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Metabolic Bone
Disorders
Objectives
 Differentiate metabolic bone disorders by
etiology, treatment and outcome.
 Outline common nursing diagnoses,
outcome criteria and interventions for
common metabolic bone disorders.
Bone Cell Types
 Osteoblast
 Forms bone & mineralization of
matrix
 Osteocyte
 Transformed osteoblast
 Maintains bone found in matrix
 Osteoclast
 Breaks down bone salts
 Responsible for bone
reabsorption
Bone Cell Mnemonics
Osteoblasts
 “Baby bone cells”
 “Building Blocks”
Osteoclasts
 “Clean up” cells
Osteocytes
 “Cycle” of bone
Question #1: Which statement is
true of osteoblasts?
a. They transform
osteocytes into
osteoblasts.
b. They maintain cells within
the bone matrix.
c. Osteoblasts form bone
cells within matrix.
d. Osteoblasts break down
bone salts.
Answer #1. Which statement is
true of Osteoblasts?
c. Osteoblasts form bone cells within matrix.
Rationale: Osteoblasts are “bone builders”;
the other responses are related to
functions of other bone cell types.
Bone Remodeling
Process
PHASE I
PHASE II
PHASE III
Hormonal, Biochemical
Physiological Indicators
Osteoclasts
Resorb Bone
Osteoblasts
Form Bone
Activate Precursors
Creates Cavities in
Cortical & Cancellous Bone
Create New Bone
In Formed Cavities
Osteoclast Formation
Hormonal Regulation
of Bone Metabolism
 Thyroid gland
 Thyroxine, triodothronine & calcitonin
 Regulated by TSH / TRH & calcitonin by
plasma levels of calcium
 Parathyroid gland
 Parathormone PTH (protein hormone)
 Regulated by serum ionized calcium levels
Hormonal Regulation
of Bone Metabolism
 Anterior pituitary gland
 ACTH / TSH / FSH / LH / Prolactin
 Regulated by hypothalamus
 Adrenal cortex
 Glucocortcoids / mineralcorticoids &
androgens
 Estrogen
 Increased osteoblast activity
 Retention of calcium and phosphate
Question #2: Which hormone is the
most important for regulating
serum calcium levels because it
acts directly on bone and kidneys?
a. Parathyroid hormone.
b. Growth hormone.
c. Calcitonin.
d. Adrenal corticosteroids.
Answer #2: Which hormone is the
most important for regulating
serum calcium levels because it
acts directly on bone and kidneys?
a. Parathyroid Hormone.
Rationale: As noted earlier,
this hormone acts
directly on bone and
kidneys
Hyperparathyroidism
 Mainly two types
 Primary- cause unknown but thought to be
familial and characterized by excessive secretion
of PTH
 Secondary-usually due to disease state such as
renal failure which causes decrease in ionized
serum calcium levels
 Excess Secretion of PTH
 Interrupts metabolism of calcium / phosphate /
Bone
Hyperparathyroidism- Pathophysiology
 Although primary/secondary cause either
hypo or hypercalcemia, end result remains
elevated levels of PTH which causes
eventual hypercalcemia and multisystem
problems
Hyperparathyroidism
 Primary
 Secondary
Results in:
Hypercalcemia
Causes
Adenoma /
Carcinoma
Genetic / Multiple
Endocrine Disorder
Results in initial
hypocalcemia followed
by hypercalcemia
Causes
Chronic Renal
Failure /
Malabsorption
Syndromes / Vitamin
D Deficiency
Hyperparathyroidism
 Clinical manifestations
•Bones – Demineralization due to
excessive osteoclast and osteocyte
activity
•Kidneys – renal calculi, UTI
•GI– Anorexia / NV, pancreatitis,
peptic ulcers, constipation,
hypergastrinemia
•Psychiatric issues
•Muscle weakness, myalgias
Hyperparathyroidism
 Diagnostics
 All other causes of hypercalcemia must be
eliminated first
 6 month history of symptoms of hypercalcemia
 Kidney stones, hypophosphatemia,
hypochloremia
 Serum Calcium Levels -  >10mg/dl
 PTH Assay – ↑1°
 Radioactive Iodine Uptake Test - ↓
 Subclinical / Post- Partum / Acute Thyroiditis
 Urinary Calcium – ↑(24 Hr Specimen)
 DEXA Bone Density - ↓
Hyperparathyroidism
 Clinical Management
 Adequate Hydration
 Increase urinary excretion of Ca++ with
diuretics
 Drugs that decrease resorption of Ca++ by
bone-biphosphates, calcitonin
 Surgery
 Parathyroidectomy – NOT Often
Recommended
 Leaves ½ of one Lobe of the Parathyroid
 Remove Adenoma
Question #3: Ms. Jones is a 60-year-old female
who presents in the Clinic with a 6 month
history of frequent renal stones, abdominal
pain, muscle aches and several fractures of
her metatarsals. The nurse would suspect:
a. Gout.
