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Internal Medicine > Endocrinology- Brittle Bones > Flashcards

Endocrinology- Brittle Bones Flashcards

1
Q

A 67-year-old woman trips on the edge of her carpet at home and fractures her left neck of femur. She is otherwise well and has no known comorbid chronic medical illnesses

A
  • Does she have brittle bones and what are the causes for brittle bones?
  • Which cells are found in bone and what are their respective functions?
  • What constitutes a low impact fall?
  • What is her diagnosis?
  • What are the endocrinological causes for osteoporosis?
  • What are some non-endocrinological causes for osteoporosis?
  • How do you diagnose and treat osteoporosis?
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2
Q
  1. Does she have brittle bones, and what are the causes of brittle bones?
A

Brittle bones refer to bones that are more prone to fractures due to decreased bone strength and density. This is typically seen in osteoporosis, a condition characterized by reduced bone mass and deterioration of bone tissue.

Causes of brittle bones (osteoporosis):
- Aging (bone density naturally decreases with age)
- Hormonal changes (especially in postmenopausal women due to reduced estrogen)
- Inadequate calcium and vitamin D intake
- Sedentary lifestyle or lack of weight-bearing exercise
- Smoking and excessive alcohol consumption
Medications (e.g., long-term corticosteroid use)
- osteomalacia and metatastic process

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3
Q
  1. Which cells are found in bone, and what are their respective functions?
A

Osteoblasts: These cells are responsible for bone formation. They produce the bone matrix and mineralize it, helping in the growth and repair of bone.

Osteoclasts: These are large, multinucleated cells responsible for bone resorption. They break down bone tissue, releasing calcium and phosphate into the bloodstream.

Osteocytes: These are mature osteoblasts that have become trapped in the bone matrix. They help maintain bone tissue by detecting mechanical stress and signaling to osteoblasts and osteoclasts.

Bone-lining cells: These cells cover inactive bone surfaces and help regulate the movement of calcium and other nutrients in and out of the bone.

Osteogenic cells (osteoprogenitor cells): These are stem cells found in the bone marrow and periosteum. They differentiate into osteoblasts and are essential for the growth and repair of bones.

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4
Q
  1. What constitutes a low-impact fall?
A

A low-impact fall refers to a fall from standing height or lower that wouldn’t typically cause a fracture in a healthy bone. In this case, the fracture after tripping on a carpet suggests that the patient’s bones are fragile, a hallmark of osteoporosis.

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5
Q
  1. What is her diagnosis?
A

The woman likely has a fractured neck of femur (hip fracture), which is common in elderly individuals with osteoporosis following a low-impact fall.

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6
Q
  1. What are the endocrinological causes of osteoporosis?
A
  • Estrogen deficiency (e.g., postmenopausal women)
  • Testosterone deficiency (in men)
  • Hyperthyroidism or thyrotoxicosis
  • Hyperparathyroidism (excessive parathyroid hormone increases bone resorption)
  • Cushing’s syndrome (excess cortisol production, leading to bone loss)
  • Diabetes (insulin deficiency or resistance can lead to bone density issues)
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7
Q
  1. What are some non-endocrinological causes of osteoporosis?
A
  • Aging (natural loss of bone mass with age)
  • Vitamin D deficiency (reduces calcium absorption, leading to bone weakness)
  • Calcium deficiency (inadequate dietary calcium impairs bone maintenance)
  • Chronic kidney disease (leading to altered calcium and phosphate balance)
  • Prolonged immobilization or sedentary lifestyle (lack of mechanical stress on bones)
  • Medications (e.g., long-term use of corticosteroids, anticonvulsants, or proton pump inhibitors)
  • Smoking and excessive alcohol intake
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8
Q

How do you diagnose and treat osteoporosis?

A

Diagnosis:

  • Dual-energy X-ray absorptiometry (DEXA) scan: Measures bone mineral density (BMD). A T-score of ≤ -2.5 indicates osteoporosis.
  • Fracture risk assessment: Tools like FRAX (Fracture Risk Assessment Tool) can help evaluate the 10-year probability of fractures.
  • Blood tests: To check calcium, vitamin D, parathyroid hormone (PTH), and other relevant marker

Treatment:

Lifestyle modifications:
- Adequate calcium (1200 mg/day) and vitamin D (800-1000 IU/day) intake.
- Weight-bearing and resistance exercises to strengthen bones.
- Smoking cessation and reduction of alcohol consumption.

