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Gen Med: Ednocrine > Parathyroid > Flashcards

Flashcards in Parathyroid Deck (39):

What is the phys of calcitonin release?

1. Parafollicular cells (C-cells) of thyroid gland secrete calcitonin in response to high Ca levels, this counteracts effects of PTH


What is the phys of PTH release?

1. PTH secreted by chief cells of parathyroid gland
A. Parathyroid cells sense low serum Ca

2. PTH released → ↑ renal absorption of Ca → initiates conversion of Vit D to active form → intestinal absorption of dietary Ca → initiate bone resorption

3. Decreases renal absorption of phosphorus, lowering serum phosphate level


What is hyperparathyroidism?

1. Excessive secretion of PTH
A. ↑ Plasma calcium levels
3. Excessive excretion of phosphorus
A. Phosphaturia
B. ↓ Plasma phosphate levels


What is hypoparathyroidism?

1. Inadequate secretion of PTH
A. ↓ Plasma calcium levels
B. ↑ Plasma phosphate levels


Define primary hyperparathyroidism

1. Overproduction of PTH → abnormal calcium homeostasis
2. F > M
A. Prevalence 1:1000 in US
3. Mean age 52-56yo
4. ↑ risk w/ age
5. ↑ in menopausal women


What is the most common cause of primary hyperparathyroidism?

1. Most caused by single parathyroid adenoma
A. Chief Cell Adenomas 85% of all cases
B. Some multiple adenomas
C. Etiology of most adenomas unknown
D. Some familial as part of Multiple Endocrine Neoplastic syndromes (MEN 1 and 2)


What is the pathophys of primary hyperparathyroidism?

1. PTH “shut-off” feedback is lost
2. Leads to excessive production of PTH


What are complications from primary hyperparathyroidism?

1. Leads to excessive resorption of Ca from bone
A. Osteopenia
B. Osteitis Fibrosa Cystica (OFC) in severe cases
(diffuse demineralization, pathological fractures, and cystic bone lesions)
2. Leads to renal tubular reabsorption of calcium
A. Predisposes to formation of renal stones
B. ↑ Ca in filtrate results in hypercalciuria


What is the clinical presentation of hyperparathyroidism?

1. Most cases discovered incidentally by routine chemistry panel (hypercalcemia)

2. Symptoms:“bones, stones, abdominal groans, psychic moans, w/fatigue overtones”


What are the skeletal sxs of hyperparathyroidism?

1. Cortical bone loss
2. Bone & joint pain
3. Pseudogout
A. Chondrocalcinosis- Calcium phosphate deposition
B. Crystal deposits in joints on X-ray
C. Streaking of soft tissue w/ calcium


What are the renal manifestations of hyperparathyroidism?

1. Nephrolithiasis
2. Polyuria
3. Hypercalciuria
4. Rare nephrocalcinosis: calcification of kidneys


What are the abdominal sxs of hyperparathyroidism?

1. Abd pain
2. Anorexia
3. N/V -> dehydration
4. Constipation
5. Peptic ulcers
6. Acute pancreatitis


What are the psychologic moans of hyperparathyroidism?

1. Subtle
2. Depression
3. Inability to concentrate
4. Memory problems


What are the CNS manifestations of hyperparathyroidism?

1. Fatigue overtones
A. Malaise
B. Irritability
C. Insomnia


What are the neuromuscular manifestations of hyperparathyroidism?

1. Fatigue overtones
A. Muscle cramps
B. Weakness
C. Paresthesia


What are the cardiac manifestations of hyperparathyroidism?

1. fatigue overtones?
A. Hypertension
B. Bradycardia


What are the CMP results in hyperparathyroidism?

1. inc Serum Calcium > 10.5 mg/dL

2. ↓ Serum Phosphate (PO4)
A. Normal 2.7-4.5 mg/dL
B. > 60 yr M 2.3-3.7 mg/dL
C. > 60 yr F 2.8-4.1 mg/dL

3. ↑ Alkaline Phosphatase only if bone turnover is present
A. M 38-126 U/L (nl)
B. F 70-230 U/L (nl)

4. BUN/Cr
5. Lipase/Amylase if abd pain


What are the PTH results of hyperparathyroidism?

↑ (or high normal), confirms Dx


What do you do if the pt has ↑ PTH & normal serum calcium?

1. Evaluate for 2°hyperparathyroidism (vit D or calcium deficiency, hyperphosphatemia, or renal failure)
2. If no secondary cause found:
A. Cont. monitoring
B. ≈ 19% will develop hypercalcemia over next 3 years


What do you do if the pt is positive for hyperparathyroidism?

1. Screen for Familial Benign Hypocalciuric Hypercalcemia (FBHH) w/ 24-hour urine for calcium & creatinine
2. Calcium excretion of < 50 mg/24 hr atypical for primary hyperparathyroidism & indicates possible FBHH


When are imaging studies used in hyperparathyroidism?

