Crystalline Arthropathies (Gout (Signs/symptoms (Acute, severely painful,…
monosodium urate (MSU)
Negatively birefringent: yeLLow in paraLLel
9:1 male:female (postmenopausal)
Acute, severely painful
Monoarticular (first flare & most flares). Later flares can be polyarticular.
First flare great MTP (podagra)
Warm, swollen, often erythematous.
Tender to palpation
MSU crystals internalized by monocytes, activating NALP3 inflammasome
Triggers increase/decrease serum uric acid (acute illness, trauma, surgery, EtOH, seafood, red meat, change in urate therapy)
Time b/w flares
Avg length to second attack = 12-18 mos
Disease progression yields less time b/w attacks, eventually continuous.
Elevated serum uric acid:
Rule-out infection, find/type crystals
Self-limited & PAINFUL attacks. Treatments cover acute symptoms and DO NOT prevent future attacks.
(indomethacin): high dose, short time
Inhibits tyrosine phosphorylation in PMNs in resp. to crystals
Blocks activation of NALP3 inflammasome
Inhibits neutrophil adhesion
Bone marrow suppression (renal failure pts)
Oral for polyarticular disease
IA injection for monoarticular disease
Don't start/stop urate-lowering therapy during flare b/c can worsen flare!
Symptom-free periods shorten. Attacks incompletely resolve.
Oligo-/poly-articular arthritis, ongoing symps, less painful than acute attack
Incr. involvement of UE joints
~10 yrs of disease
Goal = lower serum (/tissue) uric acid.
Promote crystal dissolution/prevent crystal formation: serum urate
For asymptomatic pts?
Uric acid >13 in men
Uric acid >10 in women
Uricosuria >1000 mg/dl
Xanthine Oxidase (XO) Inhibitors
Hypersensitivity Synd (20-30%) HLA-associated, Hahn Chinese
Non-purine XO inhib
Metabolized in liver (OK for decr renal function)
Remember to add therapy to prevent flare when starting XO inhib (colchicine, low-dose pred)
PEGylated recombinant (porcine-baboon) uricase
IV q2 wks
Infusion rxn common -- pre-treat w/ steroid + histamine
$ $ $ $
Non-PEGylated recombinant fungal enzyme
Short half-life, highly immunogenic
Under-excretors (<1000 mg/dl)
Good renal function necessary.
Losartan (HTN + gout)
Dietary modifications (lower by ~1 mg/dl)
CPPD Arthropathy ("Pseudogout")
calcium pyrophosphate dihydrate (CPD
Positively birefringent = blue in parallel
Incr prevalence w/ incr age
triangular fibrocartilage of wrist
Potential causes wide-ranging
Inflamm 1-2 joints,
Provoked by trauma, surgery, illness, etc.
Wrist, MCP, maybe C1
(-) RF (-) CCP
Clinical picture + Aspiration
Steroids -- acute
Colchicine -- less effective than in gout. Low-dose prophylaxis.
Basic Calcium Phosphate
basic calcium phosphate
Alizarin red stain to visualize: binds Ca++. Alternatively, scanning EM.
Deposits in tendons, discs, joint capsule, synovium, cartilage, skin, arteries, etc.
Milwaukee Shoulder Synd
Elderly female (80%)
Dominant shoulder (95%)
Rapid glenohumeral joint destruction
High-riding humerus b/o rotator cuff tear
Low WBC (<500)
2.7% Caucasian office workers
In poorly vascularized portion of supraspinatus laterally
Resolves over weeks
Looks just like gout
Resolves over weeks