Musculoskeletal System Notes PDF

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Musculoskeletal Osteoarthritis (Degenerative Arthritis) Definition A degenerative disease of joints resulting from wear of the articular cartilage, which may lead to secondary changes in the underlying bone. Can be primary (no obvious predisposing factor) or secondary due to damage to the cartilage ...

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Musculoskeletal Osteoarthritis (Degenerative Arthritis) Definition A degenerative disease of joints resulting from wear of the articular cartilage, which may lead to secondary changes in the underlying bone. Can be primary (no obvious predisposing factor) or secondary due to damage to the cartilage from inflammation or trauma e.g. intraarticular fractures. It is the most common joint condition. Joint involvement is asymmetrical in OA in comparison to RA and there is no systemic features or marked early morning stiffness as with RA. Only transient stiffness occurs after rest up to 30mins. Symptoms 1. Painful movement (worse at end of day) 2. Decreased range of movement 3. Joint Tenderness commonly DIP, thumb, carpo-metacarpal joints and knees 4. Background pain at rest 5. Joint gelling-stiffness after rest 6. Joint Instability 7. In the knee: Varus or valgus deformity 8. Derangement 9. Mild synovitis Signs 1. Deformity 2. Crepitus 3. Heberden’s Nodes (DIP) bony swelling 4. Bouchard’s Nodes (PIP) bony swelling Pathophysiology Result of active reparative process (often with inflammation) rather than due to trauma and ageing. Characterised by progressive destruction and loss of articular cartilage. The exposed subchondral bone becomes sclerotic, with increased vascularity and cyst formation. Attempts at repair produce cartilaginous growths at margins which later calcify (osteophytes). These bone changes, together with the inflammation, can be both painful and debilitating. Investigations Plain radiographs show LOSS Loss of joint space (due to loss of cartilage) Osteophytes Subchondral sclerosis Subchondral cysts Management 1. Patient Education-encourage moderate exercise to improve muscle strength and joint stability. Also assist patient with weight-loss if necessary. 2. Regular Paracetamol +/- Codeine is first line treatment, topical NSAIDs for knee and hand involvement (consider oral NSAIDs+PPI if paracetamol ineffective but use intermittently) 3. Intra-articular steroid injection (temporary symptomatic relief), no systemic corticosteroids 4. Surgery- joint replacement or realignment

Rheumatoid Arthritis (Inflammatory Arthritis) Definition A chronic, autoimmune, inflammatory disease, characterised by symmetrical, deforming, peripheral polyarthritis. There is extra-articular involvement e.g. the lungs. Prevalence is 1% with a greater risk in smokers. Pre-menopausal women have a 3x greater risk than men, with equal gender incidence thereafter. Differential diagnosis  Psoriatic arthritis  Sjogrens  Lupus Clinical Features Diagnosis of RA if ≥4 are present out of the 7 criteria RF RISES Rheumatoid factor Finger/hand joint involvement (PIP, MCP, wrist not DIP) Rheumatoid nodules Involvement of ≥3 joints Stiffness- early morning lasting for >30mins (distinguishing feature) Erosions/decalcification on x-rays Symmetrical arthritis of hands and feet Other symptoms may include: 1. Joint Effusions 2. Joint Instability 3. Subluxation (partial dislocation) 4. Muscle Wasting 5. Deformity 6. Sudden onset widespread arthritis (less common) Extra-Articular Symptoms (SEN RHCRO) 1. Systemic: pyrexia, fatigue, weight loss 2. Skin: rheumatoid nodules in elbows, extensor surface of the ulnar, finger joints, Achiles tendon, pyoderma gangrenosum, palmar erythema, vasculitic lesions (Bywater’s lesions around nail folds and leg ulcers) 3. Eyes: Sjogren’s syndrome, episcleritis, scleritis, keratoconjunctivitis sicca, scleromalacia 4. Neurological: entrapment neuropathies, peripheral neuropathy, atlanto-axial sublaxation, carpal tunnel syndrome 5. Respiratory: pulmonary nodules, pleural effusion, fibrosing alveolitis, obliterative bronchiolitis, Caplan’s syndrome (RA + pneumoconiosis) 6. Haematological: anaemia (very common), thrombocytosis 7. CVS: endocarditis, myocarditis, pericarditis 8. Renal: Amyloidosis 9. Other: Lymphadenopathy, Raynaud’s, Felty’s syndrome (RA + splenomegaly + neutropenia) Signs 1. Spindling of fingers due to swelling of PIP and not DIP 2. Bursitis 3. Ulnar deviation of fingers 4. Boutonniere deformities (hyperflexion of PIP, hyperextension of DIP) 5. Swan-neck deformities (hyperflexion of DIP, hyperextension of PIP) 6. Z-shape thumb

