Rheumatology Part 1 (Gout)- Paulson (Exam 2) Flashcards
Gout definition?
Recurring attacks of acute arthritis Chronic deforming arthritis
Gout epidemiology/RF?
- Men>women
- Pacific islanders
- Alcohol consumption, esp beer
- Red meat, seafood, fructose
- Obesity
- Meds: thiazide & loop diuretics, low dose ASA
Gout pathophys:
- Hyperuricemia needed (but doesn’t always mean gout)
- Serum urate levels > 6.8mg/dL
- Monosodium urate (MSU) level has to be high enough for crystals to precipitate (causes inflammation in joints)
- Resolution of acute inflammation is mediated by immune mechanisms (even w/o tx)
- Over time, chronic inflammatory process, leads to tophi (deposits of MSU) formation, erosion of bone, joint injury
Gout uric acid balance: Underexcreters v overproducers
Underexcreters (majority):
- Renal insufficiency
- Meds: diuretics (loop/thiazide), ASA, levodopa, ethambutol, pyrazinamide)
- Acidosis (dka, ketogenic diet, lactic acidosis)
- Volume depletion/dehydration
- Lead exposure
Overproducers (minority):
- Inherited defect of metabolism
- Lesch-Nyhan syndrome
- Kelley-Seegmiller syndrome
- Myeloproliferative and lymphoproliferative disorders, polycythemia, carcinoma
- Chronic hemolytic anemias
- Transient hyperuricemia associated with ATP consumption
- strenuous exercise, status epilepticus, MI, sepsis
3 stages of gout?
- Acute gouty arthritis 2. Intercritical (interval) gout 3. Chronic articular and tophaceous (MSU crystals) gout
Acute gouty arthritis sx?
- “My big toe hurts”
- Sudden onset, often at night
- Severly painful and tender, swollen joint, red, warm
- May complain of fever
- Reaches maximal severity in about 12-24hrs
- May have hx of similar attacks prior
Seen on acute gouty arthritis exam?
- Swollen, very tender, red, warm overlying skin
- May see desquamation
- May see tophi
-
MTP of great toe is classic sign “podagra”
- usually monoarticular and in the lower extremity
- polyarticular is possible
What is tophi?
- Irregular, asymmetric, macroscopic deposits of urate
- Pathognomonic for gout
- Common sites include external ear, hands, olecranon, feet, knee, achilles tendon, forearm
- Usually painless but can become acutely inflamed Usually develop after years
- Maintain state of inflammation
- promote tissue and joint destruction around them
Gout renal manifestations?
- Uric acid nephrolithiasis (kidney stones)
- Chronic urate nephropathy
- __MSU crystals are deposited in the renal medulla and pyramids
- Uric acid nephropathy
-
ARF (acute renal failure) when large amounts of uric acid crystals precipitate in the collecting ducts and ureters
- usually seen as part of tumor lysis syndrome
-
ARF (acute renal failure) when large amounts of uric acid crystals precipitate in the collecting ducts and ureters
Gout diagnosis?
- Aspirate of synovial fluid showing monosodium urate (MSU) crystals
- “negatively birefringent”, needle-like, when viewed with polarized light microscopy
- US: hyperchoic linear density (double contour sign) over the joint cartilage or deposits that look like tophi
- Radiographs: “rat bite” lesions later in disease process (if next to a tophus=gout)
What labs would you order for suspected gout?
- Serum uric acid (can be normal or low, though)
- Peripheral WBC can be high
- ESR/CRP can be elevated
How many criteria needed to make clinical dx?
>6 Or MSU crystals in joint fluid or tophus
Gout tx?
- If asymptomatic hyperuricemia: don’t treat
- Lifestyle mods:
- lose wt
- reduce etoh
- reduce purine-rich food consumption
- drink lots of water
- Avoid hyperuricemic meds, if possible
Tx of acute gout attack?
- Goal is to relieve pt’s pain
- Start tx asap
- Urate-lowering meds (allopurinol) : don’t help in acute attacks so don’t start one
Gout tx contraindications for NSAIDs
CKD with CrCl< 60, active ulcer, NSAID allergy, concurrent use of anticoagulant, CV disease (esp uncontrolled CHF or HTN)
3 types of Gout meds for acute attack?
NSAIDs 1st choice
- naproxen (Aleve)
- indomethacin
- Discontinue 1-2 days after complete clinical resolution. (Typical course might be 5-7 days)
Colchicine:
- good for pts w/ nsaid intolerance
- commonly causes diarrhea and abd cramping
- possible reversible peripheral neuropathy
- Contraindications: severe hepatic or renal impairment with colchicine use in past 2 wks, concomitant use of a mod-strong inhibitor of P-gp and/or CYP3A4 inhibitor (antifungals, antivirals, some antiarrhythmics)
Corticosteroids:
- good for people who can’t take nsaids or colchicine
- intra-articular injection: triamcinolone
- oral prednisone
- IV methylprednisolone
- IM triamcinolone
- Caution for pts with CHF, glucose intolerance, poor control of HTN
How do we prevent gout?
