Monoarthritis Flashcards
Describe the pathologies that may present as monoarthritis.
INFECTION
Gout = crystal arthritis
Trauma/haemoarthrosis (bleeding into joint space)
Osteoarthritis
Other sero-negative arthritis (psoriatic/IBD)
Reactive arthritis
Sarcoid
RA (unlikely)
Questions to ask with regards to monoarthritis?
Pain (SOCRATES + sleep affected) Fever/rigors/systemic upset Previous episodes Trauma Peceding illness - GI/GU Sexual history Family history Psoriasis/IBD/Eye disease/other PMH Other joint pains Medication/alcohol Systems review
Key questions when asking about monoarthritis?
Onset Trauma Previous episodes Systemic upset Associated conditions
What is septic arthritis?
Acute inflammation of joint caused by direct infection
What are the common pathogens associated with septic arthritis?
Bacterial
- Staphylococcus aureus (majority)
- Gonococcus (younger adults)
- Streptococcus
- E.coli /others (salmonella, proteus)
Mycobacterial
Fungal/viral (rarely)
Typical presentation of septic arthritis?
Suddent / subacute onset with:
- Pain = difficulty weight-baring and moving at all
- Swelling
- Erythema
What are pre-disposing factors of Septic Arthritis?
Prosthetic joint
Immunosuppressed/elderly
RA
Existing joint damage
IV drug abuse
Source of infection: haematogenous (majority), direct infection, adjacent bone
What would the outcome be if septic arthritis was left untreated?
Rapid joint destruction
Sinus (cavity within bone)/abcess formation
Septicaemia
Multi-organ failure
What is the likely outcome if treated?
High morbidity (50%)
Mortality up to 50% (10%)
What can septic arthritis look like on radiograph?
Narrowing of joint space
Irregularity of subchondral bone
- subchondral erosions
- osteonecrosis
Investigations and results for septic arthritis?
Sepsis? => Bloods - FBC => raised WCC and neutrophilia - U+E, LFT - CRP usually elevated - Blood cultures - Urate, etc. X-ray Joint fluid aspiration - look at it (NOT prosthetic joints) - normal => cooking oil - infection => cloudy
What tests do we use for joint fluid aspiration?
Gram stain (urgent)
MC+S (multiple chemical sensitivity)
Crystals
TB (AFBs)
Fungal culture
How to treat suspected septic arthritis?
IV antibiotics (2 wks IV, 4 weeks PO) - choice depends on resistance patterns - e.g. Ceftriaxone for Gonococcus - empirical = Flucloxacillin + fusidic acid - eyrthromycin if penicillin allergy - MRSA = teicoplannin instead of flucloxacillin Monitor closely Look for infection source
What is better surgery or drainage?
Similar outcome
Surgery will improve health faster
Repeated washouts / drainage may be needed
What is gout?
A clinical syndrome caused by an inflammatory response to:
- monosodium urate monohydrate crystals
May form in people with hyperuricaemia
Acute and chronic forms are recognised
What is a possible reason for increased monosodium urate monohydrate crystals?
Hyperuricaemia due to:
- increased production of urate
- decreased clearance of urate (90%)
What is uric acid (urate) produced from?
Metabolic product of purines
Theories for uric acid?
1) Adjuvant (enhance body’s own immune system)
2) Antioxidant
3) BP control
4) Intelligence
What is the purine metabolic pathway for uric acid formation?
Adenosine –> Inosine –> Hypoxanthine –> Xanthine –> Urate
Guanine –> Xantine –> Urate
What causes underexcretion of urate?
Can be down to renal impairment
What causes overproduction of urate?
Purine rich diet
Increased synthesis of purines
Which age is gout at its peak?
Male: 40 - 50
Female: >60
Which gender is it most prevalent in?
Males
M:F = 2-7 :1
What is the prevalence of gout?
M: 0.5 - 2.8%
F: 0.1 - 0.6%