Medications:
- Bisphosphonates (e.g., alendronate, risedronate): Inhibit osteoclast activity, reducing bone resorption.
- Selective estrogen receptor modulators (SERMs): Mimic estrogen’s bone-protective effects.
- Denosumab: A monoclonal antibody that inhibits osteoclast formation and function.
- Teriparatide: A form of parathyroid hormone used for severe osteoporosis to stimulate bone formation.
- Hormone replacement therapy (HRT): Sometimes used in postmenopausal women, though with risks.

Fall prevention: Home safety modifications to prevent future falls.

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9
Q

What constitutes a low-impact fall?

A

A low-impact fall is a fall from standing height or lower that typically wouldn’t result in a fracture in a healthy individual. In older adults with osteoporosis, low-impact falls can cause significant fractures due to brittle bones.

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10
Q

What is the mechanism of action in a low-energy trauma causing fractures, particularly in older adults

A

Low-energy trauma often occurs in older patients with osteoporosis, leading to fractures.

Direct trauma: A fall onto the greater trochanter causes valgus impaction. Alternatively, forced external rotation of the lower extremity impinges the osteoporotic femoral neck onto the posterior lip of the acetabulum, resulting in posterior comminution (fragmentation of bone).

Indirect trauma: Muscle forces acting on the femur overwhelm the strength of the femoral neck, causing a fracture, especially in osteoporotic bone.

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11
Q

How does direct trauma cause a femoral neck fracture in a low-impact fall?

A

Direct trauma, such as a fall onto the greater trochanter, leads to valgus impaction. Alternatively, forced external rotation of the lower extremity impinges the osteoporotic femoral neck onto the posterior acetabulum, causing posterior comminution.

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12
Q

How does indirect trauma cause a femoral neck fracture in older patients?

A

Indirect trauma occurs when muscle forces acting on the femur overwhelm the weakened, osteoporotic femoral neck, leading to a fracture without direct impact on the bone.

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13
Q

Which bones fracture in osteoporosis

A

Wrist fracture
Spinal fracture
Hip fracture

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14
Q

Endocrine disease or metabolic causes of osteoporosis

A

hypogonadism
hyperadrenocorticism
thyrotoxicosis
anorexia nervosa
hyperprolactinemia
porphyria
hypophosphatasia, in adults
diabetes mellitus type 1
hyperparathyroidism
acromegaly

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15
Q

nutritional conditions that causes osteoporosis

A

malabsorption syndromes
malnutrition
chronic cholestatic liver disease
gastric operations
vitamin D deficiency
calcium deficiency
alcoholism
hypercalciuria

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16
Q

drugs that cause osteoporosis

A

glucocorticoids
excess thyroid hormone
heparin
GnRH agonists
phenytoin
phenobarbital
depo provera
aromatase inhibitors

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17
Q

disorders of collagen metabolism that can cause osteoporosis

A

osteogensesis imperfecta
homocystinuria
ehlers- danlos syndrome
marfan syndrome

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18
Q

other causes of osteoporosis

A

rheumatoid arthirtis
myeloma and some cancers
immobilization
renal tubular acidosis
COPD
organ transplantation
mastocytosis
thalassemia

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19
Q

most common causes of secondary osteoporosis- diseases

A
  • hypogonadism
  • malabsorption
  • COPD
  • rheumatoid arthritis
  • cholestatic liver disease
  • hyperthyroidism
  • hyperparathyroidism
    -myeloma
20
Q

most common causes of secondary osteoporosis- conditions

A

Vitamin D deficiency
Hypercalciuria
Alcoholism

21
Q

most common causes of secondary osteoporosis- Drugs

A
  • Steroid therapy
  • Antiepileptics
  • GnRH agonists
  • Depo provera
  • Aromatase inhibitors
  • Excess thyroxine
22
Q

Workup of the patient with osteoporosis

A

Careful medical history and physical examination

  • Known diseases and medications that affect bone
  • Signs of symptoms of underlying conditions
  • Evidence for vertebral fractures ]
  • Height loss (1.5-2)
  • Distance between occiput and wall <0cm
  • Distance between ribs and pelvis <2 finger breadths
23
Q

What aspects of medical history should be considered in a patient with osteoporosis?

