Rheumatology Flashcards
(132 cards)
what is arthritis
- inflammation of the joints
what is arthrosis
- non-inflammatory joint disease
what is arthralgia
- joint pain
what is bone
- mineralised connective tissue
how is bone dynamic
- Bone in continuously changing
- Always forming and being resorbed and replaced
- Gives bone ability to adapt to changing stresses in the environment and also allow use for self-repair to take place
how is bone self-repairing
- Processes for dynamic change are the same as for repairing bone damage
- Bone is removed by osteoclasts and deposited by osteoblasts
- Clasts eat away at the bone matrix and are replaced by blasts which deposit an osteoid matric which is then mineralised to leave resting bone
- Cycle takes over 3-6 months
what do you need the correct amount of for bone formation
- calcium
- phosphate
- vitamin D
how are bone and calcium linked
- bone forms a store for calcium
- exchangeable and not
- exchangeable moves from bone to ECF and calcium is absorbed from the gut into ECF
how is calcium lost
- lost through the gut and urine
- Important for normal body function that the calcium level in blood is maintained at a very precise level
- Because it is involved in nerve and muscle function
where is the parathyroid hormone
- in the thyroid gland
what does PTH do
- Maintains serum calcium level
- Raised if calcium level falls
- Increases calcium release from bone
- Reduces renal calcium excretion
- The level of PTH is tightly maintained but can change if there is a tumour or if surgery accidentally removes these glands resulting in an injury to not secrete enough PTH
what is hypoparathyroidism
- lower serum calcium
- low PTH
what is hyperparathyroidism
- high PTH
- primary and secondary
- both types result in increased bone resorption
what is primary hyperparathyroidism
- Gland dysfunction = tumour
- Results in higher serum calcium
- Inappropriate activation of osteoclasts
what is secondary hyperparathyroidism
- Causes low serum calcium
- PTH being high will activate osteoclasts in bone but this time appropriately to maintain serum calcium level
how does vitamin D work
- from the sun or diet
- turns into cholecalciferol in the skin
- becomes bound cholecalciferol in the blood
- becomes 25-hydroxycholecalciferol in the liver
- becomes 1,25-dihydroxycolecaliciferol in the kidneys
- calcium absorbed in the gut
what happens if there re low levels of vitamin D
- effect bone health
what are reasons for poor vitamin D
- Low sunlight exposure= housebound, dark skinned in Northern country
- Poor GI absorption = poor nutrition, small intestine disease (malabsorption)
- Drug interactions = some antiepileptic drugs (Carbamazepine, phenytoin), can interfere with vitamin D synthesis
- Often a combination of factors
how are dark skinned people living in northern countries often deficient in vitamin D
- Skin absorbed sunlight less efficiently due to pigment in the skin and this, combined with more clothing in northern countries covering most of the skin, then the amount of vitamin D able to absorb through sunlight is reduced
what is osteomalacia
- Poorly mineralised osteoid matrix
- Bone formed normally but not calcified properly
- Normal amounts of osteoid but inadequate mineralisation of tissue
- Poorly mineralised cartilage growth plate
- calcium deficiency
what is osteoporosis
- Loss of mineral and matrix
- Mineral and matrix are normal, just not enough of it made
- Reduce bone mass
what is osteomalacia result in during bone formation
- rickets
what does osteomalacia results in after bone formation
- osteomalacia
what type of bone is produced from osteomalacia
- bone that is soft and can be bent to pressure