Gout

Introduction

Gout is a crystalline inflammatory disease, due to monosodium urate monohydrate crystals deposition in the joint and tissues. It is a common form of arthritis that causes intensive pain, swelling and stiffness in the joints.
It is due either to excessive uric acid production from intrinsic purine metabolism or extrinsic (dietary)
Due to decrease renal excretion of uric acid and resultant accumulation in the blood.
It is commonly seen in males (40 years and above) and post menopausal females

Types

4 major types

  1. Asymptomatic
  2. Acute
  3. Inter critical
  4. Chronic Tophaceous

It could be either primary (no identifiable cause) or secondary.
Secondary causes include:

  • Dehydration
  • Fasting
  • Renal impairment
  • Hypertension
  • Malignancy such as lymphoma, leukemia
  • Psoriasis
  • Sickle Cell Disease
  • Use of cytotoxic agents
  • Excessive alcohol intake especially beer
  • Low dose Aspirin
  • Drugs such as Pyrazinamide, Diuretics

Clinical Presentation

  • Usually mono-articular, occasionally Polyarticular (in elderly persons and in renal failure)
  • Sudden onset of pain and swelling
  • Pain and swelling maximal within 24-48 hours
  • Tendency to start at night or early hours of the morning
  • Usually follows binge of alcohol or consumption of offal of animals
  • Recurrent painful episodes
  • Affects big toe (Podagra), but also large joints-forefoot, ankles, knees, wrists.
  • There may be associated fever, vomiting, diaphoresis, rigors

Chronic Tophaceous Gout

  • Follows long standing attacks of acute gout, usually up to 7 years
  • Tophi deposit in the skin, ear lobes, over joints
  • Tophi may deposit in the kidneys and brain

Differential Diagnosis

  • Septic Arthritis
  • Osteoarthritis
  • Rheumatoid arthritis
  • Gonococcal arthritis.
  • Traumatic synovitis
  • Pseudogout
  • Osteomyelitis.
  • Reactive Arthritis.

Investigations

  • Serum Uric Acid- may be normal in acute Gout
  • Haematocrit, white blood cell count,
  • ESR
  • Creatinine, Urea- to exclude associated renal impairment
  • Cholesterol, Triglycerides- usually coexist with Gout
  • Plasma glucose (high serum uric acid may be a component of metabolic syndrome)

Treatment objectives

  • Treatment of pain
  • Lower Serum Uric Acid to below 6mg/100ml

Non-drug treatment

  • Dietary control avoid offal, salmon, sea food, red meat
  • Avoid alcohol especially beer, wine
  • Reduce weight
  • Control cholesterol level
  • Avoid tight shoes
  • Rest affected joints
  • Avoid surgical operation of tophi

Drug Treatment

Acute Gout

NSAIDs at higher doses above
normal

  • e.g. Naproxen-500mg tds
  • Diclofenac-75mg BD
  • Prednisolone – 40mg daily for 1 week then taper quickly and stop

Intra articular steroids

Triamcinolone

  • 5- 40 mg by intra articular/ intradermal injection
    according to patient’s size (maximum 80 mg), may be
    repeated when relapse occurs

Or:

Methylprednisolone

  • 4- 80 mg (depending on patient’s size) intra articularly; may be repeated at intervals of 7-35 days

Chronic Tophaceous Gout

Oxidase Inhibitor

  • Allopurinol – gradual escalation from 100mg daily up to 600mg daily

Uricosuric agent

  • Sulfinpyrazone
    • Adults: starting dose of sulfinpyrazone is 100 mg or 200 mg a day (one-half of a 100-mg tablet two times a day, one 100-mg tablet one or two times a day, or one 200-mg capsule or tablet once a day). Then, the dose is usually increased by 100 mg or 200 mg every few days, up to 800 mg a day.
  • Probenecid (used only to prevent attacks)
    • Adults: 250 mg two times a day for about one week, then 500 mg two times a day for a few weeks. After this, the dose will depend on the amount of uric acid in your blood or urine.

Adverse Drug Reactions

NSAIDs

  • Dyspepsia,
  • Peptic Ulcer Disease,
  • Gastrointestinal haemorrhage, renal insufficiency, hepatotoxicity, heart failure (especially elderly persons)

Allopurinol

  • Elevated liver enzymes,
  • Allopurinol Hypersensitivity Syndrome:
    • liver failure, renal failure, eosinophilia, hypersensitivity skin.