Gout- Purine metabolism disorder
- Gout is a metabolic disease associated with overproduction of uric acid. (Hyperuricemia)
- Two types of Gout-
Primary Gout– defect in enzymes leads to overproduction of purine nucleotides. Enzymes are-
- Deficiency of HGPRTase
- Increased activity PRPP synthetase
- Increased activity of PRPP amindotransferase
- Glucose 6- phosphatase deficiency
2. Secondary Gout-
- Increased production of uric acid leads to leukemia, Lymphoma
- Decreased excretion rate leads to renal failure, thiazide diuretics, lactic acidosis.
- ln severe hyperuricemia, crystals of sodium urate get deposited in the soft tissues, particularly in the joints. Such deposits are commonly known as Tophiresulting in acute gouty arthritis.
- Common joint to be affected most is the Knee joint.
- Lead poisoning leads to kidney damage and decreased uric acid excretion causing gout.
- Group of disorders presented with- Hyperuricemia, Uric acid Nephrolithiasis, Acute Inflammatory Arthritis.
- Negatively befringent needle shaped monosodium urate crystals using polarized light microscopy.
- Colchicine (anti-inflammatory drug)
- Uricosuric agents
- Allopurinol- the drug of choice for primary gout.
- Pseudogout caused due to deposition of calcium pyrophosphate crystals in joints.
- Pseudogout most often seen in persons age 60 or older.
- Characterized by acute, recurrent and rarely chronic arthritis involving large joints (most commonly the knees and the wrists and is almost always accompanied by chondrocalcinosis of the affected joints.
- Diagnosis– Positively-birefringent rhomboidal crystals are classically found in cases of pseudogout.
- Glucose-6- phosphate deficiency (Van Gierke’s disease)- generates large amout of ribose -5- phosphate.
- Gout is caused due to overproduction of uric acid.
- The typical characteristic of Gout is Tophi deposits, hyperuricemia, acute gouty arthritis.
- The most common joint affected by gout is the Knee joint.
- Lead poisoning leads to gout.