7. Trigger finger- nodule is present at base of finger which becomes stiff and stuck when extending flexed finger as tendon cannot pass smoothly through pulley (thumb, index or middle finger). Aetiology & Pathophysiology Cause is unknown but the initiating event is thought to be the activation of synovial T cells by an unknown antigen. RA is characterised by synovitis, which occurs secondary to hyperplasia of synovial cells, excess synovial fluid, and the development of pannus (proliferation of synovium) .The pannus grows out of the cartilaginous surface and destroys articular cartilage and subchondral bone, producing bony erosions. Chronic synovitis is maintained by rheumatoid factors and continuous stimulation of macrophages. Investigations 1. Bloods- Increased ESR, platelets and CRP due to inflammation as well as normochromic, normocytic anaemia. 2. Serum Autoantibodies- Rheumatoid Factor (RhF) is positive in approximately 70%. RhF is not specific for RA however, and can occur in connective tissue diseases. Anti-cyclic citrullinated peptide antibodies (anti-CCP) are highly specific (98%) for RA and can be used to distinguish erosive RA from acute transient synovitis. 3. Radiography- shows soft tissue swelling initially and later joint narrowing, bony erosions and porosis of periarticular bone and cysts. Management No cure, therapeutic aims are remission of symptoms. Management requires and MDT approach. Smoking cessation reduces risk of cardiovascular disease. 1. DMARDs- are first line and should be used within 3 months of diagnosis to prevent irreversible effects of long-term inflammation. DMARDS inhibit cytokines to reduce inflammation and slow development of joint erosions. Take up to 6 months to achieve maximum effect. E.g. Methotrexate (starting at 7.5mg weekly), Hydroxychloroquine, Leflunomide and Sulfasalazine. All cause side-effects (e.g.myelosuppression) so regular monitoring of blood is necessary. With methotrexate, folic acid 5mg weekly should be co-prescribed. 2. NSAIDs- relieve joint pain and stiffness but do not slow disease progression. Try several different drugs to find most suitable as there is individual response variability. Slow release preparations e.g. diclofenac may produce dramatic relief of symptoms on the following day. 3. Corticosteroids- rapidly reduce inflammation and other symptoms, avoid giving before seeing a rheumatologist as they mask symptoms. Seldom used except in the elderly or those with explosive RA or severe extra-articular manifestations. 4. Anti-cytokine agents- inhibit action of TNF-alpha which slows or halts erosion. Used in patients with active disease despite being on adequate treatment (2 DMARDs) E.g. Infliximab, Etanercept, Adalimumab 5. Surgery- to prevent joint destruction and deformity or to replace joint.

Systemic Lupus Erythematous (SLE) Definition A chronic multisystem autoimmune disease in which autoantibodies are made against a variety of autoantigens (e.g. ANA). It is the most common of the connective tissue disorders. It often mimics other disorders due to its multisystem nature. Type III hypersensitivity reaction caused by antibody-immune complex formation. The non-systemic form which affects only the skin is discoid lupus. Epidemiology

