Systemic, Nutritional & Endocrine Bone Diseases

What is osteopenia?

A radiographic finding of decreased bone density (not a diagnosis)

What is osteoporosis?

A diagnosis of decreased bone quantity with normal mineralization

How much bone loss is required before osteopenia is visible on x-ray?

30- 50% bone loss

Bone quality vs bone quantity - which disease affects which?

Osteoporosis = quantity decrease ; Osteomalacia/Rickets = quality decrease

Hormones that increase bone formation

Growth hormone, Vitamin D, Calcitonin

Hormones that decrease bone formation

Parathyroid hormone (PTH), Cortisol

Primary effect of excess PTH on bone

Bone resorption

Primary osteoporosis types

Postmenopausal, Senile

Secondary causes of osteoporosis

Steroids, malignancy, infection, disuse, endocrine disorders

Most common cause of secondary osteoporosis

Chronic steroid use

Most common fracture location in osteoporosis

Thoracic spine > lumbar spine > hip > wrist

Non-modifiable osteoporosis risk factors

Age, female sex, race, menopause

Modifiable osteoporosis risk factors

Smoking, alcohol, inactivity, poor nutrition

Best test for diagnosing osteoporosis

DEXA scan

DEXA T-score: Normal

> or equal to -1.0

DEXA T-score : Osteopenia

-1.0 to -2.5

DEXA T-Score: Osteoporosis

< or equal to -2.5

Best imaging to differentiate acute vs chronic compression fracture

MRI

MRI finding of an acute fracture

Bone marrow edema

What does a bone scan detect best?

Increased metabolic activity

Are bone scans specific

No - sensitive but not specific

General radiographic appearance of osteoporosis

Diffuse radiolucency

Cortical appearance in osteoporosis

Cortical thinning

Trabecular pattern in osteoporosis

Vertical trabecular accentuation

Common vertebral fracture types

Wedge, biconcave (codfish), compression

Disuse osteoporosis - cause

Immobilization or lack of weight-bearing

Radiographic feature of disuse osteoporosis

Localized demineralization

Complex Regional Pain Syndrome (CRPS)

Regional osteoporosis with pain disproportionate to injury

CRPS imaging appearance

Patchy periarticular demineralization

Transient osteoporosis of the hip (TOH)

Self-limiting bone marrow edema syndromeW

Who commonly gets TOH?

Pregnant women and middle-aged men

Best imaging for TOH

MRI

Osteomalacia definition

Defective bone mineralization in adults

Rickets definition

Defective done mineralization in children

Primary cause of osteomalacia/rickets

Vitamin D deficiency

Classic radiographic sign of osteomalacia

Looser zones (pseudo fractures)

Hyperparathyroidism radiographic hallmark

Subperiosteal bone resorption

Common location for subperiosteal resorption

Radial aspect of middle phalanges

Brown tumors are associated with which disease?

Hyperparathyroidism

Why x-rays are poor for early osteoporosis detection

Too much bone loss required before visible changes

Why left untreated osteoporosis is dangerous

High fracture risk with minimal trauma

Most reliable modality for bone density monitoring

DEXA

One phrase to remember bone scans

Sensitive, not specific