Gout: Pathophysiology and Clinical Aspects

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Questions and Answers

What primarily surrounds an aggregate of dissolved urate crystals in a gouty tophus?

Epithelial cells and neutrophils

Mast cells and plasma cells

Reactive fibroblasts and mononuclear inflammatory cells (correct)

Red blood cells and macrophages

Which type of reaction is associated with gouty tophus formation?

Acute inflammatory response

Cellular apoptosis response

Chronic foreign body giant cell reaction (correct)

Allergic hypersensitivity reaction

What type of cells are prominently seen in the giant cell reaction around urate crystals?

Dendritic cells

Plasma cells

Giant cells (correct)

Lymphocytes

Gouty tophi are primarily formed from which type of aggregates?

Urate crystals Signup and view all the answers

In a gouty tophus, which cell type is NOT typically involved in the associated inflammatory response?

Basophils Signup and view all the answers

What is the primary characteristic of gout?

Transient attacks of acute arthritis Signup and view all the answers

Which of the following defines hyperuricemia in the context of gout?

A plasma urate level above 6.8 mg/dL Signup and view all the answers

What percentage of gout cases are classified as primary gout?

90% Signup and view all the answers

What is a common underlying cause of secondary gout?

Congenital factors Signup and view all the answers

Which enzyme's defect is primarily linked to primary gout?

Hypoxanthine guanine phosphoribosyl transferase Signup and view all the answers

What is a common risk factor associated with gout?

Obesity Signup and view all the answers

At what age is the risk of gout generally increased?

Greater than 30 years Signup and view all the answers

Which of the following is NOT a recognized clinical stage of gout?

Chronic joint deformity Signup and view all the answers

Which symptom is associated with acute arthritis in gout?

Localized hyperemia Signup and view all the answers

Which of the following factors is NOT typically linked to an increased risk of gout?

Gender equality Signup and view all the answers

What is a hallmark feature of chronic tophaceous arthritis in gout?

Visible chalky deposits in the synovium Signup and view all the answers

What is the typical shape and appearance of urate crystals associated with gout?

Long, slender, and needle-shaped Signup and view all the answers

Which of the following describes the changes that occur to the synovium in gout?

Hyperplastic, fibrotic, and thickened Signup and view all the answers

What does the term 'pannus' refer to in the context of gout?

A thickened growth of synovial tissue that destroys cartilage Signup and view all the answers

Tophi are typically found in which areas in patients with gout?

Articular cartilage, ligaments, tendons, and bursae Signup and view all the answers

Study Notes

Rheumatoid Arthritis (RA) Extra-articular Manifestations (EAM)

EAM are manifestations outside of the joints affected by RA
Skin: Rheumatoid nodules, Raynaud's phenomenon, palmar erythema, leukocytoclastic vasculitis, peripheral ulcers, cutaneous vasculitis
Pleuropulmonary: Pleuritis, pleural effusion, rheumatoid lung nodules, small airway disease, interstitial lung disease, scleritis, episcleritis, keratoconjunctivitis sicca
Eyes: Scleritis, episcleritis, keratoconjunctivitis sicca
Cardiovascular: Atherosclerosis, myocardial infarction, pericarditis, arrhythmias, valvular heart disease
Neurological: Entrapment neuropathy, mononeuritis multiplex, cervical subluxation
Musculoskeletal: Osteoporotic changes, tendon, and ligament rupture
Renal: Glomerulonephritis, secondary amyloidosis
Hematological: Felty's syndrome, LGL syndrome, anemia, thrombocytosis
Vascular: Vasculitis

Gout

Gout is characterized by transient attacks of acute arthritis, initiated by urate crystals within and around joints.
Hyperuricemia (excessive uric acid) in tissues and body fluids is a key feature, with plasma urate levels above 6.8 mg/dL.
Gout can be primary (caused by an enzyme defect) or secondary (resulting from other underlying diseases).

Causes of Gout

Primary Gout (90%): Enzyme defect in uric acid metabolism, such as a deficiency in hypoxanthine guanine phosphoribosyl transferase (HGPRT).
Secondary Gout (10%): Linked to chronic renal disease, congenital conditions, and increased nucleotide turnover (e.g., leukemia).

Gout Pathophysiology

Purine metabolism produces uric acid
Normal serum urate levels are around 4-6 mg/dL (240-360 μM) in humans and below 1 mg/dL (60 μM) in mice.
Uric acid excretion occurs primarily through the kidneys (80%) and gastrointestinal tract (20%).
Elevated levels of uric acid lead to hyperuricemia and the deposition of urate crystals.
Urate crystals induce inflammation and joint damage.

Gout Morphology

Acute arthritis: Dense inflammatory infiltrate in the synovium and synovial fluid. Synovium is edematous and congested. Urate crystals are long, slender, and needle-shaped.
Chronic tophaceous arthritis: Urate crystals cover the articular surface, forming chalky deposits in the synovium. Synovium becomes hyperplastic, fibrotic, and thickened. Synovium forms a pannus that destroys the cartilage. Tophi (masses of urate crystals) appear in cartilage, ligaments, tendons, and bursae.
Gouty nephropathy: Accumulation of urate crystals/tophi in renal medullary interstitium or tubules. Uric acid nephrolithiasis and pyelonephritis can occur.

Gout Clinical Course

Gout is associated with male sex, obesity, metabolic syndrome, excess alcohol intake, renal failure, and age greater than 30 years.
Stages: Asymptomatic hyperuricemia, acute arthritis (joint pain, hyperemia, warmth; often monoarticular, 50% in the first metatarsophalangeal joint), asymptomatic interval, and chronic tophaceous gout (loss of joint space).

Calcium Pyrophosphate Crystal Deposition Disease (CPPD)

Also known as pseudogout, CPPD is characterized by calcium pyrophosphate crystal deposition.
It primarily affects individuals over 50 years old.
CPPD is categorized as sporadic (idiopathic), hereditary, or secondary.
Secondary types are associated with previous joint damage, hyperparathyroidism, hemochromatosis, and diabetes.
Crystals initially deposit in articular cartilage, menisci, and with enlargement, may rupture and seed the joint.
Inflammation, while present, is usually milder than in gout.
CPPD is often asymptomatic.
Joint involvement can be monoarticular or polyarticular.

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Description

Test your knowledge on gout, its pathophysiology, and clinical features with this quiz. Discover key concepts surrounding gouty tophi, hyperuricemia, and risk factors. Ideal for medical students and healthcare professionals looking to strengthen their understanding of this condition.