The disease occurs 9x more often in women than in men with a peak age of onset between 20-40yrs. It affects 0.1% of the population and is commoner in Afro-Carribeans and Asians. Aetiology The cause of SLE is multifactorial and includes: 1. Genetics-SLE runs in families, but no single, causal, gene has been identified. Instead, multiple genes appear to influence a person's chance of developing lupus when triggered by environmental factors. The most important genes are located in the HLA region on chromosome 6, where mutations may occur randomly (de novo) or may be inherited 2. Immunological-Antinuclear antibodies are present which are thought to arise from polyclonal activation of B cells by an antigenic stimulus. May be associated with impaired T cell regulation and deficiencies in complement. 3. Drugs-Hydralizine, isoniazid, procainamide, quinidine, phenytoin and certain antiTNF therapies cause drug-induced lupus erythymatous, which often resolves after the drug is withdrawn 4. Infection-Viral infections may be responsible Symptoms General 1. Pyrexia 2. Fatigue 3. Depression Musculoskeletal 1. Small joint arthralgia 2. Myalgia 3. Aseptic necrosis of hip or knee Skin 1. ‘Butterfly’ rash- erythymatous rash on bridge of nose and cheeks 2. Vasculitis 3. Urticaria 4. Photosensitivity 5. Alopecia 6. Raynaud’s Phenomenon Blood 1. Anaemia 2. Leucopenia/Lymphopenia 3. Thrombocytopenia Lungs 1. Pleurisy 2. Pleural Effusions Heart and CVS 1. Pericarditis and pericardial effusions 2. Myocarditis 3. Aortic valve lesions 4. Thrombosis (both arterial and venous) 5. Accelerated atherosclerosis Kidneys 1. Glomerulonephritis Nervous System 1. Epilepsy 2. Migraine

3. 4. 5. 6.

Cerebellar Ataxia Aseptic Meningitis Cranial Nerve lesions Polyneuropathy

Diagnosis of SLE if ≥4 are present out of the 11 criteria A RASH POIN MD Arthritis- non-erosive arthritis involving ≥ 2 joints (tenderness, swelling or effusion) Renal Dysfunction- persistent proteinurea (>0.5g/dL or >3+ on urinalysis) or cellular casts ANA Serositis- carditis or pleuritic chest pain due to pleural effusion Haematological disorder- haemolytic anaemia, leukopenia, lymphocytopenia, thrombocytopenia Photosensitivity Oral Ulcers Immunological disorder- Anti dsDNA antibody, Anti Smith antibody or Antiphospholipid antibody Neurological- psychosis or seizures in the absence of drugs or metabolic imbalance Malar Rash-fixed erythema which affect the cheeks and spares the nasolabial folds Discoid Rash- erythematous raised patches with keratotic scales Pathophysiology In SLE, the body's immune system produces antibodies against itself, particularly against proteins in the cell nucleus. Patients have a defect in apoptosis resulting in abnormal programmed cell death. Apoptotic cells and cell fragments are poorly cleared and certain antigens, especially nuclear, are processed by antigen presenting cells with stimulation of the immune response to autoantigens. Clinical manifestations are usually due to the formation of antibodies and the development and deposition of immune complexes and complement activation. Investigations 1. Bloods-ESR is raised however CRP is normal. Normochromic, normocytic anaemia with lymphopenia and thrombocytopenia. 2. Serum autoantibodies- antinuclear antibodies (ANA) are positive, RhF in 25% of cases 3. Serum complement- reduced levels in active disease 4. Histological Biopsy- for instance renal biopsy, shows vasculitis Management 1. Lifestyle changes- Avoiding sunlight is the primary change to the lifestyle of SLE sufferers, as sunlight is known to exacerbate the disease. Drugs unrelated to SLE should be prescribed only when known not to exacerbate the disease. Smoking cessation is also recommended. 2. Topical Steroids- for cutaneous rashes 3. NSAIDs- symptomatic relief of arthralgia in mild disease 4. Chloroquine and Hydroxychloroquine- when symptomatic relief cannot be achieved with NSAIDs or for cutaneous disease. 5. Corticosteroids- prednisolone 30mg/24h for 4 weeks to control disease activity, then dose gradually reduced. Used in moderate to severe disease

6. Immunosuppressives- usually in combination with corticosteroids for patients with severe manifestations e.g. renal (lupus nephritis) or cerebral disease. E.g. azathioprine, cyclophosphamide. 7. Rituximab- is an anti-CD20 monoclonal antibody which can treat B cell depletion Prognosis 10 year survival is approximately 90% although lower if there is major organ involvement. Early onset of disease is a poor prognostic factor.

