Musculoskeletal Flashcards
Define amyloidosis
• Heterogenous group of diseases characterised by extracellular deposition of amyloid fibrils
Explain the aetiology / risk factors of amyloidosis
• Amyloid fibrils are polymers of low-molecular-weight subunit proteins
• These are derived from proteins that undergo conformational changes to adopt an anti-parallel beta-pleated sheet configuration
• Their deposition progressively disrupts the structure and function of normal tissue
• Amyloidosis is classified according to the fibril subunit proteins
o Type AA - serum amyloid A protein
o Type AL - monoclonal immunoglobulin light chains
o Type ATTR (familial amyloid polyneuropathy) - genetic-variant transthyretin
Summarise the epidemiology of amyloidosis
- AA - incidence of 1-5% amongst patients with chronic inflammatory diseases
- AL - 300-600 cases in the UK per year
- Hereditary Amyloidosis - accounts for 5% of patients with amyloidosis
Recognise the presenting symptoms & signs of amyloidosis
- Renal - proteinuria, nephrotic syndrome, renal failure
- Cardiac - restrictive cardiomyopathy, heart failure, arrhythmia, angina
- GI - macroglossia (characteristic of AL), hepatosplenomegaly, gut dysmotility, malabsorption, bleeding
- Neurological - sensory and motor neuropathy, autonomic neuropathy, carpal tunnel syndrome
- Skin - waxy skin and easy bruising, purpura around the eyes (characteristic of AL), plaques and nodules
- Joints - painful asymmetrical large joints, enlargement of anterior shoulder
- Haematological - bleeding tendency
Identify appropriate investigations for amyloidosis and interpret the results
• Tissue Biopsy • Urine - check for proteinuria, free immunoglobulin light chains (in AL) • Bloods o CRP/ESR o Rheumatoid factor o Immunoglobulin levels o Serum protein electrophoresis o LFTs o U&Es • SAP Scan - radiolabelled SAP will localise the deposits of amyloid
Define ankylosing spondylitis
• Seronegative inflammatory arthropathy affecting preferentially the axial skeletal and large proximal joints+A10:B10
Explain the aetiology/risk factors of ankylosing spondylitis
• UNKNOWN
• Strong association with the HA10:B12LA-B27 gene (> 90% of cases are HLA-B27 positive)
• Infective triggers and antigen cross-reactivity with self-peptides have been hypothesised
• Pathophysiology
o Inflammation starts at the entheses (where ligaments attach to vertebral bodies)
o Persistent inflammation leads to reactive new bone formation
o Changes begin in the lumbar vertebrae and progress superiorly
o Vertebral bodies become more square
o Syndesmophytes (vertical ossifications bridging the margins between adjacent vertebrae)
o Fusion of syndesmophytes and facet joints
o Calcification of anterior and lateral spinal ligaments
Summarise the epidemiology of ankylosing spondylitis
- COMMON
* Earlier presentation in males
Recognise the presenting symptoms of ankylosing spondylitis
• Lower back and sacroiliac pain
• Disturbed sleep
• Pain pattern
o Worse in the morning
o Better with activity
o Worse when resting
• Progressive loss of spinal movement
• Symptoms of asymmetrical peripheral arthritis
• Pleuritic chest pain (due to costovertebral joint involvement)
• Heel pain (due to plantar fasciitis)
• Non-specific symptoms (e.g. malaise, fatigue)
Recognise the signs of ankylosing spondylitis on physical examination
- Reduced range of spinal movement (particularly hip rotation)
- Reduced lateral spinal flexion
- Schober’s Test
o Two fingers are placed on the patients back about 10 cm apart
o The patient is asked to bend over
o The distance between the two fingers should increase by > 5 cm on forward flexion
o Reduced movement would suggest ankylosing spondylitis
• Tenderness over the sacroiliac joints
• LATER STAGES:
o Thoracic kyphosis
o Spinal fusion
o Question mark posture
• Signs of Extra-Articular Disease: 5 As o Anterior uveitis o Apical lung fibrosis o Achilles tendinitis o Amyloidosis o Aortic regurgitation
