GOUT........

GOUT

Definition
: A group of conditions with deposition of mono-sodium-urate-monohydrate crystals in the connective tissues, due to a hyperuricemic state, causing arthritis, tenosynovitis, bursitis, tophaceous deposits, urolithiasis, and urate nephropathy.

Epidemiology :

Affects both males & females. Males commonly post-pubertal and females post-menopausal.

Etiology :

May be due to either increased production (25%) or decreased excretion (75%) of uric acid from the body.

Decreased excretion of uric acid :

Renal failure

Drugs - diuretics, salicylates (aspirin)

Lead poisoning

Hyperparathyroidism

Myxedema

Lactic acidosis due to any cause -

Starvation

Alcohol

Exercise

Vomiting

Toxemia of pregnancy

Due to inherited defect in excretion.

Overload of uric acid
(if renal function is normal - hyperexcretors of uric acid).

Increased synthesis of purines de novo (faulty nucleotide synthesis --loss of negative feedback).

Increased turnover of purines -

Pathology :

Urate crystal deposition in joints

2ndary degenerative changes with inflammation --- destruction of joint.

Acidic urine --- urate ppts esp in hyperexcretors of uric acid --- urolithiasis.

Urate crystals in soft tissue --- chalky deposits with later 2ndary changes -- Tophi / tophaceous deposits.

C/F :

Gouty arthritis
:

ACUTE gouty arthritis
:

Commonly acute attack occurs 1st in MTP joint of great toe.

Joint swollen, hot, red, tender, with restricted movements.

May be accompanied with fever, malaise, leucocytosis.

Subsides even without treatment spontaneously.

Recurrent attacks in most patients at increasing frequency and increasing duration --- attacks blend into each other --- chronic "gouty" arthritis.

Precipitating factors
-

Sudden rises in urate - dietary excess, alcohol, diuretics

Sudden falls - Start of therapy.

Chronic arthritis with tophi
:

Recurrent acute attacks

Bony erosion & joint destruction

Tophi deposited - can be found in ear cartilage, bursae, tendon sheaths.

Progressive limitation of joint function.

Urolithiasis -

Common in high excretors

Common in hotter climates

With uricosuric drugs

With acidic pH of urine - diarrhea, ileostomy.

Urate nephropathy -

D.t. a combination of renal tubular obstruction, urolithiasis, hypertension, DM, 2ndary pyelonephritis.

Associated conditions -

Obesity

DM

Hyper lipoproteinemia type IV

HT

IHD

Pseudogout (D/D) :

Rheumatoid arthritis

Chondrocalcinosis - calcium pyrophosphate dihydrate (CPPD) deposition.

Investigations :

S. uric acid
- not very useful because -

may be asymptomatic hyperuricemia.

Normal serum uric acid levels
- 2.5-8.0 mg% in males & 1.5-6.0 mg% in females.

Acute attack may occur with normal uric acid.

X-Ray of joint
- no characteristic changes

Synovial fluid
- Variable color, viscosity , under polarized light shows urate crystals.

Therefore
diagnosis is mostly clinical
.

General Treatment :

Avoid excess purine intake - meat.

Avoid excess alcohol - ppts acute attack

Weight loss in obese patients.

Avoid starvation - ppts lactic acidosis - Acute attack