A

Assess for known diseases that affect bone health (e.g., hyperthyroidism, Cushing’s syndrome, rheumatoid arthritis).

Review medications that may lead to bone loss (e.g., corticosteroids, anticonvulsants, proton pump inhibitors).

24
Q

What signs and symptoms might suggest an underlying condition contributing to osteoporosis?

A

Signs of thyroid disease, malabsorption disorders, or hypogonadism.

Symptoms of chronic kidney disease or hormonal imbalances affecting bone density.

25
Q

What clinical findings suggest evidence of vertebral fractures in a patient with osteoporosis?

A
  • Height loss of 1.5-2 cm or more.
  • Occiput-to-wall distance of greater than 0 cm (difficulty standing straight with the head touching the wall).
  • Distance between ribs and pelvis of less than 2 finger breadths.
26
Q

Why is height loss significant when assessing a patient with osteoporosis?

A

Height loss of 1.5-2 cm or more can indicate vertebral compression fractures, a common consequence of osteoporosis, leading to changes in posture and spinal deformity.

27
Q

How is the occiput-to-wall distance used to assess vertebral fractures in osteoporosis?

A

If the occiput (back of the head) cannot touch the wall when the patient stands straight, it indicates kyphosis or vertebral fractures, a sign of advanced osteoporosis.

28
Q

How is the rib-to-pelvis distance measured and why is it significant in osteoporosis?

A

A rib-to-pelvis distance of less than 2 finger breadths suggests compression fractures in the spine, indicating severe vertebral deformity due to osteoporosis.

29
Q

What is the leading cause of secondary osteoporosis?

A

Glucocorticoid use is the number one cause of secondary osteoporosis, leading to significant bone loss and increased fracture risk.

30
Q

How many Americans are on long-term oral glucocorticoid therapy?

A

Approximately 1 million Americans require long-term oral glucocorticoid therapy, making them vulnerable to osteoporosis and fractures.

31
Q

What percentage of chronic glucocorticoid users experience osteoporotic fractures?

A

30-50% of chronic glucocorticoid users will experience osteoporotic fractures during their treatment.

32
Q

Critical Steps in Osteoporosis Intervention

A
  • Identify appropriate candidates for treatment
  • Evaluate for contributory causes
  • Correct physiologic abnormalities
  • Ensure adequate Ca and Vitamin D
  • Treat with an effective agent
  • Follow up- optimize adherence
33
Q

Pharmacological treatment

A

Alendronate
Risedronate
Ibandronate
Zoledronic acid
Clacitonin
Raloxifene
Teriparatide
DEnosumab

34
Q

Question 1 A 67-year-old woman who falls on the edge of her carpet and sustains a neck of femur fracture
a. This patient most certainly has osteoporosis
b. Osteoporosis, osteomalacia and a metastatic process should be considered in this patient
c. osteoporosis, osteomalacia, metastatic process, physiological abnormalities such as recurrent falling, smoking and tobacco use should be considered.
d. Secondary causes of osteoporosis, osteomalacia, metastatic process, physiological abnormalities, such as recurrent falling, smoking and tobacco use should be considered.

A

d. Secondary causes of osteoporosis, osteomalacia, metastatic process, physiological abnormalities, such as recurrent falling, smoking and tobacco use should be considered.

35
Q

Question 2
a. Osteoporosis can be diagnosed on X-ray if there is osteopenia.
b. Osteoporosis should be diagnosed on DEXA scan if the T scores >2.5 for postmenopausal women and men
c. osteoporosis should be diagnosed on DEXA scan if the T scores are <-2.5 for postmenopausal women, Z scores < -2.0 for premenopausal women and men less than the age of 50 years.
d. Osteoporosis can be diagnosed using vitamin D levels, calcium, alkaline phosphatase and bone turnover markers

A

c. Osteoporosis should be diagnosed on DEXA scan if the T scores are <-2.5 for postmenopausal women, Z scores < -2.0 for premenopausal women and men less than the age of 50 years.