Identify appropriate investigations for ankylosing spondylitis
• Bloods o FBC - anaemia of chronic disease o Rheumatoid factor - negative o ESR/CRP - high • Radiographs o Anteroposterior and lateral radiographs of the spine • May show Bamboo spine
o Anteroposterior radiograph of sacroiliac joints
• Shows symmetrical blurring of joint margins
o LATER STAGES: • Erosions • Sclerosis • Sacroiliac joint fusion o CXR - check for apical lung fibrosis • Lung Function Tests o Assess mechanical ventilatory impairment due to kyphosis
Define gout
• A disorder of uric acid metabolism causing recurrent bouts of acute arthritis caused by deposition of monosodium urate crystals in joints, and also soft tissues and kidneys
Explain the aetiology/risk factors of gout
• The main metabolic disturbance is hyperuricaemia
• This may be caused by:
o Increased urate intake or production
• Increased dietary intake
• Increased nucleic acid turnover (e.g. lymphoma, leukaemia, psoriasis)
• Increased synthesis of urate (e.g. Lesch-Nyhan syndrome)
o Decreased Renal Excretion
• Idiopathic
• Drugs (e.g. ciclosporin, alcohol, loop diuretics)
• Renal dysfunction
Summarise the epidemiology of gout
- 10 x more common in MALES
- Very rare pre-puberty
- Rare in pre-menopausal women
- More common in HIGHER social classes
Recognise the presenting symptoms and signs of gout
• Acute Attack
o Precipitating factors:
• Trauma
• Infection
• Alcohol
• Starvation
• Introduction or withdrawal of hypouricaemic agents
o Symptoms:
• Sudden excruciating monoarticular pain
Usually affecting the metatarsophalangeal joint of the great toe (podagra)
• Symptoms peak at 24 hrs
• They resolve over 7-10 days
• Sometimes, acute attacks can present with cellulitis, polyarticular or periarticular involvement
• Attacks are often recurrent
• Patients are symptom-free between attacks
• Intercritical Gout
o DEFINITION: asymptomatic period between acute attacks
• Chronic Tophaceous Gout
o Follow repeated acute attacks
o Symptoms:
• Persistent low-grade fever
• Polyarticular pain with painful tophi (urate deposits)
Best seen on tendons and the pinna of the ear
• Symptoms of urate urolithiasis (renal calculi symptoms)
Identify appropriate investigations for gout
• Synovial Fluid Aspirate
o Monosodium urate crystals will be seen
o They are: • Needle-shaped • NEGATIVE birefringence under polarised light microscopy o Microscopy and culture will also be performed to exclude septic arthritis • Bloods o FBC - raised WCC o U&Es o Raised urate o Raised ESR • AXR/KUB Film o Uric acid renal stones may be seen
Define fibromyalgia
• A chronic pain disorder with an unknown cause.
Explain the aetiology/risk factors of fibromyalgia
- UKNOWN aetiology
* Thought to be something to do with altered pain perception
Summarise the epidemiology of fibromyalgia
- COMMON
- 10 x more common in WOMEN
- Usual age of presentation: 20-50 yrs
Recognise the presenting symptoms and signs of fibromyalgia
- Pain at multiple sites (MAIN SYMPTOM)
- Fatigue
- Sleep disturbance
- Morning stiffness
- Paraesthesia
- Feeling of swollen joints
- Problems with cognition
- Headaches
- Light headedness
- Anxiety
- Depression
Identify appropriate investigations for fibromyalgia
• CLINICAL diagnosis
• Key features of fibromyalgia:
o Widespread pain involving both sides of the body, above and below the waist for at least 3 months
o Presence of 11 tender points among the 9 pairs of specific sites shown in the diagram below
Define giant cell arteritis
• Granulomatous inflammation of large arteries, particularly branches of the external carotid artery, most commonly the TEMPORAL ARTERY
Explain the aetiology/risk factors of giant cell arteritis
- UNKNOWN
- More common with increasing age
- Some associations with ethnic background and infections
- Associated with HLA-DR4 and HLA-DRB1
