Monoarthritis Flashcards
(80 cards)
1
Q
What are the functions of the bone?
A
- Haematopoiesis
- Movement
- Structure
- Protection
- Calcium reservoir
- Energy store
2
Q
What types of bone shape are there?
A
- Long
- Short
- Irregular
- Flat
- Sesamoid
3
Q
What hormones are involved in day to day bone homeostasis?
A
- Vitamin D3
- Parathyroid hormone
4
Q
Why is vitamin D3 a hormone?
A
Made in one place and acts in another
5
Q
Which populations are mainly at risk of developing vitamin D deficiency?
A
- Populations lacking sunlight
- Populations with a poor diet
6
Q
Where is PTH synthesised?
A
Parathyroid glands
7
Q
What is the purpose of calcium homeostasis?
A
Maintaining constant blood calcium concentration
8
Q
Skeleton is divided into two organisation compartments?
A
Axial
Appendicular
9
Q
What do embryonal bone development, longitudinal bone growth, and fracture healing all make use of?
A
Endochondral ossification
10
Q
What types of cells are involved in bone metabolism?
A
- Osteoclasts
- Osteoblasts
- Osteocytes
- Blood vessels and nerves
11
Q
What do tendons do?
A
Connect muscle to bone
12
Q
What do ligaments do?
A
Connect bone to bone
13
Q
What do aponeuroses do?
A
Connect muscle to muscle
14
Q
How is muscular force transmitted to bone?
A
Initially via the musculotendinous junction
15
Q
What are the two sites of muscular/tendinous attachment to bone?
A
Origin and insertion
- Origin is stationary
- Insertion moves
16
Q
What are both tendons and muscles subdivided into?
A
Fascicles
17
Q
What are two models of skeletal unloading?
A
Astronauts
Bed rest
18
Q
How do you measure bone density?
A
DEXA scan
qCT: quantitative computerised tomography
Ultrasound
19
Q
What is the gold standard for measuring outcomes of a trial for osteoporosis?
A
Fractures
20
Q
What canals do osteocyte processes occupy?
A
Canaliculi
21
Q
How to osteocytes respond to loading/mechanical stress?
A
In terms of bone metabolism
22
Q
Where are osteocytes derived from?
A
They are derived from osteoblasts
23
Q
Where do chondrocytes live?
A
In a hole called a lacuna
24
Q
What are the major components of articular cartilage?
A
- Water
- Type II collagen
- Proteoglycans
25
What are the main reasons cartilage heals poorly?
- Avascular
- Double diffusion systems
- Loss of stem cell population in older people
26
What is the major proteoglycan
Aggrecan
27
What interventions can be used for small to medium sized defects in articular cartilage?
- ACI
- Debridement
- Regeneration enhancement - includes microfracture
- Osteochondral grafting
- Cell based therapies
28
What are the functions of articular cartilage?
- Distribute and transmit load of bone whilst moving
- Minimise peak stresses on subchondral bone
- Withstand low-friction repeated movement in everyday lifestyle
29
What do cartilage cells make?
- Proteoglycan: aggrecan, decorim and biglycan
| - Collagen
30
Why is aggrecan important?
It brings water into the cartilage which helps with compressive forces
31
What are the key radiological features of osteoarthritis?
- Reduced joint space
- Bone cysts (cracking in cartilage then fluid builds and cysts form)
- Subchondral bone sclerosis
- Osteophytes: bony spurs sticking up from the surface, an attempt to repair the bone
32
What are the histological features of osteoarthritis?
- Cartilage degradation and proteoglycan loss
- Surface fibrillation (breaking up)
- Loss of metachromasia (staining)
- Chondrocyte clustering (rather than being orderly organised in columns)
- Chondrocyte apoptosis
- Hyperplasia of synovium (thickened and inflamed and produces more fluid and thus swelling in the joints)
33
What are the features of cartilage focal lesions?
- Focal lesions resulting from trauma mainly affect younger subjects, often during sports
- Focal cartilage injury - either repetitive or traumatic impact
- Pain, swelling and mechanical symptoms can be ongoing and lead to loss of function and joint degradation
34
What are chondral lesions?
Lie entirely within the cartilage and do not penetrate subchondral bone
- Don't heal spontaneously
35
What are osteochondral defects?
They penetrate through vascularised subchondral bone, some spontaneous repair occurs as chondroprogenitor cells invade the lesion
36
What is the treatment for advanced osteoarthritis?
Total knee arthroplasty
- Expensive
- Tend to wear
37
What are the possible first line intervention strategies for small defects?
- Debridement
| - Microfracture
38
What are the second line treatments for small defects?
- Osteochondral grafting
- Cell based therapies
- Osteotomy
39
What does debridement do?
Aim to reduce friction and inflammation by shaving off frayed edges of a cartilage tear
40
What does microfracture treatment do?
- Perforation chondroplasty
- Reparative procedure
- Fibrocartilage repair
41
What is an osteotomy?
Alters geometry of the knee to restore normal loading and relieve pain
42
What is osteochondral grafting?
Regenerative procedure using either an autograft (from patient) or allograft (from donor) tissue to replace damaged area
43
What is autologous chondrocyte implantation?
Cell based therapy, regenerative procedure that fills the defect
44
What is matrix induced autologous chondrocyte implantation?
Modification of the ACI procedure but collagen in scaffold membrane
45
What are stem cells?
Multipotent or pleuipotent cells capable of differentiating into a variety of mature cell types
46
What is the meniscus?
Helps to distribute load over the joint and reduce wear and tear
47
What can be done when the meniscus is damaged?
