GOUT
A
metabolic disease marked by red, swollen, and acutely painful joints
Gout
affects any joint but is found mostly in the of the feet
Great
toe
Ankle
Midfoot
Pathophysiology
(Note: Click here for
supplemental pathogenesis information on gout.)
Men
over 30 and postmenopausal women who take diuretics.
Follows
an intermittent course
Pt can be
symptom free for years between attacks
Underlying
cause of primary gout is unknown
In many
patients it results from κ excretion of uric acid by the kidneys.
Can be a
genetic defect called hyper-uricemia that causes an overproduction of uric acid
Secondary gout may develop from another
disease such as:
Obesity
Diabetes
High blood
pressure
Leukemia
Bone cancer
Kidney
disease
Secondary
gout can also follow treatment with certain drugs such as
hydrochlorothiazid or pyrazinamide
A Painful Progression
Four
Stages of Progression (if untreated):
1. Pt develops asymptomatic hyperuricemia
Urate levels
rise but dont produce symptoms
2. Acute gouty arthritis
Painful
swelling and tenderness
When pt
seeks medical attention
3. The interictal stage
May last for
months to years
Pt may be
asymptomatic or may experience exacerbations
4. Chronic stage
urate pools
in the joints
tophi
(clusters of urate crystals) develop in cartilage, synovial membranes, tendons,
and soft tissues.
Final
unremitting stage called tophaceous gout
Tale of the Tophi
Tophi
- clusters of urate crystals surrounded by inflamed tissue
Can cause
deformity and destruction of hard and soft tissues
In joints
tophi lead to destruction of cartilage and bone
Tophi
form in diverse areas:
hands
knees
feet
outer sides
of the forearms
pinna of the
ear
Achilles
tendon
Rarely,
internal organs such as the kidneys and heart may be affected and cause
dysfunction
Hyperuricemia
Urates
are uric acid salts
hyperuricemia
is a plasma urate level Ψ 7 mg/dl
Hyperuricemia
results from
ι
urate production
κ
excretion of uric acid
a combination
of the above
With
hyperuricemia, plasma and extracellular fluids are supersaturated with urate
This
leads to urate crystal formation
When
crystals are deposited in other tissues, a gout attack strikes
Provoking Factors
Stress
Trauma
Infection
Hospitalization
Use
of some medications
Surgery
Starvation
Weight
reduction
Excessive
food intake
Use
of alcohol
Relief in Sight
A
sudden increase in serum urate may cause new crystals to form.
A
drop in serum and extracellular urate may cause previously formed crystals to
partially dissolve and be excreted
What to Look for
First
attack strikes suddenly and peaks quickly
First
attack is extremely painful
Attacks
resolve in 10-14 days
Second
attacks are usually 6 months to 2 years later
Tophi are
hard
irregular
yellow-white nodules
Found
especially on
ears
hands
feet
In
late chronic stage gout the skin over the tophi may ulcerate and release a
chalky white exudate or pus results in joint degeneration, deformity and
disability
joints may
be warm and tender
pts may have
a hx of HTN and kidney stones
Pain
often wakes the pt in the night with pain in the great toe or other part of the
foot
Pain
may become so severe that pt cant bear weight of bed linens or even vibrations
May
report chills and fever
Complications
Renal
calculi
Infections
Nerve
damage
Circulatory
problems
CVA
Coronary
thrombosis
HTN
Cardiovascular
lesions
Tests
Needle
aspiration of synovial fluid or tophi reveals sodium crystals (mono-sodium urate) in the cells
Blood
and urine tests to determine serum and urine uric acid levels
X-rays
initially produce normal results.
Chronic
gout shows damage to cartilage and bone
Treatment
Three
goals:
1. Terminate the acute attack
2. Reduce uric acid levels
3. Prevent recurrent gout and renal calculi
Treatment of Acute Attacks
Bed
rest and elevation of the extremity
Immobilization
and protection of the inflamed, painful joins
Local
application of cold
Bed
Cradle
Tylenol
for relief of mild pain
NSAIDs
or cortisone for acute inflammation
Cholchicine
or corticosteroids are occasionally used to treat acute attacks
Drink
2 L fluids per day to help prevent renal calculi
Acute
attacks can occur 24-96 hours after any kind of surgery
Cholchicine may be administered before and after to help
attacks
Treatment of Chronic Gout
Serum
uric acid levels are reduced to less than 6.5 mg/dl
Overproduction
of uric acid θ
allopurinol
Underproduction
of uric acid θ
probenecid or sulfinpyrazone
Serum
uric acid levels monitored
NaH2CO3
given to make urine alkaline
Adjunctive Therapy
Avoiding
alcohol especially beer and wine
Avoiding
purine rich foods such as anchovies, liver, sardines, kidneys, sweetbreads, and
lentils
Weight Loss
Obese
pts. should begin a weight-loss program because weight reduction decreases uric
acid levels and stress on painful joints