Diseases of the Musculoskeletal System - Diseases (53 & 54) Flashcards
How many bones?
206
What is arthritides?
Pain and stiffness of joint
Cause of arthritides
Inflammation of the joint, not a single disease
Acute arthritis
Pain, heat, redness and swelling
Chronic arthritis commonest types
Osteoarthritis and RA
Osteoarthritis
commonest type, degenerative, progressive erosion of articular cartilage
What to osteoarthritis result iin
Formation of bony spurs and cysts at margins of joints (subchondral cysts)
Secondary OA
Due to wear and tear, frequent use of a joint
Causes of OA
Aging, underling systemic disease (diabetes and obesity)
Commonest location of OA
Knees and hand in women and hip in men
OA pathogenesis
Deterioration and loss of cartilage (protective cushion),
Cellular basis of OA
Chondrocytes, produce IL-1 (matrix breakdown)
Prostaglandins derivatives > release of lytic enzymes (prevents matrix synthesis)
Primary OA
Abnormal stress in weight bearing joints
Where does primary OA affect?
Fingers (Herberden’s/Bouchard’s nodes), knees and cervical and lumbar spines
RA
Chronic systemic disorder, non-suppurative proliferative synovitis - destruction of articular cartilage and ankylosis of joints
RA affects..
Skin (rheumatoid nodules), muscles, heart, lung, spleen and blood vessels (Small joints of hands and feet > deformed joint)
RA is more common in men or women?
3-5 times more in women than men
Pannus (RA)
Inflammatory substances between two bones, sticky erodes into articular cartilage and penetrates subchondral bone and cyst formation > ankylosis of joint space
RA clinical features
Malaise, fatigue, generalised musculoskeletal pain, swollen, pain, warm and stiff joints
RA disease course
Slow/rapid course, fluctuates over 4-5 years
RA pathogenesis
Genetic (HLA-DR4 and DR1), EBV, Viruses, Borrelia, Autoimmune reaction with synovial membranes (CD4 positive T-cells), mediators of joint damage (cytokines), IL-1-6 and TNF-a/B
Criteria for diagnosis
- Morning stiffness
- Arthritis in 3 or more joint areas
- Arthritis of hand joints
- Symmetric arthritis
- Rheumatoid nodules
- Serum Rheumatoid factor
(4 of above)
Rheumatoid factor
Present in most but not all
Analyse synovial fluid
Presence of neutrophils - inflammation
Sero-Negative arthritides
Lack RF
Examples of Sero-negative arthritis
Ankylosing spondylitis, Reiter’s syndrome, Psoriatic arthritis, Eneteropathic arthritis
Gout
Hyperuricemia (Uric acid end product of purine metabolism - deficiency of some enzymes involved)
Gout clinical features
Acute arthritis, chronic arthritis, tophi in various sites (uric acid crystals in joint spaces) > chronic gouty nephropathy and deposition of masses of rates in joints other sites (Tophi)
Pyogenic osteomyelitis clinical features
Systemic illness - fever, malaise, chills, marked pain over affected region
Pyogenic OM examinations
X-ray lytic focus of bone destruction surrounded by zone of sclerosis, Blood cultures positive (essential), biopsy (shows neutrophils not cause)
Pyogenic OM causes
Bacteria, haematogenous spread, extension from contiguous site, direct implantation
Infective arthritis
Acutely painful and swollen joints with restricted movements
Infective arthritis clinical presentation
Fever, leucocytosis and elevated ESR
Causes of infective arthritis
Bacterial (Staph, Strep, Gonococcus, Mycobacteria), Trauma, IVDU, debilitating illness
Osteoporosis
Increased porosity of skeleton, reduction in bone mass, locailised/entire skeleton, primary/secondary
Who does osteoporosis effect?
Primary-Age, post menopausal , physical activity, muscle strength, diet, hormonal status
Osteoporosis clinical features
Vertebral fractures, kyphosis, scoliosis
Secondary osteoporosis caused by
Endocrine disorders (Hyperparathyroidism, Type 1 diabetes), neoplasia (multiple myeloma), malnutrition
Osteoclast dysfunction causes
Paget’s disease (collage of matrix madness), usually tidy up
- Osteolytic stage
- Predominant osteoblastic activity
- Burnt out ostesclerotic stage
- Net effect - gain in bone mass
- Newly formed bone is disordered and architecturally unsound
What is osteoclast dysfunction caused by
Paramyxovirus infection
Histological hallmark of osteoclast dysfunction
Mosaic pattern
Paget’s disease affects who?
