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Rheum: Crystal Induced Arthritis (Gout)

Terms in this set (41)

Gout is a heterogenous metabolic d/o associated with elevated uric acid and is primarily characterized by what three factors?
Episodic severe monoarthritis
Potential for chronic deformity
Extra-articular complications
What is the epidemiology of gout? (gender, age, association)
MC in men (9:1)
Peak age of onset 40-50 in men & > 60 women (usually menopause)
Strong association w/ organ transplants
Metabolic syndrome overlap
Gout is the most common cause of inflammatory arthritis in men over what age?
Men over 40 years old
What factors cause hyperuricemia?
Impaired renal function
Overproduction of uric acid
&/or overconsumption of purine-rich foods that are metabolized to urate
How does uric acid crystals cause arthritis?
Arthritis is caused by precipitation of uric acid crystals in joint space
Hyperuricemia increases the risk of what kidney condition?
Nephrolithiasis (kidney stones)
(50% risk if uric acid level > 13 mg/dl)
What are the two classifications of gout and what are the two subsets of each classification?
Primary and Secondary
Divided into metabolic and renal
Secondary gout refers to gout related to what conditions?
Related to:
Another disease
To an identifiable causes of hyperproduction of uric acid OR
to its undersecretion in the kidneys
In primary gout, there are overproducers and underexcretors, which one is more common?
Underexcretor (80-90%)
Classified as renal
Usually idiopathic
In primary gout, what causes overproduction of uric acid?
Overproducer (10-20%)
Specific enzyme deficiencies
Classified as metabolic
(Lesch-Nyhan syndrome & von Gierke's dz)
In secondary gout, what diseases or drugs cause overproduction of uric acid?
Myeloproliferative d/o
Lymphoproliferative d/o
Malignancy
Psoriasis
Chronic hemolytic anemia
Cytotoxic drugs
In secondary gout, what diseases or drugs cause the underexcretion of uric acid?
Renal insufficiency
Drugs: CANT LEAP
Cyclosporine
Alcohol
Nicotinic acid (Niacin)
Thiazide diuretics
Lasix (Loop diuretics)
Ethambutol
Aspirin
Pyrazinamide
How would you describe the articular pain that gout causes?
Acute, painful, often nocturnal mono-oligoarticular pain
How is the joint affected in gout?
Joint usually swollen, exquisitely tender w/ overlying skin tense, warm, and dusky red (sometimes difficult to differentiate b/w gout and cellulitis)
In gout, what part of the body is affected the most, lower or upper extremities?
Lower extremities more often
MTP big toe (podagra) - 50% of first attacks
Ankles, heels
Knees
Wrist
Fingers
Elbows
How many gout patients will have a recurrence of gout (or second attack) in the future?
Almost all pts (> 90%)
How long does it take for tophaceous gout to develop?
It develops years after initial attack
What are some features of the clinical diagnosis of gout?
Acute monoarticular arthritis (MC onset at night, great toe)
Hyperuricemia
Dramatic response to NSAIDs/colchecine
What are the different clinical stages of gout?
Asymptomatic hyperuricemia - before gout attack
Acute gouty arthritis
Intercritical gout (after resolution of acute attack)
Chronic tophaceous gout
What needs to be present from lab results to be a definite diagnosis of gout?
Definite dz made by presence of uric acid crystals in joint fluid
In gout, polarized microscopy exam will show (negative/positive) birefringent and needle-like sodium urate crystals?
Negative
What are some common lab results that help diagnose gout?
Elevated serum uric acid (> 7.5 mg/dl)
Elevated WBC, ESR-acute attack
What are some expected radiographic findings when related to gout?
Normal initially
"Rat bites" lesions in latter disease
Destroys bone
What are the DDx for gout?
Cellulitis
Pseudogout
RA
What meds are used for the acute tx of gout?
NSAIDs
Colchicine
Corticosteriods (oral, intramuscular, intra-articular)
Other analgesics (like opiates)
What kind of drugs do you not give during an acute gout attack?
Do not start chronic urate lowering drugs during an acute gout attack
How do you manage gout between attacks?
Assess for possible secondary conditions
Review meds (like HCTZ which is associated underexcretions, niacin, ASA)
Measure uric acid when asx
What are some reversible causes of hyperuricemia?
High purine diet
Obesity
ETOH (beer)
What are some uricosuric agents and what are their indications for use?
Probenecid
Sulfinpyrazone
Indicated for increased frequency or severity of gout attacks of underexcretors
What precautions do you use when prescribing uricosuric agents?
Use only if renal function is preserved
Avoid in pt w/ history of uric acid stones
ASA > 3 g/day- uricosuric & antagonizes this agent, low doses do not
(reduce does to 325 mg or less if ASA is needed)
What is the prognosis for gout?
Asx periods become shorter as dz progresses
Younger age of onset = great tendency to a progressive course
Chronic gouty arthritis occurs after repeated attacks of acute gout or inadequate tx
Destructive arthropathy rarely seen in pt whose first attack is after age 50
Thought to have increased incidence of HTN, renal dz, DM, atherosclerosis, and high triglycerides
In what disease does calcium salt deposits in cartilage (chondrocalcinosis) precipitate in a joint and cause painful arthritis?
Pseudogout or
Calcium pyrophosphate dihydrate (CPPD) deposition disease
How is pseudogout classified?
Primary and secondary
What are the two different subsets of primary pseudogout?
Idiopathic (aging)
Hereditary
What are the different subsets of secondary pseudogout?
Hyperparathyroidism
Hemochromatosis
Hypothyroidism
Chronic electrolyte imbalances (hypo-magnesium/phosphate)
What are the clinical manifestations of pseudogout?
Acute monoarticular/oligoarticular arthritis (4 or more joints)
MC in pts > 60
MC associated w/ acute medical illness or surgeries (postop, post-MI pts)
ALWAYS suspect in elderly hospitalized pt with new acute monoarthritis
What lab findings are suggestive of pseudogout?
Normal serum uric acid
Crystal analysis of joint aspirate: Ca++ pyrophosphate crystals w/ + birefringence
What radiologic findings would you expect to find in pseudogout?
Calcifications-chondrocalcinosis esp. in knee
Signs of degenerative changes (OA)
How can you differentiate b/w gout and pseudogout using labs?
Gout has strong, negative birefringence
Pseudogout is weak, positive birefringence
How do you treat pseudogout?
Joint aspiration
NSAIDs/COX 2 (acute episode)
Corticosteriods
Colchicine (more effective in prophylaxis but rare)
Assessment for secondary causes, especially younger pts (electrolytes, Alk Phos, TSH, Ferritin)
What is the most common joint affected in gout? Pseudogout?
Gout - 1st MTP
Pseudogout - knee
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