R2 LOCO3 Flashcards
Which region of the muscle tissue connects the muscle fibre to the tendon?
Endomysium is around each muscle fibre & blends into tendon
Whats the difference between tendinitis and tendinosis? [2]
Tendinitis: acute inflammation of tendon, does not have microscopic tendon damage
Tendinosis: chronic inflammation of tendon; characterised by disorganised fibres and a hard, thickened, scared and rubbery appearance
What is difference in structure between normal tendon and tendon with tendinosis? [2] Why is this clinically significant [1]
Normal structure: tendon allows contraction of muscle to cause movement of skeletal system
Tendinosis: disorganiesd collagen means that stresses are not transmitted efficiently: can lead to full thickness tear
Note the disorganise collagen
Achilles tendinitis
Which physiological process may occur during the healing process? [1]
Form heterotopic calcified regions (formation of extraskeletal bone in muscle and soft tissues)
Where in the tendon does tendonitis usually occur? [1]
Tendonitis usually occur in the middle of the tendon as this is the weakest spot [1]
Explain the pathophysiology of heterotopic bone [3]
Fibroblasts, osteoblasts and chondroblasts come from same precursors
Tendon fibroblast differentiate into chondrocytes / hypertrophic chondrocyte and osteoblasts via COX-2
Pro-inflammtory cytokines like prostaglandin E2 induces osteoblasts to differentiate
Describe how healing compares when undergo unloading by temporary paralysis versus overloading by active mobility or exercise for:
- tendon-bone healing
- flexor tendon healing
Complete unloading by temporary paralysis:
* Beneficial for tendon-bone healing
* Detrimental for flexor-tendon healing
Overloading by active mobility or exercise:
* Detrimental for tendon-bone healing
* Beneficial for flexor-tendon healing
State which is more beneficial for shorter [1] or longer [1] tendons
Unloading by temporary paralysis
Overloading by active mobility or exercise
Short: Unloading by temporary paralysis / cast immobilisation
Long:loading by active mobility or exercise
Describe the different types of enthesis in body [2]
Fibrous
* tendon extends all way up to bone: collagen bundles extend all the way to periosteum & become calcified
* Both are made from type 1 collagen
Fibrocartilaginous: when want to dissapate the stress
* Small section of fibrocartilage at attachment site
* Fibrocartilage calcififies at insertion
* Helps stiffen the tendon / ligament and creates a gradual change in mechanical properties
Name two locations of fibrous enthesis ligaments [2]
Name three locations of fibrocartilage enthesis ligaments [2]
Fibrous enthesis
* spring ligament
* periodontal ligament
Fibrocartilage enthesis
* rotator cuff muscles
* achilles tendon
* plantar fascia
What type of enthesis is depicted? [1]
Fibrous enthesis
Define sharpey fibres [1]
Sharpey’s fibres: are a matrix of connective tissue consisting of bundles of strong predominantly type I collagen fibres connecting periosteum to bone.
