Clin Path: Uric Acid Metabolism

Front 1

What fraction of urate is excreted by kidney

Back 1

66-75% of urate (remaining excreted by intestine)

Front 2

Urate exists majorly as what form

Back 2

Monosodium urate (98%)

Front 3

Process of excretion of uric acid by kidney involves 4 steps

Back 3

● Filtration

● Reabsorption (98-100% is reabsorbed)

● Secretion (50% of reabsorbed quantity is secreted)

● Post secretory reabsorption (40% of secreted is reabsorbed)

Overall, about 8-12% of uric acid filtered is excreted

Front 4

Hyperuricemia is uric acid level above

Back 4

7mg/dl (420µmol/L)

Front 5

What is nucleic acid turnover

Back 5

It is process of synthesis and degradation of nucleic acids (purine and pyrimidine nucleotides). Increased turnover can lead to hyperuricemia

Front 6

Hyperuricemia is present in what percent of ambulatory patients

Back 6

5% of ambulatory patients

Front 7

Clinical manifestations of hyperuricemia

Back 7

● Gouty arthritis

● Asymptomatic hyperuricemia

● Renal sequelae (nephrolithiasis, nephropathy)

● Hyperuricemia and Syndrome X

Front 8

Monosodium urate is produced from uric acid at what pH

Back 8

pH of 7.4

Front 9

Gout majorly affects which joint of the body

Back 9

1st metatarsal of the big toe (called PODAGRA)

Front 10

Medications that increase uric acid secretion/excretion in urine are called

Back 10

Uricosuric medications (eg probenecid)

Front 11

What is tophi?

Back 11

Tophi (Latin for Stone) are nodules of monosodium urate crystals permanently in the joints of individual with Chronic gout.

Front 12

What are the 4 stages of gout

Back 12

● Asymptomatic hyperuricemia

● Acute gouty arthritis (acute flares of crystallization)

● Intercritical gout (Intervals between flares)

● Chronic tophaceous gout

Front 13

What happens in acute gouty arthritis (acute flares of crystallization)

Back 13

● Abrupt onset of inflammation in joints of urate accumulation

● This causes pain (due to sharp crystals), redness, swelling

● This usually resolves in 3-10 days itself if untreated

● 90% of 1st acute flares attacks are monoarticular (occur in 1 joint) of which 50% are Podagra

● Eventually 90% of attacks are podagra

Front 14

Tophi are found majorly in what parts of body

Back 14

Upper extremities of the body (hands, elbows, fingers)

Front 15

Tophi are seen in what stage of gout

Back 15

Chronic stage (hence called Chronic tophaceous gout)

Front 16

Methods of assaying uric acid

Back 16

● Uricase method

● High Performance liquid chromatography (HPLC) method

● Phosphotungstic acid spectrophotometry

Front 17

Management of gout

Back 17

● NSAIDs (for pain and against inflammation)

● Corticosteroids (against inflammation)

● Allopurinol (xanthine oxidase inhibitor)

● Fluids

Gouty arthritis is inflammatory so anti inflammatory drugs are used against it.

Front 18

Risk factors for gout

Back 18

● Sex (males at higher risks)

● Age (older people at higher risk)

● Hypertension

● Post menopausal women

● Drugs (diuretics, salicylates/aspirin, cyclosporine)

Front 19

Hypouricemia occurs when uric acid levels are

Back 19

Less than 2mg/dl (120 µmol/L)

Front 20

Reference range for uric acid is

Back 20

● 3-7mg/dl (180-420µmol/L) for men

● 2-6mg/dl (120-360µmol/L) for women

Front 21

Are there any adverse effects of hyouricemia

Back 21

No