Painful Joints Flashcards
What is Gout?
Most common inflammatory arthritis in men and older women – caused by the deposition of monosodium urate monohydrate crystals in and around synovial joints
What are the risk factors for gout?
- Sex - Men
- Age
- Increased serum uric acid (SUA) levels - Hyperuricaemia - defined as an SUA of more than 2 standard deviations from the mean (increases with age, BMI and sex - males)
- Other diseases - General Osteoarthritis - reduction in levels of proteoglycan and other inhibitors of crystal formation
Even though, Hyperuricaemia is a strong risk factor for Gout, only a minority of Hyperuricaemia individuals develop gout
Increased prevelance in affluent socities - increased levels of obesity and metabolic syndrome.
Describe the metabolism of uric acid in the body.
1/3 of uric acid pool derived from the diet (purine intake), whereas the other 2/3 derived from endogenous purine metabolism
Network of enzymes involved in uric acid production – main one - xanthine oxidase catalyses the conversion of hypoxanthine to xanthine and xanthine to uric acid
Product of purine metabolism - Adenosine and guanine
Concentration of uric acid in body fluids depends on the balance between endogenous synthesis, and elimination by the kidneys (two-thirds) and gut (one-third)
What is the main cause of hyperuricaemia?
Main cause of hyperuricaemia (90% of patients) is reduced uric acid excretion from the kidney – genetically determined + also occurs during renal failure
Attached image shows the different potential drivers/causers of high hyperuricaemia
Regardless… build up of uric acid crystals – drives activation of inflammation
How does gout present clinically?
Classical presentation – acute monoarthritis - affects the first metatarsophalangeal in 50% of cases (big toe)
Other common sites include… ankle, midfoot, knee, small joints of hands, wrist and elbow. Axial skeleton and large proximal joints are rarely involved
Typical feature – presents as ‘attacks’
a) rapid onset, reaching maximum severity in 2–6 hours, and often waking the patient in the early morning
b) Severe pain, often described as the ‘worst pain ever’
c) Extreme tenderness, such that the patient is unable to wear a sock or to let bedding rest on the joint
d) Marked swelling with overlying red, shiny skin
e) Self-limiting over 5–14 days, with complete resolution.
f) After attack subsidies – pruritus (itchy dry skin) & desquamation (skin peeling)
- Possibility of accompanying fever, malaise and even delirium – larger joints involved like the knee
Can people develop chronic gout?
Yes, people with continuous attacks may end up suffering from chronic gout
Tophi – feature of longstanding gout – crystal deposition in joints and tissue as irregular soft nodules
What is the differential diagnosis for gout?
Differential diagnosis - septic arthritis, infective cellulitis or reactive arthritis
What type of investigations are performed to confirm the presence of gout?
Gout can be confirmed by identifying urate crystals in the aspirate of a joint, bursa or tophus.
Appearance
- Acute gout – synovial fluid appears turbid – presence of neutrophils
- Chronic gout – variable presentation – occasionally fluid appears white due to urate crystal presence
Biochemical screen should be performed…
- renal function, uric acid, glucose and lipid profile – note during an attack serum urate levels may be normal as they drop when in an inflammatory state
- Acute gout – elevated levels of ERP (erythrocyte sedimentation rate) and CRP (C-reactive protein)
X-ray
- X-rays normally look normal but high levels of joint erosion is apparent in chronic and tophaceous gout
How is gout managed (general terms)?
Focus on dealing with the acute attack and then introducing prophylaxis to lower SUA and prevent further episodes.
What treatment is used in an acute attack of gout?
Acute episode
- First choice of treatment – Colchicine – inhibits microtubule assembly in neutrophils. Note oral NSAIDs are also effective but are typically not used as patients have other conditions (cardiovascular, cerebrovascular or chronic kidney disease)
- Oral prednisolone (15–20 mg daily) or intramuscular methylprednisolone (80–120 mg daily) for 2–3 days - effective for elderly patients that have increased risk of toxicity towards colchicine and NSAIDs
- Local ice packs help alleviate symptoms
- Joint aspiration coupled with intra-articular glucocorticoid injection
What type of prophylatic treatment is used for gout?
Prophylaxis – more than 1 attack in 12 months – consider prophylaxis treatment – goal reduce levels of serum uric acid
a) Allopurinol – first drug of choice - inhibits xanthine oxidase – reducing uric acid levels
b) Febuxostat – given when there is an inadequate response to allopurinol
c) Lifestyle measures – equally as important - lose weight where appropriate, reduce excessive alcohol intake, examine patient’s current drug use as some can elevate SUA and avoid the consumption of high amounts of seafood and offal
What is septic arthritis?
Septic arthritis is an infection in the joint (synovial) fluid and joint tissues
Most rapid and destructive bone disease
Associated with significant morbidity and mortality – 10%, for which the most important risk factor is age
What is the pathogenesis of septic arthritis?
Normally occurs via the haematogenous (blood) spread from infections of the skin or upper respiratory tract
Infection from direct puncture wounds or joint aspiration is less common
What are the risk factors for septic arthritis?
