Gout Flashcards
What are the key characteristics of gout
Characterised by hyperuricaemia and the deposition of monosodium urate crystals in and around the joints
What effect does urate crystals have when they are deposited in and around the joints
Cause attacks of acute inflammatory arthritis resulting in the joint to become hot, swollen and painful
What type of arthropathy is gout
crystal arthropathy
arthropathy just means joint disease
Gout is associated with chronically high levels of what in the blood?
uric acid
What is gouty tophi
Occurs in gout
It is subcutaneous deposits of uric acid typically affecting the small joints and connective tissues of the hands, elbows and ears.
What joints in the hand is most commonly affected by gouty tophi
Occurs in gout
The distal interphalageal joints (DIP) joints
Name some of the risk factors for gout
- Developed countries
- Male gender
- Older age
- Obesity
- High purine diet e.g. meat and seafood
- AKI and CKD
- Diabetes
- Family history of crystal arthropathy
Gout is a disorder of which form of metabolism
Purine metabolism
Uric acid is a breakdown product of what?
Purine
How is uric acid excreted by the body
Predominantly renal excreted (70%) with the remaining excreted via GI tract
Imbalance between production and excretion of uric acid causes hyperuricaemia leading to supersaturation and precipitation of monosodium urate crystals.
What are the three places these crystals typically end up
Soft tissue
Joints
Kidneys
Imbalance between production and excretion of uric acid causes hyperuricaemia leading to supersaturation and precipitation of monosodium urate crystals.
What are the three main mechanisms leading to the crystal formation?
Purine overproduction e.g. increased cell turnover or lysis of cells leading to release of purines
Increase purine intake e.g. seafood, red meat, alcohol
Decreased uric acid secretion e.g. CKD, medication such as diuretics
How does increase in cell turnover or lysis of cells causing hyperuricaemia
The destruction of the cell causing the release of purines
Purines are broken down into uriac acid
Thus there is imblanace between production and excretion causing the hyperuricaemia
Hyperuricaemia does not always lead to gout, but the incidence of gout increases with urate level.
What 3 types of food and drink is there a high purine content
Seafood
Red meat
Alcohol
The deposition of urate crystals may occur asymptomatically.
Give two examples of when this occurs?
In chronic gout
Formation of gouty tophi
Gout is characterised by episodes of acute attacks/flare ups that trigger an acute inflammatory reaction leading to acutely painful swollen joints.
What triggers these acute attacks?
Generally due to increased production of uric acid either exogenous or endogenous
Name an exogenous trigger that causes an increase in the production of uric acid trigger an acute attack of gout
High purine foods e.g. seafood, red meat
Name two endogenous trigger that causes an increase in the production of uric acid trigger an acute attack of gout
Chemotherapy (increased cell breakdown)
Trauma and surgery
How long does an acute inflammatory attack of gout usually last?
Several days
What are the 3 key clinical features of an acute inflammatory attack of gout
Pain/tenderness of the affected joint(s)
Swelling of the affected joint(s)
Erythema of the affected joint(s)
Gout is characterised by acute attacks of inflammation and then a period of remission.
What symptoms does a patient usually experiences during these periods of remission
Often symptom-free
What joint is usually the first presentation/affected joint in gout
1st metatarsophalangeal (MTP) joint
The 1st metatarsophalangeal (MTP) joint is the usually first joint affected in gout.
What other joints are commonly affected
Other joints include knees, ankles, carpometacarpal joints, wrists
In the majority of cases it is monoarticular (affecting only one joint at a time)
What is Chronic tophaceous gout
Occurs when hyperuricaemia is left untreated
Characterised by hard subcutaneous nodules (tophi) which are the result of deposition of uric acid and formation of urate crystals in soft tissues e.g. ear, fingers, toes etc
The DIP joints are most affected in the fingers
How is gout diagnosed
Clinical diagnosis that can be confirmed with arthrocentesis i.e. joint aspiration
Arthrocentesis is a useful investigation for gout.
What can it tell you that makes it useful
Can rule out other diagnoses - particularly septic arthritis that can commonly present with similar presentation to gout
Arthrocentesis is another name for joint aspiration
Gout is a clinical diagnosis however investigations can be useful to rule out other potential causes and to confirm the diagnosis
What is the gold standard investigation in gout
Arthrocentesis
What characteristics would be seen in arthrocentesis for gout
Presence of needle-shaped monosodium urate crystals that are negatively birefringent under plane-polarised light
Blood uric acid levels are not usually checked when a patient presents with gout
Why?
Patients typically present when they have an acute attack of gout
Uric acid must be checked once the acute episode has settled down (typically 2 weeks later)
Uric acid must be checked once the acute episode of gout has settled down (typically 2 weeks later).
Why is this?
As the uric acid level at the time of an acute attack is not a true representation of the level
May be high, normal or low during the acute attack
The goal of managing an acute attack of gout is symptom relief and preservation of joint function.
What 3 pharamceutical options are available?
NSAIDs, corticosteroids or colchicine
The goal of prophylaxis management of gout is to prevent recurrent attacks and chronic joint destruction.
What are the two ways in which this is done?
Combination of lifestyle changes and urate lowering therapy
Lifestyle changes is part of the prophylaxis management of gout.
Name some of the lifestyle changes
- Reduce alcohol intake
- Avoid purine-based foods e.g. seafood
- Medication review, particularly those that may cause hyperuricaemia e.g. diuretics, chemotherapy
Urate Lowering Therapy is part of the prophylaxis management of gout.
When are patients offered this medication
Should only be started at least one week after an acute episode has resolved as it may worsen the acute episode
Offered to all patients after their first attack of gout
Why must urate lowering therapy be started at least one week after an acute episode of gout has resolved?
Starting or increasing urate lowering therapy can itself cause a gout flare
What is the 1st line urate lowering therapy given in the prophyalxis management of gout
Allopurinol
What role does Allopurinol have in the management of gout
Urate lowering therapy
used to prevent recurrent attacks and chronic joint destruction
What drug class if allopurinol
Xanthine oxidase inhibitor
What is the 2nd line urate lowering therapy used in the prophylaxis management of gout
Febuxostat
What are the three complications of gout
Joint destruction
Kidney disease
Urolithiasis (kidney stones comprised of urate)
