Metabolic Bone Diseases Practice Questions

Q: Commonest deformity in Rickets is

Genu valgum. ***Genu valgum*** - **Genu valgum**, or **knock knees**, is very common in rickets due to the softening of bones. - The softened bones cannot bear weight properly, leading to bowing of the legs where the knees turn inward. *Genu recurvatum* - **Genu recurvatum (back-knee)** involves hyperextension of the knee joint. - While it can occur in some bone and joint disorders, it is not the most common or characteristic deformity of rickets. *Cubitus valgus* - **Cubitus valgus** refers to an increased carrying angle at the elbow, an deformity of the upper limb. - Rickets primarily affects weight-bearing bones and growth plates, leading to lower limb deformities more frequently. *Genu varum* - **Genu varum**, or **bowlegs**, is also a common deformity in rickets, but **genu valgum** is considered more prevalent in many populations. - It involves bowing of the legs outward, with the knees remaining apart when the ankles are touched together.

Q: Not seen in osteogenesis imperfecta

Thick cortical bone. ***Thick cortical bone*** - Osteogenesis imperfecta (OI) is characterized by **fragile bones** due to defects in **Type I collagen** synthesis, leading to abnormally **thin cortical bone**. - **Thick cortical bone** would indicate increased bone density or strength, which is the opposite of the fundamental pathology in OI. *Wormian bones* - **Wormian bones** (intrasutural bones) are frequently seen in individuals with **osteogenesis imperfecta**, particularly in types I and III. - They are small, irregular bones that develop within the **cranial sutures**. *Coxa vara* - **Coxa vara**, a deformity where the angle between the femoral neck and shaft is decreased, is a common orthopedic complication of **osteogenesis imperfecta**. - This deformity is primarily due to the **bone fragility** and remodeling issues inherent to the condition. *Saber shin* - **Saber shin** refers to an anterior bowing of the tibia, which is a classic orthopedic manifestation in patients with **osteogenesis imperfecta**. - This bowing results from repeated microfractures and **abnormal bone remodeling** characteristic of the disease.

Q: Albers Schonberg disease is also called as -

Osteopetrosis. ***Osteopetrosis*** - Albers-Schonberg disease is a common synonym for **osteopetrosis**, also known as **marble bone disease**. - This genetic disorder is characterized by abnormally **dense bones** due to a defect in **osteoclast function**, leading to unresorbed bone. *Osteoporosis* - **Osteoporosis** is a condition of **reduced bone density** and mass, leading to fragile bones and increased fracture risk, which is the opposite of Albers-Schonberg disease. - It results from an imbalance where **bone resorption** by osteoclasts outpaces bone formation by osteoblasts. *Osteitis punctata* - This term is not a recognized medical condition but might refer to a non-specific localized inflammation or lesion of bone characterized by "dots" or points. - It does not describe a systemic bone density disorder like Albers-Schonberg disease. *Osteodystrophy* - **Osteodystrophy** is a general term referring to a **bone disease** or malformation, often due to a metabolic disorder like **renal osteodystrophy**. - It is a broader category and not a specific synonym for Albers-Schonberg disease.

Q: Which of the following is true about osteoporosis?

Cod fish vertebrae. **Cod fish vertebrae** - **Cod fish vertebrae** (or biconcave vertebral bodies) are a characteristic radiological sign seen in **osteoporosis**, resulting from weakened vertebral bodies bulging under pressure from disc material. - This appearance is due to the softening of the vertebral endplates, allowing the intervertebral discs to indent the adjacent vertebral bodies. - This is a classic finding in severe osteoporosis on lateral spine radiographs. *Raised alkaline phosphatase* - **Alkaline phosphatase (ALP)** levels are typically **normal in osteoporosis** because bone turnover, while unbalanced, does not involve a significant increase in osteoblastic activity that would elevate ALP. - **Elevated ALP** is more characteristic of conditions with increased osteoblastic activity, such as **Paget's disease of bone**, **osteomalacia**, or bone metastases. *Low calcium* - **Serum calcium levels** are typically **normal in osteoporosis** as the body maintains calcium homeostasis through hormonal regulation, even if bone density is low. - **Low calcium (hypocalcemia)** is more commonly associated with conditions like **hypoparathyroidism** or severe **vitamin D deficiency** leading to **osteomalacia**. *Low phosphate* - **Serum phosphate levels** are typically **normal in osteoporosis**, similar to calcium, due to tightly regulated homeostatic mechanisms. - **Low phosphate (hypophosphatemia)** can be seen in conditions like **osteomalacia** (especially those related to vitamin D deficiency or renal phosphate wasting) but not typically in osteoporosis.

Q: A 70-year-old female has been on alendronate for 7 years for osteoporosis and now complains of pain in her right thigh. What is the next investigation to be performed?

