Chem Path

Question 2

What are Metabolic Bone Diseases (MBD)?

Answer 2

A group of diseases characterized by an abnormal bone chemical milieu with an imbalance between bone formation and resorption, leading to defective skeleton and bone abnormalities.

Question 3

List examples of Metabolic Bone Diseases.

Answer 3

• Osteoporosis
• Osteomalacia/Rickets
• Renal osteodystrophy (CKD-MBD)
• Paget’s disease of bone
• Bone metastases

Question 4

What regulates bone metabolism?

Answer 4

• Mineral levels
• Parathyroid hormone (PTH)
• 1,25(OH)2 Vitamin D

Question 5

True or False: Osteoporosis usually presents with abnormal serum biochemical parameters.

Answer 5

False

Question 6

What is the composition of bone?

Answer 6

• 70% inorganic matter (minerals)
• 30% organic matter (osteoid)

Question 7

What is the primary function of osteoblasts?

Answer 7

To synthesize and deposit the bone matrix.

Question 8

What is the main histological type of mature bone that comprises up to 85% of bone mass?

Answer 8

Cortical or compact bone.

Question 9

Fill in the blank: The organic component of the bone matrix consists predominantly of _______.

Answer 9

type-1 collagen

Question 10

What is the role of osteoclasts?

Answer 10

To resorb bone matrix.

Question 11

How does parathyroid hormone (PTH) affect calcium metabolism?

Answer 11

PTH enhances calcium reabsorption in the kidneys and increases intestinal calcium absorption.

Question 12

What are the key markers of bone formation?

Answer 12

• Procollagen Type 1 N-terminal propeptide (P1NP)
• Bone alkaline phosphatase (BALP)
• Osteocalcin (OC)

Question 13

What is osteoporosis?

Answer 13

A progressive reduction in bone mineral density (BMD) with abnormal micro-architecture of bone tissue, leading to weak, fracture-prone bones.

Question 14

What is the difference between primary and secondary osteoporosis?

Answer 14

Primary osteoporosis is due to hormonal changes or aging, while secondary osteoporosis is due to other medical conditions or lifestyle factors.

Question 15

What is osteomalacia?

Answer 15

A condition characterized by the softening of bones due to inadequate mineralization.

Question 16

What is the typical age when peak bone mass is attained?

Answer 16

30 years.

Question 17

What causes increased osteoclast activity in osteoporosis?

Answer 17

Decreased estrogen levels, especially in post-menopausal women.

Question 18

What is the effect of chronic metabolic acidosis on bone?

Answer 18

Bone acts as a buffer system, releasing phosphate to help regulate pH.

Question 19

Fill in the blank: The principal regulator of the active transport of phosphate is _______.

Answer 19

1,25(OH)2 VitD

Question 20

What is the role of osteocytes?

Answer 20

To act as mechanosensory cells and maintain bone structure and mass.

Question 21

What is the significance of the balance between osteoblasts and osteoclasts?

Answer 21

Normal bone physiology depends on their interaction; disruption leads to metabolic bone diseases.

Question 22

What is renal osteodystrophy?

Answer 22

A bone disorder associated with chronic kidney disease, affecting bone metabolism.

Question 23

What are the hormonal modulators of bone metabolism?

Answer 23

• Parathyroid hormone (PTH)
• Calcitriol (1,25(OH)2 VitD)
• Growth hormone/IGF-1
• Estrogens and testosterone
• Glucocorticoids
• Thyroid hormones
• Calcitonin

Question 24

What does osteopenia refer to?

Answer 24

A descriptive term for a loss of bone mineral density (BMD) observed radiologically.

Question 25

What is the biochemical marker for bone resorption?

Answer 25

* Type I Collagen Telopeptides * Tartrate-Resistant Acid Phosphatase (TRACP5b)

Question 26

What is the primary characteristic of Paget’s disease?

Answer 26

Abnormal and excessive bone remodeling, leading to enlarged and weakened bones.

Question 27

What is Type I osteoporosis?

Answer 27

Occurs due to post-menopausal bone loss, affecting trabecular bone leading to vertebral body collapse ## Footnote Also known as post-menopausal osteoporosis.

