Case 77: Gout

1. Case 77: Gout Presented by Nicole Valdez

2. What is Gout? • Characterized by hyperuricemia (elevated plasmic uric acid concentrations) and severe, recurrent bouts of arthritis caused by monosodium urate (MSU) crystals deposited in the joint spaces. • Syndrome of abnormal purine metabolism or excretion. • Existed for over 2,000 years and used to be known as “disease of kings” • Usually not life-threatening, but can be painful, chronic, and disabling.

3. Pathophysiology

4. Patient’s Chief Complaints “I woke up in the middle of the night last evening and my right big toe felt as if it was on fire. It’s hot, swollen, and so tender that even the weight of a blanket on it is nearly intolerable. And there’s no way that I can put a shoe on.”

5. History of Mr. J.H.’s Present Illness • 47 year old male • Severe pain in right great toe – wore open toe sandals to clinic • Began previous evening and kept him up through the night (acute onset) • Taking extra-strength acetaminophen to keep the pain under control • Unable to bear weight on his right foot • No history of injury to right foot

6. Past Medical History • Hypercholesterolemia X 9 years • Hypertension (HTN) X 9 years • Transient Ischemic Attack (TIA/Mini Stroke) 3 months ago, appears to have no residual neurological deficits • Chronic sinus drainage/rhinitis (S/P laryngoscopy) • Allergies: NKDA

7. Medications • Hydrochlorothiazide (HCTZ) 25 mg po QD with supper • Aspirin (ASA) 325 mg po Q AM • Atorvastatin 10 mg po QD • Flunisolide 2 sprays each nostril QD • Psudoephedrine 60 mg po Q6h PRN • Patient Case Question • Why should the use of psuedoephedrine by this patient by carefully monitored by the primary care provider? • Patient already on Flunisolide (corticosteroid) for Nasal Rhinitis • High use of a nasal decongestant could be detrimental.

8. Family History • Educated throughout high school • Mother living with type 2 DM • Father died at age 68 from osteosarcoma • Four adult children are all healthy • No siblings

9. Social History • Non-smoker • Uses alcohol weekly (averages 5-6 drinks/week) • Married x2 with 4 adult children (1 from 1st marriage) • Employed 17 years as a truck driver and is frequently away on the road • Lives with wife of 22 years, happily married • Diet is heavy on red meat and other high-purine foods

10. Causes and Risk Factors • Genetics: ¼ people with gout have a postive family history. • Medical conditions and medications can increase plasma and synovial urate concentrations and can cause secondary gout. • Diabetes mellitus, dehydration, sickle cell anemia, and kidney disease • Thiazide diuretics, low-dose aspirin, cyclosporine, and tacrolimus • Plasma uric acid levels begin to increase at puberty in males and at menopause in females • Adult males and postmenopausal females are at risk

11. Causes and Risk Factors • Foods that are rich in purines will increase frequency of attacks • Consuming too much alcohol, especially beer can inhibit renal excretion of uric acid and can contribute to gout

12. Causes and Risk Factors • Obesity and trauma: excessive weight can cause trauma to weight-bearing joints and lead to uric acid deposits • Starvation and rapid weight loss can also increase plasma uric acid concentrations • Great toe is subject to chronic strain from walking • Certain occupations, such as truck driving, may cause significant strain to the great toe and cause an attack.

13. Review of Patient’s Systems • Denies headache (HA) , dizziness, chest pain, SOB, and generalized swelling or tenderness • Weight has increased approximately 15 lbs in the last year • No previous episodes of joint pain

14. Physical Examination • General: White male in mild acute distress • Vital Signs: • BP 145/85 • HR 92 • RR 17 • T 100.2 °F • HT 6’1 • WT 225 lbs • Patient Case Questions • Has an optimal target blood pressure management been reached in this patient? • Normal BP 120/80 • Normal BP for 47 yr old male is 127/84 • High BP for 47 yr old male is 139/88 • Other considerations: Patient has HTN and patient is in pain • Are any of the patient’s vital signs consistent with a diagnosis of gout? • Fever: Acute gout can cause a high fever and leukocytosis • HTN: Acute pain from gout can cause a high BP by increasing sympathetic activity • Obesity: Doubles gout risk.

15. Patient Case Questions • Is this patient underweight, overweight, obese or is this patient’s weight considered normal and healthy for his height? • Patient height: 6’1” • Patient weight: 225 lbs • BMI = 29.7 = Overweight • BMI over 30 is obese • Identify 8 risk factors from the case study that predispose the patient to gout. • Alcohol • Diet • Weight gain • Male over 40 • History of Hypertension • HCTZ medication (diuretic) • ASA medication • Truck driver

16. Physical Examination • Neck/Lymph Nodes: Normal with no swelling, thyromegaly, masses or jugular vein distention • Eyes: Pupils equal at 3mm, round and reactive to light and accomdation (PEARRLA). Normal funduscopic exam • Lungs: Clear to Auscultation (CTA) • Cardiac: Regular Rate and Rhythm (RRR). S1 and S2 with no extra cardiac sounds. No gallops, rubs or murmurs • Abdomen: Non-tender and non-distended. No Hepatosplenomegaly (HSM). Normal bowel sounds.

