Other MSK Knowledge Flashcards
What are the 3 main types of joint?
Fibrous
Cartilaginous
Synovial
What are some examples of fibrous joints?
Peridontal ligament
Cranial sutures
Interosseus membranes
What is the difference between a primary and secondary cartilaginous joint?
Primary - only hyaline cartilage.
Secondary - has both hyaline cartilage and fibrocartilage.
What are some examples of cartilaginous joints?
Synchrondrosis (primary) between arm or leg bone ends.
Symphysis (secondary) intervertebral discs.
What are some common features of synovial joints?
Synovial cavity that is fluid filled.
Articular cartilage present between 2 articular heads.
Fibrous capsule
Synovial membrane.
What are some different types of synovial joints?
Plane e.g. acromiocoricoid joint. Hinge e.g. elbow joint Pivot e.g.radiculoulnar joint Condylar e.g. axis of skull Saddle e.g. sternoclavicular joint Ball and socket e.g. glenohumeral joint
What provide joint stability?
Shape of articulating surfaces
Capsule and ligaments
Muscles
What are some characteristics of articular (hyaline) cartilage?
Superficial layer has flattened chondrocytes that produce collagen and glycoproteins e.g. lubricin.
Transitional layer has round chondrocytes that produce proteoglycans such as aggrecan.
> 75% water which makes it incompressible.
What are glycoproteins?
Proteins to which oligosaccharide chains are attached.
More protein than carb.
What are proteoglycans?
Proteins that are heavily glycosylated.
Tend to be more carb than protein. E.g. aggrecan.
What are glycosaminoglycans (GAGs)?
Long unbranched polysaccharides which are highly polar and thus attract water.
E.g. hyaluronic acid
What is the average thickness of articular cartilage?
2-3mm
Interphalangeal joint it is 1mm
Patella it is 5-6mm
How does cartilage get nutrients and remove waste if it is avascular?
Synovial fluid produced by synovial membrane provides these features for cartilage.
What are the features of the synovium?
Synoviocytes produce fluid
Rich capillary network present
No epithelial lining
Direct exchange of oxygen, carbon dioxide and metabolites between blood and synovial fluid.
What are the characteristics of type A synoviocytes?
Look like macrophages
Remove debris from synovial cavity.
Contribute to synovial fluid production.
What are the characteristics of type B synoviocytes?
Fibroblast like
Main producer of synovial fluid.
What is synovial fluid?
Fluid that fills synovial cavity of joints. Mixture of hyaluronic acid and lubricin. Fluid component if from blood plasma.
Very viscous.
What are the functions of synovial fluid?
Provide nutrition for cartilage
Remove waste products from cavity.
Provide lubrication to protect the joint from damage.
How does synovial fluid provide lubrication?
Glycoproteins such as lubricin bind to receptors on articular surfaces to form a thin film.
Surfaces are kept apart by liquid pressure and the viscosity changes with load and velocity of movement.
Fluid present within cartilage is squeezed out into the synovial cavity to increase fluid volume.
What are bursae?
Fluid filled pouch that provides cushioning and protecting to certain joints. Produced by synovial membrane they also help to reduce friction.
How does ageing affect synovial joints?
Viscosity of synovial fluid increases with age so there is slower joint movements and reduced lubrication.
Water content of cartilage decreases so there is reduced shock absorption.
Less protection of articular surface and increased risk of damage.
What are the signs of osteoarthritis?
Bone spurs
Loss of joint space
Loss of articular cartilage
What is an infection in the bone called?
Osteomyelitis
What is an infection in the joint called?
Septic arthritis
What are risk factors for acute osteomyelitis?
Children Boys>girls History of trauma DM Rheumatoid arthrits Immune compromise Long term steroid treatment Sickle cell disease
What are some common sources of infection in acute osteomyelitis?
Haematogenous spread - children and elderly e.g infected umbilical cord, boils, tonsilitis, skin abrasions, UTI, arterial line.
Local spread from contiguous site of infection e.g. surgery, trauma, joint replacement.
Secondary to vascular insufficiency.
What are the most common infecting organisms of acute osteomyelitis?
Staph Aureus Group B streptococci E.coli Strep pyogenes Haemophilus influenzae Mycobacterium tuberculosis Coagulase negative staphylococci Pseudomonas aeroginosa.
What are some less common causative organisms of osteomyelitis?
Diabetic foot and pressure sores - mixed infection including anaerobes.
Sickle cell disease - salmonella spp.
