13. Introduction to diseases of the musculoskeletal system

Question 1

tendonitis

Answer 1

Tendon problem.

Question 2

bursitis

Answer 2

Inflammation of bursa. Bursae are synovial membrane lined pockets that serve to allow free movement of adjacent structures where otherwise, there could be friction.

Question 3

enthesitis

Answer 3

Inflammation of an enthesis. Entheses are the points where tendons, ligaments or joint capsules insert into bone. The largest site is the Achilles insertion.

Question 4

Osteoperosis

Answer 4

reduced bone density

Question 5

osteomalacia

Answer 5

poor bone mineralisation

Question 6

osteomyelitis

Answer 6

bone infection

Question 7

osteosarcoma

Answer 7

an example of malignant bone tumour

Question 8

myalgia

Answer 8

• Pain in muscles.
• Very common.
• Commonly associated with viral infections.
• Can be drug induced (eg by statins).

Question 9

myositis

Answer 9

Inflammation of the muscles.

Far less common than myalgia and can be autoimmune

Question 10

what is a joint?

Answer 10

A joint is formed where two or more bones meet each other

This is an example of a normal joint

Question 11

Approach to a patient with a musculoskeletal disorder

Answer 11

Full history
& } Often enough to
Physical examination make a diagnosis

Serological tests – help to support the diagnosis

Question 12

Some ways of classifying rheumatic disease

Answer 12

Articular or Non articular/ Periarticular
Inflammatory or non-inflammatory/degenerative/mechanical

number of joints affected - suspect infection in all acute monoarthritis
duration of onset

Question 13

Periartciular joint pain

Answer 13

Point tenderness over the involved structure,
Pain reproduced by movement involving that structure
then think about which structure? bursa, tendon, tendon sheath, ligament, others?

Question 14

articular joint pain

Answer 14

joint line tenderness
pain at the end range of movement in any direction
inflammatory or mechanical? any signs of inflammation? features of mechanical problems? locking, catching etc

Question 15

joint inflammation nomenclature

Answer 15

MonoARHRITIS – arthritis affecting 1 joint

OligoARTHRITIS – arthritis affecting 4 or fewer joints (2-4)

PolyARTHRITIS – arthritis affecting 5 or more joints (>=5)

Question 16

Soft tissue conditions

Answer 16

Problems with radiolucent moving tissues
Very common, part of everyday life

Some examples:

- tennis elbow (lateral epicondylitis) 
- golfers elbow (medial epicondylitis) 
- carpal tunnel (median nerve compression as it passes through the carpal tunnel in the wrist)

Question 17

importance of rheumatic disease

Answer 17

Common and getting more common
Expensive
Important
Leading cause of disability

Question 18

Worldwide impact of rheumatic disease

Answer 18

MSK disorders are the second most common cause of disability worldwide, measured by years lived with disability (YLDs)
Low back pain is the single leading cause for disability globally
Disability due to MSK disorders is estimated to have increased by 45% from 1990 to 2010, in particular OA, and is expected to continue to rise with an increasingly obese, sedentary and ageing population.

Question 19

UK impact of rheumatoid disease

Answer 19

Third greatest impact on the health of the UK population, considering both death and disability (Lancet 9 March 2013)
– Musculoskeletal disorders account 15.6%
– Low back pain accounts for over half of this
– Ranking of major causes of death and disability

Question 20

MSK disorders and work

Answer 20

Poor musculoskeletal health is a major barrier to workplace participation. People with musculoskeletal conditions are less likely to be employed than people in good health, and more likely to retire early.

Question 21

Septic arthritis

Answer 21

Differential diagnosis of hot swollen joint is wide – ALWAYS consider joint aspiration and gram stain

The commonest organisms are staph and strep

Question 22

Septic arthritis

Answer 22

Always think about it in a patient with a (usually) single, hot and swollen joint.
Mortality rates are of 11%. This increases to 50% in polyarticular disease with sepsis.

They do not have to be systemically unwell and they may be able to weight bear.