Summarise the epidemiology of giant cell arteritis
- More common in FEMALES
* Peak age of onset: 65-70 yrs
Recognise the presenting symptoms of giant cell arteritis
• Subacute onset (usually over a few weeks)
• Headache
• Scalp tenderness
• Jaw claudication
• Blurred vision
• Sudden blindness in one eye
• Systemic: malaise, low-grade fever, lethargy, weight loss, depression
• Symptoms of polymyalgia rheumatica - early morning pain and stiffness of muscles of the shoulder and pelvic girdle
o NOTE: 40-60% of GCA has polymyalgia rheumatica
Recognise the signs of giant cell arteritis on physical examination
- Swelling and erythema overlying the temporal artery
- Scalp and temporal tenderness
- Thickened non-pulsatile temporal artery
- Reduced visual acuity
Identify appropriate investigations for giant cell arteritis
• Bloods
o High ESR
o FBC - normocytic anaemia of chronic disease
• Temporal Artery Biopsy
o Must be performed within 48 hrs of starting corticosteroids
o Negative biopsy doesn’t necessarily rule out GCA
Generate a management plan for giant cell arteritis
- High dose oral prednisolone IMMEDIATELY to prevent visual loss
- Reduce the dose of prednisolone gradually
- Many patients will need to be kept on a maintenance dose of prednisolone for 1-2 yrs
- Low dose aspirin (with PPIs and gastroprotection) - reduces risk of visual loss, TIAs and stroke
- Annual CXR for up to 10 yrs to look for thoracic aortic aneurysms
Identify possible complications of giant cell arteritis
- Carotid artery aneurysms
- Aortic aneurysms
- Thrombosis
- Embolism to the ophthalmic artery leading to visual disturbance and loss of vision
Summarise the prognosis for patients with giant cell arteritis
• In most cases the condition will last for around 2 years before complete remission
o Can detect osteoarthritic change
o Rarely diagnostic if non-traumatic
• MRI
o Allows assessment of root and cord compression
o Helps exclude spinal cord tumour and nerve root infiltration by granulomatous tissue
• Needle Electromyography (EMG)
Define polymyositis and dermatomyositis
• Connective tissue diseases characterised by inflammation of muscles.
Explain the aetiology/risk factors of polymyositis and dermatomyositis
- Autoimmune basis
* Viral infection has been implicated in its pathogenesis
Summarise the epidemiology of polymyositis and dermatomyositis
- Polymyositis presents between 30-60 yrs
- Dermatomyositis can occur at any age (peak onset: 5-10 (children) and 50 (adults))
- Both diseases are 2 x more common in FEMALES
Recognise the presenting symptoms of polymyositis and dermatomyositis
• Polymyositis
o Inflammatory myopathy with onset over weeks or months
o Steady progression of symptoms
o Diffuse weakness in proximal muscles
• Causing difficulty rising from a low chair, climbing steps, lifting objects and combing hair
• Also fatigue, myalgia and muscle cramps
o Distal muscles are spared - so fine motor coordination tends to be preserved in the early stages
o Pharyngeal weakness –> dysphagia
o NO rash
• Dermatomyositis
o Inflammatory myopathy with onset over weeks or months
o RASH
o Systemic upset with fever, arthralgia, malaise and weight loss
o Possible cardiac disease (e.g. conduction blocks, tachyarrhythmia)
o GI ulcers and infections
o Interstitial lung disease (30-50%)
o Children have more non-muscular features (e.g. GI ulcers and infections)
Recognise the signs of polymyositis and dermatomyositis on physical examinations
• Polymyositis o Muscle weakness o NOT painful in most patients o Proximal myopathy o Extraocular muscles and distal muscles are spared o Weak forced flexion of the neck o Muscular atrophy o Muscles may be tender on palpation • Dermatomyositis o RASH characteristics
• Blue-purple discolouration of the upper eyelids with periorbital oedema
• Flat red rash involving the face and upper trunk
