Lecture 4: Intro to Rheumatology Flashcards
What is connective tissue?
- binds together, supports and strengthens other body tissues
- protects and insulates internal organs
- compartmentalises structures such as skeletal muscle
- major transport system within the body
- site of stored energy reserves
- main site of immune responses
What are the 3 classes of components in connective tissue?
- cells
- fibres
- ground substance
3 key features of connective tissue?
- doesn’t occur on free surfaces
- has a nerve supply (except cartilage)
- highly vascular (except cartilage and tendons)
What is ground substance?
macromolecules and multi-adhesive glycoproteins that are between cells and fibres
- supports cells
- binds them together
- provides medium through which substances are exchanged e.g. hyaluronic acid
What are the 3 types of fibres found in connective tissue?
- collagen fibres
- elastic fibres
- reticular fibres
Key features of collagen fibres?
- strong, resist forces, flexible
- made of collagen (most abundant protein in the body)
- toughest type of fibre
Key features of elastic fibres?
- smaller in diameter than collagen fibres
- branch to form network
- made of protein elastin
- found in blood vessels , skin etc.
Key features of reticular fibres?
- provide support for walls of blood vessels
- net/mesh-like structure
- made of collagen w/glycoprotein covering
What cell types are found in connective tissue?
- fibroblasts
- macrophages
- mast cells
- adipocytes
What are fibroblasts?
- large flat cells w/branching processes
- migrate throughout connective tissue secreting fibres and ground substance
What are macrophages?
- develop from white blood cells
- surround and engulf material by phagocytosis
What are mast cells?
- alongside blood vessels that supply connective tissue
- produce histamine: chemical that dilates blood vessels
What are adipocytes?
- fat cells
- store triglycerides
What are the 4 main types of connective tissue?
- connective tissue proper
- cartilage
- bone tissue
- blood
What is the function of connective tissue proper?
- binding tissue
- resists mechanical stress especially tension
What cells make up connective tissue proper?
- fibroblasts
- fibrocytes
- defense cells
- fat cells
What is the matrix of connective tissue proper?
- gel like ground substance
- collagen, reticular and elastic collagen
What is connective tissue proper split into?
- loose connective tissue
- dense connective tissue
What is loose connective tissue split into?
- areolar (structural support, lots of ground substance, most common form of loose connective tissue)
- adipose (fat tissue, energy reserve)
- reticular (mesh network, supports spleen etc.)
What is dense connective tissue split into?
- regular (tight collagen fibres e.g. tendon, ligaments etc)
- irregular (skin dermis, irregular formation of collagen)
- elastic (vertebrae)
What are 2 key features of cartilage?
- avascular
- no nerve supply (except perichondrium)
What is the function of cartilage?
- strengthen + support connective tissue
- resists compression
- cushions and support body structures
What cells are found in cartilage?
- chondroblasts (in growing cartilage)
- chondrocytes
What matrix is found in cartilage?
- gel-like ground substance
- fibres: collagen, elastic fibres in some
What are the 3 types of cartilage?
- elastic cartilage
- fibrocartilage
- hyaline cartilage
Key facts about hyaline cartilage?
- gel-like ground substance
- end of long bones to cushion joints + at epiphyseal plates
- found in many articular surfaces
- most abundant cartilage in the body
- weakest of 3 types of cartilage
- chondrocytes have gloss like appearance
Key facts about fibrocartilage?
- chondrocytes scattered among visible bundles of collagen fibres
- strongest of 3 collagen types
- no perichondrium
- found in intervertebral discs
- shock absorbing
- lots of thick collagen fibres
Key facts about elastic cartilage?
- chondrocytes located in threadlike network of elastic fibres
- provides strength, elasticity and maintains shape of certain structures e.g. external ear
- similar to hyaline but w/increased elastin
What is the function of bone tissue?
- resists compression + tension
- protect + support
What cells are in bone tissue?
- osteoblasts
- osteocytes
What is the matrix of bone tissue?
- gel-like ground substance
- calcified with inorganic salts
- fibres: collagen
What are the 2 types of bone tissue (osseous tissue)?
- compact
- spongy
What is compact bone tissue made of?
