137; Monoarthritis, Gout & Pseudogout Flashcards
List some possible causes of Monoarthritis
Septic arthritis
Gout
Pseudogout
Trauma/haemoarthritis
Sero-neg arthritis (psoriasis/IBD)
Reactive arthritis
Sarcoid
What is septic arthritis?
Acute inflammation of the joint caused by direct infection
What are the main bacterial causes of septic arthritis?
- Strep Aureus; from local damage to skin
- Gonococcus
- Streptococcus
- E.Coli
- Mycobacteria- TB
What are the predisposing factors for developing Septic Arthritis?
Prosthetic joint
Immunosupressed/elderly
Diabetic
Rheumatoid arthritis
Joint damage
IV drug abuse
Source of infection from elsewhere
What are the outcomes of Septic Arthritis; untreated and treated?
Untreated;
Rapid, irreversible joint destruction
Sinus/Abscess formation
Osteonecrosis
Septicaemia- organ failure
Treated;
50% Morbidity
10% Mortality
How should a monoarthritis be investigated?
- Aspirate joint fluid
Gram stain
Macroscopic appearance
Crystals
- Blood test
Urate
CRP
FBC
Blood cultures
- X-ray
How should a case of Septic Arthritis be treated?
Abx; 2wk IV & 4wk oral
Identification of infection source
Washout surgery *gold standard*
Drainage (when surgery not viable)
What is Gout?
Inflammatory response to Monosodium Urate Monohydrate Crystals;
HyperUricaemia
Epidemiology of Gout?
Male gender (oestrogen is protective)
Age
Impaired renal function
Hyperuricaemia
High purine diet
Regular alcohol
Obesity
Drugs (some diuretics)
What is Uric Acid a break down product of?
Purine
How is uric acid excreted?
1/3 in faeces
2/3 in urine
90% of gout patients have impaired Urate excretion
What are the modifiable risk factors for gout?
Purine-rich diet
Hyperuricaemia
Regular alcohol consumption
Obesity
Medications (diuretics)
What clinical features are associated with the chronic form of Gout?
Tophi
Bone & joint destruction
Which joint does Gout most commonly affect?
1st MCP joint
>50% of cases
What are the investigations for Gout?
Fluid examination
Urate crystals; wit negative birefringance
Bloods
Hyperuricaemia
Urinalysis
Urea levels may be normal during an acute attack
How is Gout treated?
Correcting Hyperuricaemia
Prevention; low purine diet, regulate alcohol, weight loss, treat hypertension
Urate lowering drugs
NSAIDs
Colchicine
Steroids; oral and intra-articular
Which patients should use urate-lowering drugs?
Second attack within a year
Renal impairement orUrate stones
Tophi tissue damage
What are the 2 main Urate lowering drugs?
- Xanthine Oxidase inhibitors
Reduce Uric acid production
- Uricosuric agents
Increase Uric acid secretion
Urate Lowering drugs should not be commenced during an attack; wait 1-2 weeks after for inflammation to subside
Give 2 examples of Xanthine Oxidase inhibitors
- Allopurinol
- Febuxostat
Name 3 Uricosuric agents
- Sulphinpyrazone
- Probenectid
- Benzobromarone
What is Pseudigout?
Calcium Phosphopyrate crystals; CPPD
Calcium PyroPhosphate Dihydrate
Knees & wrists more comon
Attacks last longet than gout
Similarities to gout;
Red, swollen, painful joint
What demographic is most likely to get Pseudogout?
Elderly
Female
How is Pseudogout diagnosed?
Aspirate joint fluid
Brick shaped crystals
Weak positive birefringence
X-ray
Chondrocalcinosis present often
What are the risks for developing Pseudogout?
Hyper-parathyroidism
Osteoarthritis
Haemochromatosis
Diabetes
Acromegaly
How is Pseudogout treated?
Analgesia
Steroid injections
Joint replacement
