Updated: 3/11/2020

Hyperparathyroidism

0%
Topic
Review Topic
0
0
N/A
N/A
Questions
7 7
0
0
0%
0%
Evidence
3 3
0
0
0%
0%
Videos
1 1
Snapshot
  • 55-year-old woman presents to the clinic for an annual well exam. Routine laboratory tests demontrates elevated levels of hypercalcemia. The patient reports some mild diffuse abdominal pain over the past 2 weeks but otherwise denies any chest pain, palpitations, or fatigue. A follow up PTH level is high. 
Introduction
  • Clinical definition
    • disorder characterized by the over secretion of parathyroid hormone (PTH) by one or more of the parathyroid glands
    • high levels of PTH leads to increase in serum calcium levels, causing hypercalcemia
    • can be of primary, secondary, or tertiary causes  
  • Epidemiology
    • demographics
      • occurs in 0.1% of the population and 90% of cases result from a single adenoma
    • risk factors
      • severe, prolonged calcium or vitamin D deficiency
      • menopause
      • neck radiation
      • lithium use
  • Pathogenesis
    • PTH leads to
      • activation of osteoclasts leading to increased Ca2+ and phosphate reabsorption at the bone
        • stimulates osteoclasts by binding to its receptor on osteoblasts, inducing RANK-L and M-CSF synthesis 
      • increased reabsorption of Ca2+ in the distal convoluted tubule at the kidney
      • stimulation of kidney 1α-hydroxylase in the proximal convoluted tubule to increase calcitriol production
Classification
  • Primary hyperparathyroidism 
    • most commonly results from parathyroid adenoma or hyperplasia 
    • associated conditions
      • osteitis fibrosa cystica
        • high osteoclast activity at bone resulting in cystic bone spaces with brown fibrous tissue
        • commonly occurs at the jaw
      • multiple endocrine dysplasia (MEN) 1 and 2A
  • Secondary hyperparathyroidism  
    • secondary parathyroid hyperplasia as a result of low Ca2+  absorption and/or high phosphate levels
    • associated conditions
      • chronic renal disease
        • renal disease causes hypovitaminosis D
          • leads to ↓ Ca2+ absorption 
      • renal osteodystrophy
        • bone lesions due to secondary hyperparathyroidism 
  • Tertiary hyperparathyroidism
    • dysregulation of parathyroid glands following chronic renal disease
      • will secrete PTH regardless of Ca2+ levels
    • associated conditions 
      • chronic renal disease 
      • renal osteodystrophy 
     
    Serum Ca
    Serum Phos
    Serum PTH
    Primary
    Secondary
    normal or ↓
    Tertiary
Presentation
  • Symptoms
    • asymptomatic (most common)
    • weakness
    • kidney stones (“stones”)
    • bone pain (“bones”)
    • constipation (“groans”)
    • abdominal/flank pain
    • depression (“psychiatric overtones”)
    • uncommon cause of secondary hypertension  
  • Physical exam
    • hypertension
Imaging
  • Bone mineral density test
    • dual energy X-ray absorptiometry (DEXA) is the most common test to measure bone mineral density
    • allows for measurement of bone reabsorption 
  • Computed tomography (CT)
    • abdominal CT may be indicated to determine if kidney stones or other abnormalities are present
  • Radiograph
    • cystic bone spaces (“salt and pepper”) most common at the skull
    • loss of phalange bone mass with increased concavity 
    • subperiosteal thinning (cortical resorption) 
  • Sestamibi parathyroid scan
    • allows for visualization of the parathyroid glands
    • indicated if surgery is expected
Studies
  • Serum calcium test 
    • best initial test
    • primary hyperparathyroidism
      • hypercalcemia
    • secondary/tertiary hyperparathyroidism
      • hypocalcemia/normocalcemia   
  • Serum PTH
    • best initial test
    • levels will be elevated in all forms of hyperparathyroidism
  • 24-hour urinary calcium  
    • routinely measured in patients to assess risk of renal complications
    • helps to distinguish hyperparathyroidism from familial hypocaloric hypercalcemia (FHH)  
    • hypercalciuria/normocalciuria
  • Serum 25-hydroxyvitamin D
    • helps in differentiating from FHH
    • guides management
  • Genetic testing
    • may be indicated in patients suspected of MEN 1 or MEN 2A
Differential
  • Paraneoplastic syndrome (e.g., squamous cell cancer of the lung)
    • distinguishing factors
      • serum PTH levels will be low due to negative feedback
  • Familial hypocalciuric hypercalcemia (FHH)
    • distinguishing factors
      • urine calcium will be low
Treatment
  • Acute hypercalcemia
    • IV fluids
    • loop diuretics
  • Asymptomatic patients
    • first-line
      • observation with follow-up
    • second-line
      • surgical intervention indicated in select patients with abnormal studies indicating skeletal and renal damage
  • Symptomatic patients (e.g., nephrolithiasis)
    • first-line
      • parathyroid surgery is the only definitive therapy
        • complications include post-op hypocalcemia (e.g., numbness, tingling, and muscle cramps)
        • treat with IV calcium gluconate
    • second-line
      • cinacalcet indicated in patients who are unable to have surgery 
        • decreases PTH levels by sensitizing Ca2+ - sensing receptors at the parathyroid gland
Complications
  • Peptic ulcer disease
    • ↑ gastrin production stimulated by ↑ Ca2+
  • Acute pancreatitis
    • ↑ lipase activity stimulated by ↑ Ca2+
  • CNS dysfunction
    • anxiety, confusion, and coma
    • result of metastatic calcification of the brain
 