- OSTEON: basic unit of compact bone
- LAMELLAE: concentric circles of matrix
- LACUNAE: spaces in matrix that house cells
- OSTEOCYTES: mature bone cells
What is spongy bone tissue made of?
TRABECULAE: columns of bone w/spaces filled with red bone marrow
What is the function of blood?
- transport oxygen, CO2, nutrients, waste and other substances
What cells are in blood?
- RBCs (erythrocytes)
- WBCs (leukocytes)
- platelets
What is the matrix of blood?
- liquid
- plasma
- no fibres
Name 2 rheumatological disorders?
- rheumatoid arthritis (RA)
- system lupus erythematosus (SLE)
What is rheumatoid arthritis?
- autoimmune disorder primarily affecting joints resulting in warm, swollen, painful joints
- symptoms typically worse following rest
What is SLE?
- autoimmune disorder of connective tissues, affects multiple organ systems and joints
What are the general macroscopic changes in RA?
- synovitis
- bone
- cartilage
- erosion
- angiogenesis diagram
What are the general microscopic changes in RA?
- cells
- IL
- ANF
- synoviocytes
- osteoclasts
- proteases
- CD4 cells
- plasma cells
- neutrophils
What are the joint changes in RA?
- swollen inflamed synovial membrane
- hyaline cartilage wears away
- reduced joint space
- bone erosion
What immune system factors are involved in RA?
- IL-6: role in inflammation
- TNF-alpha: role in inflammation
- IL-17: role in starting inflammation, cartilage destruction and bone destruction by making cells produce other ILs
Possible causes of RA?
- environmental factors
- epigenetic modifications
- susceptibility genes
likely a combination of factors
Key features of RA?
- symptoms last >6 weeks + often last remainder of life
- inflammatory synovitis = palpable synovial swelling, morning stiffness >1 hr and fatigue
- symmetrical + polyarticular (more than 3/4 joints affected)
Which joints are typically involved in RA?
- typically involves wrists, MCP and PIP joints (metacarpophalangeal and proximal interphalangeal)
What joints are usually spared in RA?
- thoracolumbar spine
- DIPs of fingers and IPs of toes (distal interphalangeal and interphalangeal)
What are the 3 COMMON SYMTOMS of RA?
- JOINT PAIN
- STIFFNESS
- SWELLING
Key differences between RA and osteoarthritis?
- RA = inflammatory, Osteo = degenerative
- RA = autoantibodies, Osteo = no antibodies
- RA = small joints, Osteo = large weight bearing joints (hips, knees, shoulders)
What are some signs of RA?
- may have nodules: subcutaneous or periosteal at pressure points
- rheumatoid factor in blood (not specific for RA but high titre early is bad sign)
- marginal erosions and joint space narrowing on x-ray
What x-ray changes are there in RA?
- soft tissue swelling
- joint space loss
- erosions (juxta-articular)
- subluxation
What are the treatment principles of RA?
- confirm diagnosis
- determine severity
- treatment: start aggressive treatment early, use safest plan that matches aggressiveness of disease
- monitor: treatment for adverse effects, disease activity, revise prescription (Rx) as needed
What are the critical elements of assessment in a treatment plan?
- assess current activity
- document degree of damage
- document extra-articular manifestations
- assess prior Rx responses + side effects
What are the critical elements of therapy in a treatment plan?
- education
- exercise (ROM, conditioning and strengthening exercises)
- medications (analgesic and/or anti-inflammatory, immunosuppressive, cytotoxic + biologic)
What are the drug treatment options for RA?
- NSAIDs - symptomatic relief, improved function, no change in progression
- Low-dose prednisone - may substitute NSAID, bridge therapy
- Intra-articular steroids - useful for flares
- DMARDs- minocycline, sulfasalazine, hydroxychloroquine, intramuscular hold
- immunosuppressive drugs - methotrexate, azathioprine, cyclophosphamide, cyclosporine
What new drugs/DMARDs are being used for RA?
- leflunomide
- etanercept
What extraarticular manifestations of RA are there?
- liver
- cardiovascular
- neurological
- musculoskeletal
- bone marrow
- spleen
What are the common symptoms of SLE?
- alopecia
- malar rash (butterfly skin rash)
- arthralgia
- oral ulcers
- photosensitivity
