Crystalline Arthropathies

1
Crystalline Arthropathies

• Walter Eisenhauer MMSc, PA-C

2
Gout

• The Disease of Kings, The King of Diseases
• Predominately disease of adult men
• Females spared until postmenopause
• Uric Acid by product of Purine metabolism
• 10 of those with gout overproduce- the remaining
  90 are underexcretors

3
Gout

• Urates circulate in plasma mainly in unbound form
• Referred to as urate pool
• Pool increases as Uric acid levels increase
• Excreted by two mechanisms
• Renal
• Bacterial oxidation in the gut

4
Gout

• Total Body urate Pool 1200 mg males/600 mg
  females
• 85 denovo synthesis
• 15 dietary intake of purines
• Purine restricted diet may only decrease serum
  urate level by 1-1.2 mg/dl
• 50-60 urate pool turns over each day

5
Gout

• Urate complete filtration
• Presecretory tubular resorption 99
• Tubular excretion 50
• Post secretory resorption 80
• Excretion of 10 filtered load (600 mg/day)
• Additional 1/3 excreted by pancreatic and
  intestinal juices

6
Gout

• Influenced by
• Heredity
• Pharm Agents
• Salicylates
• Diuretics
• Cyclosporine

7
Gout

• Two Main Classifications
• Overproducers
• Under Excreters

8
Gout

• Overproducers
• 10
• Primary
• Idiopathic
• Enzyme abnormalities in purine metabolism
• Secondary
• Excessive dietary uptake
• Myeloproliferative disorders
• Severe muscle exertion

9
Gout

• Decreased excretion- 90
• Primary Vs Secondary
• Primary
• Unidentified defect in tubular secretion ( up to
  40 less)

10
Gout

• Secondary
• Renal insufficiency
• Diuretics
• Low dose ASA
• Cyclosporine
• Ethambutol
• Lead toxicity
• Saturnine gout due to nephropathy
• DKA
• Starvation
• Ketosis
• Ethanol
• Lactic acidosis
• Predisposing illness- HTN, DM etc
• Combined ETOH/G6PD deficiency

11
Gout

• Urate Pool substantially enlarged in Gout
• Non Tophaceous- 2-4gm
• Tophaceous 30 gm or more

12
Gout

• Urate solubility
• At physiologic ph 99 as urate not uric acid
• Soluability at 37degrees is 7.0 vs 30 degrees is
  4.5 mg/dl
• Intrarticular temp at the knee is 33 degrees-
  ankle 29 degrees

13
Gout

• Acute Gout clinical features
• Males 4th-6th decade
• Consider enzyme abnormality if before 60
• 38 with normal uric acid
• Monoarticular 85-90
• Podagra in 50, ultimately 90
• Primarily lower extremity joints
• Precipitated by
• Surgery
• Trauma
• Febrile Illness
• Excessive eating or ETOH consumption

14
Gout

• Systemic symptoms in polyarticular forms
• Fever
• Chills
• Elevated WBC/ESR
• Spontaneous resolution over days to weeks
• Females older, post menopausal

15
Gout

• Intercritical gout
• 7-10 only experience initial attack
• 62 with second attack within 1 year
• Majority with attack within 6-24 months
• Ultimately attacks more frequent and polyarticular

16
Gout

• Tophaceous Gout
• 3-21 develop
• Average 11.6 years after initial episode
• Typically ear, elbows, fingers, Achilles tendons
  but may appear anywhere
• Synovial tophi can lead to bone erosions

17
Gout

• Transplant Gout
• Primarily related to cyclosporine
• Acute gout often after one year
• Tophaceous gout within 5 years
• 13 decrease in ADLs secondary to gout

18
Gout

• Renal Manifestations
• Stones presenting manifestation of up to 1/3
• Gouty Nephropathy-inter parenchymal deposits of
  monosodium urate crystals causing inflammation
  and scarring
• Acute Uric Acid Nephropathy caused by obstruction
  of tubules with uric acid crystals

19
Gout

• Diagnosis
• Can not make dx with blood studies
• Demonstrate crystals in synovial fluid
• Presence of tophi
• Presumptive on basis of clinical presentation
• Strongly negative birefringent, needle shaped,
  often intracellular crystals

20
Gout

• Xray
• Punched out lesions
• Asymmetric nodular soft tissue swelling
• Joint space narrowing- often asymmetric

21
Gout

• Treatment
• Acute
• Colchicine
• 0.6 mg each hour up to 8.0mg
• 80 response within 48 hours
• 91 with GI Toxicity
• Iv Colchicine
• 1-3 mg diluted in 20 ml of D5W through good IV
  access
• No additional colchicine for 7 days
• Avoid in renal/hepatic insufficiency
• Avoid with concurrent erythromycin or cimetadine
• Toxicity includes marrow suppression, DIC,
  hypotension, myopathy, localized phlebitis

22
Gout

• Indomethacin
• 50 mg TID
• Difficult to use in PUD, Renal, Hepatic
  insufficiency
• Corticosteroids
• Tapering course of PO prednisone
• Intrarticular
• ACTH

23
Gout

• Prophy
• Colchicine 0.6mg BID
• Effective in 80-90
• Use for 1-2 weeks before initiating Uric Acid
  Lowering agents

24
Gout

• Hypouricemic therapy
• Indications
• Tophaceous gout
• Recurrent attacks
• 24 hour urine is useful in determining choice of
  agents
• Under-excretor gets probenicid or sulfinpyrazone
• Overproducer-Allipurinol

25
Gout

• Asymptomatic Hyperuricemia
• Treat only when gt 13 mg/dl

26
Pseudogout

• CPPD- Calcium Pyrophosphate Dihydrate
• Chondrocalcinosis when calcium in cartilage
• Mimics presentation of Gout attacks
• Treat with NSAIDS
• Rule out Hyperparathyroidism