Question 28

What is Type II osteoporosis?

Answer 28

Results from natural bone loss with age, affecting trabecular and cortical bone, often associated with femoral neck fractures ## Footnote Also referred to as senile osteoporosis.

Question 29

List some endocrine causes of secondary osteoporosis.

Answer 29

* Hyperthyroidism/Thyrotoxicosis * Cushing’s Syndrome * Hypogonadism * Hyperparathyroidism * Diabetes Mellitus

Question 30

What lifestyle factors contribute to secondary osteoporosis?

Answer 30

* Smoking * Alcohol abuse * Poor nutrition (Calcium deficiency)

Question 31

Name some drugs that can cause secondary osteoporosis.

Answer 31

* Chronic alcoholism * Glucocorticoids * Corticosteroids * Heparin * Anticonvulsants

Question 32

What gastrointestinal issues can lead to osteoporosis?

Answer 32

* Malabsorption * Anorexia nervosa

Question 33

What are common clinical findings of osteoporosis?

Answer 33

* Mild vertebral fractures may be silent * Fractures of vertebrae, hip, distal radius, and femoral neck occur most often.

Question 34

How is osteoporosis diagnosed?

Answer 34

By measuring bone mineral density using dual-energy X-ray absorptiometry.

Question 35

What is the primary goal of osteoporosis treatment?

Answer 35

Prevention through adequate nutrition (Calcium, Vitamin D, protein) and regular exercise.

Question 36

What are some antiresorptive therapies for osteoporosis?

Answer 36

* Bisphosphonates * Calcitonin * Strontium ranelate

Question 37

What is osteomalacia?

Answer 37

Refers to the softening of bones due to defective mineralization of the bone matrix or cartilage.

Question 38

What is the basic cause of osteomalacia and rickets?

Answer 38

Calcium or phosphate deficiency, leading to abnormal mineralization.

Question 39

What are the types of rickets?

Answer 39

* Nutritional (Calcium, Phosphate, Vitamin D deficiency) * Non-nutritional * Familial hypophosphataemia * Vitamin D dependent rickets Type I * Vitamin D dependent rickets Type II

Question 40

What clinical features are common in children with rickets?

Answer 40

* Bone pain * Fractures * Skeletal deformities (e.g., rachitic rosary, genu varum, genu valgus)

Question 41

What biochemical findings are associated with osteomalacia and rickets?

Answer 41

* Decreased Calcium * Decreased Phosphate * Increased ALP * Increased serum PTH levels

Question 42

What is chronic kidney disease metabolic bone disease (CK-MBD)?

Answer 42

A metabolic bone disease consisting of osteitis fibrosa, osteomalacia, secondary hyperparathyroidism, and osteosclerosis due to chronic renal failure.

Question 43

What are common clinical features of CK-MBD?

Answer 43

* Bone pain * Skeletal deformities (in growing children) * Leg and hip pain * Back pain

Question 44

What is Paget's disease characterized by?

Answer 44

Excessive osteoclastic bone resorption followed by abnormal bone formation.

Question 45

What are the common biochemical findings in Paget's disease?

Answer 45

* Normal serum calcium and phosphate levels * Elevated serum ALP levels * Increased urinary hydroxyproline during active disease

Question 46

What is the most common skeletal complication of malignancy?

Answer 46

Bone metastases.

Question 47

What are the types of bone metastases based on tumor characteristics?

Answer 47

* Osteolytic * Osteoblastic * Mixed

Question 48

What biochemical markers are useful in assessing bone metastases?

Answer 48

* Bone formation markers (e.g., PINP) * Resorption markers (e.g., DPD) * Serum ICTP

Question 49

What tests are performed for the diagnosis of metabolic bone diseases?

Answer 49

* Routine tests for Calcium, Phosphate, ALP, PTH, Vitamin D * Radiographic examination * Bone biopsy (if indicated)

Question 50

What are the two categories of biochemical markers for bone turnover?

Answer 50

* Bone Formation: BALP, Osteocalcin, P1NP, P1CP * Bone Resorption: Hydroxyproline, DPD, NTX, CTX, TRACP5b