ORTHO 137 Monoarthritis and Gout Flashcards
Define Gout
An inflammatory response to monosodium urate monohydrate crystals in the joint
How does gout typically present?
As an acute monoarthritis: joint inflammation
What joint is gout most common in?
the metatarsophalangeal joint - big toe
What are tophi?
Solid lumps of uric acid that may develop in those with chronic gout
What are some of the causes of gout?
Purine rich diet e.g. beer, cider (alcohol excess0
Diuretics and renal impairment
How would you investigate gout?
Joint fluid: crystals
Blood: check for metabolic syndrome (blood sugar, fasting lipids, LFT’s); urea, urate and creatinine
Urinalysis: blood and protein
How would you manage and treat gout?
Lifestyle changes
Pain relief
Correct hyperuricaemia
What pain relief would you give in gout?
NSAID’s
Colchicine (NSAID but without GI SE’s)
Steroids: oral or intraarticular
How would you correct the hyperuricaemia in gout?
Xanthine oxidase inhibitors e.g. allopurinol & febuxostat
Uricosurics: increase secretion of uric acid
What is Septic Arthritis?
Invasion of a joint by a pathogenic organisms causing joint inflammation
What are differential diagnoses for a monoarthritis?
Septic arthritis
Crystal Arthritis
Trauma
What are the normal physiological roles of calcium?
Formation of calcified tissues
Normal activity of nerve and muscle
NT release, hormonal and glandular secretions
Excitation/contraction coupling
Integrity and permeability of cell membranes
Cell adhesion
Blood clotting
What 3 organs tightly regulate blood calcium?
Gut, kidenys and bone
What 3 hormones contro blood calcium?
PTH, Calcitonin and Vitamin D3
Where is PTH released from?
Chief cells in the paraythyroid glands
What does PTH stimulate?
Bone resorption
Renal tubular reabsorption of Calcium
1-alpha hydroxylation of 25 (OH)D3
What does PTH respond to?
Falling calcium levels
What is the precursor to Vitamin D3 and how is it converted?
7 dehydrocholesterol converted to vitamin D3 in the skin
What happens to vitamin D3 in the liver?
It is hydroxylated to 25(OH)D3
What happens to 25(OH)D3 in the kidneys?
It is hydroxylated to 1,25(OH)D3 = active metabolite
What are the actions of 25(OH)D3?
Gut: transepithelial transport of calcium and phosphate (increase Calcium uptake)
Bone: terminal differentiation of osteoclasts (increased bone resorption)
PTH: -ve feedback to inhibit transcription of PTH
Where is calcitonin synthesised?
C cells of thyroid gland
What is the general action of calcitonin?
Decrease calcium levels in blood
Why does articular cartilage have a limited capacity for repair?
As it is avascular - nutrients only move in an out slowly through synvovium
What is a focal lesion?
Small area of cartilage damage
What is a chondral lesion?
Lesion within the cartilage but no subchondral bone penetration
What is an osteochondral defect?
Lesion in cartilage that penetrates to the subchondral bone
Why can osteochondral defects repair better than condral lesions?
As OC defects have access to subchondral blood supply and chondroprojenitor cells whereas chondral lesions do not
What is a Grade 1 articular cartilage defect?
fissures into superficial cartilage
What is a Grade 2 articular cartilage defect?
multiple fissures extending hald the depth of cartilage
What is a Grade 3 articular cartilage defect?
fissures extending full depth of cartilage
What is a Grade 4 articular cartilage defect?
complete cartilage loss and subchondral bone exposure
What are the 5 current options for treating a small/interediate articular cartilage defect?
Debridement Microfracture Osteotomy Osteochondral grafting Autologous chondrocye implantation
Describe debridement for an articular cartilage defect?
Shave off frayed edged to reduce pain and swelling - no repair but pain relief
Describe what microfracturing is in the treatment of an AC defect
Make holes in bone surface to stimulae bleeding and clotting response
Fibrocartilage usually forms which is less effective than hyaline
When would an osteotomy be performed?
In response to deformed/malaligned joint to avoid wear and tear and re-establish normal loading and gait
What is osteochondral grafting?
Taking good cartilage from another siter and adding it to the defect site - can be autograft or allograft
What is autologous chrondrocyte implantation?
A regenerative cell based therapy: chondrocytes grown in lab and placed into focal lesion using periostal flap
