HPI

• A 52 yo male presents to his PCP on a Monday morning with exquisite right knee pain that started overnight. He spent Sunday tailgating with friends. He denies trauma or any previous episodes.

• What else would you like to know?

PMH

• Medical Hx: hypertension, right ACL repair (1980)

• Family Hx: Father has gout, Mother has hypertension and hyperlipidemia

• Social: Former collegiate football player, divorced with 3 children, works as a cook at a diner

• What is your differential diagnosis?

DDx

• Gout – primary, secondary• Chrondrocalcinosis (pseudogout)• Infective arthritis (gonococcal)• Septic joint• Rheumatoid arthritis• Osteoarthritis• Meniscal Injury• Ligamentous Injury (ACL, PCL, MCL, LCL)

• What do you want to do next?

Physical Exam

• Height, 6’ 5”; Weight, 300 lbs; BMI, 36• Vitals: BP 150/90; T 98.9, HR 70, RR 18• Gen: Patient is cooperative but sitting uncomfortably with

right leg slightly flexed• HEENT, CV, Respiratory, Abdominal, Neuro, and Psych Exams:

wnl• Skin: warm, erythematous right anterior knee• Musculoskeletal: exam limited by patient’s pain tolerance

• What labs do you want to orderand why?

Lab Tests

a) Joint aspiration with synovial fluid analysis – Can differentiate gout/pseudogout, osteroarthritis, and

septic joint based on number of leukocytes– Can differentiate gout and pseudogout based on

crystals

b) CBC, ESR, CRP – rule out septic joint, infective arthritis

c) Serum uric acid level – limited value, can be high without gout or low during

acute attack

Lab Results

• CBC – normal• ESR – 24 mm/h• CRP – 15 mg/L• Serum Uric Acid – 8.5 mg/dL• Synovial Fluid– 20,000/mm3 leukocytes• Osteoarthritis < 2,000, Gout/Pseudogout 5,000-50,000,

Septic Joint > 50,000

– See next slide for microscopic view

Synovial Fluid

• negatively birefringent, needle-shaped crystals

Overview of Gout

• “The king of diseases and the disease of kings”– Hippocrates

• Deposition of monosodium urate crystals in the synovium and periarticular sites creates inflammatory reaction– Painful arthritis/bursitis

negatively birefringent, needle-shaped

Hallmarks of Gout

• Monoarticular in most cases– 1st MTP joint is the most frequent site of involvement

• Middle-aged men• Familial pre-disposition• Often precipitated by large meal or alcohol intake – ask about recent diet (red meat, fish)

• Acute – develops over hours, resolves in 3-10 days

Hallmarks of Gout

• Signs & Symptoms: pain, redness, swelling, fever/chills, malaise

• Risk Factors: hypertension, hyperlipidemia, obesity

Associated Diseases

• Can be secondary to hyperuricemia due to:1. Increased cellular turnover

– e.g. leukemia, multiple myeloma

2. Decreased urate excretion– e.g. chronic renal disease, medications (diuretics,

cyclosporin), toxins (ethanol, lead)

3. Lesch-Nyhan Syndrome– X-linked hypoxanthine-guanine phosphoribosyl-transferase

(HGPRT) deficiency– Severe neurologic symptoms, self-destructive behavior

Chronic Gout

• Tophi – large accumulations of urate crystals, usually in ear, PIP joints, and elbow

Chronic Gout

• Tophi are seen as the pale areas of urate crystals surrounded by lymphocytes and macrophages

Chronic Gout

Treatment

• Acute gout is treated by reducing pain and inflammation– NSAIDs – 1st line treatment– Colchicine – 2nd line treatment due to potential

toxicity– Corticosteroids – if patient has contraindications

to NSAIDs and colchicine

Prevention

• For patients suffering from recurrent attacks, prophylactic measures to lower serum urate levels may be initiated following the acute phase

• Lifestyle Modifications:– Decrease dietary protein intake and alcohol consumption– Weight loss

• Medications:– Colchicine– Allopurinol– Probenecid

• Stop thiazide diuretics

Hallmarks of DDx

1. Chondrocalcinosis (Pseudogout)– Deposition of calcium pyrophosphate dihydrate

crystal deposition creating inflammatory reaction– Clinically similar to gout– Associated with previous joint surgery or

underlying metabolic condition – Differentiate based on synovial fluid analysis

Pseudogout Crystals

• Positively birefringent, rhomboid-shaped crystals

Pseudogout on X-ray

Normal KneeKnee with pseudogout (calcified

cartilage) and osteoarthritis

(decreased joint space)

Hallmarks of DDx

2. Gonococcal Arthritis– Neisseria gonorrhoeae infection– Usually monoarticular • knee, wrist, or small joints of the hand

Hallmarks of DDx

3. Rheumatoid Arthritis– Autoimmune– Bilateral involvement – PIP & MCP joints, knees– Rheumatoid nodules

Hallmarks of DDx

4. Osteoarthritis– Degenerative joint disease– Weight-bearing joints– Heberden Nodes at DIP joints– Bouchard Nodes at PIP joints

Pearls

• Podagra = gout in 1st MTP

• Crystals under polarized light:– Gout = negatively birefringent, needle-shaped– Pseudogout = positively birefringent, rhomboid-

shaped

Summary

• Patient is started on NSAID therapy and counseled on recurrence rates of gout– 78% have a second attack within 2 years

• Patient states that he will try to start losing weight and cutting back on beer