Seek senior advice. Do not delay antibiotic therapy.

Question 23

Gout

Answer 23

Most common inflammatory arthropathy worldwide

• Serum urate levels > physiological saturation point (around 408 μmol/L)

Monosodium urate crystals form and deposit in cartilage, bone and periarticular tissues of peripheral joints

Question 24

Clinical aspects of gout

Answer 24

Crystal deposition is often clinically silent
About 10% of people with hyperuricaemia develop clinical gout
UK GP Studies show the prevalence of gout per 1,000 has been steadily increasing from 2.6 in 1975, to 3.4 in 1987, and 9.5 in 1993
1 in 40 adults in the UK is affected by gout= 2.5% - 15 years analysis (2014)
Clinical cure is achievable with treatment which is cheap, widely available, and under-prescribed

Question 25

Who gets gout?

Answer 25

Men aged 40 years and over Women over 65 years. It increases with age, affecting 15% of men aged over 75 in the United Kingdom Epidemiological studies show that the metabolic syndrome and its components (insulin resistance, obesity, hyperlipidaemia, and hypertension) are strongly associated with gout

Question 26

gout risk factors

Answer 26

Male sex, older age Genetic factors (mainly reduced excretion of urate) Chronic kidney disease (reduced excretion of urate) Metabolic syndrome, obesity, hypertension, hyperlipidaemia, loop and thiazide diuretics (reduce urate excretion) osteoarthritis (enhanced crystal formation) deitary factors (increased production of uric acid)

Question 27

Gout crystals

Answer 27

Gout is caused by negatively birefringent rods – monosodium urate Pseudogout (CPPD) by positively birefringent rhomboids – calcium pyrophosphate

Question 28

Gout management

Answer 28

Acute attacks: NSAIDs e.g. naproxen, colchicine, steroids Long-term: urate-lowering therapy e.g. allopurinol or febuxostat

Question 29

Rheumatoid arthritis

Answer 29

Common, chronic, multisystem inflammatory condition affecting up to 0.5-1% of world population More common in women (3:1). Peak onset is 45-65 years Unknown cause with around 30% genetic susceptibility and the rest environmental

Question 30

Main problem in rheumatoid arthritis

Answer 30

The main problem in inflammatory arthritis is with the SYNOVIUM whereas in osteoarthritis, the main problem is with the CARTILAGE

Question 31

What is the most important environmental risk factor for rheumatoid arthritis?

Answer 31

smoking

Question 32

rheumatoid arhritis pathophysiology

Answer 32

``` Early lymphocyte invasion of synovium Acute inflammatory reaction - swelling and increased vascular permeability synovial proliferation pannus formation cartilage destruction and bone erosion ```

Question 33

Symptoms and signs of rheumatoid arthritis

Answer 33

Onset varies, can be acute or chronic Symmetrical pain and boggy swelling of the small joints of the hands and feet (MCP, PIP, wrist, MTP, subtalar, NOT the DIPs) early morning stiffness > 1 hour malaise and fatigue are common systemically unwell examination - look for pain, swelling and restriction of movement also really important to examine other organ systems as RA is a systemic disease

Question 34

Extra-articular manifestations of RA

Answer 34

``` nodules (20%) bursitis/tenosynovitis eyes: dry eyes (secondary Sjogren's)/scleritis/scleromalacia splenomegaly (Feity's) Anaemia of chronic disease Lung fibrosis/effusion/nodules (Caplan's) pericarditis neurological: atlanto-axial sublucation/carpal tunnel syndrome/mononeuritis multiplex renal amyloidosis (RA) leg ulcers/pyoderma gangenosum vasculitis increased risk of CVD ```

Question 35

RA investigations

Answer 35

ESR and CRP FBC: anaemia of chronic disease (normochromic normocytic) rheumatoid factor positive - IgM antibody against Fc portion of human IgG antibodies (but this can be falsely elevated by illness and are normally raised in 1/20 of population) Anti CCP antibodies - cyclic citrullinated peptide antibodies (antigen present on inflamed synovium - 98% specific for RA diagnosis) X-rays: normal in early disease... erosions/peri-articular osteoperosis and reduced joint space/cysts

