Musculoskeletal Flashcards
(204 cards)
What is amyloidosis?
A (heterogenous) group of diseases characterised by extracellular deposition of amyloid fibrils
What are the two main subtypes of amyloidosis?
Type AA: serum Amyloid A protein
-non-familial secondary amyloidosis: inflammatory polyarthropathies account for 60% of cases
Type AL: immunoglobulin light chain amyloidosis (primary amyloidosis)
Which are the main 2 organs affected by amyloidosis?
Kidneys
Heart
What is the epidemiology of amyloidosis?
In the UK, the age-adjusted incidence is between 5.1 and 12.8 per 1 million per year, with around 60 new cases annually- RARE
What are the presenting symptoms of amyloidosis?
PMH of inflammatory conditions (RF) Chronic infections (RF) Positive FH (RF) Fatigue Weight loss Dyspnoea on exertion
What are the signs of amyloidosis on physical examination?
Jugular venous distension- high right-sided filling pressure
Lower extremity oedema (nephrotic syndrome)
Macroglossia- most specific finding for AL
Diffuse muscular weakness
Shoulder pad sign- psudeohypertrophy of amyloid
What are the appropriate investigations for amyloidosis?
1st line:
Serum/ urine immunofixation- presence of monoclonal protein
Immunoglobulin free light chain assay- diagnosing AL
Bone marrow biopsy- clonal plasma cells
Others:
Tissue biopsy, ECG (for conduction abnormalities)
What is ankylosing spondylitis?
A chronic progressive inflammatory arthropathy (arthritis which affects multiple joints) affecting preferentially the axial skeleton and large proximal joints
What is the aetiology of ankylosing spondylitis?
A strong genetic component in the risk of developing AS with a link to HLA-B27.
Inflammation starts at the entheses (sites of attachment of ligaments to vertebral bodies)
Persistent inflammation is followed by reactive new bone formation resulting in the calcification of ligaments
Changes start in lumbar and progress to thoracic and cervical regions
What is the epidemiology of ankylosing spondylitis?
Common: Affects 0.25–1% of UK population.
Earlier presentation in males (M:F is 6:1 at 16 years and 2:1 at 30 years)
What are the presenting symptoms of ankylosing spondylitis?
Inflammatory back pain (Low back and sacroiliac) pain
Disturbances in sleep (worse in morning, improves on activity, returning with rest).
Progressive loss of spinal movement.
Symptoms of asymmetrical peripheral arthritis.
Non-specific symptoms: malaise, fatigue.
Lower limb pain (enthesitis)
What are the signs of ankylosing spondylitis on physical examination?
Reduced range of spinal movements (particularly hip rotation).
Reduced lateral spinal flexion
Schobers test: reduced flexion
There may be tenderness over SI joints
Signs of extra-articular disease:
-Anterior uveitis (red eye)
-Apical lung fibrosis
-Reduced chest expansion (fusion of costovertebral joints)
-Aortic regurgitation (cardiac diastolic murmur)
What is Schobers test?
A mark is made on the skin of the back in the middle of a line drawn between the posterior iliac spines.
A mark 10 cm above this is made. The patient is asked to bend forward and the distance between the two marks should increase by >5 cm on forward flexion.
*This is reduced in ankylosing spondylitis
What are the appropriate investigations for ankylosing spondylitis?
Bloods: ESR/CRP
Pelvic X-ray: sacroiliitis
Radiographs: “bamboo spine” vertebral body fusion
HLA-B27
What is 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
What is the aetiology of gout?
Underlying metabolic disturbance is hyperuricaemia which may be caused by:
- Increased urate intake or production: dietary, lymphoma, leukaemia
- Decreased renal excretion: idiopathic, drugs, renal dysfunction
What drugs can cause decreased renal excretion?
CANT LEAP: Ciclosporin Alcohol Nicotinic acid Thiazides Loop diuretics Ethambutol (AB for TB) Aspirin Pyrizinamide (AB for TB)
What is the epidemiology of gout?
Prevalence 0.2 %. M:F is 10:1.
Very rare in pre-puberty and in pre- menopausal women. More common in higher social classes
What are the presenting symptoms of gout?
Acute attacks: sudden excruciating monoarticular pain, the symptoms peak at 24 h and resolve in 7–10 days
Foot joint distribution: most commonly involved are joints in the feet, especially the first metatarsophalangeal
Joint stiffness: morning stiffness is prominent
*Attacks are often recurrent, but the patient is symptom free between attacks.
What is the asymptomatic period between acute attacks known as?
Intercritical gout
What can precipitate an acute attack of gout?
Trauma Infection Alcohol Starvation Introduction or withdrawal of hypouricaemic agents
What is the main symptom of ankylosing spondylitis?
Lower back and sacral pain that is worse in the morning and better with exercise
What are the two main x-ray findings in ankylosing spondylitis?
Bamboo spine
Sacroiliac joint fusion
What are the signs of gout on physical examination?
Foot joint distribution Swelling and joint effusion Tenderness Erythema and warm Painful tophi (urate deposits)- best seen on tendons and the pinna of the ear