Please rate topic.

Average 4.5 of 8 Ratings

Questions (7)
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK

(M1.EC.15.75) A 54-year-old female presents to her primary care physician with complaints of fatigue, constipation, and what the patient describes as "aching in her bones." Her medical history is significant for hypertension, well-controlled on lisinopril, and two prior kidney stones that both passed spontaneously without need for surgery. Vital signs are within normal limits, and physical exam is not significant for any notable findings. Preliminary lab work is ordered and reveals: calcium 11.6 mg/dL (normal range 8.5 - 10.9 mg/dL), phosphorus 2.1 mg/dL (normal range 2.4 - 4.1 mg/dL), and an elevated parathyroid hormone (PTH) level. Which of the following findings would most likely be expected on radiographic evaluation of this patient's hands? Tested Concept

QID: 106788
1

Joint space narrowing at the proximal and distal interphalangeal joints

4%

(6/163)

2

Osteoid matrix accumulation around bony trabeculae

18%

(29/163)

3

Subperiosteal cortical thinning

69%

(113/163)

4

Ulnar deviation of the metacarpophalangeal joints

1%

(2/163)

5

Dense bone filling the medullary cavity of the phalanges and metacarpals

6%

(9/163)

M 2 D

Select Answer to see Preferred Response

(M1.EC.13.14) A 52-year-old female presents to clinic complaining of sudden onset of flank tenderness that was fluctuating and radiating into her groin. Laboratory analysis reveals a serum calcium of 12.4 (normal 8.4-10.2) and a serum phosphorous of 2.5 (normal 2.7-4.5) and a chloride:phosphorous ratio >33. You suspect primary hyperparathyroidism. Which of the following mechanisms is responsible for the patient’s current condition? Tested Concept

QID: 101951
1

PTH binding to receptors on osteoclasts

29%

(8/28)

2

Parafollicular, or C-cell, synthesis of calcitonin

7%

(2/28)

3

Increased RANK-L production

61%

(17/28)

4

Decreased M-CSF production

4%

(1/28)

5

Increased synthesis of osteoid by osteoblasts

0%

(0/28)

M 1 D

Select Answer to see Preferred Response

(M1.EC.13.21) A 65-year-old female with chronic renal failure presents with recent onset of bone pain. Serum analysis reveals decreased levels of calcium and elevated levels of parathyroid hormone. One of the mechanisms driving the elevated PTH is most similar to that seen in: Tested Concept

QID: 100322
1

End stage liver failure

23%

(7/31)

2

Insufficient Ca intake

35%

(11/31)

3

Parathyroid adenoma

13%

(4/31)

4

Decreased functioning of the calcium-sensing receptor (CASR)

23%

(7/31)

5

Sarcoidosis

3%

(1/31)

M 2 E

Select Answer to see Preferred Response

Question locked
Sorry, this question is for
PEAK Premium Subscribers only
Upgrade to PEAK
Evidence (6)
POSTS (1)
VIDEOS (1)
Topic COMMENTS (22)
Private Note