Rheumatology Flashcards
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
what are the investigation results for osteomalacia
- serum calcium = decreased
- serum phosphate = decreased
- alkaline phosphatase (measure of bone turnover) = very high
- plasma creatine = increased if renal cause
- plasma PTH = increased if secondary hyperparathyroidism
what is the term given to the formation of the legs in rickets
- bow-legs
- because bones are unable to support the weight of the child
- rarely seen nowadays
why did rickets used to be so common
- due to the inadequate diet and poor sunlight exposure due to overcrowding and construction of tenements
what does osteomalacia cause in adults
- pain in nerves affecting lower limb
- vertebra compression
what are the affects of hypocalcaemia
- Muscle weakness = trousseau and chvostek signs positive (carpal muscle spasm, facial twitching from VII tapping)
how is osteomalacia managed
- correct the cause
- Malnutrition = control GI disease
- Sunlight exposure = 30 mins x 5 weekly
- Dietary vitamin D = supplements perhaps the easiest way to restore deficiencies nowadays
what is osteoporosis
- reduced quantity of normally mineralised bone
- age relate change
- inevitable
- Loss of mineral and matrix
- Mineral and matrix are normal, just not enough of it made
- Reduce bone mass
wha are the risk factors of osteoporosis
- AGE = as you get older bone mass reduces
- Female sex
- Endocrine = oestrogen & testosterone deficiency (cushing’s syndrome, increase in corticosteroid levels in te blood)
- Genetic = family history, race (Caucasian & Asian women)
- Early menopause
- Patient factors = Inactivity, Smoking, Excess alcohol use, Poor dietary calcium
- Medical Drugs use (steroids, antiepileptics)
who is osteoporosis foundinmore
- women
- 15% women aged 50
- 30% women aged 70
- 40% women aged 80
why are women more likely to get osteoporosis
- Males have a higher peak bone mass
- Peak bone mass in skeleton is less in women
- Oestrogen withdrawal increases bone mass loss rate in women
- Artificially boosted by oestrogen, but when women go through menopause and it is lost, that protection is lost too and rapid loss of bone occurs
- In men, rate of decline is similar but peak is higher
- Takes longer for me to lose enough bone mass to reach osteoporosis point that it does women
what are the affects of osteoporosis
- Bone mass may no longer be adequate to maintain stress applied to bone
- Increased bone fracture risk = Long bones (femur), If patient falls on outstretched arm will cause fracture, Often this can be the first sign to a patient that they are at osteoporosis risk
- Vertebrae = Height loss, Kyphosis and scoliosis, Kyphosis, Scoliosis
- Nerve root compression back pain
- Lifetime risk of hip fracture >50 years of age = 17.5% women, 6% men
- After osteoporosis related hip fracture = 20% increase in 5 years mortality, Maximal in initial 6 months, 40% unable to walk unaided, 60% unable to live independently
what is kyphosis
- Bending forward of spine as vertebral bodies collapse under the weight of the upper body causing tipping
- Usually due to osteoporosis
what is scoliosis
- Shifting of the lateral position of the vertebrae caused by the same compression
how can osteoporosis be prevented
- build maximal peak bone mass = exercise, high dietary calcium intake
- reduce rate of bone mass loss = continue exercise and calcium intake, reduce hormone related effects
- oestrogen replacement therapy
- reduce drug related effects
- consider ‘osteoporosis prevention rugs’
is oestrogen replacement therapy goof
- Reduces osteoporosis risk
- Increases breast cancer risk
- Increase endometrial cancer risk
- Patient who has NOT had a hysterectomy
- Combine with a progestogen to reduce risk
- May reduce ovarian cancer risk
- Increases DVT risk
- Benefit is lost after HRT is stopped
- 5-year post treatment BMD is ‘norma’
- Net benefit and risk can be a difficult balance for patient
- MOST effective if early menopause
- Not sure yet if these are good or not
- Not a permanent benefit
what are osteoporosis preventing drugs
- bisphosphonates
what are bisphosphonates
- Act by preventing osteoclast action by poisoning osteoclasts and reducing their numbers
- If there are reduced osteoclasts, less bone can be removed and therefore bone mass will be preserved
- non-nitrogenous = main ones
- nitrogenous
- sue drugs to prevent bone loss and in some cases even build-up the bone mass again
what are non-nitrogenous bisphosphonates
- Etidronate = 1 (potency)
- Clodronate = 10
- Tildronate = 10
what are nitrogenous bisphosphonates
- Pamidronate =100
- Neridronate =100
- Olpadronate =500
- Alendronate =500
- Ibandronate =1000
- Risedronate =2000
- Zoledronate =10000
what ar the effectiveness of bisphosphonates
- Alendronate or Risedronate is an osteoporosis risk population
- Reduce vertebral fracture risk by 50%
- Reduce other fracture by 30-50%
- Benefit lost if drug discontinued
- Can be combined with HRT
what are the problems with bisphosphonates and dentistry
- issue when extracting teeth
what are the symptoms of joint disease
- Pain
- Immobility stiffness
- Loss of function
what are the signs of joint disease
- swelling = fluctuant (if lots of fluid), bony (if being going on for years) synovial (enlargement mainly in RA)
- deformity = lead to changes in joint surfaces
- redness
- crepitus
- loss of function
what is crepitus
- Noise made by bone ends moving
* Associated with loss of normal cartilaginous covering of the bone ends
how are connective tissue diseases investigated
- radiographs = MRI more common now, arthography
- blood = C-reactive proteins (inflammatory markers), rheumatoid factors, extractable nuclear antigens, anti ds-DNA, anti-nuclear antibody)
- arthroscopy and bops
what is arthography
- where radiopaque die is injected into the joint onto outline the articular surface and joint capsule
what are some crystal arthropathies
- acute monoarthopathies
- gout
what is acute monoarthropathies
- acute arthritis of a single joint
- common causes = infection, crystal arthropathy (gout)
- can be the initial stage of poly arthritis