Chapter 23: Abnormalities of Purine Metabolism (Gout) Flashcards
1
Q
Gout
A
- Chronic systemic disease
- Characterized by buildup of uric acid crystals
2
Q
Gout is a common form of
A
- Arthritis
- 5% of all cases
3
Q
Symptoms of Gout
A
- Sudden acute attack of unbearable pain
- Typically in toe, ankle, or knee
- Comes on overnight
4
Q
Gout effetcs
A
- 840/100,000 individuals
5
Q
Gout is more common in
A
- Males
- Younger age people
6
Q
Gout results from
A
- Overproduction of uric acid
- Excessive intake of foods that are rich in purines
- Inability to excrete uric acid
7
Q
Gout usually only affects
A
- 1 or 2 joints at a time
8
Q
Peripheral joints have
A
- Lower body temperature
9
Q
Uric acid is overproduced by the
A
- Liver
10
Q
Foods rich in purines that may cause Gout
A
- Red meats
- Cream sauces
- Red wine
11
Q
Gout may occur as a consequence of
A
- Trauma
- Surgery
12
Q
Inability of the kidney to excrete uric acid in the urine is due to
A
- Decreased filtration
13
Q
Podagra
A
- Large red swelling on first metatarsal joint
14
Q
First stage of gout
A
- Asymptomatic hyperuricemia
15
Q
Second stage of gout
A
- Acute symptomatic attacks
- Interrupted by asymptomatic intervals of decreasing length
16
Q
Third stage of gout
A
- Intercritical gout
- Symptom free periods for months or years
17
Q
Untreated gout may result in
A
- Chronic tophaceous gout with crippling gouty arthritis
18
Q
90% of patients with gouty arthritis also have
A
- Renal impairment
19
Q
Hyperuricemia occurs when
A
- Serum levels of uric acid are markedly elevated
- Currently affects 18% of the US population
20
Q
Urate levels may be determined by
A
- Urate formed minus urate excreted
21
Q
2/3 of urate excretions occurs in the
A
- Kidney
22
Q
1/3 of urate excretion occurs in the
A
- Gut
23
Q
Hyperuricemia may be associated with
A
- Obesity
- Gender
- Higher socioeconomic status
24
Q
Medications that predispose to hyperuricemia
A
- Levodopa (for Parkinson’s)
- Diuretics
- Niacin
- Aspirin
25
Radiation therapy for cancer may result in
- Hyperuricemia
26
Metabolic syndrome/syndrome X can contribute to
- Hyperuricemia
27
Perfect range of uric acid in US males
- 2.7 - 7.0 mg/dL
28
Hyperuricemia may be elevatd due to
- Increased formation
| - Decreased excretion
29
Approximately 10% of patients with gout are
- Overproducers
30
Alcohol ingestion increases
- De novo purine production
| - Contributes to uric acid overproduction
31
Approximately 90% of patients with gout have a
- Defect in uric acid excretion due to reduced renal clearance
32
Lactic acid may compete with
- Uric acid for renal secretion
| - Reduces renal clearance (decreased excretion)
33
Diagnosis of MSU crystals in synovial fluid involves observing
- Symptoms
| - Joint examination
34
"Gold standard" for diagnosis
- Joint aspiration
35
Monosodium Urate (MSU) can be demonstrated in
- Fresh synovial fluid
36
Crystals are characteristically
- Long
- Needle-shaped
- Birefringent
37
Gout symptoms/diagnosis may be easily confused with
- Rheumatoid arthritis
- Osteoarthritis
- Septic arthritis
- Pseudogout
38
Rheumatoid arthritis or osteoarthritis in elderly can be confused with gout because
- They can present as polyarticular disease
39
Septic arthritis has
- High degree of mortality
40
Pseudogout crystals are
- Calcium pyrophosphate dihydrate
41
Pathogenesis of gout
- Acute inflammatory response
42
The crystalline deposits of urates on bone trigger
- An inflammatory response
| - Neutrophils are the "first responders"
43
Knee joint in gout is characterized by
- Chalky tophaceous urate deposits covering the articular surface of the knee joint
44
Dietary measures to help manage gout
- Avoidance of alcohol and relevant drugs (especially diuretics)
- Weight loss
45
Anti-inflammatory drugs to help manage gout symptoms
- NSAIDs (indomethacin/aspirin)
46
Drugs to help with gout management
- Colchicine
| - Corticosteroids (prednisone)
47
Urate-lowering drugs that assist in gout management
- Probenecid
- Synthetic C-7, N-8 position isomer of hypoxanthine
- Febuxostat
48
Febuxostat
- Non competitive inhibitor
49
Synthetic C-7, N-8 position isomer of hypoxanthine
- Converts allopurinol to alloxanthine
50
Uric acid is produced from
- Purine nucleotide turnover
51
Final step in uric acid production is catalyzed by
- Xanthine oxidase
52
Enzyme defects involved with gout
- Partially inhibited HGPRT activity
- Overactive PRPP synthetase
- Reduced glucose-6-phosphatase activity
53
Overactive PRPP synthetase causes
- Reduced allosteric control
54
Reduced glucose-6-phosphatase activity is characteristic of
- Von Gierke's disease
| - Results in increased PPP activity
55
Lesch-Nyan syndrome
- Inherited disorder
| - Sex linked and recessive (more common in males)
56
Lesch-Nyan syndrome is a result of a deficiency of
- HGPRTase
| - Prevents salvage of hypoxanthine or guanine
57
Prevention of hypoxanthine/guanine salvage by Lesch-Nyan syndrom causes
- Hyperuricemia due to PRPP accumulation
58
HGPRTase deficiency results in
- An increase in de novo purine biosynthesis
59
Characteristic neurological features of Lesch-Nyan syndrome include
- Self-mutilation
- Involuntary movements
- Mental retardation
60
In Lesch-Nyan syndrome, the distal portions of several fingers are often
- Shortened due to prior uncontrolled self-mutilation
61
Patients with Lesch-Nyan syndrome have an increased risk of
- Kidney stones
62
Treatment for Lesch-Nyan syndrome invovles
- Hydration/Allopurinol
- Management of behavioral concerns is difficult
- Brain stimulation/antispasticity medications/benzodiazepines
63
Gout is a chronic systemic condition arising from
- The accumulation of monosodium urate crystals in the synovial joints
- Crystal accumulation causes pain and inflammation
64
A significant number of people with hyperuricemia do not develop gout, and those who suffer from repeated gout attacks have
- Normal or even diminished circulating levels of uric acid
65
The "gold standard" for gout diagnosis is aspirating a sample of
- Joint fluid and observing the presence of monosodium urate crystals in the synovial fluid
66
Crystals are often surrounded by
- Red and white blood cells and are negatively birefringent
67
The most frequently prescribed medications for acute gout attacks are
- NSAIDs
| - Colchicine
68
Allopurinol reduces the amount of uric acid in the blood by
- Inhibiting xanthine oxidase and slowing uric acid production
- May be used for the long-term treatment of gout
69
Febuxostate is a newer, noncompetitive inhibitor of
- Xanthine oxidase
70
Absence of HGPRT due to an inborn error of metabolism results in
- Lesch-Nyan syndrome
71
Lesch-Nyan syndrome is a rare
- X-linked recessive disorder