b. Hyperparathyroidism.
c. Hypoparathyroidism.
d. Paget’s Disease.
Answer # 3: Ms. Jones is a 60-year-old female
who presents in the Clinic with a 6 month
history of frequent renal stones, abdominal
pain, muscle aches and several fractures of
her metatarsals. The nurse would suspect:
b. Hyperparathyroidism.
Rationale: As defined
earlier, these are
common s/s of
hyperparathyroidism
Question #4: In order to confirm this
diagnosis, diagnostic testing needs to be
performed. As the Nurse you know:
a. That you can rely on one blood sample
to give complete results.
b. The patient will need blood work,
DEXA scans, and 24 hour urine
samples
c. That you can rely on urine testing
alone.
d. The tests will most likely be
inconclusive.
Answer #4: In order to confirm this
diagnosis, diagnostic testing needs to be
performed. As the Nurse you know:
b. You will need to have results of serum
Ca++, phosphate, magnesium,
bicarbonate levels as well as a DEXA
scan and a 24 hour urine for excreted
Ca++
Rationale: DEXA scan shows
demineralization of bone, 24 hour urine
shows excess Ca++, and abnormal
serum levels of trace elements
Question #5: Mrs. Jones is diagnosed with
hyperparathyroidism. As the nurse doing the
patient teaching, you are aware that
adequate hydration is essential in
preventing:
a. Constipation.
b. Hypercalcemia.
c. Alteration in fluid balance.
d. All of the above.
Answer #5: Mrs. Jones is diagnosed with
Hyperparathyroidism. As the nurse doing
the patient teaching, You are aware that
adequate hydration is essential in
preventing:
d. All of the above.
Rationale: Adequate
hydrationhelps to prevent constipation,
hypercalcemia and fluid
balance alterations
Hypoparathyroidism
 Decreased Secretion of PTH
 Most commonly caused by injury to
parathyroid gland during surgery
 Can also be caused by hypomagnesemia
 Pathophysiology
 Bones –  Mineralization  Bone
Resorption
 Hypocalcemia /  Intestinal Ca+
Absorption
 Metabolic Alkalosis (Mild)
 Parkinson-like Symptoms
Hypoparathyroidism
 Clinical Presentation
 Mental Fatigue
 Abdominal Pain
 Patient History of Alcoholism
 Physical Examination
 Muscle Spasm / Tetany / Excitability
  Deep Tendon Reflexes
 Dry Skin / Hair Loss /
 Weakened Tooth Enamel
Hypoparathyroidism
 Diagnostics
 Serum Calcium Levels –
DECREASED
 Serum Phosphorus – INCREASED
 Low Vitamin D Levels
 Urinary Calcium –DECREASED
 X-Rays
 Increased Bone Density
Hypoparathyroidism
 Clinical Management
 Acute condition
 MEDICAL EMERGENCY
 Prevent larygneal spasms- administer IV
Ca++ gluconate/carbonate STAT!
