Undersecretion of uric acid (90% of Patients). Seen with:   Primary Idiopathic cases, Renal disease, diabetes mellitus, hypertension, metabolic acidosis, Sarcoidosis, Lead exposure, Hypothyroidism, Hyperparathyroidism, Toxemia of pregnancy, Bartter’s syndrome Drugs: Salicylates, Diuretics, alcohol, sinemet, Ethambutol, Pyrazinamide, cyclosporine, niacin
	Overproduction of uric acid: can occur with:   Abnormal enzymes in purine matabolism: hypoxanthin-guanine phosphoribosyltransferase or phosphoribosylpyrophosphate synthetase. Hemolytic process; increased cell turnover: hemotologic malignancy; Rhabdomyolysis, Polycythemia vera, severe psoriasis, Paget’s disease Behavioral: consumption of alcohol, foods high in purine (bacon, salmon, scallops, turkey, sweetbreads), exercise, obesity
	A gouty attack CAN occur with NORMAL URATE LEVELS (20%)

 

	Acute Arthritis: Usually monoarticular; CAN be POLYarticular; typically (>50%) first MTP joint (PODAGRA), then ankle, knee, wrist, shoulder, finger.   Acute onset of excruciating pain and tenderness with warmth, erythema, swelling; pain often starts at night. Can present with low-grade fever, chills, leukocytosis. Self-limited: if untreated, will resolve in 7-10 days.
	Renal:   Nephrolithiasis (10-25%); acidic urine increases risk of crystallization  Long term deposition: nephropathy Acute Renal Failure with treatment of Myeloproliferative and lymphoproliferative diseases.
	Tophi: soft tissue nodules of monosodium urate crystals – usually at base of great toe, fingers, olecranon, achiles tendon, hand, wrist.   Typically takes approx 12 yrs from 1st acute attack to develop tophi Can cause deformity, pain, nerve compression: carpal tunnel syndrome etc

 

	Isolation of crystals from synovial fluid or tissue: ASPIRATE the Joint: Will see: Negatively Birefringent Needle shaped crystals under polarized light with polymorphonucleur leukocytes.
	LAB: increased WBC with occasional neutrophilia, Increased Urate level, elevated ESR (AGAIN, CONSIDER INFECTION)
	X-Rays: generally not helpful; Long term untreated gout: “punched out” bony erosions with sclerotic borders.
	NOTE: In Calcium Pyrophosphate Dihydrate deposition (CPPD), the crystals are Positively Berefringent under polarized light; CPPD usually affects the Knee.