X-ray. **X-ray** - Alendronate, a **bisphosphonate**, is associated with **atypical femoral fractures** after prolonged use, and an X-ray is the most appropriate initial investigation to visualize such a fracture. - Complaints of thigh pain in a patient on long-term bisphosphonate therapy should prompt imaging to rule out this serious complication. *DEXA scan* - A DEXA scan assesses **bone mineral density** but does not provide information about acute fractures or structural integrity in response to specific pain. - While it's used for osteoporosis diagnosis and monitoring, it won't directly identify an atypical femoral fracture. *Serum vitamin D levels* - Maintaining adequate **vitamin D levels** is important for bone health, but its measurement won't explain acute thigh pain or identify a fracture. - Low vitamin D levels can contribute to osteoporosis but are not the primary cause of pain suggestive of an atypical femoral fracture. *Serum alkaline phosphate levels* - **Alkaline phosphatase** levels can be elevated in conditions involving increased bone turnover, such as healing fractures or certain bone diseases. - However, it is not a direct diagnostic tool for identifying atypical femoral fractures and would not be the first line investigation.

Q: Brittle bone disease is -

Osteogenesis imperfecta. ***Osteogenesis imperfecta*** - **Osteogenesis imperfecta** is an inherited disorder characterized by **brittle bones** that fracture easily, due to a defect in **collagen type I** synthesis. - Patients often present with **blue sclera**, **dentinogenesis imperfecta**, and **hearing loss**, in addition to frequent fractures. *Osteoporosis* - **Osteoporosis** is a condition of **decreased bone density**, making bones fragile and prone to fracture, but it is not typically referred to as "brittle bone disease" in the same congenital sense. - It is more common in older adults and is often related to **hormonal changes** (e.g., post-menopause) or lifestyle factors. *Paget's disease* - **Paget's disease of bone** involves abnormal bone remodeling with excessive bone resorption followed by disorganized and expanded bone formation, leading to **enlarged, weakened bones**. - It typically affects older individuals and can lead to bone pain, deformities, and fractures, but it's not the primary condition associated with "brittle bone disease." *Osteopetrosis* - **Osteopetrosis** is characterized by **abnormally dense bones** due to impaired osteoclast function, leading to a buildup of bone. - While bones are dense, they are also **brittle** and prone to fracture, and the condition is also known as "marble bone disease" rather than "brittle bone disease."

Q: Blue sclera is seen in:

Osteogenesis imperfecta. ***Osteogenesis imperfecta*** - Blue sclera in **osteogenesis imperfecta** is due to the underlying defect in **collagen type I synthesis**, which causes the sclera to be thin and translucent [1]. - This thinness allows the underlying **choroidal pigmentation** to show through, giving it a characteristic blue hue. *Rheumatoid arthritis* - While rheumatoid arthritis can affect the eyes (e.g., scleritis, episcleritis), it does not typically cause **blue sclera**. - Ocular manifestations are usually related to inflammation and can lead to **scleral thinning** or perforation but are distinct from the blue appearance seen in osteogenesis imperfecta. *Diabetes mellitus* - Diabetes mellitus can lead to various ocular complications, such as **diabetic retinopathy**, **cataracts**, and **glaucoma**. - It does not cause a change in the color of the sclera to blue. *Hypertension* - Hypertension can affect the eyes, particularly the **retinal vasculature** (hypertensive retinopathy), and increase the risk of conditions like **glaucoma**. - It has no direct association with the phenomenon of **blue sclera**.

Q: A 65-year-old female attended the Orthopaedics OPD with a chief complaint of chronic backache. The radiograph of the lumbar spine is obtained. What could be the most probable diagnosis?

Osteoporosis. ***Osteoporosis*** - Chronic backache in a 65-year-old female is a classic presentation of **osteoporosis**, often due to vertebral compression fractures. - Radiographs would show **decreased bone density**, possibly wedging or collapse of vertebral bodies. *Renal Osteodystrophy* - This condition is associated with **chronic kidney disease**, which is not mentioned in the patient's history. - Radiographic features typically include **subperiosteal bone resorption** (especially in phalanges), osteosclerosis ("rugger-jersey spine"), and bone cysts. *Paget's Disease* - Paget's disease is characterized by localized areas of **increased bone turnover**, resulting in disorganized and enlarged bone. - Radiographs would show characteristic features like **bone enlargement**, cortical thickening, and a "cotton wool" appearance, which is not suggested by general backache. *Rheumatoid Arthritis* - Rheumatoid arthritis primarily affects **synovial joints** and typically presents with symmetrical polyarthritis, morning stiffness, and swelling in peripheral joints, not isolated chronic backache. - While it can affect the cervical spine, it rarely presents as isolated chronic low back pain in this age group and has specific radiographic changes like **joint erosions** and narrowing not indicative of osteoporosis.