- Risk factors include….
a) Increasing age
b) Pre-existing joint disease (principally RA)
c) Diabetes mellitus
d) Immunosuppression (by drugs or disease)
e) Intravenous drug misuse.
What are the clinical features of septic arthritis?
- Acute or subacute monoarthritis
- Joint is usually swollen, hot and red, with pain at rest and on movement
- Fever
- Commonly Knee and hip joint
Responsible organism - Staphylococcus aureus (most common), gonococcus (- Young, sexually active adults), Gram-negative bacilli or group B, C and G streptococci (edlerly and intravenous drug users)
What investigations are performed to confirm the presence of septic arthritis?
- Joint aspiration – if the joint is not accessible, this should be performed under imaging guidance in theatre –> Synovial fluid sent for gram stain and culture – cultures are positive in 90% of cases, whereas gram stains are positive in 50% of cases
- Blood cultures should also be taken
- The synovial fluid is usually turbid or blood-stained but may appear normal.
- Blood panel - Leucocytosis (elevation in white blood cell count) with raised ESR and CRP in most patients - may be absent in eldelry and immunocompromised
What is the treatment/management for septic arthritis?
Medical emergency - Patient should be admitted to hospital
- Intravenous antibiotic - Flucloxacillin - antibiotic of choice
- Pain releif - oral and/or IV intravenous analgesics - consider ice pack use.
What is rheumatoid arthritis?
Rheumatoid arthritis - auto-immune inflammatory arthritis - causing pain, swelling and stiffness in joints
Occurring throughout the world and in all ethnic groups
Prevalence of 0.8-1% and it is more common in women
Chronic disease characterized by exacerbations and remissions
Stiffness for 1-2 hours in the morning
Outline the pathophysiology of RA?
Interplay between genetic and environmental factors
GWAS - 100 loci associated with RA - strongest association with HLA variants
Current theory – environmental stimulus (infection) triggers an autoimmune response by modulating host surface proteins
Disease characterized by infiltration of the synovial membrane with lymphocytes, plasma cells, dendritic cells and macrophages
Evidence for a strong role for T and B cells
a) T-cells produce cytokines
b) B-cells produce auto-antibodies
c) macrophages also involved
Net result inflammation
What are the clinical features of RA?
Typical presentation is with pain, joint swelling and stiffness affecting the small joints of the hands, feet and wrists in a symmetrical fashion.
Large joint involvement, systemic symptoms and extra-articular features may also occur
Characteristic deformities may develop with long-standing uncontrolled disease, although these have become less common over recent years with more aggressive management
What are some systemic features associated with RA?
- Anorexia, weight loss and fatigue may occur throughout the disease course
- Osteoporosis is a common complication and muscle-wasting may occur as the result of systemic inflammation and reduced activity.
- Extra-articular features are most common in patients that have a longstanding history with the condition - this includes…
a) Nodules
b) Vasculitis
c) Ocular Involvement
d) Serositis (inflammation of the serous – lining of the lungs, heart and abdomen)
e) Cardiac involvement
f) Pulmonary involvement
g) Peripheral neuropathy
e) Spinal cord compression
What investigations are performed for a RA diagnosis?
Clinical diagnosis - The process of identifying a disease, condition, or injury from its signs and symptoms.
Assess patient history - multiple joints with pain and tenderness, symmetrical and symptoms for weeks to months
Investigations are useful to confirm the diagnosis and assess disease activity
a) ESP and CRP are usually raised
b) Tests for ACPA (Anti-citrullinated peptide antibody)
c) RF (Rheumatoid factor) is also elevated - less specific than ACPA
d) X-ray used to assess the amount of damage towards joints
What are the pharmacological and non-pharmacological therapies used for RA?
Pharmacological
Disease modifying antirheumatic drugs (DMARD) – should be introduced for all patients as this improves disease outcome, main ones
a) Prednisolone
b) Methotrexate
But a range of others can be used if these are shown to be ineffective
Suppress inflammation using…
a) Nonsteroidal anti-inflammatory drugs
b) Corticosteroid
Biologic treatment also a possibility - TNF inhibitors
Transient flares can be treated with glucocorticoids but if sustained flares appear than changes in systemic DMARD or biologic therapies need to be considered.
Non-Pharmacological therapy
Physical and occupational therapy play important roles
Is surgery an option for RA?
Surgery
- Synovectomy can be considered if DMARD fails - refers to the destruction or surgical removal of the membrane (synovium) that lines a joint.
- Joint replacement surgery may be required but the need for this has diminished over recent years
What is the difference between incidence and prevelance?
Prevalence: Number of people in a population who have a disease or other health outcome at one point in time
Incidence: Number of people in a population who develop a disease or other health outcome over a period of time (i.e. new cases over a period of time)
What’s the difference?
Prevalence includes all cases, both new and pre-existing, in the population at the specified time, whereas incidence is limited to new cases only.
What are the clinical symptoms associated with sepsis?
What should you do if you have an acute hot, inflammed, tender joint?
Exclude septic arthritis!
Aspirate joint, send blood cultures