Antiphospholipid Syndrome (APS) A syndrome characterised by autoantibodies directed against either phospholipids or plasma proteins bound to anionic phospholipids. 3 types of antibodies have been described: 1. Lupus Anticoagulant 2. Anti-cardiolipin 3. Beta 2-Glycoprotein 1 antibodies Antibodies are thought to play a role in thrombosis by reacting with plasma proteins and phospholipids with an effect on platelet membranes, endothelial cells and clotting compounds such as prothrombin. Can be associated with SLE (20-30%). More often it occurs as a primary disease. Clinical features Due to thrombosis CLOT Coagulation Defect Livedo Reticularis- swelling of medium-sized veins, purple discolouration of lower extremities Obstetric- recurrent miscarriage Thrombocytopenia Other features include 1. Arteries: stroke, ischaemic attacks, myocardial infarction 2. Veins: DVT 3. Placenta: recurrent abortions 4. Valvular heart disease 5. Migraine 6. Epilepsy Management Treat with low-dose aspirin or warfarin if recurrent thromboses.

Sjogren’s Syndrome Sjogren syndrome (SICCA syndrome) is characterised by immunological mediated destruction of epithelial exocrine glands. Especially, the lacrimal and salivary glands. It predominantly affects middle-aged women (late 40s). Sjogren’s can occur as an isolated disorder (primary) or an association with other

autoimmune diseases (secondary) such as rheumatoid arthritis, SLE, scleroderma, primary biliary cirrhosis, where it usually occurs around 10 years after initial onset. Sjogren’s affects:  Eyes (lacrimal ducts)  Mouth (salivary glands)  Skin  Nose  Vagina (dryness)  Kidneys  Blood vessels  Lungs  Liver  Pancreas  Peripheral nervous system and brain Clinical features 1. Dry eyes (keratoconjunctivitis sicca is a reduction in tear formation causing gritty eyes) 2. Dry mouth (xerostomia is a reduction in saliva) 3. Vaginal dryness 4. Arthritis 5. Raynaud’s phenomenon 6. Vasculitis 1. Renal tubular defects causing diabetes insipidus and renal tubular acidosis 2. Pulmonary fibrosis 3. Sensory neuropathy (distal axonal sensorimotor neuropathy) Patients have difficulty eating a dry biscuit and have absence of pooling of the saliva when the tongue is lifted. There may be symptoms of the underlying cause if secondary cause. There is an increased incidence of Non-Hodgkin’s lymphoma. There is an association with Hoshimoto’s thyroiditis. N.B Sicca symptoms refer to the dry eyes and mouth. Investigations 1. Bloods- Hypergammaglobinaemia and low C4 2. Serum autoantibodies- ANA (80% of patients), Anti-Ro (60-90%), Anti-La and rheumatoid factor (RhF) in primary Sjogren’s syndrome. 3. Labial gland biopsy (between mucous membrane and orbicularis oris around the orifice of the mouth) - shows characteristic changes of focal lymphocyte infiltration and destruction of acinar tissue. 4. Schirmer test- a standard strip of filter paper is placed on the inside of the lower eyelid; wetting of less than 10mm in 5min is positive and confirms defective tear production Management 1. Artificial saliva and tears e.g. tears naturale, hypromellose drops 2. Cyclosporin eye drops (reduce inflammation of tear glands) 3. Pilocarpine may stimulate saliva production (avoid in asthma and glaucoma)

4. Vaginal lubricant and saline nasal spray 5. Hydroxychloroquine for muscle and joint pain 6. Prednisolone, azathioprine or cyclophosphamide for vasculitis

