11: Gout - Bennett Flashcards
define gout
An acute arthritic process, which develops from the accumulation of uric acid
initial presentation of gout
Initial presentation is usually a painful attack of monoarticular arthritis
who gets gout?
Usually affect men older than 25 and women who are post-menopausal
Various precipitating factors (trauma, alcohol, surgery, diet, and drugs
primary vs. secondary gout
Primary Gout: may be inherited as idiopathic or secondary to a defect in purine metabolism leading to an overproduction of uric acid.
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.
where does gout first occur?
first metatarsalphalangeal joint
DDx gout
Crystal arthropathies
Infection (cellulitis or osteomyelitis or septic gout)
Sarcoidosis
Trauma
symptoms of gout
Pain of the involved joint
Redness
Swelling
Mild fever and chills
four phases of gout
- Asymptomatic Hyperuricemia
- Acute Gouty Arthritis
- Intercritical Gout (still has high uric acid, had one acute gouty attacky, may have another attack)
- Chronic Tophaceous Gout (continuous high uric acid with deposits in joint, soft tissue, not necessarily assoc with pain)
criteria for diagnosis for 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:
- 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
gout work up
- Blood work
(serum uric acid level 3-7mg/dl) often blood normal during the acute attack - Joint aspiration: *** synovial fluid analysis
- normal is Thick straw colored fluid, Glucose level (same as blood serum), WBC (should not be present)
tophi (gout) under microscope ****
Negatively birefringent crystals seen under a polarized microscope
pseudogout under microscope **
Weakly positive birefringent rhomboid crystals under polarized scope
RA vs. gout periarticular erosions
gout are bigger (5cm +) than RA erosive changes
why attack 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. (acute flare ups often happen at bedtime)
tx acute gout
- NSAID’S
- Colchicine (antiinflammatory and breaks down)
- Corticosteroids
- analgesics
long term gout management meds
allopurinol: blocks formation of uric acid
50 - 300 mg/day
probenecid: increases excretion of uric acid in urine
250-500 mg/day
Febuxostat/uloric 40-80 mg/day
short and long term
drug of choice acute gout attack
Initiate NSAIDs (indomethacan) at maximum dosage until 24 hours after resolution of attack, then taper dosage over 2-3 days
if NSAIDs contra, use colchicine
if NSAIDs and colchicine contra, use coritcosteroids (help inflammation only)
prophylaxis of acute attack tx
colchicine - discontinue after 1-3 mo w/o attack
tx hyperuricaemia
allopurinol
Uricosuric agents (e.g. probenecid, sulfinpyrazone) may be used as an alternative in patients who are younger than 60 years have normal renal function underexcrete uric acid (
Foods with High and Moderate Purine Content
High* : Bacon, Fish: anchovies, codfish, herring, salmon, sardines, trout, Kidneys, Liver, Shellfish: mussels, scallops, Veal, Venison
Turkey
workout with high muscle break down can also stimulate attack
moderate: Shellfish: lobster, crabs, shrimp, oysters Asparagus Beef Duck Ham Kidney beans Spinach legumes
acquired causes of sustained hyperuricemia
Alcohol consumption Exercise Fructose Consumption High purine intake Myeloproliferative disorders Obesity and hypertriglyceridemia
acquired causes of reduced urate excretion
Drugs (diuretics, low-dose salicylate (aspirin) , and cyclosporine)
Intrinsic renal disease
Metabolites (lactate, ketones, angiotensin, and vasopressin)
Renal causes (plasma-volume concentration, hypertension, urine flow 1 mL/min)
genetic –> Reduced clearance or fractional excretion of urate
The development of a stone or calculus composed of urate precipitate within the bladder, ureter, or the renal pelvis
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.
Urate stones are formed by 1 of 3 general mechanisms:
overproduction,
increased tubular secretion,
decreased tubular reabsorption.
adult v. child uric acid stones on radiograph
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
diagnosis and tx uric acid stones
Uric acid stones are usually diagnosed by the symptoms of pain and occasionally blood in the urine
Work-up:
- 24 hour urinalysis
- Ct scan
- urine chemistry
Treatment: hydration
T1 MRI
bones and fat
white