Question 36

RA principles of management

Answer 36

Early and aggressive treatment to reduce inflammation and joint damage -> Non-steroidal anti-inflammatory drugs for short periods -> Corticosteroids: intra-articular joint injections if only 1 or 2 troublesome. Systemic if many joints are problem - main routes are IM or PO though in severe disease maybe IV

Question 37

RA drugs

Answer 37

DMARDs (disease modifying anti-rheumatoid drugs) | biologic agents

Question 38

Synthetic DMARDs

Answer 38

Methotrexate Sulfasalazine Hydroxychloroquine Leflunomide

Question 39

Biologic agents

Answer 39

Anti TNF agents ( Etanercept, Adalimumab, Infliximab) Anti B-cell (Rituximab) Anti Interleukin-6 receptor blocker (Tociluzumab) Anti T-cell – selective co-stimulation modulator- CTLA4-Ig (Abatacept) Janus kinase inhibitor (JAK 2) (Tofacinitib, Baricitinib)

Question 40

Multidisciplinary aspects of RA management

Answer 40

Multidisciplinary team input – Nurse specialist (education and disease monitoring) – Physiotherapy (improve strength and stamina) – Occupational Therapy (work, home environments) – Podiatry

Question 41

Osteoarthritis

Answer 41

Common, degenerative disease of which the prevalence increases with age Affects 70% of over 65 years olds Most commonly clinically affects the knees, hips and small joints of the hands (DIP, PIP, 1st CMCJ) Characterised by joint pain and very variable degrees of functional limitation

Question 42

Osteoarthritis pathophysiology

Answer 42

Metabolically active, dynamic process involving all joint tissues (cartilage, bone, synovium, capsule, ligaments/muscles) -> Focal destruction of articular cartilage -> Remodelling of adjacent bone = hypertrophic reaction at joint margins (osteophytes) -> Remodelling and repair process (efficient but SLOW) -> Secondary synovial inflammation and crystal deposition

Question 43

Clinical features of osteoarthritis

Answer 43

``` Age > 50 years Morning stiffness < 30 minutes Persistent joint pain aggravated on use Crepitus NO INFLAMMATION Bony enlargement and/or tenderness ```

Question 44

Osteoarthritis investigations

Answer 44

A clinical diagnosis Blood tests not helpful X-rays do not correlate well with symptoms

Question 45

OA management

Answer 45

physiotherapy, weight loss if overweight/obese, education and advice NSAIDS, paracetamol opioids, capsaicin, intra-articular corticosteroid injections, local heat and cold, joint arthoplasty, supports and braces, shock-absorbing shoes, manual therapy (manipulation and stretching)

Question 46

Systemic lupus erythmatosus

Answer 46

Chronic, relapsing, remitting disease Broad spectrum of clinical features involving almost all organs and tissues Prevalence in the UK: 97 per 100,000 F:M= 10-20:1 Peak onset between 15- 40 years More common and severe in those of Afro-Caribbean, India, Hispanic and Chinese origin living in USA and Europe> Caucasians

Question 47

PATHOPHYSIOLOGY

Answer 47

UV light results in cell death (apoptosis) but cells not cleared quick enough, there is abnormal immune response and autoantibodies are formed, leads to inflammation systematically leading to damage

Question 48

Classification criteria for SLE

Answer 48

4 of 17 factors have to apply (at least 1 clinical) or biopsy-proven nephritis compatible with SLE in presence of ANA antibodies or anti-dsDNA antibodies

Question 49

SLE investigations

Answer 49

``` Urinalysis - urinary protein:creatinine ratio full blood count urea and electrolytes ESR CRP liver function test antibodies: ANA, ENA, Anti-dsDNA, lupus anticoagulant, anti C1q C3, C4 ```