Males > females
What age does Paget’s disease effect?
5th decade
What’s mainly involved in Paget’s disease?
Axial skeleton and proximal skeleton
What’s most common symptom of Paget’s disease?
Pain
Complications of Paget’s disease
- Chalk stick type fractures
- Tumours (Benign - giant cell, malignant - osteosarcoma, chondrosarcoma, malignant fibrous histiocytoma)
Osteomalacia
Defects in matrix mineralisation, lack of Vit d, decreased bone density (osteopenia), skeletal deformities not seen
Hyperparathyroidism increases
- Bone resorption and calcium metabolism from skeleton
- Renal tubular reabsorption and retention of calcium
Hyperpararthyoridism complications
Hypercalecemia, osteitis fibrosa cystica (loss of bone mineral with osteoporosis)
Real osteodystrophy
Skeletal changes of CKD
- Increased osteoclastic bone resorption
- Delayed matrix mineralisation
- Osteosclerosis
- Growth retardation
- Osteoporosis
Soft tissue
Non-epithelial extraskeletal structures exclusive of supportive tissue of organs and lymphoid/hematopoietic tissue
Embryological origin of soft tissue
Mesodermal
Are benign soft tissue tumours common or rare?
Common
Sarcomas
Malignant soft tissue tumours, rare and lymph node involvement is uncommon
Neurofibromatosis Type 1
Neurofibroma
Gardner syndrome
Fibromatosis
Carney syndrome
Myxoma, melanotic schwannoma
Turner syndrome
Cystic hygroma
Diagnosis of soft tissue tumour
- Ultrasound guided core biopsy
- Cytogenetics (fresh tissue and karyotype)
- Molecular genetics (FISH, PCR and RT-PCR)
Benign bone tumours
Osteomas, Osteoblastomas
Benign cartilage tumours
Chondromas
Mixed benign tumours
Osteochondromas
Malignant bone tumours
Osteosarcoma
What age group does malignant bone tumours effect?
Young
Where is commonest site for malignant bone tumours?
Knee (60%)
Other bone tumours
Chrondosarcomas, Ewing’s sarcoma, Giant cell tumours
Metastatic bone tumours
Thyroid, prostate, kidney, breast, GI tract
SLE
Complex multi-system disease, predominantly cutaneous
Is SLE more common in males or females?
Females
Clinical presentation of SLE
Butterfly rash, cardiomegaly, endocarditis, CNS (convulsions, hemiplegia), 45% patients nephron syndrome and glomerulonephritis
Pathogenesis of systemic sclerosis
Vessel damage, inflammatory response, cytokines, diffuse - widespread cutaneous lesions
Which systems does systemic sclerosis effect?
Renal, Cardiorespiratory, GIT, osteoarticular involvement (arthralgia, arthritis)
What is prognosis for systemic sclerosis?
Poor
Localised variant of systemic sclerosis
Limited cutaneous and oesophageal involvement, SI malabsorption, CREST syndrome
CREST syndrome
Calcinosis, Raynaud’s phenomenon, Oesophageal dysfunction, Sclerodactyly, Telangiectasia
Symptoms of Polymyalgia Rheumatica
Stiffness, weakness, aching and pain in muscles of neck, limb girdles and upper limbs
Polymylagia Rheumatica associated with
Giant cell arteritis
Giant cell arteritis affects what
Occipital or facial arteries
Giant cell arteritis symptoms
Pyrexia, headache and severe scalp pain
Myopathy
Muscle disease unrelated to any disorder of innervation/neuromuscular junction
Myositis
Muscle fibres and overlying skin are inflamed and damaged resulting in muscle weakness
Muscular dystrophy
Heterogenous group, inherited, progressively severe muscle weakness and wasting
When’d does muscular dystrophy start
Childhood
Malignant hyperthermia
(Inherited) Fast rise in body temperature and severe muscle contraction
When does malignant hyperthermia occur?
When affected person gets general anaesthesia
Rhabdomyolysis
Destruction of skeletal muscle, release of muscle fibre content into blood, myoglobin is released into blood, filtered through kidneys > myoglobinuria (brown urine)
Causes of rhabdomyolsis
Trauma, crush injuries, drugs (cocaine, amphetamine), extreme temp, severe exertion, lengthy surgery, severe dehydration, complication (acute renal failure)
Metabolic myopathies
Glycogen synthesis and degradation, disorders of mitochondrial metabolism
Symptoms of malignant hyperthermia
Bleeding, dark brown urine, muscle rigidity, quick rise in body temp 40 degrees and higher