits of MSU)
3. gouty nephropathy
4. uric acid nephrolithiasis (kidney stones)

Question 3

____ usually refers to acute or chronic arthritis 2a to MSU crystals.

Answer 3

Gout

Question 4

Hyperuricemia without symptoms is referred to as _____, not gout.

Answer 4

asymptomatic hyperuricemia

Question 5

What are the 4 stages of gouty arthritis?

Answer 5

1. asymptomatic hyperuricemia
2. acute gouty arthritis
3. intercritical gout
4. chronic tophaceous gout

Question 6

What are the features of asymptomatic hyperuricemia?

Answer 6

elevated serum uric acid (>7.0mg/dL) w/o gouty arthritis, tophi, or uric acid nephrolithiasis

Question 7

What are the features of acute gouty arthritis?

Answer 7

• Acute onset of painful, warm, red, swollen joint, especially at night or morning.
• MTP of great toe most common (podagra) but also can be insteps, ankles, heels, knees, wrists, fingers, and elbows.
• Resolves after 3-10 days.

Question 8

What is intercritical gout?

Answer 8

asymptomatic intervals between acute attacks of gout

Question 9

What is chronic tophacous gout?

Answer 9

• subcutaneous, synovial, or subchondral bone deposits of MSU crystals
• commonly on digits of hands and feet, olecranon bursa, extensor surface of the forearm, Achilles tendon, or antihelix of the ear

Question 10

Gout typically occurs in _____, age _____.

Answer 10

men; 30+ (peak incidence 50)

Question 11

What other conditions are associated with gout?

Answer 11

EtOH abuse
obesity
insulin resistance
hypertension

Question 12

How is gout definitively diagnosed?

Answer 12

synovial fluid evaluation

Question 13

In gout, the intracellular crystals in the PMNs are _____-shaped and _____ when parallel to the axis.

Answer 13

needle; yellow

Question 14

In gout, the synovial fluid is inflammatory (______-_____ leukocytes/mm3) with predominance of ______.

Answer 14

20,000-100,000; neutrophils

Question 15

Hyperuricemia can result from ______ or _____ of urate.

Answer 15

increased production; decreased renal excretion

Question 16

The majority of pts (90%) with 1a gout are _____ of uric acid.

Answer 16

underexcretors

Question 17

Urinary uric acid excretion occurs thru a 4 compartment model:

Answer 17

1. glomerular filtration
2. pro-secretory filtration
3. secretion back into the tubule
4. post-secretory reabsorption

Question 18

Net tubular reabsorption is about ____ of the filtered uric acid, therefore only ____ of the UA is excreted in the urine.

Answer 18

90%; 10%

Question 19

What is the urate/organic ion exchanger in the proximal tubule?

Answer 19

URAT1

Question 20

Certain drugs/metabolites decrease the renal excretion of uric acid by activating URAT1, including ____.

Answer 20

nicotinate, pyrazinoate, diuretics, and low-dose aspirin

Question 21

Certain drugs/metabolites increase the urinary excretion of UA by inhibiting URAT1, including _____.

Answer 21

probenecid, sulfinpyrazone, a metabolite of losartan, and high-dose aspirin

Question 22

Uric acid is a product of _____ metabolism bc humans lack the enzyme, _____.

Answer 22

purine; uricase

Question 23

In rare cases, overproduction of UA can be due to superactivity of _____ or deficiencies of ______.

Answer 23

PRPP; HGPRT

Question 24

Complete deficiency of HGPRT results in ______.

Answer 24

Lesch-Nyhan syndrome

Question 25

What are the features of Lesch-Nyhan Syndrome?

Answer 25

mental retardation, spasticity, choreoathetosis, and self-mutilation

Question 26

What factors affect urate solubility?

Answer 26

1. temperature (cold) 2. dehydration 3. trauma 4. pH (less soluble at low pH)

Question 27

Uric acid crystals interact with synovial lining cells leading to the activation of ____ and _____.

Answer 27

monocytes; mast cells

Question 28

How is acute gout treated/prevented?

Answer 28

``` weight loss reduction of dietary purines limitation of fructose and EtOH NSAIDs colchicine corticosteroids ```

Question 29

How is chronic gout treated?

Answer 29

- uricosuric (probenecid) | - xanthine oxidase inhibitor (allopurinol, febuxostat)

Question 30

What does CPDD stand for?

Answer 30

calcium pyrophosphate dihydrate deposition disease

Question 31

CDDD is a type of arthritis associated with the release of ______ crystals into the joint space and chondrocalcinosis.

Answer 31

calcium pyrophosphate dehydrate (CPPD)

Question 32

_____ is the term used to describe an acute episodic arthritis due to CPPD crystals.

Answer 32

Pseudogout

Question 33

Psuedogout attacks are characterized by?

Answer 33

sudden onset pain, swelling, warmth, and redness of a large joint, most often the knee

Question 34

Unlike gout, in pseudogout the ____ joint is rarely involved.

Answer 34

first MTP

Question 35

CPDD is a disease of the ______, with associations to ____ and _____ disease.

Answer 35

elderly; hyperparathyroidism, hemachromatosis

Question 36

What are risk factors for CPDD?

Answer 36

osteoarthritis, trauma, surgery

Question 37

In CPDD, the synovial fluid will have _____-shaped crystals and will be _____ when parallel to the red compensator light.

Answer 37

rhomboid; blue

Question 38

In CPDD, the synovial fluid will be inflammatory (____-____ leukocytes/mm3) with predominately _____.

Answer 38

2000-80,000; neutrophils

Question 39

What does PPi stand for?

Answer 39

pyrophosphate

Question 40

The source of PPi is from the metabolism of ______, particularly from articular chondrocytes.

Answer 40

nucleoside triphosphates (NTP)

Question 41

What gene can be mutated in CPDD?

Answer 41

ank gene (ANKH)

Question 42

CPDD crystals do not form spontaneously in the synovium- they are released by the _______ of pre-formed crystals in the cartilage matrix.

Answer 42

"shedding phenomenon"

Question 43

What is the treatment of CPDD?

Answer 43

anti-inflammatory drugs similar to gout