 Chronic condition
 Lifetime Vitamin D therapy
 Calcium supplementation- 1 to 3 gm/day
 Muscle relaxants to control muscular
spasms
 Drugs to reduce GI absorption of
phosphorous
Osteomalacia (Adult Rickets)
 Inadequate and delayed mineralization
of osteoid in mature compact and
spongy bone
 Major deficit is in Vitamin D , which is
required for Ca++ uptake in intestines
 Decreased Ca++ stimulates PTH, which
does increase Ca++, but also increases
phosphate excretion by kidney
 When phosphate levels too low,
mineralization cannot occur
Osteomalacia (Adult Rickets) con’t
 Etiology
 More prevalent in extreme preemies, elderly, those
following strict macrobiotic vegetarian diets and
persons on anticonvulsant Rx
 Pancreatic insufficiency
 Hepatobiliary diseases
 Lack of bile salts decreases absorption of Vit D
 Malabsorption syndromes
 Hyperthyroidism
 Rare in US due to fortification of foods
 Common in GB and Middle Eastern Countries
Osteomalacia
 Clinical Presentation
 Generalized body aches /LBP as well as
hip pain
 Lower extremity pain & deformity
 Physical examination
 Scoliosis / kyphosis of spine
 Deformities of weight bearing bones
 Muscle weakness leading to classic
waddling gait
 Generalized Malaise
Osteomalacia
 Diagnostics







Serum Ca++ –↓ or Normal
Serum inorganic Phosphate ↑> 5.5
Vitamin D ↓
BUN & creatinine ↑
Alkaline Phosphatase & PTH ↑
Bone bx to determine aluminum levels
X-Rays
 Demineralization
 Pseudofractures
 Bowing of long bones
Osteomalacia
 Clinical Management





Correcting serum Ca++ & phosphorous
Chelating bone aluminum if needed
Suppressing hyperthyroidism
Supplement with Vitamin D
Administer Ca++ carbonate to ↓
hyperphosphatemia
 Renal dialysis/transplant for renal
osteodystrophy
 Correction of associated intestinal disorders
Question #6: X-rays of a
patient with Osteomalacia
would reveal:
a. Increased bone
density.
b. Stress fractures.
c. Normal joint
alignment.
d. Demineralization.
Answer #6: X-rays of a patient
with Osteomalacia would
reveal:
d. Demineralization.
Rationale: As calcium
and phosphorus levels
are decreased,
demineralization can be
noted on x-ray
Osteoporosis
 Most common metabolic bone disease
 Reduction of bone mass density (BMD)
 fractures
 Estrogen deficiency leads to a rapid  in
BMD
 Rapid bone loss may occur
 Up to 20% during the first 5-7 years
post-menopause
 Surgically induced menopause
 Results in severe decrease in BMD
regardless of age
Osteoporosis
Type I - Postmenopausal
Type II - Senile
Secondary
Predominantly in Females
Affects Males & Females
Affects Males & Females
10-15 Years Postmenopause
Common After Age 70
Occurs At Any Age
Decreased Levels of Estrogen
Related to Nutrition
Decreased Physical Activity
Result of Disease Process
Or Medical Treatment
Loss of Trabecular Bone
Loss of Cortical & Trabecular Bone
Loss of Cortical & Trabecular Bone
Accelerated Bone Loss
Non-Accelerated Bone Loss
Osteoporosis – Risk Factors
 Inherited
 Gender / Ethnicity
 Body composition
 Gyn considerations
 Family History
 Hx. Of osteoporosis
 Medical Conditions
 Rheumatoid arthritis
 Thyroid / Liver Dz
 Spinal cord injury
 Behavioral
 Physical activity level
 Nutritional status
 Lifestyle habits
 Medications




Thyroid replacement
Corticosteroid use
Antacids
Long term anticonvulsant use