Label A
sharpey fibres
State the 4 zones of the fibrocartilage enthesis [4]
- Tendon proper
- Fibrocartilage
- Mineralised fibrocartilage
- Bone
What is name for inflammed enthesis? [1]
Enthesitis
Describe enthesitis pathogenesis:
Normal enthesitis insertion occurs at a location with lots of which structure? [1]
How does this influence enthesitis pathogenesis? [3]
Normal enthesis inserts into porous bone at a location with lots of small transcortical vessels (TCV)
Mechanical trauma; TCVs become inflammed:
* Vasodilation
* Efflux of immune cells (neutrophils)
* Osteoblasts form bone at enthesis - causes bone to be formed
Enthesitis is associated with which three conditions? [3]
Ankylosing spondylitis
Psoriatic arthritis
IBD
How do you differentiate between enthesophytes and osteophytes? [2]
Enthesophytes: originate from insertion of the joint capsule, ligament or tendons: no articular border involvement
Osteophytes: orginate from border of articular cartilage
How do you treat enthesitis:
- If mechanical? [2]
- If Inflammatory [5]
Mechanical:
* RICE
* NDSAIDs
Inflammatory:
* Sulfasalazine
* Methotrexate
* Anti-TNF therapy (restricted use for severe autoimmune enthetitis)
* Local radiotherapy
* Corticosteroid injection
* Hyperosmolar dextrose (initiates proliferation of intrinsic fibroblasts - race to repair damage c.f. osteoblasts)
Which drug class is used for ankylosing spondylitis enthesitis? [1]
Anti-TNF treatment
What are the names for arteries that supply tendons (of the hands)? [1]
Vincular arteries
Name two tenosynovitis conditions [2]
De Quervain’s tenosynovitis
Trigger finger
Explain pathophysiology of De Quervien tenosynovitis [3]
Fibrosis and narrowing of tendon sheath: extensor retinaculum
Around anatomical snuffbox
Causes tendons and sheath rubbing over radial styloid process
Thickening and narrowing of tendon sheath
Lymphocyte inflammation
State and describe the name for test of De Querviens tensynovitis [1]
Finkelstein test:
- Patient resting their forearm on a surface in a neutral position with the wrist hanging off and unsupported
- The examiner holds the patient’s thumb and passively flexes the thumb into the palm, causing the wrist to adduct (ulnar deviation), putting **strain on the APL and EPB tendons. **
- If this causes pain at the radial aspect of the wrist, the test is positive, indicating De Quervain’s tenosynovitis.
Describe lesions seen in SLE [1]
Discoid lesions
Describe the arthritis seen in SLE patients [1]
Jaccoud arthropathy: due to tendinitis
Can move back into the correct position.
Describe the role of Langerhan cells [3]
Dendritic cell - spine-like projections
Efficient at presenting antigen to CD4+ helper T-cell
Pick up antigens that enter the skin and transport them to the lymph node
Staining dendritic cells n epidermis in a patient with skin infection.
Describe pathway of mast cell degranulation after exposure to an antigen [3]
APC picks up the antigen and presents to the T cell.
Th2 produces IL4 & IL5, which activates the B cells to make IgE, which then activate the mast cell and degranulation occurs
IgE producition- produced after a second exposure.
Histamine is important as it causes which symptoms seen in an allergic reaction? [6[
Smooth muscle contraction
Vessel leak and oedema
Bronchospasm
Arteriole dilatation causing headache and hypotension
Modulation of immune response via H2 receptors
Name an allergen produced by dust mice [3]
How does it cause damage to airway epithelium? [1]
Der P1 is an enzyme allergen
from the faecal pellets
of the dust mite.
Der P1 breaks down components of tight junctions which helps it to cross mucosa.
Binds to mast cells and causes degranulation
What is Pemphigus Vulgaris? [2]
autoimmune disease caused by antibodies directed against desmoglein 3, a cadherin-type epithelial cell adhesion molecule
Antibody and complement binds to desmoglein 3: causes acantholysis (loss of coherence between epidermal cells due to the breakdown of intercellular bridges)
Describe the features of Immune Complex Mediated Vasculitis [4]
Antigen and antibody form an immune complex
This causes production of proteins and aggregation of platelets into micro thrombi
This results in:
* Deposition of fibrin
* Leaky vessel and extravasation of blood and oedema.
* The proteases degrade vessel BMZ
* Necrosis of the vessel wall
Name this disease [1]
Leukocytoclastic Vasculitis: Blood induced- there are black and necrotic areas on the legs.
Allergic Contact Dermatitis pathogenesis? [3]
Promotion of Th1 response:
- Secretion of IL2, IL3, GM-CSF, IFNg and TNF
- This promotes a macrophage rich response
- Causes inflammation to the skin around 48 hours to 72 hours after the challenge
Describe formation of granulomas
Clonal T-cell expansion
Secretion of
Th1 cytokines:
IL-2, IFN-g, TNF causes the creation of macrophages
