Acute Hot Joint Flashcards
(2) most common organisms causing septic arthritis
- most common organism overall is Staphylococcus aureus
- in young adults who are sexually active Neisseria gonorrhoeae should also be considered
The most common location of septic arthritis in adults
in adults, the most common location is the knee
Criteria for diagnosis of septic arthritis
The Kocher criteria for the diagnosis of septic arthritis:
- fever >38.5 degrees C
- non-weight bearing
- raised ESR
- raised WCC
Management of septic arthritis
- synovial fluid → obtained before starting treatment
- IV antibiotics → which cover Gram-positive cocci (flucloxacillin or clindamycin if penicillin allergic)
*antibiotic treatment is normally be given for several weeks (6-12 weeks)
- needle aspiration → to decompress the joint
- arthroscopic lavage may be required
Differential diagnosis of acute hot joint
- Septic arthritis (bacterial, mycobacterial ,fungal)
- Lyme disease
- Crystal arthritis (gout, pseudo-gout -calcium pyrophosphate deposition disease)
- Trauma
- Haemarthrosis (eg haemophilia)
What to ask in Hx of hot joint?
- How quickly did the pain and swelling come on?
- Are any other joints involved?
- Do they feel unwell? Fever/sweats? Have systemic symptoms eg urinary, chest?
- Have they damaged the joint? eg recent intra-articular injection
- Have they had a recent infection of any kind?
- Is there a history of IV drug use? (consider infection)
- Have they had previous episodes of pain and swelling in other joints that resolved spontaneously? (consider crystal arthritis)
- Do they have a history of arthritis? Gout?
- Are they immunosuppressed? (diabetes, steroids, DMARDs)
- Do they have a bleeding diathesis? Anti-coagulated? (consider haemarthrosis)
- Ask about genito-urinary symptoms and sexual history
What to examine in the patient with an acute hot joint?
- Examine the joint – red, hot and swollen!
- Examine the other joints – are others involved
- Signs of arthritis eg OA, RA? Tophi?
- Systemic examination – skin eg rashes, track marks; chest; heart sounds etc
- Vital signs – pay particular attention to BP
Is there any fever in septic arthritis?
fever – can be misleading: often present in septic arthritis but can be absent.
Can be a feature of acute gout or pseudogout.
Ix for septic arthritis
- FBC, U+E
- CRP or ESR (useful for monitoring response to treatment)
- Blood cultures x 2
- JOINT ASPIRATION → synovial fluid analysis is the single most useful diagnostic test for a hot joint
- Request cell count, gram stain, culture, crystal examination
- Consider imaging eg baseline Xray, ultrasound to guide joint aspiration
Ranges of synovial fluid WCC
Synovial fluid white cell count:
< 500/mm3 → non-inflammatory fluid
> 1500/mm3 → inflammatory fluid
> 50,000/mm3 → think of septic arthritis
How bacteria reach the joint in septic arthritis?
Risk factors for the development of septic arthritis
Abnormal/damaged joint
- Pre-existing arthritis eg RA, OA
- Prosthetic joints
Impaired host defense
- Elderly (>65y), children (<5y)
- Chronic illness eg diabetes, liver cirrhosis, chronic renal disease, alcoholism, cancer
- Immunosuppressed eg steroids, chemotherapy, hypogammaglobulinaemia, HIV
- Intravenous drug abuse
Antibiotic choice in septic arthritis
- No risk factors for atypicals → cover staph and strep: flucloxacillin + penicillin
- High risk of gram negative sepsis → 2nd/3rd generation cephalosporin eg cefuroxime
- MRSA risk, eg nursing home resident, leg ulcers → vancomycin
Length of treatment with antibiotics in septic arthritis
IV antibiotics for 2/52 then orally for 4/52
Other (than antibiotic and aspiration) notes on the management of septic arthritis
- Analgesia
- Drain the joint to dryness regularly eg repeated joint aspiration
- Immobilise the joint for a day or 2, then gentle physical therapy
- Treat the focus of infection and manage sepsis eg IV fluids
- DVT prophylaxis
What’s gout?
Gout is a form of microcrystal synovitis (inflammation) caused by the deposition of monosodium urate monohydrate in the synovium.
It is caused by chronic hyperuricaemia (uric acid > 0.45 mmol/l)
Risk factors for the development of gout
Decreased excretion of uric acid
- drugs: diuretics, aspirin 75-150 mg (but continue if CVD)
- chronic kidney disease
- lead toxicity
Increased production of uric acid
- myeloproliferative/lymphoproliferative disorder
- cytotoxic drugs
- severe psoriasis
- excess dietary purine consumption
- alcohol
- tumour lysis
Which syndrome predisposes to gout?
Lesch-Nyhan syndrome
- hypoxanthine-guanine phosphoribosyl transferase (HGPRTase) deficiency
- x-linked recessive therefore only seen in boys
- features: gout, renal failure, neurological deficits, learning difficulties, self-mutilation
Symptoms of gout
Patients typically have episodes lasting several days when their gout flares and are often symptom-free between episodes
The acute episodes typically develop maximal intensity with 12 hours/ The main features it presents with are:
- pain: this is often very significant
- swelling
- erythema
Which joints are affected by gout?
Around 70% of first presentations affect the 1st metatarsophalangeal (MTP) joint.
Other commonly affected joints include:
- ankle
- wrist
- knee
Radiological features of gout
- joint effusion
- well-defined ‘punched-out’ erosions with sclerotic margins ina juxta-articular distribution, often with overhanging edges
- relative preservation of joint space until late disease
- eccentric erosions
- no periarticular osteopenia (in contrast to rheumatoid arthritis)
- soft tissue tophi may be seen
Acute management of Gout
Acute management
- NSAIDs or colchicine are first-line
*the maximum dose of NSAID should be prescribed until 1-2 days after the symptoms have settled. Gastroprotection (e.g. a proton pump inhibitor) may also be indicated
*colchicine has a slower onset of action.
The main side-effect is diarrhoea
- oral steroids may be considered if NSAIDs and colchicine are contraindicated. A dose of prednisolone 15mg/day is usually used
- another option is intra-articular steroid injection
- if the patient is already taking allopurinol it should be continued
Indications for allopurinol
Indications for urate-lowering therapy (ULT)
- offer urate-lowering therapy to all patients after their first attack of gout
ULT is particularly recommended if:
- → >= 2 attacks in 12 months
- → tophi
- → renal disease
- → uric acid renal stones
- → prophylaxis if on cytotoxics or diuretics
Lifestyle modification for gout
- reduce alcohol intake and avoid during an acute attack
- lose weight if obese
- avoid food high in purines e.g. Liver, kidneys, seafood, oily fish (mackerel, sardines) and yeast products
