Flashcards in Rheumatology: Crystal Arthropathies Deck (43)
The _____ are a group of diseases characterized by tissue deposition of monosodium urate (MSU) crystals due to hyperuricemia.
Name the 4 manifestations of crystal arthopathies.
1. gouty arthritis
2. tophi (deposits of MSU)
3. gouty nephropathy
4. uric acid nephrolithiasis (kidney stones)
____ usually refers to acute or chronic arthritis 2a to MSU crystals.
Hyperuricemia without symptoms is referred to as _____, not gout.
What are the 4 stages of gouty arthritis?
1. asymptomatic hyperuricemia
2. acute gouty arthritis
3. intercritical gout
4. chronic tophaceous gout
What are the features of asymptomatic hyperuricemia?
elevated serum uric acid (>7.0mg/dL) w/o gouty arthritis, tophi, or uric acid nephrolithiasis
What are the features of acute gouty arthritis?
- Acute onset of painful, warm, red, swollen joint, especially at night or morning.
- MTP of great toe most common (podagra) but also can be insteps, ankles, heels, knees, wrists, fingers, and elbows.
- Resolves after 3-10 days.
What is intercritical gout?
asymptomatic intervals between acute attacks of gout
What is chronic tophacous gout?
- subcutaneous, synovial, or subchondral bone deposits of MSU crystals
- commonly on digits of hands and feet, olecranon bursa, extensor surface of the forearm, Achilles tendon, or antihelix of the ear
Gout typically occurs in _____, age _____.
men; 30+ (peak incidence 50)
What other conditions are associated with gout?
How is gout definitively diagnosed?
synovial fluid evaluation
In gout, the intracellular crystals in the PMNs are _____-shaped and _____ when parallel to the axis.
In gout, the synovial fluid is inflammatory (______-_____ leukocytes/mm3) with predominance of ______.
Hyperuricemia can result from ______ or _____ of urate.
increased production; decreased renal excretion
The majority of pts (90%) with 1a gout are _____ of uric acid.
Urinary uric acid excretion occurs thru a 4 compartment model:
1. glomerular filtration
2. pro-secretory filtration
3. secretion back into the tubule
4. post-secretory reabsorption
Net tubular reabsorption is about ____ of the filtered uric acid, therefore only ____ of the UA is excreted in the urine.
What is the urate/organic ion exchanger in the proximal tubule?
Certain drugs/metabolites decrease the renal excretion of uric acid by activating URAT1, including ____.
nicotinate, pyrazinoate, diuretics, and low-dose aspirin
Certain drugs/metabolites increase the urinary excretion of UA by inhibiting URAT1, including _____.
probenecid, sulfinpyrazone, a metabolite of losartan, and high-dose aspirin
Uric acid is a product of _____ metabolism bc humans lack the enzyme, _____.
In rare cases, overproduction of UA can be due to superactivity of _____ or deficiencies of ______.
Complete deficiency of HGPRT results in ______.
What are the features of Lesch-Nyhan Syndrome?
mental retardation, spasticity, choreoathetosis, and self-mutilation
What factors affect urate solubility?
1. temperature (cold)
4. pH (less soluble at low pH)
Uric acid crystals interact with synovial lining cells leading to the activation of ____ and _____.
monocytes; mast cells
How is acute gout treated/prevented?
reduction of dietary purines
limitation of fructose and EtOH
How is chronic gout treated?
- uricosuric (probenecid)
- xanthine oxidase inhibitor (allopurinol, febuxostat)