Musculoskeletal Flashcards
What is osteomyelitis
an infection of bone
What is the most common cause of osteomyelitis and which antibiotic is used to treat it?
Staphylococcus aureus
Flucloxacillin IV is the treatment of choice for
osteomyelitis
What is septic arthritis
Inflammatory reaction in joint space (arthritis) caused by infection
Result from direct invasion of the joint
Can be native or prosthetic joints
What is the pathogenesis of osteoarthritis?
Chondrocytes produce interleukin-1 – initiates matrix breakdown
Prostaglandin derivatives induces the release of lytic enzymes – prevents matrix synthesis
What are the criteria for diagnosis of Rheumatoid arthritis?
Morning stiffness Arthritis in 3 or more joint areas Arthritis of hand joints Symmetric arthritis Rheumatoid nodules Serum Rheumatoid factor
4 of the above criteria
What are the sero-negative artheritides? (lack rheumatoid factor)
Ankylosing spondylitis
Reiter’s syndrome
Psoriatic arthritis
Enteropathic arthritis
What is gout?
End point of a group of disorders producing hyperuricemia
Uric acid is the end product of purine metabolism
Deficiency of the enzymes involved
what are tophi?
Tophi = Latin for ‘‘stone’’
A deposit of uric acid crystals
What is Paget’s disease of the bone caused by?
osteoclast dysfunction caused by paramyxovirus
What is osteomalacia?
Defects in matrix mineralization due to lack of Vit D
Decreases bone density - if too little bone = osteopenia
Skeletal deformities are not seen
What is the treatment for a native joint infection with staph. aureus?
Flucloxacillin IV
What are the treatments for a prosthetic joint infection with staph. aureus and Coagulase negative Staph. respectively
Flucloxacillin plus rifampicin IV for s. aureus
Vancomycin plus rifampicin IV for CoNS
What is osteoporosis?
Osteoporosis is a reduction in bone mass in the presence of normal mineralisation
How does chronic renal disease cause renal osteodystrophy?
Inadequate renal tissue - impaired activation of vit D causes osteomalacia
High serum phosphates - inhibit renal enzymes activating vit D and decreases ionised calcium in serum causing hyperparathyroidism
What is ankylosis of joints?
Ankylosis (bent, crooked) is a stiffness of a joint due to abnormal adhesion and rigidity of the bones of the joint
What is the pathogenesis of Rheumatoid arthritis?
Polypoid fibrovascular thickening of the synovium with synoviocyte hyperplasia, producing a pannus that is eroding into the articular cartilage
Continued growth of the pannus and erosion of the cartilage with penetration into the subchondral bone and cyst formation
Filling of joint space with pannus producing ankylosis of joint space-
Which genes increase susceptibility to Rheumatoid arthritis?
(Human Leucocyte antigen) HLA- DR4
and
HLA-DR1
What cellular immunological abnormalities occur in rheumatoid arthritis?
A type IV hypersensitivity reaction
CD4 Tcells attract macrophages and synoviocytes which secrete TNF-alpha and IL-1
What is Malignant Hyperthermia?
Inherited disease – fast rise in body temperature and severe muscle contraction when the affected person gets general anaesthesia
What is Rhabdomyolysis and what are its symptoms?
Destruction of skeletal muscle
Release of muscle fibre content into blood
Myoglobin is released into the blood stream
Filtered through the kidney and enters urine- myoglobinuria- brown urine
What is Duchenne muscular dystrophy?
Sex-linked recessive disorder
Mutation of the gene coding for dystrophin
Relentlessly progressive wasting, chair-bound by 12 years
Proximal muscle weakness
Hypertrophy of calves
what is Emery-Dreifuss Muscular Dystrophy?
Defects of muscle cell nuclear membrane-related proteins called emerins and lamin A/C
X-linked recessive
Weakness of proximal arm and distal leg muscles
Early contractures
Cardiomyopathy
What is Core disease?
Dominantly inherited
The central core is a well demarkated zone in the centre of a muscle fibre, devoid of normal histochemical reactivity (NADH-Tr)
Cores only occur in type I fibres
Not usually detected until child has started walking
What is myasthenia gravis?
Autoimmune disease with antibodies, usually IgG, against the acetylcholine receptor
