Gout is a
metabolic disorder that causes an
extremely uncomfortable arthritic
pain in the joints and synovial
fluids. It is due to an increased
amount of uric acid (the final end
product of purine metabolism), also
known as hyperuricemia, in
biological fluids.
Gout causes
extreme discomfort because of the
deposited amounts of uric acid
crystals that become lodged in
joints and other small spaces in the
body. All mammals except humans
possess an enzyme called uricase,
which assists in the breakdown of purines
for excretion from the body. Tophi (deposits of uric acid) can
accumulate and cause inflammation
and the destruction of the joint spaces,
bones, and cartilage. [1] In some cases, tophi can break
through the skin and appear as white
chalky nodules that look like crab
eyes.
Uric acid is produced
from purines that are manufactured
in human cells (usually DNA and
RNA), from the breakdown in energy
substrates, and are also obtained
from foods. Uric acid is excreted
through the kidneys into urine.
A small amount passes through
the intestines where it is broken
down by specialized bacteria. Men typically
excrete 1200 mg and women
approximately 600 mg of uric acid
daily. In the
past, gout was
considered a "rich man's disease",
suffered by kings and other lordly
men, who were overweight, inactive, and consumed a diet rich in meat and
wine. This theory may have
some legitimacy, as organ meats are particularly
high in purines and were a
significant source of protein in
earlier years. Alcohol also slows down
uric acid excretion by interfering
with the kidney and liver's normal
functioning and was readily consumed
during this time period as well.
Gout is classified as
either primary or
secondary depending on the cause
of the hyperuricemia. More than 99%
of primary gout cases are
considered idiopathic, meaning that
there is no clear cause. It is most
likely due to a combination of
genetic and hormonal factors that
cause either an overproduction, or
reduced excretion of uric acid.[2]
Secondary gout is usually
caused by drug therapy or by other
medical conditions. Medications such
as diuretics and low doses of
aspirin can reduce uric acid
excretion and increase the chance of hyperuricemia. Alcohol use and renal
(kidney) insufficiency can also
cause gout, especially in older
patients. Exposure to lead is also
associated with build up of uric
acid and should be ruled out in all
suspected cases. [3]
The initial gout
symptom experienced is a severe,
nearly debilitating pain in one
joint, most often in the lower
limbs. About 60% of cases occur in
the big toe. In the elderly,
symptoms are more likely to occur in
the upper extremities, especially in
the fingers. If the attack
continues, fever and chills can
occur. The pain usually peaks in the
late evening and will often awaken
the patient.
Gout is often
divided into four symptomatic
stages:
-
Asymptomatic-
the patient is unaware of the high
uric acid levels and has no
symptoms at present
-
Acute gouty
arthritis- the patient has
developed high levels and is
experiencing pain and discomfort
from the formation of tophi under
the skin and in joint spaces. The
attacks come on quickly, can last
for days, and may reoccur
sporadically. The condition
usually worsens and the attacks
become more frequent.
-
Intercritical
gout-
this is the period between attacks
when there are no clinical
symptoms present.
-
Chronic
tophaceous gout-
this is when
the condition has become chronic
and has caused lasting damage to
the joints and the kidneys. It is
unusual for patients to reach this
stage in today's medical system.
Diagnosing gout is
often based on clinical signs and
symptoms. Infections should always
be ruled out as the cause of
symptoms. A serum uric acid test
should be run, as well as an
aspiration of fluid, to culture and
evaluate for crystal formation. [4]
-
Gout affects
over 2 million Americans a year
-
Over 95% of
sufferers of gout are men over the
age of 30
-
Gout is
responsible for approximately 5%
of all arthritic cases in the
country
-
Some degree of
kidney dysfunction occurs in
nearly 90% of patients with gout
and they will at an elevated risk for
the development of kidney stones
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