Parathyroid
Hyperparathyroidism
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Hyperparathyroidism
, Primary Hyperparathyroidism
See Also
Hypercalcemia
Parathyroid Hormone
(PTH)
Pathophysiology
Overactive
Parathyroid Gland
s (>=1 of 4 glands)
Produce excessive
Parathyroid Hormone
(PTH)
Results in disorder of bone metabolism
Epidemiology
Prevalence
Women: 2-3 cases per 1000 women over age 65 years
Men: 1 case per 1000 men over age 65 years
Ages
Range: 40-70 years old
Mean: 55 years old
Causes
Primary Hyperparathyroidism
Single
Parathyroid
Adenoma (82 to 85%)
Parathyroid Gland
Hyperplasia or hypertrophy (15%)
Parathyroid
Malignancy (rare, accounts for 0.5 to 3% of Primary Hyperparathyroidism)
Familial Hyperparathyroidism (10-20%): Younger patients
Multiple Endocrine Neoplasia Type I
(
MEN I
)
Multiple Endocrine Neoplasia Type I
(
MEN II
)
Familial Hypocalciuric Hypercalcemia
Hyperparathyroidism-Jaw Tumor Syndrome
Neonatal severe Primary Hyperparathyroidism
Other
Parathyroid
related causes
Lithium
Therapy
External neck radiation exposure
Neck surgery with
Parathyroid
injury or resection
Tertiary Hyperparathyroidism
Accelerated response to chronic
Hypocalcemia
(in advanced
Renal Failure
)
Parathyroid
over-produces PTH causing
Hypercalcemia
Causes
Secondary Hyperparathyroidism
Vitamin D Deficiency
Decreased
Calcium
intake
Renal Osteodystrophy
Chronic Kidney Disease
stage 4 or stage 5 and
Decreased 1,25 dihydroxyvitamin D
Hyperphosphatemia
Hypocalcemia
Normocalcemic Hyperparathyroidism (associated with
Osteoporosis
)
Diagnosis of exclusion after ruling-out
Vitamin D Deficiency
and
Chronic Kidney Disease
Symptoms
See
Hypercalcemia
Asymptomatic
Hypercalcemia
(up to 80% of cases)
Diagnosis
Mnemonic (classic presentation is uncommon)
Stones
Bones
Abdominal groans
Psychic moans
Constellation of findings
See
Hypercalcemia
Calcium
oxalate renal stones (
Nephrolithiasis
)
Bony changes
Osteitis fibrosa
Salt and pepper skull
Bone resorption
Acute Pancreatitis
Psychosis
and depression
Labs
Parathyroid Hormone
(PTH) Level elevated
Measure
Intact PTH
See
Parathyroid Hormone
for algorithm
Serum
Electrolyte
abnormalities
Hypercalcemia
(Use
Corrected Serum Calcium
)
Draw
Fastin
g with minimal
Occlusion
Discontinue
Thiazide Diuretic
s for 2 weeks before
Repeat serum testing in 2 weeks if normal
Hyperchloremia
Hypophosphatemia
Hypokalemia
Miscellaneous
1,25 Dihydroxyvitamin D3
Indicated if
Serum Calcium
low
Urine Calcium
and Phosphate
Hypercalciuria
(
24 hour Urine Calcium
)
Hyperphosphaturia
Arterial Blood Gas
Non-Anion Gap Metabolic Acidosis
Renal Function
tests
Creatinine Clearance
Imaging
Classic XRay Findings
Skull XRay
"Salt and pepper" skull
Chest XRay
Distal Clavicle resorption
Hand XRay
Second and third middle phalange bone resorption
Dental XRay
Bone resorption of Lamina dura around teeth
Sestamibi Technetium Tc 99mParathyroid Scan
Test Sensitivity
for localizing adenoma: 95%
Causes of non-localizing scan
Ectopic PTH production
Diagnostic error
Four-gland hyperplasia
End-organ evaluation
Renal
Ultrasound
Bone Densitometry
(
DEXA Scan
)
Lumbar Spine
Hip
Forearm
Differential Diagnosis
See
Hypercalcemia
Familial Benign Hypocalciuric Hypercalcemia
Does not improve with surgery, unlike primary disease
Calcium
to
Creatinine
ratio <0.01
Management
Medical Monitoring
Indications
Asymptomatic patients without surgical indications
Serum Calcium
level only mildly increased
No priot life-threatening
Hypercalcemia
Normal
Renal Function
Creatinine Clearance
>70%
No
Nephrolithiasis
No Nephrocalcinosis
Normal
Bone Mineral Density
(
Osteopenia
or better)
Avoid provocative factors
Thiazide Diuretic
s and
Lithium
Avoid Volume depletion (maintain hydration)
Avoid prolonged bedrest or inactivity
Avoid High
Calcium
diet
Avoid
Vitamin D
supplementation
Encourage moderate
Physical Activity
Minimize bone resorption
Encourage 64 ounces non-caffeinated fluid per day
Minimize risk of
Nephrolithiasis
Encourage moderate
Calcium
intake (1000 mg/day)
Low
Calcium
diet may surge
Parathyroid Hormone
Medications
Calcium
Lowering Therapy
See
Hypercalcemia
Pharmacologic Measures: Reduce bone resorption
Estrogen Replacement Therapy
(Postmenopausal)
Bisphosphonates
Management
Surgery
Precautions
Re-evaluate on a periodic basis
Up to 15% of originally asymptomatic Hyperparathyroidism cases develop a surgical indication within 4.7 years
Yu (2011) QJM 104(6): 513-21 [PubMed]
Indications in Primary Hyperparathyroidism
Serum Calcium
>12 mg/dl (or >1 mg/dl above the upper limit of normal)
Hypercalcemic Crisis
(
Serum Calcium
>14 mg/dl)
24 hour Urine Calcium
>400 mg/day
Osteoporosis
(or
T-Score
<-2.5 at hip, spine or wrist)
Osteitis fibrosa cystica
Nephrolithiasis
Nephrocalcinosis
Young patient age (e.g. age <50 years)
Exacerbating factors
Dehydration
Immobile patient
Creatinine Clearance
<60 ml/min/1.73m2 or 30% below age-matched peers
Persistent
Hypercalcemia
symptoms (esp neuromuscular)
Efficacy
Successful in up to 95% of cases
Few complications
Single
Parathyroid
Adenoma
Surgery to locate and remove adenoma
Biopsy a second gland to rule out atrophy
Parathyroid
hyperplasia or hypertrophy
Remove 3.5 glands
Autotransplant tissue into arm muscle
Monitoring of medically managed patients
Every 6 month labs
Serum Calcium
Every 12 month labs
Serum Creatinine
Urinary
Calcium
Excretion
Every 6-12 month labs for women
Bone Density (
DEXA Scan
)
References
Spiegel in Goldman (2000) Cecil Medicine, p. 1402-5
(1991) Ann Intern Med 114:593-7 [PubMed]
Bilezikian (2002) J Clin Endocrinol Metab 87:5353-61 [PubMed]
Taniegra (2004) Am Fam Physician 69(2):333-40 [PubMed]
Michels (2013) Am Fam Physician 88(4): 249-57 [PubMed]
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