Musculoskeletal Flashcards by laura amarin

What proportion of bone is organic/ inorganic?

Organic = 65% (calcium hydroxyapatite)
Inorganic = 35%

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Give the four functions of bone

Structure, mechanical, protective, metabolic.

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Which region joins the diaphysis and epiphysis?

The metaphysis.

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Describe the structure of the diaphysis

Diaphysis = main long part of the bone.
Inner part = medulla
Outer part = Cortex
Most outer part = periosteum

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What is another name for the diaphysis?

The shaft

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What are the three ways in which we can classify bone?

Anatomical (long, short, flat), macroscopic (trabecular/cortical) and microscopic (woven/lamellar)

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What is the difference between cortical and cancellous bone?

Cortical = long bones i.e. appendicular
Cancellous = vertebrae and pelvis i.e. axial

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Which is mainly structural and which is mainly metabolic between cortical and cancellous bone?

Cortical = mainly structural
Cancellous = mainly metabolic

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What is the function of osteoblasts?

To make new bone: osteoid

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What are osteocytes?

Bone cells in mature bone

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Which cells do osteoclasts derive from compared with osteoblasts?

Osteoclasts = monocytes
Osteoblasts = mesenchymal cells

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Name x3 metabolic bone diseases

Osteoporosis, osteomalacia and Paget’s disease.

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What is osteoporosis defined as?

Bone mineral density T-score of -2.5 or lower.

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What is the difference between osteoporosis and osteomalacia?

Osteoporosis: reduction in bone mass

Osteomalacia = reduction in bone mineralisation.

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Name the two types of osteomalacia causes.

Deficiency in Vitamin D

Deficiency in PO4.

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What will blood phosphate levels be like in hyperparathyroidism?

Low; PTH inhibits reabsorption.

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What will PTH and Ca2+ levels be like primary hyperparathyroidism?

PTH = high
Calcium = high

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What will PTH and Ca2+ levels be like secondary hyperparathyroidism?

PTH = high
Calcium = normal/ low

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What are the signs and symptoms associated with hyperparathyroidism?

Stones, bones (osteitis fibrosa cystica), abdominal groans and psychic moans

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What are the clinical symptoms of Paget’s disease?

Pain, microfractures and nerve compression

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Is RANK on the osteoblast or osteoclast?

Osteoclast; RANKL is on the osteoblast

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What do mature osteoblasts produce that blocks the RANK/RANKL binding?

Osteoprotegrin

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Which type of ossification leads to the formation of long bones?

Endochondral ossification

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Which type of ossification leads to the formation of flat bones?

Intramembranous ossification

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Which three forms of imaging are used to look at bone density?

X-rays, CT and bone densitometry (DEXA).

When is an MRI requested in bone disease?

To look at biochemical composition

Which test is primarily used to diagnose Osteoporosis?

DEXA (bone densitometry)

What does a T test score of -1.5-2.5 indicate?

Osteopenia

What does a T test score of

Osteoporosis

Give x2 radiological signs of osteoporosis

Cortical thinning | Loss of trabeculae

What is the radiological sign for osteomalacia and ricket's?

Looser's zone = pseudo-fractures at stress areas of bone

What is a radiological sign seen in osteoporosis and osteomalacia?

Codfish (Biconcave) vertebrae.

What is a brown tumour?

Osteitis cystica fibrosa = due to excessive osteoclast activity. Seen in hyperparathyroidism.

What marker will be raised in Paget's disease?

Alkaline phosphate.

Compare the microstructure in osteoporosis compared with osteomalacia.

Osteoporosis = normal Osteomalacia = Too little mineral (osteopenia) Looser's zones

What is osteopenia?

Reduced mineral and protein content.

Name the pathology for increased density of bone (hardness).

Osteosclerosis

What is lucency?

An area that allows x-rays through and so appears darker on the image.

Define arthralgia

Pain in the joint without demonstratable inflammation when examined physically.

Define subluxation

A partial dislocation

The rheumatoid factor is what type of antibody and recognises which antigen type?

IgM antibodies which are anti- IgG

Which substance makes synovial fluid viscous?

Hyaluronic acid

What is hyaluronic acid?

A non-sulphated GAG (glycosaminoglycan)

What is reactive arthritis?

STERILE inflammatory synovitis FOLLOWING an infection.

Which HLA is seen in rheumatoid arthritis?

HLA-DR4

Which HLA is seen in reactive arthritis?

HLA-B27

What is osteoarthritis primarily a disease of?

ARTICULAR CARTILAGE (irreversible)

Define proteoglycan

A glycoprotein containing sulphated GAG. Not hyaluronan as this is non-sulphated! e.g. Aggrecan

Which is the major collagen type found in articular cartilage?

Type II Collagen (not IV!)

In which bone disorder is bone chemistry (ALP, serum Ca2+, PTH) normal?

Osteoporosis

The T score is used to diagnose which bone disorder?

Osteoporosis

What is the form of Rickets seen in adults?

Osteomalacia

Why would we want a drug with a slower elimination?

To avoid major fluctuations in the blood.

What is the MoA of Diazepam? What drug type is benzodiazepam?

Binds to GABA-A receptors: sedative effects. | Diazepam is a benzodiazepam.

What drug type are fluoxetine and venlafaxine?

Anti-depressants. SSRIs. Fluoxetine = specific for serotonin receptors (blocks reuptake) Venlafaxine = serotonin, noradrenaline AND dopamine receptors

What does SSRI stand for? Give an example.

Selective serotonin reuptake inhibitor. | Fluoxetine.

Overstimulation of which pathway leads to schizophrenia?

Mesolimbic; excessive dopamine release

Which form of cannabis is particularly associated with psychosis?

delta-9 THC.

What does 'QD' mean?

Once daily.

What is Haloperidol? Where is it used?

Dopamine receptor (D2) antagonist. Used to treat psychosis.

On a particularly difficult day a gentleman takes double the recommended dose of haloperidol and attends A&E because his upper body is stiff and neck is rotated to the left and locked in flexion. The adverse effects are due to what system?

Extra-pyramidal tracts.

What is Carbidopa?

a Dopamine decarboxylase inhibitor = prevents breakdown of L-DOPA.

Give x2 drugs used in the treatment of Alzheimer's disease.

Cholinesterase inhibitors e.g. Rivastigmine | NMDA receptor antagonists e.g. memantine (only for moderate-severe alzheimer's).

Is the calcium hydroxyapatite part of the organic or inorganic bone?

Inorganic

Describe the structure of a long bone

Epiphysis, metaphysis, diaphysis, metaphysis, epiphysis.

How do we define the 'microscopic' structure of the bone?

Lamellar (mature) | Woven (immature)

What type of needle do you use for inaccessible, sclerotic lesions?

Open needle. (not Jamshidi - the closed needle).

What are in effect the two causes of Osteomalacia?

1. Phosphate deficiency | 2. Vitamin D deficiency

Give two potential radiological signs in Osteomalacia.

``` Looser's zones Codfish vertebrae (also seen in osteopenia). ```