Bone diseases or disorders are medical conditions, which affect bones in our body. Let’s learn about some of the common bone diseases, their causes, symptoms and pathogenesis.

1. Osteoporosis

It is the most common disease in the elderly. There is a reduction in bone mass. Bones become more fragile and there is an increased risk of fractures. Osteoporosis is of various types depending on the causes.

Primary osteoporosis occurs due to demineralisation. It is most common in post-menopausal women. It is an age-related disorder. Lower estrogen level after menopause is a primary cause of rapid loss of bone mass in women.

This type of osteoporosis is rare in young individuals and children.

Secondary osteoporosis is caused by certain other disorders or due to some medications. Cystic fibrosis patients show a marked decrease in bone density. Hyperthyroidism, renal defect leading to low Ca reabsorption, estrogen deficiency due to genetic disorders, chronic illness, etc. may also lead to low bone mass. Alcoholism, smoking, less exercise, certain medications such as glucocorticoids, chemotherapy may also cause osteoporosis.

2. Rickets and Osteomalacia

Rickets and osteomalacia are caused by inadequate levels of Calcium, phosphate, Vitamin D levels leading to skeletal deformities and fractures.

Rickets affects children. There is delay in the deposition of calcium phosphate in growing bones leading to deformities in bones.

Osteomalacia occurs in adults causing softening of bones and leads to fractures.

3. Paget’s Disease

In this disease, the recycling or remodelling process of bone is interfered. It mostly affects, pelvis, spine, legs and skull. It is a progressive disorder. There is an excessive loss of bones at the affected site, this leads to rapid production of disorganized new bone formation and causes weakening of the bones and deformities. Localized sites contain numerous osteoclasts.

Paget’s disease is associated with a viral infection and also to genetic defects.

4. Osteogenesis Imperfecta (OI)

It is also known as brittle bone disease. It is a developmental skeletal disorder. The bones of the deceased break easily. OI may be caused due to mutation or genetic defects. These defects lead to impaired production of type I collagen protein. OI is of four main types, which vary in their severity. Type II is the most severe form and type I is the most common and is related to the mildest symptoms.

5. Bone Tumours

Bone tumours are not inherited and are acquired later in life. Primary tumours originate in the bones, whereas secondary or metastatic tumours originate outside of the skeleton. Osteosarcoma is a form of the malignant primary tumour, whereas osteochondroma is a common benign tumour.

This was a brief note on Disorders of Bones. Explore notes on Disorders of Joints and other important concepts related to NEET, only at BYJU’S.

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