11 - Gout and Uric Acid Lithiasis Flashcards
What is gout?
- An acute arthritic process, which develops from the accumulation of uric acid.
- Intense swelling, pain, redness, heat
How does uric acid accumulate
From an exogenous source, the purine intake contributes
What are the general characteristics of gout?
- Usually affect men older than 25 and women who are post-menopausal
- Initial presentation is usually a painful attack of monoarticular arthritis
- Various precipitating factors (trauma, alcohol, surgery, diet, and drugs)
Most will have gout in the first metatarsal phalangeal joint
What is primary gout?
Primary Gout: may be inherited as idiopathic or secondary to a defect in purine metabolism leading to an overproduction of uric acid.
What is secondary gout?
Secondary Gout: may be the result of an inherited disorder (Lesch-Nyhan or glycogen storage) or the result of over production due to increase of cellular turnover, or in under secretion.
What is on the differential diagnosis for gout?
- Crystal arthropathies
- Infection
- Sarcoidosis
- Trauma
Think about differential as you obtain H&P
What are the symptoms of gout?
- Pain of the involved joint
- Redness
- Swelling
- Mild fever and chills
What are the four phases of gout?
- Asymptomatic Hyperuricemia
- Acute Gouty Arthritis ***
- Intercritical Gout
- Chronic Tophaceous Gout
Describe Asymptomatic Hyperuricemia
High uric acid in system, either high intake or high production, but no symptoms
Describe Acute Gouty Arthritis
Acute Gouty Arthritis ***
- MOST COMMON to diagnose
- Hot, painful, inflamed joint is present
- First attack
- Lasts for 3-7 days
Describe Intercritical Gout
- The period of time after the first gout attack
- You will see sustained high uric acid following attack
- This can last for months to years
- Patient may have another attack, but hard to predict when that may be
Describe Chronic Tophaceous Gout
- High uric acid will remain
- The uric acid starts to collect into “tophi” in soft tissue
- The only way you can evaluate this is with a soft tissue mass, uric acid crystals present
What are the criteria for the diagnosis of acute gout?
A. The presence of characteristic urate crystals in the joint fluid (if a past attack then C1 and C4 also)
B. A tophus proved to contain urate crystals by chemical means or polarized light microscope and C1 and C4
C. Presence of six of the following 12 clinical, laboratory, and radiographic phenomena
What are the 12 clinical, laboratory and radiographic phenomena?
- Maximum inflammation developed within one day
- More than one attack of acute arthritis
- Presents with monoarticular arthritis
- Redness is observed over the affected joint(s)
- First metatarsophalangeal pain or swelling
- Unilateral first metatarsophalangeal joint attack
- Unilateral tarsal joint attack
- Tophus is suspected
- Hyperuricemia
- Asymmetric swelling within a joint
- Subcortical cysts without erosions in radiograph
- Joint fluid culture negative for organisms
What are on the differential for this?
- Fracture
- Osteoarthritis
- Septic joint
- Pseudogout
Describe the gout work-up
- Blood work
- Joint aspiration
Describe the blood work for a gout work-up
Serum uric acid should be between 3-7 mg/dl
Describe the joint aspiration of synovial joint fluid
Synovial fluid analysis
- Fluid will be thick and straw colored during a gout attack
- Glucose will be the same as blood serum during a gout attack
- WBCs or bacteria are NOT present in the joint fluid during a gout attack
Describe the crystals seen in gout
KNOW THIS ***
Negatively birefringent crystals seen under a polarized microscope
More pink with red crystals (slide 13)
Describe the crystals seen in pseudogout
KNOW THIS ***
Weakly positive birefringent rhomboid crystals under polarized scope
More purple with blue crystals (slide 13)
What will you see with tophaceous gout?
- Very red, very inflamed joint superficially
- Large soft tissue mass
- Radiographically, you can see that the first PMTJ is involved too, not just soft tissue
What are the radiographic findings of gout?
- Erosions at the level of the joint
- May need to compare this to other erosive activities
- In gouty arthritis, they will be greater than 5 mm in diameter
- RA will be smaller erosions (less than 5 mm in diameter)
- In RA, you will see cystic changes more proximal to the joint, not right at the joint
- Gout you see all erosion in the joint
So, why the 1st MPJ?
- An increase in uric acid will decrease the solubility resulting in crystal formation
- Trauma of walking initiates a low grade inflammation resulting in a lower pH
- Decrease in temp of toe
- Cooling of the extremities and decrease heart rate while sleep.
