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Gout
UMSOPPY3 Gout Notes
26
Pharmacology
Graduate
04/10/2011

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Cards

Term
Gout results in deposition of ______ in synovial fluid and other tissues or the formation _______ stones in the kidney.
Definition
monosodium urate crystals, uric acid
Term

In general gout is uncommon before what age?

 

In women, gouty arthritis attacks are uncommon before?

Definition

30

 

menopause

Term

What is hyperuricemia?

 

What is significant about this level?

Definition

serum uric acid conc.>7mg/dL (420μmol/L)

 

this concentration is the limit of solubility for monosodium urate in plasma

 

 

Term
At what serum concentration is monosodium urate more likely to precipitate in the tissues?
Definition
<8mg/dL
Term
At a pH=7, what % of uric acid exists as monosodium urate?
Definition
90%
Term

Uric acid is an end product of _____ metabolism?

 

Since humans lack uricase, the uric acid cannot be broken into the water-soluble product ______.

Definition

purine

 

allantoin

Term
Increased serum uric acid occurs by 1 of 2 mechanisms. What are they?
Definition

1. overproduction of uric acid

2. underexcretion of uric acid

Term
Is overproduction or underexcretion more prominent?
Definition
90% by underexcretion
Term
Which medications can contribute to decreased excretion of uric acid?
Definition

Salicylates (<2g/day)

Diuretics

Alcohol

Levodopa-Carbidopa (Sinemet)

Ethamutol (Myambutol)

Pyrazinamide

Nicotinic acid (Niacin)

Cyclosporine (Sandimmune)

Term
Overproduction of uric acid may result from abnormalities in the enzymes that regulate purine metabolism. What are the 2 documented enzymatic abnormalities?
Definition

1. increased phosphoribosylpyrophosphate synthetase activity

2. deficiency of hypoxanthine-guanine phosphoribosyltransferase 

Term
What level of uric acid production over 24-hours indicates overexcretion? (on a non-restricted diet)
Definition
800mg/24h
Term

2/3-3/4 of all uric acid produced daily is excreted where?

 

normally, uric acid is filtered in the ________, reabsorbed in the_________, and secreted __________.

Definition

kidneys

 

glomeruli, proximal tubule, distally

Term

Which joint is commonly affected by an acute gout attack?

 

What is podagra?

Definition

metatarsophalangeal joint

 

acute attack of gout in the great toe (>50% of all attacks)

Term
What % of pt experience podagra at some point in the disease?
Definition
~85-90%
Term
In addition to podagra, gout can aggect:
Definition
insteps, heels, ankles, knees, fingers, wrists, and elbows
Term
What are some modifiable risk factors for gout?
Definition

1. alcohol consumption

2. obesity

3. HTN

4. occupational/environmental exposure to lead

Term
How long does an untreated attack last?
Definition
7-10 days, peaking 1-2 days after onset
Term
What are the nodular masses of monosodium urate cyrstals deposited in the soft tissues called?
Definition
Tophi (tophaceous gout)
Term
What are the most common sites of tophi?
Definition
base of great toe, fingers, wrist, hand, olecranon bursae, and Achilles tendon
Term

When do tophi generally occur?

 

What are the complications of tophi?

Definition

approximately 12 years after the initial attack

 

pain, soft tissue damage, deformity, joint destruction, nerve compression syndromes (carpal tunnel syndrome)

Term
What are the 3 renal manifestations of gout?
Definition

1. nephrolithiasis

2. acute gouty nephropathy

3. chronic gouty nephropathy

Term

How often does nephrolithiasis occur?

 

What is the pathophysiology of nephrolithiasis?

Definition

10-25% of pt with primary gout

 

uric acid crystals become more soluble as the urine pH becomes alkaline. acidic urine can become saturated with uric acid crystals and spontaneously form a stone (other stones may also develop as uric acid acts as a nidus for calcium oxalate or phosphate stones)

Term
What causes acute gouty nephropathy?
Definition
massive malignant cell turnover that occurs with the treatment of myeloproliferative or lymphoproliferative disorders, blockage of urine flow secondary to the precipitation of uric acid in collecting ducts and ureters can lead to acute renal failure
Term

Chronic urate nephropathy can occur after long-term deposition of cyrstals where?

 

Microtophi cause a massive inflammatory reaction resulting in what?

Definition

renal parenchyma

 

proteinuria and the inability of the kidney to concentrate urine

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