Osteoporosis
 Clinical Presentation




Attire
Height
Spine (Posture)
Chest/ Abdomen
 Gait
Ill fitting clothes
Recent loss of height
Kyphosis
Chest resting on
protruding abdomen
Slow reciprocal –
Wide base stance
Osteoporosis
 Differential Diagnosis
 Urinary calcium - ↑ in secondary
osteoporosis
 Biochemical markers of bone resorption
 Urinary pyridinoline- ↑ for a variety of
metabolic bone diseases
 X-Rays
 ↑ density often not seen until 50% loss
 DEXA
 Hip / Lumbosacral spine -↑
Osteoporosis – Fracture
Risk
• Essential to ALL groups
 Post-menopausal & elderly MOST at
risk for fracture
• Bone strength depends on
 Mass
 Architecture
 Bone Quality
• BMD Testing
 Bone Mass Measurement Act
Osteoporosis
 Nutritional support
 Calcium intake levels
 RDA based on age
 Co-Factors
 Vitamin D
 Serum 1,25-dihydroxyvitamin D3
 Exercise
 Weight bearing exercise 2-3 x week
Recommended Daily Calcium
Intake
1600
1400
1200
1000
800
600
400
200
RDA
Suggested
0
0-6
mos.
6-12 1-5 yrs
mos.
5-10
yrs
11-24
yrs
25-50
yrs
+65
yrs
Anti-Resorptive Medication
 Estrogen
 Prevents bone resorption
 Most commonly used
 Start within 3 Yrs of menopause
 Positive effect of calcium absorption &
calcitonin
  risk of endometrial cancer –
progesterone MUST be added if no
hysterectomy
 Oral / Transdermal
 New data shows no change in CV risk
Anti-Resorptive Medication
 Calcitonin
 Inhibits osteoclasts – prevents bone
resorption
 Tx. postmenopausal osteoporosis
 Males & females
 In conjunction with calcium & Vitamin D
 Analgesic properties
 Intranasal administration
Anti-Resorptive Medication
 Bisphosphonates
Non-Hormonal agent
 Highly selective osteoclast inhibitor
 Indicated for treatment & prevention &
osteoporosis in men
 BMD 2 standard dev. below norm for
young adults
 SE – GI disorders / Esophageal &
gastric ulcers
Anti-Resorptive Medication
 SERM - Selective Estrogen Receptor
Modulator
 Indicated for prevention
 Enhances beneficial effects of estrogen
without increasing risks to breast /
uterus
 Caution use in patients at risk for DVT
Bone Forming Agents
 Slow-Release calcium fluoride
 Stimulate osteoblast activity
 New bone matrix remains brittle
 Not effective with severe
demineralization
 Must have adequate calcium intake
See Handout for medications
Osteoporosis
 Surgical intervention for vertebral
fractures
 Vertebroplasty
 High pressure injection of bone
cement through pedicles to vertebral
body
 Contraindicated in severe vertebral
body collapse
Osteoporosis
 Surgical intervention for vertebral fractures
 Kyphoplasty
 Bone tamp through cortical window
 Inflation of bladder in vertebral body
 Injection of bone cement under LOW
PRESSURE
Osteoporosis
 Physiological
 Decreased respiratory function
 Kyphotic deformity
 GI/Bowel alteration
 Protrusion of abdomen
 Medications
 Self-care deficits
Osteoporosis
 Psychological
 Low self-esteem
 Depression
 Social isolation
 Retreat from activities
 Sleep disturbances
 Physical/Psychological component
Ms. Rice Is a 56 year old woman. She presents to
the GYN for her annual check-up. A detailed
nursing history reveals the following:
 Ht: 5’5” (5’6” last yr) Wt: 126 lbs.
Race: Caucasian
 Medical History
 LMP 4 years earlier
 Thyroidectomy 10 yrs
 Mild OA rt. knee
 Current Meds/Supplements
 Synthroid
 Calcium 1000 mgs.