How do you treat gout?
Depends on if it is an acute flare up or chronic treatment
What do you use to treat acute gout?
- NSAID’S (first line = endomethacin)
- Colchicine (first line)
- Corticosteroids
- Analgesics
Describe the study of managing gout
Colchicine dose options
- Single dose
- Low dose
- High dose
Don’t need to use so much medication = more does not lead to better outcomes
Now, you just give 2 or 3 tablets it will suffice for managing the acute flare up
Describe the long-term management of gout
- Allopurinol:(Zyloprim) 50-100mg/d – 300mg/day (blocks production of uric acid)
- Febuxostat (Uloric) 40-80 mg/day (newer medication, used for short and long term management)
- Probenecid (Benemid): 250mg/bid – 500mg/bid ( Increases excretion of uric acid in the urine)
- Sulfinpyrazone (Anturane): 50-100mg/bid – 200-400mg/bid
How do you approach a patiet presenting with gout?
Acute attack
- Cold pack, rest
- Hot water to make crystals more soluble
- NSAIDs (first line - endomethacin is the drug of choice)
- If NSAIDs are contraindicated, give colchicine
- If colchicine is also contraindicated, give corticosteroids
Prophylaxis of an acute attack
- Colchicine is the first line
- If this is contraindicated, low dose NSAIDs
Treatment of hyperuricaemia
- Initiate allopurinol
What foods are high in purine content?
Bacon Fish: anchovies, codfish, herring, salmon, sardines, trout Kidneys Liver Shellfish: mussels, scallops Veal Venison Turkey
What foods are moderate in purine content?
Shellfish: lobster, crabs, shrimp, oysters Asparagus Beef Duck Ham Kidney beans Spinach legumes
What else can induce a gout attack?
High level workout
- Muscle breakdown
- Stay hydrated
- Know your own limits
- Know what exercises you can and cannot do to prevent a future attack
What are the causes of sustained hyperuricemia?
ALL are acquired***
- Alcohol consumption
- Exercise
- Fructose Consumption
- High purine intake
- Myeloproliferative disorders
- Obesity and hypertriglyceridemia
What are the types of reduced urate excretion?
Acquired
- Drugs (diuretics, low-dose salicylate, and cyclosporine)
Intrinsic renal disease
- Metabolites (lactate, ketones, angiotensin, and vasopressin)
- Renal causes (plasma-volume concentration, hypertension, urine flow
What is uric acid lithiasis?
The development of a stone or calculus composed of urate precipitate within the bladder, ureter, or the renal pelvis
Describe uric acid lithiasis
- When the concentration of uric acid in urine exceeds its solubility at the urine pH, uric acid changes from a compound dissolved in solution to an insoluble precipitate.
What are the three ways in which urate stones are formed?
Urate stones are formed by 1 of 3 general mechanisms:
- overproduction,
- increased tubular secretion,
- decreased tubular reabsorption
Describe uric acid stones
- Uric acid stones are the most common cause of radiolucent stones in children
- Uric acid stones in adults tend to be non-visible on radiograph
How do you diagnose a uric acid stone?
Uric acid stones are usually diagnosed by the symptoms of pain and occasionally blood in the urine
Describe the work-up for uric acid stones
- 24 hour urinalysis
- CT scan
- Urine chemistry
What is the treatment for uric acid stones?
Hydration
Describe the case study
- 48 year old male presents with a chief complaint of a painful right foot
- History of bumping his foot 3 months earlier and developed a palpable mass
- The last 2 months the mass has enlarged
Describe the past medical history on this patient
Niddm, Htn, CHF, Hx of DVT., 4 heart attacks , 4 CVA’s, PVD, gout, arthritis, and Morbid Obesity
What medications is this patient taking?
glucovance,sulindac, K-dur, allopurinol, paxil, plavix, neurontin, hydrocodone, lasix, clonazapam, isosorbide
What was the diagnosis?
- It was an atypical presentation
- Took to surgery to evacuate the bump
- Looked like glue consistency rather than a liquid which is common
- Went to lab and did come back consistent with a gouty tophi
What things have put him at greater risk of a gouty flare up?
- bumping his foot 3 months earlier
- Niddm
- CHF
- 4 heart attacks
- Previous gout
- Arthritis
- Morbid obesity
- Medications: lasix, ecotrin, zaroxolyn
Give a summary of the management of gout
- Making the correct diagnosis
- Appropriate management
- Patient education
