Bone Disorders Flashcards
What is bone resorption?
A step in the process of bone metabolism and formation. Resorption occurs When osteoclasts remove a portion of the bone to be replaced later by the action of osteoblasts.
What is bone formation?
When osteoblasts lay down collagen and mineral deposits over the area previously remodelled by osteoclasts. Osteoblasts activity is vital for maintaining bone mineral density and strength
What nutrients and vitamins play a role in maintaining bone health?
Calcium - provides hardness and strength to bone
Phosphate - provides rigidity and strength to bone
Vitamin D - enhances the bodies absorptionof calcium and phosphate, without it bones become thin, brittle and misshapen
Magnesium - Influences the bodies utility to use calcium
Vitamin K - Essential to bone formation and mineralization
What are the two main types of bone tissue?
Compact Bone - (also known as Cortical bone) The dense, hard outer layer of the bone.
Spongy Bone - (also known as cancellous or trabecular bone) - Spondy bone found inside the ends of long bones and particularly prevalent in bones as they near joints.
Name the functions of the skeletal system
Support and structure
Protection: Bones protect internal organs from injury. For example, the skull protects the brain, and the rib cage safeguards the heart and lungs.
Movement: Bones act as levers and attachment points for muscles. When muscles contract, they pull on bones, producing movement.
Mineral Storage: Bones serve as a reservoir for minerals, particularly calcium and phosphorus, which are essential for various cellular processes. The release of these minerals into the bloodstream is regulated to maintain critical mineral balances throughout the body.
Blood Cell Production: Red marrow within bones produces red blood cells, white blood cells, and platelets in a process known as hematopoiesis. This is vital for oxygen transport, immune function, and blood clotting.
Energy Storage: Yellow marrow stores fats that can serve as an energy reserve.
What is osteoporosis?
A metabolic bone disease characterised by decreased bone density and mass.
Occurs due to an imbalance between new bone formation and bone resorption
What factors may contribute to the development of osteoporosis
Hormonal changes (especially oestrogen in women and testosterone in men)
Dietary factors (low calcium intake, low vitamin D, High sodium intake and low vitamin K intake etc)
Age associated changes in bone remodeling processes
Small body frame - higher risk due to less bone mass to draw from as they age
Heavy alcohol consumption and smoking
Long term use of corticosteroids
Thyroid pathologies
What is a DEXA scan?
A test used often in the diagnosis of osteoporosis, meausures the grams of calcium and other bone minerals packed into a segment of bone.
Stands for ‘dual-energy x-ray absorptiometry’, and is used to measure spine and hip bone density.
What medications are commonly used in the treatment of osteoporosis?
Biphosphonates: Alendronic acid, Risedronate, Ibandronic acid - used to slow bone resorption
Calcium and Vitamin D Supplemets
Selective Oestrogen Receptor Modulators (SERMs): Raloxifene - used to help maintain bone density similar to the hormone oestrogen
Hormone Replacement Therapy - Used in menopausal women to prevent further bone loss
Parathyroid Hormone: Teriparatide - Used to stimulate cells in an attempt to make new bone
What is osteomalacia?
Osteomalacia is a metabolic bone disease characterized by the softening of the bones due to impaired bone mineralization
Looser’s zones, also known as Looser’s lines or Milkman’s syndrome, refer to areas of incomplete fractures or stress fractures that are a characteristic radiographic feature of osteomalacia.
What are the primary etiological factors that contribute to the development of osteomalacia?
Inadequate exposure to sunlight: The body synthesizes vitamin D when the skin is exposed to sunlight, so limited sun exposure can lead to deficiency.
Dietary deficiencies: Not consuming enough vitamin D or calcium.
Certain medical conditions: Disorders that affect vitamin D absorption from the diet or conditions that interfere with the conversion of vitamin D into its active form, such as celiac disease, chronic kidney disease, and some liver diseases.
Medications: Some medications can affect vitamin D metabolism, such as antiseizure drugs.
What are some symptoms of osteomalacia?
Muscle weakness: Especially in the proximal muscle groups, leading to difficulty climbing stairs or getting up from a chair.
Bone pain and tenderness: Commonly affecting the lower back, pelvis, hips, legs, and ribs.
Fractures: Bones affected by osteomalacia are more prone to fractures, often with minimal or no trauma.
How is osteomalacia treated?
The treatment for osteomalacia aims at correcting the underlying cause of the vitamin D deficiency and improving bone mineralization. This often involves:
Vitamin D and calcium supplementation: To restore healthy levels of these essential nutrients.
Exposure to sunlight: To naturally increase vitamin D synthesis in the skin.
Dietary changes: Incorporating foods rich in vitamin D and calcium into the diet.
Addressing underlying conditions: Such as adjusting medication that interferes with vitamin D metabolism or treating diseases that affect nutrient absorption.
What is Paget’s Disease?
Paget’s disease of the bone is a chronic disorder that can result in enlarged and misshapen bones.
The disease is caused by the excessive breakdown and formation of bone tissue, leading to bones that are fragile and misshapen.
Paget’s disease most commonly affects the pelvis, skull, spine, and legs.
The cause of Paget’s disease is unknown, though genetic factors and viral infections have been suggested as potential contributors.
What are the three key characteristics of Paget’s disease?
Abnormal Bone Remodelling - The normal bone renewal process is disrupted, leading to bones that are weaker, larger, and more prone to fractures.
Age-Related Prevalence - Paget’s disease typically affects older adults, usually those over the age of 50.
Localized Disease - It often affects just one or a few bones, not the entire skeleton.