Case Study con’t
 Social History
 Non-smoker
 Infrequent Exercise
 Family History:
 Mother
Osteoporosis
Question #7: Of the identified risk
factors, which would be considered to
be modifiable?
a. Use of thyroid replacement
medications.
b. Exercise level.
c. Family history of osteoporosis.
d. Loss of height.
Answer #7: Of the identified risk
factors, which would be considered to
be modifiable?
b. Exercise level.
Rationale: While Ms. Rice
can control amount of
exercise, she cannot
modify other factors.
Question #8: The nurse should assess
Ms. Rice’s dietary intake of calcium to
be sure she is getting a suggested daily
intake of:
a. 800 mgs. Daily.
b. 1000 mgs. Daily.
c. 1500 mgs. Daily.
d. Calcium is not required as
she is post-menopausal.
Answer #8: The nurse should assess
Ms. Rice’s dietary intake of calcium to
be sure she is getting a suggested
daily intake of:
c. 1500 mgs. daily.
Rationale: Noting age and history,
Ms. Rice’s dietary intake of
calcium should be the same as
an adolescent
Question # 9: Ms. Rice has a DEXA Test. It
demonstrates BMD 2.5 St. Dev. She has
been advised to start taking medication. As
part of the patient education, the nurse
understands that:
a. Estrogen can be started at any time postmenopause and retain the same level of
effectiveness.
b. Calcium alone is effective in increasing BMD.
c. SERMs  risk of breast & uterine cancer.
d. Bisphosphonates are osteoclast inhibitors
& are effective anti-resorptive agents.
Answer #9: Ms. Rice has a DEXA test. It
demonstrates BMD 2.5 St. Dev. She has
been advised to start taking medication. As
part of the patient education, the nurse
understands that:
d. Bisphosphonates are osteoclast inhibitors
& are effective anti-resorptive agents.
Rationale: As per previous discussion, other
statements are incorrect
Paget’s Disease
 Osteitis Deformas
  Bone resorption   bone formation 
develop large irregularly shaped bones
with poor mineralization  thick brittle
bones
 Etiology
 Slow progressing disease
 Often occurs between 50-70 years
 Familial tendency in males
 Usually asymptomatic
Paget’s Disease
 Clinical Presentation
 Deep aching sensation  with weight
bearing
 Pain - mild to severe unrelated to activity
 May have bony deformities – skull
 Loss of height
 Physical Examination




Kyphosis / Bowing of long bones
Conductive hearing loss
Fracture healing is impaired
Complications – CHF / Paget’s sarcoma
Paget’s Disease
 Diagnostics





Serum alkaline phosphatase -↑
Urinary hydroxyproline - ↑
Serum/ urinary citrate – ↑
Serum uric acid – ↑in < 50%
X-Rays
 Early localized demineralization
 Later bony overgrowth – irregular
 Mosaic pattern
 Bone scan
 Metabolic activity- ↑
Paget’s Disease
 Clinical Management
 Asymptomatic
 Monitor patient
 Symptomatic
 NSAIDs
 Calcitonin – relieve bone pain
 Bisphosphonates
 Ambulation with assistive devices
 Surgical Intervention
 Correction of malalignment / fractures
Question #10: Paget’s Disease
is characterized by:
a. Decreased bone formation.
b. Decreased bone resorption.
c. Mosaic patterned bone
growth.
d. Accelerated bone healing.
Answer #10: Paget’s Disease is
characterized by:
c. Mosaic patterned bone
growth.
Rationale: Decreased bone
formation, bone resorption
and accelerated bone healing
produce a mosaic pattern of
growth
Summary
 Bone cell types
 Hormonal regulation of bone formation
 Causes & consequences of / levels of
hormones
 Solutions
 Dietary considerations (note: cause & solution)
 Exercise patterns (note: cause & solution)
 Medications
 Hormonal / Non-hormonal / vitamins
 Surgical intervention (note: rx. for effect /
cause)