2.1.1 Bone and Joint Pathology I

Question 1

What are some characteristics of osteopetrosis?

Answer 1

Question 2

Draw a diagram of scurvy?

Answer 2

Question 3

What are some of the clinical features of osteopetrosis?

Answer 3

Severe infantile osteopetrosis is autosomal recessive and usually becomes evident in utero or soon after birth. Fracture, anemia, and hydrocephaly are often seen, resulting in postpartum mortality. Affected individuals who survive into their infancy have cranial nerve defects (optic atrophy, deafness, and facial paralysis) and repeated—often fatal—infections because of leukopenia, despite extensive extramedullary hematopoiesis that can lead to prominent hepatosplenomegaly. The mild autosomal dominant form may not be detected until adolescence or adulthood, when it is discovered on x-ray studies performed because of repeated fractures. These individuals may also have mild cranial nerve deficits and anemia.

Question 4

What is this an image of?

Answer 4

A, Recent fracture of the fibula. B, Marked callus formation 6 weeks later.

Question 5

What is this an image of?

Answer 5

Osteoporosis

Question 6

What is this an image of?

Answer 6

Paget Disease of Bone

Hyperostosis frontalis interna

Paget disease shows remarkable histologic variation over time and from site to site. The hallmark is a mosaic pattern of lamellar bone, seen in the sclerotic phase. This jigsaw puzzle-like appearance is produced by unusually prominent cement lines, which join haphazardly oriented units of lamellar bone

Question 7

What is the role of Osteoclasts on bone?

Answer 7

Bone reabsorption - breaks down bone into elemental units - release into microenvironment

Question 8

What are these images of?

Answer 8

Paget Disease

Mosaic pattern

Question 9

What is this an image of?

Answer 9

Osteoporosis

Question 10

What are some of the treatments associated with osteoporosis?

Answer 10

Question 11

What are the characteristics of Osetogenesis imperfecta?

Answer 11

Question 12

What are some of the hormonal influences on osteoporosis?

Answer 12

Question 13

What is this an image of?

Answer 13

Avascular necrosis

Wedge shaped - triangular infarct

Question 14

What is this an image of?

Answer 14

OSTEOPETROSIS: overgrowth of cancellous bone causes loss of marrow and pancytopenia

Question 15

How can age and reduced physical activity affect osteoporosis?

Answer 15

Question 16

What is Paget Disease of the bone?

Answer 16

Paget Disease (Osteitis Deformans)

Paget disease is a disorder of increased, but disordered and structurally unsound, bone mass. This unique skeletal disease can be divided into three sequential phases: (1) an initial osteolytic stage, (2) a mixed osteoclastic-osteoblastic stage, which ends with a predominance of osteoblastic activity and evolves ultimately into (3) a final burned-out quiescent osteosclerotic stage

Question 17

What is this an image of?

Answer 17

Osteomalacia

Question 18

Mutation in what results in osteopetrosis?

Answer 18

CA2

Question 19

What is this an image of?

Answer 19

Very dense bones throughout skeleton

Osteopetrosis

Question 20

What is this an image of?

Answer 20

Decrease in collagen makes sclera translucent allowing partial visualization of underlying choroid

Osteogenesis imperfecta

Question 21

What are some other characterisitcs of fracture healing?

Answer 21

Question 22

How does FGFR3 relate to achondroplasia? Describe the inheritance of it?

Answer 22

Question 23

What are some of the clinical characteristics of Paget Disease?

Answer 23

Question 24

What are the characteristics of avascular necrosis (osteonecrosis)?

Answer 24

Infarction of bone and marrow is a relatively common event that can occur in the medullary cavity or involve both the medulla and cortex. Most cases of bone necrosis stem from fractures or corticosteroid administration. A diverse set of other conditions also predispose to osteonecrosis ( Table 26-5 ). All are believed to lead to vascular insufficiency through mechanical injury to blood vessels, thromboembolism, external pressure on vessels, or venous occlusion.

Question 25

What were the symptoms of individuals in the 1700s who had scurvy?

Answer 25

Skin turned black, ulcers formed, difficulty breathing, teeth fell out, gum disease

Question 26

What are the characteristics of Scurvy?

Answer 26

Question 27

How can you make a diagnosis of osteogenesis imperfecta?

Answer 27

Skin biopsy - analysis of tye I collagen genes or testing of genomic DNA for mutation in COL1A1 and COL1A2

Question 28

What is Ricket's?

Answer 28

Impaired absorption of Ca2+ and PO4. Growing bones can get enough Ca2+ or PO4 to support mineralization - become soft and flexible

Question 29

What is the role of osteoblasts in bone?

Answer 29

Synthesize, transport and arrange bone into matrix proteins (Collagen type I) Initiate mineralization (catalyzed by alkaline phosphatase in matrix vesicles)

Question 30

What is the difference between Osteopenia, osteoporosis, Paget, and Osteomalacia?

Answer 30

Question 31

What is the rachitic rosary in relation to rickets?

Answer 31

Enlarged chostochondral growth plates

Question 32

What are the characteristics of a bone fracture?

Answer 32

Question 33

What are the characterisitics of Achondroplasia?

Answer 33

Reduction in proliferation of chondrocytes

Question 34

What is this an image of?

Answer 34

Rickets on XRAY

Question 35

What are the symptoms and treatment of osteomyelitis?

Answer 35

Question 36

What are the covered parts?

Answer 36

Question 37

What are the characteristics of osteomyelitis?

Answer 37

Osteomyelitis Osteomyelitis denotes inflammation of bone and marrow, virtually always secondary to infection . Osteomyelitis may be a complication of any systemic infection but frequently manifests as a primary solitary focus of disease. All types of organisms, including viruses, parasites, fungi, and bacteria, can produce osteomyelitis, but infections caused by certain pyogenic bacteria and mycobacteria are the most common. Currently in the United States, exotic infections in immigrants from developing countries and opportunistic infections in immunosuppressed individuals have made the diagnosis and treatment of osteomyelitis challenging **Staphylococcus aureus is responsible for 80% to 90% of the cases of culture-positive pyogenic osteomyelitis.** **individuals with sickle cell disease are predisposed to Salmonella infection.​**

Question 38

What are some of the affectors of osteoporosis?

Answer 38

Question 39

What are the characteristics of Osteopetrosis?

Answer 39

Osteopetrosis, also known as marble bone disease and Albers-Schönberg disease, refers to a group of rare genetic diseases that are characterized by reduced bone resorption and diffuse symmetric skeletal sclerosis due to impaired formation or function of osteoclasts. The term osteopetrosis reflects the stone-like quality of the bones. However, the bones are abnormally brittle and fracture easily, like a piece of chalk. Osteopetrosis is classified into variants based on both the mode of inheritance and the severity of clinical findings. Pathogenesis. Most of the mutations underlying osteopetrosis interfere with the process of acidification of the osteoclast resorption pit, which is required for the dissolution of the calcium hydroxyapatite within the matrix. Examples include autosomal recessive defects in the gene for the enzyme carbonic anhydrase 2 ( CA2 ). CA2 is required by osteoclasts and renal tubular cells to generate protons from carbon dioxide and water. The absence of CA2 prevents osteoclasts from acidifying the resorption pit and solubilizing hydroxyapatite, and also blocks the acidification of urine by the renal tubular cells. Other forms of the disease are caused by mutations in CLCN7, which encodes a proton pump located on the surface of osteoclasts.