Q: An intrauterine scan at the 13th week of pregnancy showed a fetus with multiple long bone fractures. What is commonly associated with this finding?

Osteogenesis imperfecta. ***Osteogenesis imperfecta*** - **Multiple long bone fractures** detected early in pregnancy are a classic presentation of **osteogenesis imperfecta (OI)**, a genetic disorder characterized by **bone fragility**. - OI is primarily caused by mutations in genes encoding **type I collagen**, leading to defective bone formation. *Achondroplasia* - This condition is a form of **dwarfism** characterized by disproportionately short limbs and a normal-sized trunk, resulting from a mutation in the **FGFR3 gene**. - While it affects bone growth, it typically does not cause **multiple fractures** prenatally. *Marfan syndrome* - This is a connective tissue disorder affecting the skeletal, ocular, and cardiovascular systems, characterized by **tall stature**, **long limbs and fingers**, and **aortic root dilation**. - It results from a mutation in the **fibrillin-1 gene** and is not primarily associated with prenatal long bone fractures. *Cretinism* - This is a historical term for **congenital hypothyroidism**, which results from severely deficient thyroid hormone production in a newborn. - It leads to developmental delays, growth retardation, and intellectual disability, but not to **multiple bone fractures**.

Q: Windswept deformity is seen in which condition?

Rickets. ***Rickets*** - **Windswept deformity** is characterized by bilateral knee deformities where one knee is in **valgus** and the other is in **varus**. - This condition is caused by a deficiency in **vitamin D**, **calcium**, or **phosphate**, leading to improper bone mineralization and subsequent bone deformities. *Rheumatoid Arthritis* - Rheumatoid arthritis is a **chronic autoimmune inflammatory disease** primarily affecting the synovial joints. - While it can cause joint deformities, they typically involve symmetric joint swelling, pain, and stiffness, with characteristic deformities like **ulnar deviation** or **swan-neck deformities**, rather than windswept deformity. *Hyperparathyroidism* - Hyperparathyroidism leads to excessive production of **parathyroid hormone**, which causes increased bone resorption and elevated blood calcium levels. - It can result in bone fragility, **osteitis fibrosa cystica**, and kidney stones, but it does not cause specific windswept deformity. *Scurvy* - Scurvy results from a severe deficiency of **vitamin C**, which is essential for collagen synthesis. - It presents with symptoms like bleeding gums, poor wound healing, and perifollicular hemorrhages, but it does not typically cause windswept deformity of the knees.

Question 1

Commonest deformity in Rickets is

Accepted Answer

Genu valgum

Answer

Genu recurvatum

Answer

Cubitus valgus

Answer

Genu varum

Question 2

Not seen in osteogenesis imperfecta

Accepted Answer

Thick cortical bone

Answer

Wormian bones

Answer

Coxa vara

Answer

Saber shin

Question 3

Albers Schonberg disease is also called as -

Accepted Answer

Osteopetrosis

Answer

Osteoporosis

Answer

Osteitis punctata

Answer

Osteodystrophy

Question 4

Which of the following is true about osteoporosis?

Accepted Answer

Cod fish vertebrae

Answer

Raised alkaline phosphatase

Answer

Low calcium

Answer

Low phosphate

Question 5

A 70-year-old female has been on alendronate for 7 years for osteoporosis and now complains of pain in her right thigh. What is the next investigation to be performed?

Accepted Answer

X-ray

Answer

DEXA scan

Answer

Serum vitamin D levels

Answer

Serum alkaline phosphate levels

Question 6

Brittle bone disease is -

Accepted Answer

Osteogenesis imperfecta

Answer

Osteoporosis

Answer

Pagets disease

Answer

Osteopetrosis

Question 7

Blue sclera is seen in:

Accepted Answer

Osteogenesis imperfecta

Answer

Rheumatoid arthritis

Answer

Diabetes mellitus

Answer

Hypertension

Question 8

A 65-year-old female attended the Orthopaedics OPD with a chief complaint of chronic backache. The radiograph of the lumbar spine is obtained. What could be the most probable diagnosis?

Accepted Answer

Osteoporosis

Answer

Renal Osteodystrophy

Answer

Paget's Disease

Answer

Rheumatoid Arthritis

Question 9

An intrauterine scan at the 13th week of pregnancy showed a fetus with multiple long bone fractures. What is commonly associated with this finding?

Accepted Answer

Osteogenesis imperfecta

Answer

Marfan syndrome

Answer

Achondroplasia

Answer

Cretinism

Question 10

Windswept deformity is seen in which condition?

Accepted Answer

Rickets

Answer

Hyperparathyroidism

Answer

Scurvy

Answer

Rheumatoid Arthritis

Metabolic Bone Diseases — MCQs

Metabolic Bone Diseases — MCQs

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