36
Q

Question 3
The most important secondary causes of osteoporosis to be excluded are:
a) aromatase inhibitors, GnRH agonists, hypercalciuria
b) hypogonadism, hyperthyroidism, multiple myeloma, hyperparathyroidism, vitamin D deficiency
c) coeliac disease, vitamin D deficiency, anticonvulsants, rheumatoid arthritis
d) hypogonadism, hyperthyroidism, multiple myeloma, vitamin D deficiency, breast carcinoma

A

A. Hypogonadism, hyperthyroidism, multiple myeloma, hyperparathyroidism, vitamin D deficiency, breast carcinoma

37
Q

Question 4
Which statement is the most correct:
a) Zolendronic acid is the most powerful bisphosphonate useful as a first-line agent for management of osteoporosis.
b) Alendronate is a powerful oral bisphosphonate, with equivalent benefit as zolendronic acid.
c) Teriparatide (parathyroid hormone) given in high doses is very useful to manage osteoporosis as first-line agent.
d) Denosumab is a first-line agent, which can be used in patients who have low calcium and impaired renal function.

A

Zolendronic acid is the most powerful bisphosphonate useful as a first-line agent for management of osteoporosis.

38
Q

What is the definition of a low impact fall giving rise to a fracture?

A. Below 2m
B. Below shoulder height
C. Below waist height
D. Below 3m

A

B. Below shoulder height

39
Q

Which scoring system is used for post-menopausal women?

A. Z-score > 2.5
B. T-score < 2.5
C. Z-score < 2.5
D. T-score > 2.5

A

B. T-score < 2.5

40
Q

What is the function of osteoblasts?

A. Forms bone matrix
B. Resorbs bone
C. Maintains bone tissue
D. Pluripotent stem cells

A

A. Forms bone matrix

41
Q

Which of the following drugs increases the risk of osteoporosis?

A. Metformin
B. Statins
C. Non-steroidal anti-inflammatory (NSAID)
D. Glucocorticoids

A

D. Glucocorticoids

42
Q

Which is the most common site of fracture in osteoporosis?

A. Femur Fracture
B. Vertebral fracture
C. Clavicle fracture
D. Humerus fracture

A

B. Vertebral fracture

43
Q

Which of the following investigations is considered the gold standard in diagnosing osteoporosis?

A. Magnetic resonance imaging (MRI) of the hip
B. Hip radiograph
C. DEXA scan
D. Computed tomography scan (CT) of the hip

A

C. DEXA scan

44
Q

A 67-year-old woman who falls on the edge of her carpet and sustains a neck of femur fracture.

Which of the following statements is TRUE?

A. Osteoporosis, osteomalacia and a metastatic process should be considered in this patient.
B. Osteoporosis, osteomalacia, metastatic process, physiological abnormalities such as recurrent falling, smoking and tobacco use should be considered.
C. Secondary causes of osteoporosis, osteomalacia, metastatic process, physiological abnormalities, such as recurrent falling, smoking and tobacco use should be considered.
D. This patient most certainly has osteoporosis.

A

C. Secondary causes of osteoporosis, osteomalacia, metastatic process, physiological abnormalities, such as recurrent falling, smoking and tobacco use should be considered.

45
Q

Which of the following malignancies metastasize have the greatest risk of metastasizing to the bone?

A. Liver
B. Oesophagus
C. Colon
D. Prostate

A

D. Prostate

46
Q

The most important secondary causes of osteoporosis to be excluded are:

A. Hypogonadism, hyperthyroidism, multiple myeloma, hyperparathyroidism, vitamin D deficiency, breast carcinoma
B. Hypogonadism, hyperthyroidism, multiple myeloma, hyperparathyroidism, vitamin D deficiency
C. Coeliac disease, vitamin D deficiency, anticonvulsants, rheumatoid arthritis
D. Aromatase inhibitors, GnRH agonists, hypercalciuria

A

A. Hypogonadism, hyperthyroidism, multiple myeloma, hyperparathyroidism, vitamin D deficiency, breast carcinoma

47
Q

What is the pathophysiology of osteoporosis?

A. ↓ Bone mineral density, ↑ osteoblasts
B. ↓ Bone mineral density, ↓ osteoblasts
C. ↓ Bone mineral density, ↑ collagen
D. ↓ Bone mineral density, ↓ collagen

A

D. ↓ Bone mineral density, ↓ collagen

Internal Medicine (14 decks)

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