Metabolic & Rheumatic Disorders Flashcards
Describe osteopenia and its causes
X-ray evidence of decreased bone mineral density (BMD) Causes Osteoporosis Osteomalacia Malignancies (multiple myeloma) Endocrine disorders
Describe osteoporosis and its causes
Decreased bone density & bone strength Matrix is weakened Mineralization is decreased Cause UKE Bone resorption exceeds bone formation
Osteoporosis is associated with…
- Gender
- Postmenopausal osteoporosis
- Male hormone declination
- Genetics, Race
- Activity level
- Nutrition
- Body size
- Age-related changes
- Decreased osteoblast activity
- Decreased physical activity levels
- Postmenopausal
- Nutrition
Causes of secondary osteoporosis
> Endocrine Disorders - Hyper/hypothyroidism - Hyperparathyroidism - Cushing syndrome - Diabetes Mellitus > Malabsorption Issues > Malignancies - Multiple myeloma > Alcoholism > Medications - Corticosteroids > Premature Infants > Cystic Fibrosis
Female athlete triad
Emphasis of leanness and low body weight: Eating disorders (i.e. dietary restrictions) combined with excess exercise result in weight fluctuations = affects gonadotropic hormones = decreased LH, FSH = decreased estrogen resulting in… - Amennorhea - Osteoporosis/Osteopenia
Osteoporosis cont’d: fractures, postmenopausal, senile
> Fractures d/t
- Loss of trabeculae from cancellous bone
- Thining of cortex
Postmenopausal Osteoporosis
- Increased osteoclastic activity results in loss of trabeculae
- Microfractures occur, bone compresses
Senile/age-related osteoporosis
- Haversian system widens dT loss of trabeculae
Osteoporosis Manifestations
> Silent disorder
Sudden onset fracture (hip, pelvis, humerous, etc.)
> Wedging/collapse of vertebrae (loss of height and kyphosis/dowager hump)
- No bone pain unless fracture.
Osteomalacia and manifestations
> Softening of bones d/t inadequate mineralization
Adult condition
> Manifestations
Bone pain, tenderness
Muscle weakness an early sign
Fractures of radius, femur
But not a significant cause of hip fractures
Delayed healing of fractures = deformities
Hyperparathyroidism d/t low calcium levels
Causes of osteomalacia
> Insufficient Ca+2 absorption from intestines d/t
- Lack of intake
- Vitamin D deficiency
> Phosphate deficiency d/t - Renal losses - Poor absorption in GI tract > Anticonvulsant use (long term) Renal rickets Vitamin D resistant rickets
Rickets (childhood disease)
> Inadequate calcium absorption from diet
Lack of Vitamin D
Failure/delayed calcification of cartilaginous growth plate = overgrowth
Metaphyseal regions widen/deform as unmineralized.
Rickets Causes
- Nutritional deficits
- Kidney failure
- Malabsorption syndromes, GI loss
- Medications (anticonvulsants, aluminum antacids)
Genetic
Risks and Manifestations of Rickets
> Risks: - Breast fed only (need a Vitamin D supplement) - Dark-skinned - Limited sunlight > Manifestations: - Enlarged skull - Oversized joints - Delayed fontanel closure - Slow tooth growth - Abnormal shaped thorax -Bowed legs - Difficult ambulation - Stunted growth
Paget disease and risks
> Abnormal bone remodelling as a result of
- Focal areas of excessive osteoclast-mediated bone resorption followed by
- Disorganized osteoblast-mediated bone repair
Unclear pathophysiology
Genetic, environmental, ? viral triggers
Risks:
Mid adulthood, progression
Men = women
Northern European heritage
Paget disease manifestations
- Isolated lesions or widespread
- Long-bone bowing and fractures
- Large joint osteoarthritis
- Skull, spine, pelvis, femur, tibia are common
- “cement lines” from new bone growth over old bone.
Rheumatoid Arthritis
> Autoimmune systemic disease
Polyarticular
> Etiology Uncertain Genetic predisposition Women > men Peak incidence 40-50 years of age
RA pathophysiology
> T-cell mediated response to trigger
- Inflammatory mediators released in response to a microbial agent
- Antibodies form against auto-antigens
> Rheumatoid factor (RF)
- Which is an antibody- occurs in 70-80% of patients
Synovial inflammation and joint destruction result