Polymyositis (PM) and Dermatomyositis (DM) Polymyositis and dermatomyositis are examples of acquired muscle disorders. There are 2 main types of inflammatory myopathy: polymyositis and dermatomyositis. They affect all age groups with an annual incidence of 8 per 100 000. These disorders are mainly sporadic. There is an underlying immune mediated process with the presence of elevated IgG in the blood and presence of circulating antibodies. Onset is usually acute or subacute occurring over several weeks to months post-infection. Patients present with systemic features followed by muscle weakness. Definition Polymyositis is a rare muscle disorder of unknown aetiology in which there is inflammation and necrosis of skeletal muscle fibres. There is an association with malignant disease and collagen vascular disorders. When the skin is involved it is called dermatomyositis. PM and DM both affect and adults and children and are more common in women. Differential diagnosis for proximal myopathy Endocrine 1. Cushings / Addisons 2. Hyperthyroidism / Hypothyroidism 3. Osteomalacia Inflammatory 1. Polymyositis 2. Dermatomyostitis 3. Idiopathic Genetic 1. Dystrophies: DMD, Beckers Metabolic 1. Mitochondrial disorders Clinical features (PM) There is symmetrical progressive muscle weakness and wasting affecting the proximal muscles of the shoulder and pelvic girdle. Patients have difficulty squatting, going up stairs, rising from a chair, and raising their hands above their heads. Pain and tenderness are uncommon. Involvement of the pharyngeal, laryngeal and respiratory muscles can lead to dysphagia, dystonia and respiratory failure respectively. 1. 2. 3. 4. 5.

Initial painless symmetric proximal muscle weakness Weakness of posterior neck muscles – lolling of head forwards Myalgia (60% cases –muscle ache) Distal limb muscle weakness occasionally Dysphagia (oesophageal muscle involvement) and dysphonia

6. Cardiac involvement 7. Respiratory failure (No eye involvement and reflexes are normal). Dermatomyositis Dermatomyositis (DMS) is an autoimmune connective tissue disease involving myositis characterized by muscle weakness, pain and swelling accompanied by skin rash. DMS is associated with paraneoplastic phenomenon. Incidence peaks in two age groups of 5-15 year olds and 40-60 year olds. Pathophysiology There is some underlying capillary damage in DMS resulting in endothelial cell damage, capillary necrosis, perivascular inflammation, ischaemia, and destruction of muscle fibres. Factors supporting autoimmune nature include:  The presence of autoantibodies  Association with other autoimmune disorders  Evidence of T-cell-mediated muscle injury  Complement-mediated vascular damage  Response to immunosuppression. It has been associated with underlying malignancy (paraneoplastic syndrome) involving lung, ovarian, pancreatic, bowel. Clinical features 1. Proximal muscle weakness 2. Myalgia 3. Arthralgia 4. Dysphagia, dysphonia 5. Macular erythematous rash over back and shoulders (shawl sign), nose and cheeks 6. Heliotropic rash on eyelids (+ oedema) 7. Nailford erythema and prominent ragged cuticles and telangiectasia in proximal nail folds. 8. Gottrons papules (roughened red papules over knuckles) 9. Subcutaneous calcifications 10. Painful rough skin tightening 11. Fever 12. Raynauds phenomenon 13. Interstitial lung fibrosis 1. Heliotrope- violaceous (purple) eruption on the upper eyelids and in rare cases on the lower eyelids as well, often with itching and oedema 2. Gottron’s papules- scaly erythymatous plaques over the MCP and interphalangeal joints (can mimic psoriasis) 3. Shawl’s sign- diffuse, flat, erythematous lesion over the back and shoulders or in a "V" over the posterior neck and back or neck and upper chest, which worsens with UV light. 4. Mechanic’s hands- rough, painful, cracked skin at the tips and lateral aspects of

fingers forming dirty-appearing lines that resemble those seen in a labourer. There are differences in presentation between childhood and adult life:  Childhood: vasculitis & ulceration of axillae and groin, and development of calcinosis  Adult life: sometimes associated with systemic malignancy Investigations for PM and DM 1. Bloods- ESR is usually NOT raised 2. Serum muscle enzymes- creatine kinase, ALT/AST, LDH, aldolase are elevated 3. Serum autoantibodies- ENA antibodies: Anti-JO antibodies (anti-tRNA synthetase) and Anti-Mi2 are positive and ANA, RhF. 4. Muscle biopsy- is the definitive test in establishing the diagnosis and excluding other causes of myopathy. There is inflammatory cell infiltration and necrosis of muscle cells. 5. Electromyography (EMG)- shows characteristic changes 6. CXR, CT CAP (malignancy screen) 7. MRI- can demonstrate areas of muscle inflammation Management (MDT approach) 1. Corticosteroids- Prednisolone 0.5-1mg/kg bodyweight is t...