17. Physical Examination • Musculoskeletal/Extremities: Pulses full throughout. Muscle strength 5/5 throughout. Right first metatarsophanlangeal joint hot, tender, erythematous, swollen • Neuro: A&O x 3 . CNs II-XII intact. Deep Tendon Reflex Normal (DTRs 2+). Babsinski (−)

18. Clinical Manifestation • Most common presentation: sudden onset of pain and swelling in metatarsophalangeal joint of great toe • Other sites: ankle, wrist, knee

19. Clinical Manifestation • Commonly confined to one joint, but can progress from one joint upward to involve more joints. • Single joint is warm, erythematous, tender, and characterized by edema. • Intercritical gout: asymptomatic intervals between acute attacks. • Systemic signs of inflammation: fever up to 102F, chills, leukocytosis, and malaise • Tophi: deposits of MSU crystals at extra-articular sites, such as the ear, along Achilles tendon, or prepatellar bursa. Characteristic of chronic gout

20. Laboratory Tests • Main procedure: joint aspiration (arthrocentesis) • X-ray: acute attacks can’t be seen, but chronic gout appears as thickened regions • Serum levels of uric acid may not be elevated, but in >95% of patients it is elevated (>7.5mg/dL) during an acute attack • Erythrocyte sedimentation rate (ESR) can also be elevated during episode of gout.

21. Laboratory Tests • 24 hour urinary excretion of uric acid >1100 mg • Serum urate concentration >13mg/dL • Having both values above the indicated values gives the patient a 50% probability for developing urate kidney stones.

22. Therapy • Terminate acute attack • Anti-inflammatory medications • Prevent recurring attacks • Diet • Avoid hyperuricemic medications • Use preventative medications: colchicine, uricosuric drugs, and allopurinol • Gradual weight loss • Prevent/reverse complications associated with MSU crystal deposits in joints • Prevent kidney stones

23. Therapy • Acute attack medications: Non-steroidal anti-inflammatory agents (NSAIDs) • Indomethacin, ibuprofen, and naproxen • Aspirin is a NSAID, but should be avoided • Corticosteroids control most attacks • Available if you can’t take NSAIDs orally • Single joint attack  intra-articular administration of triamcinolone • Polyarticular gout: methylprednisolone (IV or PO)

24. Laboratory Blood Test Results • 24 hr Urinary Uric Acid: 985 mg/day • X-Ray, Right Great Toe: Moderate, soft tissue edema; normal joint space; no erosions or sclerosis

25. Laboratory Results • Synovial Fluid Examination: Significant Polymorphonclear (PMN) infiltration. Monosodium urate (MSU) crystal confirmed microscopically with polarized light

26. Patient Case Questions • Identify 5 laboratory test values that are consistent with a diagnosis of gout? • Synovial fluid analysis • Presence of crystals • Uric acid • Normal 2.4- 7.4 mg/dL • Patient 13.1 mg/dL • ESR • Normal (males): <10 mm/hr • Patient 15 mm/hr • CBC • WBC (normal) 4,800-10,000/mm3 • WBC (patient) 13,300/mm3 • Differentiate between septic arthritis and gout • 24 hr urinary uric acid • Normal 250-750 mg/day • Patient 985 mg/day • What is the significance of this patient’s fasting blood glucose concentration? • Fasting = not eating • Normal 60-110 mg/dL • Patient 120 mg/dL • Undiagnosed diabetes • Is there a need to adjust the patient’s dose of atorvastatin upward at this time? No • Normal <200mg/dL • Patient 189 mg/dL

27. Patient Case Question Would probenecid, sulfinpyrazone, or allopurinol be more appropriate medication for this patient? Why? Probenecid is not used to treat acute attacks, and instead is used to prevent chronic attacks. Sulfinpyrazone is also used to prevent attacks, but is also contraindicated for this patient because of the high rate of excretion of uric acid. • Since the patient is excreting >800 mg urate/day, allopurinol is required. • Allopurinol decreases the synthesis of uric acid, rapidly lowers plasma urate, and facilitates mobilization of MSU while shrinking tophi. • Allopurinol acts by inhibiting xanthine oxidase, the enzyme that catalyzes the conversion of hypoxanthine to xanthine and xanthine to uric acid.

28. Sources • Bruyere, Harold J., Jr. "Case Study 77: Gout." 100 Case Studies in Pathophysiology. Philadelphia: Lippincott Williams & Wilkins, 2009. 366-69. Print. • “Crystal Induced Joint Disease Part 1” http://what-when-how.com/acp-medicine/crystal-induced-joint-disease-part-1/ • “ESR- The Test” http://labtestsonline.org/understanding/analytes/esr/tab/test/ • “Gout Explained Inside Out” http://painbehindkneecure.com/gout-explained-inside-out/ • “Gout Pictures Slideshow- Causes, Symptoms, and Treatments of Gout” http://www.webmd.com/arthritis/ss/slideshow-gout • “Uric Acid Test” http://www.healthline.com/health/uric-acid-urine#Purpose2