General Pathology Lecture 71: Congenital Bone Disorders

What condition is caused by deficient cartilage growth?

Achondroplasia

What is the main feature of achondroplasia?

Dwarfism

Is there altered or normal IQ with achondroplasia?

Normal IQ

What condition is caused by a collagen disorder?

Osteogenesis imperfecta

What are the two main features of Type I osteogenesis imperfecta?

1. Blue sclera

2. Bone fractures (> 100)

What is the medication used to treat Type I osteogenesis imperfecta?

Biphosphonates

When is Type II osteogenesis imperfecta often lethal?

Utero/perinatal period

What trait of Type III osteogenesis imperfecta makes it have high childhood mortality?

Heart complications

Which subtype of osteogenesis imperfecta is autosomal dominant?

Type IV

What is the rare disorder that causes extremely dense hypovascularized bone?

Osteopetrosis

What is the main feature of osteopetrosis?

Brittle bones/easily fracture

What risk is increased with osteopetrosis?

Bone infections

What is missing in osteopetrosis?

Osteoclastic bone resorption

What condition causes suppression of hematopoeisis in osteopetrosis?

Pancytopenia

What is the treatment method for osteopetrosis?

Bone marrow transplant

What is the radiographic appearance for osteopetrosis?

Extremely radiopaque

Is osteopenia or osteoporosis a more severe form of bone loss?

Osteoporosis

Why are females more at risk for osteoporosis?

Estrogen deficiency after menopause

What usually causes osteoporosis in men?

Long term intake of corticosteroids

What levels are measured to be normal in osteoporosis?

Serum calcium/phosphate

What is the bone scan used to look for osteoporosis, especially in women over 50?

DEXA scans

What type of osteoporosis has absolute increase of osteoclast activity and usually begins in menopause due to decreased estrogen output?

Type I osteoporosis

What type of osteoporosis is called senile osteoporosis and is due to decreased steoblastic activity?

Type II osteoporosis

Besides corticosteroids, what other drug could cause osteoporosis?

Proton pump inhibitors

Why can eating disorders like anorexia cause osteoporosis?

Promote cortisol secretion

What is the hump caused by minor trauma with osteoporosis that decreases height?

Dowager's hump

What are the two anti-resorptive agents used to treat osteoporosis?

1. Bisphosphonates

2. Denosumab

What risk is increased with using anti-resorptive agents to treat osteoporosis?

Osteonecrosis

What injury could be found in the lumbar vertebra with osteoporosis?

Compression fracture

What injury could be found in the jaw with osteoporosis?

Thinning of inferior cortical plate

What type of dental radiographs could detect osteoporosis?

Intraoral radiographs

What are the two disorders of vitamin D deficiency that causes abnormal bone metabolism

1. Rickets

2. Osteomalacia

How does vitamin D promote bone growth?

Helps absorb calcium

What is the main effect of rickets?

Decreased mineralization of new bone in growth plates

What is the main effect of osteomalacia?

Decreased mineralization of remodeled bone

What are the beaded appearance of costochondral junctions on the chest caused by rickets?

Rachitic rosary

What is the outward curvature of sternum caused by rickets?

Pectus carinatum

What are three effects of the limbs caused by rickets?

1. Shortened

2. Deformed (Bowing)

3. Frequent fractures

What is the appearance of the abdomen caused by rickets?

Potbelly

What disorder of the parathyroid severely weakens bones?

Hyperparathyroidism

What is the disease of weakened bone that is a defect in RANK gene?

Paget Disease

Does Paget Disease affect the maxilla or mandible more?

Maxilla

What levels are severely increased with Paget Disease?

Serum alkaline phosphatase

Is there normal or abnormal calcium levels with Paget Disease?

Normal calcium levels

Which cells are mostly acting in Stage 1 of Paget Disease?

Osteoclasts

Which cells are mostly acting in Stage 2 of Paget Disease?

Both osteoclasts and osteoblasts

What are the two appearances found in Stage 2 of Paget Disease?

1. Enlarged bone

2. Irregular reversal lines

What is the radiographic appearance found in Stage 2 of Paget Disease?

Cotton-wool

What is stage 3 of Paget Disease described as?

Burnt-out stage

Are the majority of Paget Disease patients symptomatic or asymptomatic?

Asymptomatic

What is the common symptom of Paget Disease caused by nerve compression?

Bone pain

What is the common symptom of Paget Disease caused by enlarged bones?

Skull shape changes

What is the teeth condition with Paget Disease only with jaw involvement?

Hypercementosis

How does Paget Disease affect long bones?

Fractures/bowing

How does Paget Disease affect the heart?

High output cardiac failure

What does the skin feel like with Paget Disease?

Warm

What medication for Paget Disease increases bone strength?

Calcitonin

What is the malignancy that Paget Disease could transform into?

Osteosarcoma

What is the risk of severe polyostotic disease with Paget Disease?

5 - 10%

How long does it take for bone fractures to heal?

6 - 8 weeks

What type of bone fracture does not have broken skin?

Simple

What type of bone fracture has broken skin and an increased risk of infection?

Compound

What type of bone fracture has fragmented bone?

Comminuted

What type of bone fracture has microfractures and is associated with repetitive activity?

Stress

What type of bone fracture extends only partially through bone and is common in infants?

Greenstick

What type of bone fracture is associated with disease?

Pathologic

What does a higher Le Fort craniofacial classification indicate?

Greater risk to brain damage

What is the disease caused by bone infarction?

Osteonecrosis

What systemic disease promotes osteonecrosis?

Sickle cell crisis

What two conditions promote osteonecrosis?

1. Ischemia/trauma

2. Thrombosis

In reactive bone formation, do infections and benign tumors promote lamellar or woven bone?

Lamellar bone

In reactive bone formation, do rapidly growing tumors and bone disorders promote lamellar or woven bone?

Woven bone

What is the condition caused by formation of reactive bone within muscle?

Myositis Ossificans

What is the main cause of Myositis Ossificans?

Blunt trauma

Despite being benign, what does Myositis Ossificans resemble?

Neoplasms

What is the main treatment for Myositis Ossificans?

Biopsy

What condition is caused by the inflammation of bone from infection?

Osteomyelitis

What is the most common pathogen that causes osteomyelitis?

Staphylococcus aureus

What are the two routes of entry for osteomyelitis?

1. Penetration of skin

2. Bloodstream

What are the two treatment method for osteomyelitis?

1. IV antibiotics

2. Surgery

What should be surgically removed to treat osteomyelitis?

Bone sequestrum

What malignancy could osteomyelitis transform into?

Osteosarcoma

What is the disorder of disorganized fibrous/osseous tissue?

Fibrous dysplasia

What gene is mutated in fibrous dysplasia?

GNAS1

What are the two main features of fibrous dysplasia?

1. Enlargement

2. Deformities

What syndrome is a comorbidity of fibrous dysplasia?

McCune-Albright Syndrome

What is the radiographic appearance of fibrous dysplasia?

Ground glass

When can fibrous dysplasia become dormant?

After puberty

When can fibrous dysplasia be stimulated to grow?

Pregnancy

What malignancy could fibrous dysplasia transform into?

Osteosarcoma

What are the four treatment methods for fibrous dysplasia?

1. Curettage

2. Cosmetic

3. Bisphosphonates

4. Denosumab

What is the main endocrine disorder in McCune-Albright Syndrome for females?

Precocious puberty

What is the skin appearance of McCune-Albright Syndrome?

Café-au-lait spots