Disorders of the Parathyroid Flashcards
Characterized by chronic poorly regulated excessive secretion of PTH
Results in excessive secretion of calcium and phosphate by the kidneys
More frequent over the age of 50
3x more common in females
Hyperparathyroidism
Usually caused by a single parathyroid adenoma
Hyperparathyroidism
Familial in about 10% of cases
Associated with MEN I and IIa
Hyperparathyroidism
What are the types of hyperparathyroidism?
Primary
Secondary
Tertiary
Which type of hyperparathyroidism is described below?
Caused by hypersecretion of PTH, usually by a single parathyroid adenoma (80%), and less commonly by hyperplasia by two or more parathyroid glands (20%), or carcinoma (≤1%)
Occurs at all ages but more commonly in the 7th decade in women (~70s)
Most common cause of hypercalcemia in the outpatient setting
Primary hyperparathyroidism
Which type of hyperparathyroidism is described below?
Renal failure is the most common cause
Other causes include: Vit D deficiency, inadequate calcium intake or absorption
Secondary hyperparathyroidism
Which type of hyperparathyroidism is described below?
Results from autonomous functioning parathyroid glands in patients with long-standing secondary hyperparathyroidism
Tertiary hyperparathyroidism
What is the most common cause of hypercalcemia in the outpatient setting?
Primary hyperparathyroidism
What is the most common cause of secondary hyperparathyroidism?
renal failure
Excessive PTH spares which type of bone?
trabecular bone
What are some complications of severe chronic hyperparathyroidism?
Diffuse demineralization
Pathologic fracture
Cystic lesions throughout the skeleton
What are the clinical findings of hyperparathyroidism?
Stones
Bones
Groans
Moans
Overtones
What ocular findings might you see in cases of hyperparathyroidism?
Band keratopathy
Appearance of a band across the central cornea, formed by the
precipitation of calcium salts on the corneal surface directly under
the epithelium
Band keratopathy
What is the hallmark lab finding in hyperparathyroidism?
Hallmark is serum Calcium >10.5 mg/dL
If serum calcium is high in a patient, what is a confirmatory test to order for hyperparathyroidism?
PTH
Diagnosis confirmation: elevated levels of intact PTH
List some differential diagnoses to consider when working up a patient with high levels of calcium
Artifact
Malignancy
Sarcoidosis or other granulomatous disorders
Exogenous intake
Familial benign hypocalciuric hypercalcemia
Vitamin D deficiency
Adrenal insufficiency
immobilization
Indicated for the treatment of severe hypercalcemia in patients with
primary hyperparathyroidism who are unable to undergo parathyroidectomy
Cinacalcet (calcimimetic)
In patients with parathyroidism, what patients is a parathyroidectomy required?
Parathyroidectomy often required for symptomatic patients with kidney stones, bone disease, and pregnancy
List some factors where a parathyroidectomy would be the best treatment
Serum calcium 1mg/dL above upper limit of normal with urine calcium >50mg in 24 hours
Urine calcium >400mg/24hr
Cortical bone density > 2 SD below normal (wrist and hip)
Patients younger than 50
Pregnancy
Difficulty with follow up
In patients with a parathyroid adenoma that is being monitored, what are the follow up guidelines?
Follow up every 6 months
Evaluate hypercalcemia symptoms
Ca, Phos, and albumin every 6 months
24 hour urine and creatinine yearly
Abdominal xrays yearly
Bone mineral density yearly
Adequate hydration
Avoid thiazide diuretics
Consider bisphosphonate therapy for prevention of osteoporosis
In this endocrine condition, many patients are asymptomatic unless it’s chronic
Hypoparathyroidism
List some causes for hypoparathyroidism
Acquired hypoparathyroidism
May occur from heavy metal damage
Granulomas
Tumors
DiGeorge syndrome
Infection
Redel thyroiditis
Magnesium deficiency
Malabsorption
Chronic alcoholism
Autoimmune (e.g. polyglandular autoimmunity Type 1)
What is the most common cause of acquired hypoparathyroidism?
Thyroidectomy
