Crystal Arthropathy

Question 1

What is gout?

Answer 1

a disorder of uric acid metabolism causing recurrent bouts of acute arthritis caused by deposition of monosodium urate crystals in joints, soft tissues + kidneys

Question 2

What is the main metabolic disturbance causing gout? What may this be caused by?

Answer 2

Hyperuricaemia
Increased urate intake or production
Decreased Renal Excretion

Question 3

List 3 causes of increased urate intake or production

Answer 3

Increased dietary intake
Increased nucleic acid turnover (e.g. lymphoma, leukaemia, psoriasis)
Increased synthesis of urate (e.g. Lesch-Nyhan syndrome)

Question 4

List 3 causes of decreased renal urate excretion

Answer 4

Idiopathic
Drugs (e.g. ciclosporin, alcohol, loop diuretics)
Renal dysfunction

Question 5

Describe the epidemiology of gout

Answer 5

M&raquo_space; F
Very rare pre-puberty
Rare in pre-menopausal women
More common in HIGHER social classes

Question 6

List 5 precipitating factors of gout

Answer 6

Trauma 
Infection 
Alcohol  
Starvation  
Introduction or withdrawal of hypouricaemic agents

Question 7

What is the main symptom of gout?

Answer 7

Sudden excruciating monoarticular pain

Usually affecting the metatarsophalangeal joint of the great toe (podagra)

Question 8

Describe the nature of symptoms in gout

Answer 8

Symptoms peak at 24 hrs
Resolve over 7-10 days
Sometimes, acute attacks can present with cellulitis, polyarticular or periarticular involvement
Attacks are often recurrent
Patients are symptom-free between attacks

Question 9

What is Intercritical Gout?

Answer 9

asymptomatic period between acute attacks

Question 10

When does Chronic Tophaceous Gout occur? What symptoms are caused?

Answer 10

Follows repeated acute attacks  
Symptoms: 
Persistent low-grade fever  
Polyarticular pain with painful tophi (urate deposits) 
Best seen on tendons + pinna of the ear

Question 11

What investigation is used to diagnose gout? What is seen? What is this sample used for?

Answer 11

Synovial Fluid Aspirate
Monosodium urate crystals
Microscopy + culture to exclude septic arthritis

Question 12

Describe monosodium urate crystals

Answer 12

Needle-shaped

NEGATIVE birefringence under polarised light microscopy

Question 13

What bloods are seen in gout?

Answer 13

FBC: raised WCC
U+Es
Raised urate
Raised ESR

Question 14

What may be seen on AXR/KUB Film in gout?

Answer 14

Uric acid renal stones may be seen

Question 15

What is pseudo gout?

Answer 15

arthritis associated with deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the joint cartilage

Question 16

Describe the pathophysiology of pseudogout

Answer 16

CPPD crystal formation is initiated in cartilage located near the surface of chondrocytes
Linked with excessive calcium pyrophosphate production: Abundance leads to formation of CPPD crystals
Shedding of crystals into the joint cavity leads to acute arthritis

Question 17

What predisposes to pseudo gout?

Answer 17

Most causes of joint damage (e.g. osteoarthritis, trauma)

Question 18

List 4 conditions that increase risk of pseudo gout

Answer 18

Haemochromatosis
Hyperparathyroidism
Hypomagnesaemia
Hypophosphatasia

Question 19

List 3 precipitating factors of pseudogout

Answer 19

Intercurrent illness
Surgery
Local trauma

Question 20

Describe the epidemiology of pseudogout

Answer 20

F > M

More common in the ELDERLY

Question 21

What symptom of acute arthritis is seen in pseudogout?

Answer 21

Painful swollen Joint (e.g. knee, ankle, shoulder, elbow, wrist)

Question 22

List 3 symptoms of chronic arthropathy in pseudogout

Answer 22

Pain
Stiffness
Functional impairment

Question 23

List 3 rarer symptoms of pseudogout

Answer 23

Tendonitis
Tenosynovitis
Bursitis

Question 24

List 5 signs of acute arthritis in pseudogout

Answer 24

Red  
Hot  
Tender  
Restricted range of movement  
Fever

Question 25

List 4 signs of chronic arthropathy in pseudogout

Answer 25

Similar to osteoarthritis 
Bony swelling  
Crepitus  
Deformity 
Restriction of movement

Question 26

What bloods should be taken in pseudogout?

Answer 26

High WCC in acute attacks
High ESR
Blood culture: to exclude septic arthritis

Question 27

What is seen on joint aspiration in pseudogout?

Answer 27

Rhomboid, brick-shaped crystals
POSITIVE birefringence
Culture or Gram-staining to exclude septic arthritis

Question 28

List 5 features seen on radiographs in pseudogout?

Answer 28

Chondrocalcinosis  
Loss of joint space  
Osteophytes  
Subchondral cysts  
Sclerosis