```
Allograft
Cells (chondrocytes or stem cells) to develop an implant to restore joint function
```
48
What are the functions of calcium?
- Formation of calcified tissues
- Normal activity of nerves and muscle
- Neurotransmitter release, hormonal and glandular secretion
- Excitation-contraction coupling (particularly in cardiac and smooth muscle)
- Integrity and permeability of cell membranes
- Cell adhesion
- Blood clotting
49
What is the primary purpose of calcium homeostasis?
Maintain constant blood calcium concentration
50
How is blood calcium regulated?
- Principle organ systems: gut, bone, kidneys
- Hormones
- Integrated physiology
51
Which hormones are involved in blood calcium regulation?
Parathyroid hormone
Vitamin D3
(Calcitonin)
52
What factors affect calcium flux into the blood?
Intestinal absorption
| Bone reabsoprtion
53
What factors affect calcium flux out of the blood?
Renal excretion
| Bone formation
54
What defines a hormone?
Made in one place (or sequentially in several places) and then acts in others
55
What is vitamin D3?
A hormone
56
How is vitamin D3 synthesised?
Skin
| Digestion
57
What is hypercalcaemia?
State of blood calcium concentration above the normal range
- Too much calcium entering the blood
- Too little calcium leaving the blood
58
What are the symptoms of hypercalcaemia?
Stones, bones, groans, thrones and psychiatric overtones!
- Blocks sodium channels so suppression of activity
- CNS: altered mental state including lethargy, depression, decreased alertness, confusion, coma
- GI: anorexia, constipation, nausea, vomiting
- RENAL: diuresis, impaired concentrating ability, dehydration, hypercalciuria - risk for kidney stones
- SKELETAL: associated with increased bone reabsorption so fracture risk
- CV: cause/exacerbate hypertension, shortened QT interval
59
What are the hormonal causes of hypercalcaemia?
- Primary hyperparathyroidism
- Hypervitaminosis D
- Paraneoplastic
60
What are the non-hormonal causes of hypercalcaemia?
- Renal failure
| - Milk-alkali syndrome
61
What drugs can cause hypercalcaemia?
- Thiazides
| - Lithium
62
What is hypocalcaemia?
Blood calcium below normal range
63
How is hypocalcaemia assessed?
Ionised calcium levels
64
What are the symptoms of hypocalcaemia?
- Causes stimulation of activity as it lowers threshold for depolarisation
- Pins and needles
- Tetany
- Facial spasm
- Hyperactive tendon reflexes
- Larygospasm
- Cardiac arrhythmias
- Diarrhoea
65
What are the causes of hypocalcaemia?
Hypoparathyroidism
- Post surgical
- Autoimmune
- Pseudohypoparathyroidism (PTH resistance)
- Idiopathic
Hypovitaminosis D
- Dietary deficiency
- Rickets, osteomalacia
Organ disfunction
- GI malabsorption
- Renal loss
Endocrine response to non-hypoparathyroid hypocalcaemia
- Secondary hyperparathyroidism
66
What should any investigations aim to rule out?
INFECTION
67
What is septic arthritis?
Acute inflammation of a joint caused by direct infection
68
What are possible bacterial causes of septic arthritis?
```
Staph. aureus (mainly)
Gonococcus (young adults)
Streptococcus
E. coli
Salmonella
Proteus
```
69
What are the other causes of septic arthritis?
- Bacterial
- Mycobacterial
- Rarely fungal/viral
70
What are typical features of septic arthritis?
- Sudden/subacute onset
- Pain
- Difficulty weight bearing
- Difficulty moving
- Swelling
- Erythema
- Hot
- Tender
71
What are the predisposing factors to septic arthritis?
- Prosthetic joint
- Immunosuppression
- Elderly
- Diabetic
- Rheumatoid arthritis
- Existing joint damage
- IV drug abuse
- Source of infection
72
What is the outcome of septic arthritis if left untreated?
- Rapid joint destruction
- Sinus/abscess formation
- Septicaemia
- Multi-organ failure
73
What happens in septic arthritis?
- Narrowing of the joint space and irregularity of subchondral bone
- Subchondral erosions and sclerosis of head
- Osteonecrosis and complete collapse
74
What investigations should occur in suspected septic arthritis?
- Bloods
- X-ray
- Joint fluid
75
What is gout?
Clinical syndrome caused by an inflammatory response to monosodium urate monohydrate crystals which may form in people with hyperuricaemia
Can be acute or chronic
76
What happens in gout?
Overproduction of urate
- Purine rich diet
- Increased synthesis of purines
Underexcretion of urate
- 90% of cases due to decreased urate clearance
- Can be due to renal impairment
77
What happens in purine metabolism?
Adenosine -> inosine -> hypoxanthine -> O2 and xanthine -> O2 and uric acid -> excretion - ⅔ renal, ⅓ gastrointestinal
78
What are the risk factors for gout?
- Age
- Male
- Genetics
- Impaired renal function
- Hyperuricaemia
- High purine diet
- Alcohol consumption
- Obesity
- Diuretics
79
Which drugs modify the renal excretion of urate?
- Aspirin (high dose)
- Phenyl butazone
- Probenecide
- Sulphinpyrazone
- Others
80
What are the features of acute gout?
- Pain
- Swelling and erythema
- Many attacks occur on first MTP joint (big toe) - most have osteoarthritis in and are colder so more prone to crystallisation
- Almost any joint affected though lower more than upper
- Mild attacks resolve in a few days
- Tophi are signs of gout on hands and ears
