Lecture 11 - Non-neoplastic bone diseases

Question 1

Bone is made mainly of Type ____ cartilage.

Answer 1

Type 1

Question 2

_______ is a factor belonging to the TNF family. It is expressed on cell membranes of preosteoclasts and mature osteoclasts. It is stimulated by ______, which is expressed by osteoblasts and marrow stromal cells. Stimulation of ______ leads to activation of ____-____, which in turn stimulates osteoclasts. Osteoprotegerin blocks the action of ______.

Answer 2

RANK

RANKL

RANKL

NF-kB

RANKL

Question 3

______ bone is spongy, trabecular bone, while ______ bone is compact. In which of these bone types does bone marrow differentiation occur?

Answer 3

Cancellous

Cortical

It occurs in cancellous

Question 4

There are three types of cartilage:

1. Hyaline is the most common type and is found in the ribs, nose, larynx, and trachea. It is the scaffolding for ________ ossification.
2. Fibrous cartilage is a mix of fibroconnective tissue and cartilage and is found in the ________ ____, the joint capsules, and ligaments.
3. Elastic cartilage is a mix of elastic fibers and cartilage and is found in the external ___, epiglottis, and larynx.

Answer 4

Endochondral ossification

Intervertebral discs

External ear

Question 5

The _________ is the outer lining of cartilage, and it is where the vasculature and nerves reside in cartilage.

Answer 5

Perichondrium

Question 6

Achondroplasia is the most common disease of the growth plate. It is caused by an autosomal ______ activating point mutation in ______3. Almost 80% are new mutations and most are paternally derived due to increased paternal age.

Answer 6

Dominant

FGFR3

Question 7

In contrast to achondroplasia, ________ dwarfism is caused by a missense or point mutation in FGFR3, which results in extremely small thorax (child can’t expland lungs to breathe), shortening of limbs, and frontal bossing of the skull.

Answer 7

Thorantophoric Dwarfism

Question 8

Osteogenesis Imperfecta (OI) typically results from an autosomal ______ mutation in the genes that encode the ___1 and ___2 chains of type__ collagen. It is the most common disorder of connective tissue, and patients show characteristic _____ (what color?) sclera.

Answer 8

Dominant

Alpha1

Alpha2

Type1

Blue

Question 9

What is the order of severity of the 4 types of OI?

Answer 9

2>3>4>1

Question 10

Osteopetrosis (aka marble bone disease) is caused by dysfunction of _______ (osteoblasts or osteoclasts?). The autosomal _______ severe type and autosomal ______ mild types are the most common. Look for characteristic ________ flask shaped bones. Also, patients often present with 1. ________ due to extramedullary bone marrow formation, 2. Cranial nerve palsies due to compression of nerves within cranial foramina, and 3. ______ due to reduced marrow size and activity.

Answer 10

Osteoclasts

Recessive severe

Dominant mild

Erlenmeyer flask

Hepatosplenomegally

Infections

Question 11

Osteoporosis is most common in postmenopausal women (is it more common in Caucasians or African Americans?)

Treatment can include ________, a bisphosphonate drug, though fractures are a common side effect.

Answer 11

Caucasians

Alendronate

Question 12

Paget disease of bone is common among people of Norther European descent. The hallmark of this disease is the _____ pattern of lamellar bone produced by prominent cement lines that anneal haphazardly oriented units of lamellar bone. You’ll also see clusters of _______ when this disease is in the osteolytic/osteoblastic phase. Lab values for these patients will show elevated _______ _______ ONLY (_____ and phosphorus will be NORMAL).

Answer 12

Mosaic pattern

Osteoclasts

Alkaline Phosphatase

Calcium

Question 13

Rickets and Osteomalacia are both most commonly caused by malabsorption of Vit___. Which of these disorders occurs in children and results in derangement of bone growth, and which one occurs in adults and results in remodeled bone that is poorly mineralized?

Answer 13

Vit D

Rickets in children

Osteomalacia in adults

Question 14

Hyperparathyroidism results in high levels of PTH which activates ______, increasing bone resorption and release of calcium into the blood. Look for hypercalcemia in these patients.

Answer 14

Osteoclasts

Question 15

Fracture healing is essentially _______ ossification at the site of the fracture. It initiates with hematoma formation that brings in osteoprogenitor cells and moves through the _______ stage from day 0 to day 5. From days 5-10, a soft callus is formed from unmineralized cartilage. Then fibrous tissue is laid down from days 10-16, and the bone continues to harden and remodel through day 35.

Answer 15

Endochondral ossification

Endochondral stage

Question 16

Osteonecrosis or avascular necrosis is characterized by 1. dead bone with empty _____, 2. fat necrosis, and 3. insoluble _____ soaps.

Answer 16

Lacunae

Calcium

Question 17

Osteomyelitis most commonly occurs as a result of infection with ____ ______. In sickle cell patients, ______ is a common infectious agent. _____ is a common infectious agent acquired from consumption of unpasteurized dairy.

Answer 17

Staph aureus

Salmonella

Brucella

Question 18

Within the first 48 hours of acute osteomyelitis, bone undergoes _____, which results in abscesses with _______ (which immune cell?) infiltrate. In the chronic stage, the bone undergoes _______. These patients require 6 weeks of IV antibiotics.

Answer 18

Necrosis

Neutrophil

Fibrosis

Question 19

Myositis Ossificans is a metaplasia of the bone following ______ trauma (what does the name Myositis suggest?). This means there is bone formation inside the ______.

Answer 19

Muscle trauma

Muscle