Mycobacterium marinum (fishermen, filleters)
Candida (debilitating illness, HIV, AIDS).
Where does acute osteomyelitis usually occur?
Long bones at the metaphysis e.g. distal femur, proximal tibia, proximal humerus.
Joints with intra-articular metaphysis e.g. hip, elbow.
What are the stages of progression of acute osteomyelitis?
Starts at metaphysis
Vascular stasis (venous congestions and arterial thrombosis)
Acute inflammation leading to increased pressure.
Suppuration
Release of pressure (medulla, sub-periosteal, into joint)
Necrosis of bone (sequestrum)
New bone formation (involucrum)
Resolution or if not then chronic.
What are the clinical features of osteomyelitis in infants?
May have minimal signs or may be very ill. Failure to thrive Drowsiness Irritability Metaphyseal tenderness and swelling Decrease in ROM Positional change Commonest around the knee.
What are the clinical features of osteomyelitis in children?
Severe pain Reluctant to move Not weight bearing Neighbouring joints held flexed Tender fever Tachycardia Malaise Toxaemia
What are the clinical features of osteomyelitis in adults?
Primary OM seen commonly in throacolumbar spine.
Backache
History of UTI or urological procedure.
Elderly, diabetic and immunocompromised are common.
Secondary OM is much more common often after an open fracture, surgery and is caused by a mixture of organisms.
How is acute osteomyelitis diagnosed?
History and clinical exam (pulse and temp) FBC + diff WBC (neutrophil leucocytosis) ESR CRP Blood cultures x3 at peak of temperature. U&Es X-ray Ultrasound Aspiration Isotope bone scan Labelled white cell scan MRI
What is gas gangrene?
Grossly contaminated injury due to trauma commonly caused by clostridium perfringens.
What is the treatment for acute osteomyelitis?
Supportive for paining dehydration - general care and analgesia.
Rest and splintage
Antibiotics for 4-6weeks switch from IV to oral after 7-10days. Use Fluclox + BenzylPen while waiting for blood cultures.
Surgery
What are the indications for surgery in acute osteomyelitis?
Aspiration of pus for diagnosis and culture.
Abscess drainage
Debridement of dead/infected/contaminated tissue
Resistant to non-operative treatment.
What are some complications of acute osteomyelitis?
Septicemia Death Metastatic infection Pathological fracture Septic arthritis Altered bone growth Chronic osteomyelitis
What is chronic osteomyelitis?
Related breakdown of healed wounds often due to a mixed infection. However each flare up it is usually the same organisms.
Staph aureus, e.coli , strep pyogenes and proteus.
Where does chronic osteomyelitis most commonly affect?
Cavities and sinuses
Dead bone
Involucrum
What are some complications of chronic osteomyelitis?
Chronically discharging sinus and flare ups. Ongoing metastatic infection Pathological fracture Growth disturbance and deformities Squamous cell carcinoma (rare).
What is the treatment for chronic osteomyelitis?
Long term antibiotics - local (gentamicin cement/beads, collatamp) and systemic (oral/IV/home) Eradicate bone infection surgically Treat soft tissue problems Deformity corrections reconstruction Amputation.
What is the route of infection for acute septic arthritis?
Haematogenous
Eruption of bone abscess
Direct invasion - penetrating wound, intra-articular injury, arthroscopy.
Which organisms commonly cause acute septic arthritis?
Staph aureus
Haemophilus influenzae
Strep progenes
E.coli
What are the features of acute septic arthritis?
Acute synovitis with purulent joint effusion
Articular cartilage attacked by bacterial toxin and cellular enzymes.
Complete destruction of the articular cartilage.
What may follow having acute septic arthritis?
Complete recovery
Partial loss of articular cartilage and subsequent OA.
Fibrous or bony ankylosis.
What is ankylosis?
Abnormal stiffening of joints and/or mobility due to fusion of bone.
How does septicaemia present in a neonate?
Irritability
Resistant to movement
Ill
How does acute septic arthritis present in children and adults?
Acute pain in single large joint. Reluctant to move the joint. Increased temperature and pulse Increased tenderness Often involves superficial joint (knee, ankle, wrist)
What investigations would you carry out for acute septic arthritis?
FBC WBC ESR CRP Blood cultures X-ray Ultrasound Aspiration
What is the treatment for acute septic arthritis?
General supportive measures
Antibiotics for 3-4weeks
Surgical drainage and lavage if emergency.
What are the different classifications of tuberculosis in bone and joints?
extra-articular - epiphyseal/bones with haemodynamic marrow.
