Gout & Pseudogout

Causes of Hyperuricemia

1. decreased excretion, most common form, or 2. increased production.

Treatment of Pseudogout

*NSAID*s: indicated for pain and inflammation. *Intra-articular steroids* indicated in cases of acute pain and swelling. *Colchicine* sometimes indicated for prophylaxis.

Causes of Hyperuricemia - Undersecretion

1. idiopathic; 2. renal failure; 3. hypertension; 3. diuretics, esp. thiazide diuretics; 4. alcohol consumption, excessive.

Causes of Hyperuricemia - Overproduction

1. obesity; 2. increased cell turnover, e.x. hemolysis, blast crisis, tumor lysis, myelodysplasia, psoriasis; 3. purine-rich diet, lots of red meat & alcohol;

Causes of Hyperuricemia - Others

1. use of cyclosporine; 2. Dehydration; 3. Diabetes insipidus; 4. Lead poisoning; 5. Lesch-Hyhan syndrome; 6. Salicylates, low dose; 7. Starvation.

Management of Gout: *NSAIDs, lifestyle changes, with/without intra-articular steroids* (Lifestyle changes include alcohol cessation & weight loss.)

1st line of treatment in acute attacks. *Indomethacin* is the most common NSAID used. *Colchicine* may be used but inferior to NSAID. *Intraarticular steroids* may be used if NSAID ineffective or contraindicated in chronic kidney disease.

Pseudogout

Metabolic disease resulting in deposition of *calcium pyrophosphate dihydrate (CPPD) crystals* within the joint space. Characterized by recurrent monoarticular arthritis. Mimics gout except *affects older patients > 60 years old, affects more proximal joints & positively-befringement crystal*.

Evaluation of Gout: *Joint fluid aspiration*

Required to establish diagnosis and rule out infection. Cloudy yellow fluid with 2000-50000 WBC (70% PNMs), needle-shaped negatively birefringent urate crystals

Evaluation of Gout: *Serum uric acid is > 7.5*

patients may have normal uric acid levels uric acid levels are not sensitive nor specific

Pseudogout associated with...

hyperparathyroidism, Gitelman's syndrome, gout, hypothyroidism, rickets, familial hypocalciuric hypercalcemia, hemochromatosis

Maintenance therapy of Gout with *allopurinol, colchicine, probenecid*.

Allopurinol for overproducers, but contraindicated in acute attacks. Allopurinol can lower incidence of *acute urate nephropathy*. Probenecid for undersecreters. Avoid long-term, high-dose use of thiazide diuretics.

Colchicine

Inhibits neutrophil chemotaxis & is most effective when used early in Gout flare. However, it can cause diarrhea & bone marrow suppression, presenting as neutropenia.

Evaluation of Pseudogout

Joint aspiration reveals *rhomboid shaped crystals that are positively birefringent*. Radiography shows calcification of adjacent cartilagenous structures, aka *chondrocalcinosis*.

Consider what disease in child with gout & inexplicable injuries?

Lesch-Nyhan syndrome

H&P of Gout

Most commonly affects *first MTP joint, podagra* & midfoot, knees, ankles & wrists. Joints are erythematous, swollen, tender; unilateral. *Tophi*, urate crystal deposits in soft tissue & uric acid kidney stones in chronic disease.

Gout

Recurrent attacks of *acute monoarticular arthritis* resulting from intra-articular deposition of *monosodium urate crystals* due to disorders of urate metabolism. Risks include male, obesity, postmenopause, binge drinking. Usually presents after 20-30 years of uncontrolled hyperuricemia

H&P of Pseudogout

Symptoms: acute, onset joint tenderness with warm, erythematous; commonly on knee and wrist joints. Physical exam reveals erythematous, monoarticular arthritis, tender to palpation. May observe superficial mineral deposits under the skin at affected joints

If patient is on aspirin, ASA, during acute gout flare, should we discontinue this medication?

Yes, discontinue ASA during acute gout flare as it can lower excretion of uric acid by the kidneys.

Evaluation of Gout: *Radiographs*

negative in early disease. Punched-out erosions with overhanging corticol bone. *"rat bite lesions"* in advanced cases