Diseases of Human Systems Flashcards
Arthritis
Inflammation of joints
Arthrosis
Non-inflammatory joint disease
Arthralgia
Joint pain
Disorders of bone metabolism
Osteomalacia
Osteoporosis
3 main features of bone - mineralised connective tissue
Load bearing
Dynamic - continuously changing, ability to adapt to stresses
Self repairing
Osteoclasts
Resorb bone
Osteoblasts
Deposit bone
Lay down and osteoid matrix, which is mineralised to become bone
Process takes 3-6m
What are the requirements for normal bone deposition?
Calcium
Phosphate
Vit D
Exchangeable calcium
Stored in bone
Moves from bon into the extracellular fluid
Absorbed from the gut into extracellular fluid
Lost through gut and urine
Blood calcium
Must be maintained at a very precise level as it is involved in nerve and muscle function
How is location of calcium moderated?
Bone and ECF, using parathyroid hormone
What is the effect of a low calcium diet?
-> Reduction in plasma Ca -> increases parathyroid hormone ->
- Increased Active vitD - increases intestinal Ca absorption
- Decreased urinary Ca - increased conservation of dietary Ca
- Increased bone calcium release - increased bone loss
–>Restoration of normal plasma Ca
What can affect parathyroid function and therefore hormone levels?
Accidentally removed in thyroid surgery
Parathyroid tumour
3 actions of parathyroid hormone
Maintains serum calcium levels
Increases calcium release from bone
Reduces renal calcium excretion
Hypoparathyroidism
Occurs when there is insufficient parathyroid hormone
Leads to low serum calcium
Hyperparathyroidism
Primary occurrence - problem with the gland itself, could be caused by parathyroid tumours, results in high serum calcium and inappropriate activation of osteoclasts
Secondary occurrence - caused by low serum calcium , high parathyroid hormone levels activate osteoclasts appropriately, maintain serum calcium level
Effect of both hypoparathyroidism and hyperparathyroidism
Bone resorption - appears as radiolucencies on radiographs
Vitamin D effect on bone health
Vitamin D (from sunlight or diet such as orange juice, fish) absorbed into blood, through liver and kidneys to be output as 1,25 dihydrocycoecalciferol necessary for calcium absorption in the gut
Lack of vit D can cause poor bone health
Drugs that interfere with vitamin D absorption
Phenytoin and carbamazepine - epilepsy
Osteomalacia
Normal osteoid matric laid down, but not properly mineralised - softer bone
(Rickets if during bone formation)
What is alkaline phosphotase used to measure?
Bone turnover - very high when there is a problem with calcium levels
Osteoporosis
Bone matrix and mineralisation correct, but reduced amounts of both leading to reduced bone mass
Age related, normal finding
Osteoporosis risk factors
Age
Females
Endocrine
Genetic
Inactivity
Smoking
Excess alcohol
Poor dietary calcium
Steroid
Antiepilectics
Peak bone mass
24-35
Effects of osteoporosis
Increase bone fracture risk
Vertebrae - height loss, kyphosis and scoliosis, nerve root compression (back pain)
Why might men be lower risk for osteoporosis?
Higher peak bone mass
% women at 50 and 80 osteoporosis
15% at 50
40% at 80
Osteoporosis
Build maximal peak bone mass - exercise, calcium
Reduce rate of bone mass loss - exercise and calcium, reduce hormone related effects with HRT
Bisphosphonates - osteoporosis prevention drugs
Risks of HRT
Increased breast and endometrial cancer risk
Increased DVT risk
Combine with progestrogen to reduce risks
Bisphosphonate action
Poisons osteoclasts and reduces their numbers -> less bone removal
Issues with bisphosphonates
MRONJ risk
Symptoms of joint disease
Pain
Immobility/stiffness
Loss of function
Swelling - joint disease
Fluctuant - lots of fluid infused into joint
Bony - osteophytes form at joint edges
Synovial enlargement
Crepitus
Noise made by bone ends moving, usually associated by loss of usual cartilaginous covering of bone ends
Investigations for joint diseases such as gout and osteoarthritis
Radiographs
Blood tests - inflammatory markers such as C reactive protein, markers for autoimmune disease (such as rheumatoid factors, extractable nuclear antigens, anti DS-DNA, anti nuclear antibody)
Arthroscopy - view inside joint and biopsy soft tissue swelling
Acute monoarthropathies
Acute arthritis of a single joint
Commonly caused by infection (septic arthritis), crystal arthropathy (gout)
These can be the initial stage of polyarthritis
Gout
Acute arthritis of a single joint, can be due to infection
Uric acid crystals deposited in the joint, causing irritation leading to swelling and inflammation
Severe pain
Caused by high blood uric acid
Gout incidence men/women
More common in men until menopause, then equal
Treatment for gout
NSAIDs
Gout dental relevance
Avoid apirin - interferes with uric acid removal
Drug treatments may give oral ulceration
Osteoarthritis
Degenerative joint disease
Weight bearing joints - hips and knees
NOT wear and tear - cartilage repair dysfunction
Osteoarthritis symptoms
Pain
Brief morning stiffness
Slowly progresses over years
Signs of osteoarthritis
Radiographs - loss of joint space as reduced cartilage, subchondral sclerosis, osteophyte lipping at joint edge
Joint swelling and deformity
Treatment for osteoarthritis
Nothing to alter disease progression
Pain improved by increasing muscle strength, weight loss, walking aids, NSAIDs, joint replacement
Dental relevance of osteoarthritis
TMJ can be involved
Difficulty accessing care
Chronic NSAID use - oral ulceration, bleeding tendency
Connective tissue diseases
Autoimmune - target of inflammation is tissues themselves
Vasculitic - target is blood vessels
Autoimmune connective tissues diseases
Systemic lupus erythematosis (SLE)
Systemic sclerosis
Sjogrens syndromome
Undifferentiated connective tissue disease
Categorisation of vasculitic diseases
Categorised by size of vessel involved
Large - giant cell arteritis
Medium - Polyarteritis nodosa, Kawasaki disease
Small - Wegener’s granulomatosis
Management of vasculitic disease
No cure as cause not clear
NSAIDs
Immune modulating treatment
Last resort prednisolone systemic steroids to reduce inflammatory process, long term not advised
Antibodies commonly found in autoimmune disease
Anti nuclear antibody
Anti double strand DNA
Anti ro antibody
Anti La antibody
Discoid lupus
Tissue changes without blood autoantibodies
Largely same tissue involvement, more localised, seen in skin and mouth, looks like lichen planus
Systemic lupus erythematosis
Circulating ANA, dsDNA, ARo antibodies and organ changes
Joints, skin, kidneys, muscles, blood, CVS, renal and CNS
Epilepsy
Group of conditions caused by abnormal discharge of neurons in the brain
Associated with GABA levels in brain, leading to abnormal cell to cell message propagation -> less stimulation for a neuron to pass a message on