Intra-articular - large joints
Vertebral body.
What are some clinical features of tuberculosis in bones and joints?
Insidious onset and general ill health. Contact with TB Pain esp at night Swelling Weight loss Joint swelling Decrease ROM Ankylosis Deformity
How is tuberculosis in bones/joints diagnosed?
Long history Involvement of single joint Marked thickening of synovial Marked muscle wasting Periarticular osteoporosis.
What investigations would you carry out for suspected TB?
FBC ESR Mantoux test Sputum/urine culture X-ray - soft tissue swelling, periarticular osteopaenia, articular space narrowing. Joint aspiration and biospy.
What is the treatment for bone and joint TB?
Chemotherapy - rifampicin, isoniazid and ethambutol for 8 weeks then rifampicin and isoniazid for 6-12months.
Rest and splintage
Operative drainage in rare cases.
What are some examples of connective tissue diseases?
Systemic lupus Erythematosus Scleroderma Sjogren's syndrome Auto-immune myositis Mixed connective tissue disease.
What are some examples of systemic vasculitis?
Giant cell arteritis
Granulomatosis polyangitis
Microscopic polyangitis
Eosinophilic granulomatosis polyangitis
What is the classification criteria for systemic lupus?
Any 4 of the following:
Malar rash
Discoid rash (raised, scarring permanent marks)
Photosensitivity
Oral ulcers
Arthritis in at least 2 joints
Serositis (pleurisy or pericarditis).
Renal - significant proteinuria or cellular casts in urine.
Unexplained seizures or psychosis
low WCC, platelets, lymphocytes, haemolytic anaemia
Immunological - anti ds-DNA, SM, cardiolipin, lupus anticoagulant, low complement.
ANA
What is Scleroderma?
A chronic autoimmune condition that affects the skin, connective tissue, and internal organs. Body makes too much collagen.
What are some common symptoms of Scleroderma?
Hardening of the skin Swelling of hands and feet Joint pain and stiffness Raynuad's syndrome Morphea - shiny patches of hard skin that usually appear on trunk.
What are the 2 types of scleroderma?
Limited - gradually progressing condition that usually affects face, skin, forearms, legs below knee. Lungs and digestive system may be involved over time.
Diffuse - More likely for whole body to be affected, with serious complication involving heart, lungs and kidneys.
What is Sjogren’s Syndrome?
Autoimmune condition that affects parts of the body that produce fluids such as tears and saliva.
What are the symptoms of sjogren’s syndrome?
Dry eyes, mouth and skin Tiredness Vaginal dryness Joint/Muscle pain Swelling between jaw and ears Rash especially after being out in the sun.
What are some complications of Sjogren’s syndrome?
Lymphoma Neuropathy Purpura Interstitial lung disease Renal tubular acidosis
What is Autoimmune myositis?
Group of autoimmune rheumatic disorders that cause inflammation and weakness in muscles or in the skin. Very rare.
What are some symptoms of autoimmune myositis?
Symmetrical, diffuse, proximal muscle weakness. Heliotrope rash Gottron's papules Fatigue after walking or standing. Joint pain or swelling Malaise Dysphagia
What are some complications of autoimmune myositis?
Interstitial lung disease
Cancer
What is mixed connective tissue disease?
A rare autoimmune disorder that is characterised by features commonly seen in three different connective tissue disorders: systemic lupus erythematosus, scleroderma, and polymyositis. Some affected people may also have symptoms of rheumatoid arthritis.
What are some examples of large vessel vasculitis?
Takayasu arteritis - granulomatous inflammation of the aorta and its major branches.
Giant Cell arteritis - immune system attacks blood vessels especially temporal arteries.
What are some examples of medium vessel vasculitis?
Polyarteritis nodosa - blood vessel injury resulting in damaged organs. Heart, intestines, nerves and joints usually affected.
Kawasaki disease - mucocutaneous lymph node syndrome. Normally affects < 5s.
What are some examples of small vessel vasculitis?
Microscopic polyangitis
Eosinophilic Granulomatosis with polyangiosis.
Anti-GBM disease
Cryoglobulinemic vasculitis
IgA Vasculitis
Hypocomplementemic urticarial vasculitis.
What is the classification criteria for Giant Cell Arteritis?
3 of the following: age at onset >50yrs New headache Temporal artery tenderness/reduced pulsation ESR> or = 50 Abnormal temporal biopsy.
What are some specific targets on ANA profiles of SLE, scleroderma, polymyositis and Sjogren’s syndrome?