- Adress preventative issues during the intercritical period
- Goal is to achieve a serum urate level <6mg/dL
- Slowly (not > 1-2mg/dL/month)
- use low-dose prophylactic colchicine (or low-dose NSAID) when initiating antihyperuricemic therapy to reduce risk for acute flare
Meds for chronic gout?
Xanthine Oxidase Inhibitors (XOI) - reduce production of uric acid
- Allopurinol OR Febuxostat
- Give prophylactic colchicine when initiating
Uricosuric meds?
-
Block tubular reabsorption of urate and increases the rate that uric acid is renally excreted
- Pt must have nl renal function
- Probenecid
- Do not give to a pt with G6PD (increases risk of hemolysis)
Uricase med for gout?
- Enzyme present in other mammals that breaks urate down to allantoin, which is more easily excreted
- For pts who have been refractory to all other therapies
- Pegloticase: given IV q 2 weeks
- Don’t give to people with G6PD
Gout prognosis/referral?
- Acute attack will self-resolve even w/o tx
- Over time attacks become more frequent and longer
- W/ urate lowering meds (XO allopurinol or uricase Pegloticase), much less chronic gouty arthritis, tophi, and deformity
- Can refer to rheumatology
How is pseudogout different from gout?
- Gout is urate crystal (needle-like) deposition in joints, while pseudogout is calcium pyrophospate dihydrate (CPPD) crystal (rhomboids) deposition, which can mimic gout.
- Gout usually effects the great toe, while CPPD or pseudogout usually effects larger joints such as the knee.
What is a sign of CPPD pseudogout seen on plain film radiographs?
Chondrocalcinosis: which look like white deposits in the joint space.
What does the typical CPPD pseudogout pt look like?
- Older adults (rare before 55)
- Around 50% of those >85 are affected
- Joint trauma
- Familial chondrocalcinosis
- Hemochromatosis
How would you describe an acute CPPD pseudogout attack?
- Self-limited, sudden attack of pain, redness, warmth, disability, and swelling (can be one or several joints)
-
Knee is most commonly affected with pseudogout (great toe for gout)
- Others: wrists, shoulders, elbows, ankles Possible chills/fever
- Can be provoked by surgery (parathyroidectomy), trauma, or major illness
- May have associated f/c
Chronic CPP crystal inflammatory arthritis is also known as, and can mimic sxs of what autoimmune disease?
- “pseudo RA”
- Similar sx to RA, involving multiple joints in a symmetric pattern (bilat)
- usually affects joints unaffected by OA: MCP, wrists, elbows, glenohumeral joints
Pseudogout can also mimic OA, called “pseudo-OA”. Which joint is the most common and what do you see on clinical examination?
- Knee most common for pseudo-OA (also hips, shoulder, spine, etc)
- Clinical exam is like that of OA: tenderness of joints, bony enlargement, crepitus, restriction of motion
Pseudo-neuropathic disease is another mimicking diesease of pseudogout. What does it mimic?
- Charcot joint/foot: joint degenerates and collapses from CPP crystal deposition
- Resembles neuropathic arthropathy but w/o neurologic impairment
How is a dx of pseudogout vs gout made?
- Pseudogout: “weakly positively birefringent RHOMBOID crystals”
- Gout: “negatively birefringent, needle-like, when viewed with polarized light microscopy”
How do you treat an acute pseudogout attack?
- Aspirate the joint then intraarticular glucocorticoid (triamcinolone) injection
- Nsaids: indomethacin, naproxen, salicylates
- Colchicine
- System corticosteroids
How do you treat pseudo OA?
Same way as OA Nsaids, steroid injections into joint, joint replacement
What prophylactic meds would you give for pseudogout? For pseudo-RA?
Pseudogout:
- Colchicine
- Nsaid
Pseudo-RA:
- nsaids (naproxen, indomethacin)
- Alternative: colchicine, hydroxycholorquine, low-dose glucocorticoids ie: prednisone
If the 24 hr urine uric acid test shows <800 mg/d, this means the pt is an undersecreter of uric acid and you should prescribe which class of medication?
Uricosuric agent (Probenecid) or XOI (Allopurinol or Febuxostat)
The 24 hr urine uric acid test comes back >800 mg/d, which means your pt is an overproducer of uric acid and you should prescribe which class of medication?
XOI (Allopurinol or Febuxostat)