• Raised purple-red scaly patches over the extensor surfaces of joints and fingers
o Rash may affect knees, shoulders, back and upper arms
o Rash may be exacerbated by sunlight
o Proximal myopathy
o Muscle pain and tenderness in early disease
Identify appropriate investigations for polymyositis and dermatomyositis
• Polymyositis
o Creatine kinase - up to 50 x higher than normal
o Electromyography (EMG)
o Muscle biopsy - DEFINITIVE TEST
o Autoantibodies (e.g. myositis specific antibody, anti-Jo-1 antibody)
o Enzymes (e.g. SGOT, SGPT, LDH)
• Dermatomyositis
o Creatine kinase - not as reliable as in polymyositis
o Enzymes (SGOT, SGPT and LDH may be raised)
o Autoantibodies
• ANA
• Anti-Mi-2
• Anti-Jo-1 (more common in polymyositis)
o EMG - may be helpful but can be normal as well
o Muscle biopsy
Define pseudogout
• Arthritis associated with deposition of calcium pyrophosphate dihydrate (CPPD) crystals in the joint cartilage
Explain the aetiology/risk factors for pseudogout
• CPPD crystal formation is initiated in cartilage located near the surface of chondrocytes
• It is linked with excessive calcium pyrophosphate production
• This abundance of calcium pyrophoshpate leads to the formation of CPPD crystals
• Shedding of crystals in to the joint cavity leads to acute arthritis
• Most causes of joint damage predispose to pseudogout (e.g. osteoarthritis, trauma)
• Rarer conditions that increase the risk of pseudogout:
o Haemochromatosis
o Hyperparathyroidism
o Hypomagnesaemia
o Hypophosphatasia
• Precipitating factors:
o Intercurrent illness
o Surgery
o Local trauma
Summarise the epidemiology of pseudogout
- 2 x more common in WOMEN
* More common in the ELDERLY
Recognise the presenting symptoms of pseudogout
• Acute Arthritis o Painful o Swollen Joint (e.g. knee, ankle, shoulder, elbow, wrist) • Chronic Arthropathy o Pain o Stiffness o Functional impairment • Uncommon Presentations o Tendonitis o Tenosynovitis o Bursitis
Recognise the signs of pseudogout on physical examination
• Acute Arthritis
o Red o Hot o Tender o Restricted range of movement o Fever • Chronic Arthropathy
o Similar to osteoarthritis o Bony swelling o Crepitus o Deformity o Restriction of movement
Identify appropriate investigations for pseudogout
• Bloods o High WCC in acute attacks o High ESR o Blood culture - to exclude septic arthritis • Joint Aspiration
o Rhomboid, brick-shaped crystals o POSITIVE birefringence o Culture or Gram-staining to exclude septic arthritis • Plain Radiograph of the Joint o Chondrocalcinosis
o Signs of osteoarthritis:
- Loss of joint space
- Osteophytes
- Subchondral cysts
- Sclerosis
Define osteoarthritis
• Age-related degenerative joint disease when cartilage destruction exceeds repair, causing pain and disability
Explain the aetiology/risk factors of osteoarthritis
• Can be classified according to the distribution of affected joints
• Pathogenesis
o Synovial joint cartilage destruction
o Eventually, there is loss of joint volume due to altered chondrocyte activity
o Patchy chronic synovial inflammation
o Fibrotic thickening of joint capsules
• Primary Osteoarthritis
o UNKNOWN aetiology
o Multifactorial causes
• Secondary Osteoarthritis
o Other diseases lead to altered joint architecture and stability
o Commonly associated diseases include:
• Developmental abnormalities (e.g. hip dysplasia)
• Trauma (e.g. previous fractures)
• Inflammatory (e.g. rheumatoid arthritis, gout, septic arthritis)
• Metabolic (e.g. haemochromatosis, acromegaly)
Summarise the epidemiology of osteoarthritis
- COMMON
- 25% of those > 60 yrs
- More common in FEMALES, CAUCASIANS and ASIANS
Recognise the presenting symptoms of osteoarthritis
• Joint pain and discomfort o Use-related • Stiffness or gelling after inactivity • Difficulty with certain movements • Feelings of instability • Restriction walking, climbing stairs and doing manual tasks • Systemic features are usually absent