SLE - dsDNA, Ro, Sm
Scleroderma - Scl-70, centromere
Polymyositis - Jo-1
Sjogren’s disease - Ro, La
What are some treatment options for multi-system autoimmune diseases?
Mild - Hydroxychloroquine
Moderate - Azathioprine, Methotrexate, Mycophenolate.
Severe - Cyclophosphamide, Rituximab.
What is it called if the spine is not straight in the coronal plane?
Scoliosis
What 3 muscle groups make up the erector spinae?
Iliocostalis
Longissimus
Spinalis
What are the myotomes of the upper limb?
C5 - shoulder abduction (deltoid). C6 - Elbow flexion/wrist extensors (biceps) C7 -Elbow extensors (triceps) C8 - Long finger flexors (FDS/FDP) T1 - Finger abduction (interossei).
What are the myotomes of the lower limb?
L2- hip flexion (iliopsoas)
L3/4- knee extension (quadriceps)
L4 - Ankle dorsiflexion (tibialis anterior)
L5 - Big toe extension (EHL)
S1 - Ankle plantar flexion (gastrocnemius)
What are the features of a complete spinal cord injury?
No motor or sensory function distal to lesion No anal squeeze No sacral sensation ASIA grade A No chance of recovery
What are the features of an incomplete spinal injury?
Some function is present below site of injury
More favourable prognosis overall.
What is the ASIA classification?
Grade A - Complete. NO sensory or motor function preserved in sacral segments.
B - incomplete. Sensory but no motor function.
C - Incomplete. Motor function preserved below the neurologic level, majority of key muscles have grade < 3.
D - Imcomplete. Motor function preserved below neurological level and majority of key muscles have grade > 3.
E - normal motor and sensory function.
What is tetraplegia?
Partial or total los of use of all 4 limbs and the trunk.
Loss of motor/sensory function in cervical segments of the spinal cord.
Usually caused by a cervical fracture.
What are features of spasticity?
Increased muscle tone
UMNL
Spinal cord and above (CNS)
injuries above L1
What is paraplegia?
partial or total loss of use of the lower-limbs.
Impairment or los son motor/sensory function in thoracic, lumbar or sacral segments.
Arm function spared.
Bladder/bowel function affected.
What are some examples of partial cord syndromes?
Central cord syndrome
Anterior cord syndrome
Brown-Sequard syndrome
What are the features of central cord syndrome?
Older patient Hyperextension injury. Central cervical tracts more involved. Weakness of arms>legs Perianal sensation & lower extremity power persevered
What are the features of anterior cord syndrome?
Hyperflexion injury Anterior compression fracture Damaged anterior spinal artery. Fine touch and proprioception preserved. Profound weakness Poor prognosis
What are the features of Brown-Sequard Syndrome?
Hemi-section of cord
Penetrating injuries
Paralysis on affected side.
Loss of proprioception and fine discrimination.
Pain and temperature loss on opposite side below the lesion.
What are some neuroprotective interventions that can be done to prevent a second SCI?
In-field stabilisation
ATLS (advanced trauma life support) resuscitation
Pharmacologic agents
Prompt medical/surgical care
What is spinal shock?
Transient depression of cord function below level of injury.
Flaccid paralysis
Areflexia
Last several hours to days after injury.
What is the pathological process of disc prolapse?
Tearing of annulus fibrosis and protrusion of the nucleus.
Nerve root compression by osteophytes
Central spinal stenosis
Abnormal movement - spondylolysis, spondylolisthesis.
What is sequestration of a disc?
Desiccated disc material is free in spinal canal.
What is caudal equina syndrome?
Compression of caudal equina.
Surgical emergency!
Can result in permanent bladder and anal sphincter dysfunction and incontinence.
What are some causes of caudal equina syndrome?
Central lumbar disc prolapse Tumours Trauma Infection Iatrogenic
What are the clinical features of cauda equina syndrome?
Injury or precipitating event Bilateral buttock /leg pain, weakness and dysaethesiae. Bowel and/or bladder dysfunction. Saddle anaesthesia Urinary retention
What is lumbar spondylosis?
Osteoarthritis of facet and disc joints and degeneration of ligaments.
What is spinal claudication?
Usually bilateral
Sensory dysaethesiae
Possible weakness
Takes several minutes to ease after stopping walking.
Worse walking down hills because the spinal canal becomes smaller in extension.
What is the treatment for spinal stenosis?
Non operative - nerve root injection, epidural injection.
Surgery.