1. Not useful in the Dx of hyperparathyroidism
2. Parathyroid imaging is crucial in those w/ prior neck surgery
A. MRI preferred
3. Non-contrast CT scan of kidneys to determine calcium-containing stones
4. DEXA scan (bone density scan) to determine bone loss


What is the imaging study of choice for the neck?



What are the DDX for hyperparathyroidism?

1. Lab error, initially should be repeated ALWAYS
2. Dehydration
3. Malignant tumors (breast, lung, pancreas, uterus)
4. Multiple Myeloma, especially in elderly
5. Sarcoidosis
6. Large consumption of calcium or vit D, especially w/ thiazide diuretics
7. Adrenal Insufficiency
8. Familial Benign Hypocalciuric Hypercalcemia (FBHH)
9. Hyperthyroidism


How are asymptomatic hyperparathyroid pts treated?

1. May not need therapy
2. Advise to keep active, avoid immobilization, & drink ↑ fluids
3. Avoid:
A. Thiazide diuretics
B. Large doses vit. A
C. Calcium-containing antacids
4. Follow-Up
A. Serum calcium, albumin, BUN/Cr q 6 mo
B. Urine calcium annually
C. DEXA scan q 2 yr


What is 1st line treatment for symptomatic hyperparathyroidism?



What are the indications for parathyroid surgery?

1. Symptomatic, remove adenoma - majority are benign
2. NIH surgery criteria – for asymptomatic patients
A. Serum Calcium 1.0 mg/dL above normal range
B. 24hr urine Ca excretion > 400 mg
C. 30% reduction in creatinine clearance
D. Bone Mineral Density (BMD) T-score below - 2.5 any site
E. Age < 50 yr
F. Pregnancy


What are the potential complications from parathyroid surgery?

1. Hypocalcemia (transient typical, can be permanent)
2. Injury to recurrent laryngeal nerve
3. Bleeding
4. Pneumothorax
5. Hyperthyroidism immediately after surgery
A. 2°to release of thyroid hormone during surgical manipulation of thyroid
B. Symptomatic pt may need propranolol/Inderal short-term


When are post parathyroid -surgery labs performed? What is checked?

1. 1-2 wks
2. Serum Calcium, Vit D level, PTH, (TSH, Free T4)


What is the non-surgical management for hyperparathyroidism?

1. Pharmacotherapy
2. Consider ERT in menopausal females (risk vs benefit)
A. Improve bone mineral density (BMD)
B. ↓ Serum calcium
3. Consider estrogen receptor modulators (raloxifene/Evista)
A. ↓ Serum calcium
4. Bisphosphonates (alendronate/Fosamax)
A. Improve BMD
5. Calcimimetic drugs (cinacalcet/Sensipar)
A. ↓ serum Ca
B No change in BMD


What is the emergency management of severe hypercalcemia?

1. IV volume replacement with NS
A. When volume restored give loop diuretic (furosemide/Lasix)
2. Calcitonin & bisphosphonate IV (zoledronic acid)
A. Temporary measure prior to surgery


What is hypoparathyroidism?

1. Insufficient secretion of PTH
A. Low serum calcium levels
B. High serum phosphate
C. Neuromuscular symptoms


What is the most common etiology of hypoarathyroidism?

1. Iatrogenic (surgery/radiation)
A. Thyroidectomy
B. Laryngeal, or neck malignancy


What other etiologies for hypoarathyroidism exist?

1. Heavy Metal toxicity
A. Copper (Wilson Disease)
B. Iron (hemochromatosis)
2. Magnesium deficiency
A. Chronic alcoholism, malabsorption
3. Infiltrative
A. Metastatic CA
B. Amyloidosis
4. Genetic
5. Autoimmune
A. Most common nonsurgical cause


What are most of the sxs of hypoarathyroidism caused by?

due to neuromuscular irritability


What are the sxs of hypoparathyroidism?

1. Paresthesia (fingers, toes, perioral)
2. Seizures (↑ w/ underlying seizure disorder)
3. Muscle cramps: low back, legs, feet
4. Muscle spasm: carpopedal, oral/facial (tetany)
5. Irritability, fatigue, anxiety, mood swings
6. Arrhythmias
7. Severe hypocalcemia can cause respiratory failure
A. Severe larynx spasm & bronchospasm
8. Cataracts
9. Nails thin, brittle
10. Fatigue
11. Insomnia
12. Headache


What is Chovstek's sign?

1. (+)Chvostek’s sign
2. Facial twitching near mouth induced by tapping facial nerve anterior to ear


What is trousseau's sign?

1. Carpal spasm (tetany) induced by BP cuff inflated to 20 mm/Hg above obliteration of radial pulse (takes 3-5 min)


What lab findings will be present in hypoparathyroidism?

1. ↓ Serum calcium ( 60 M 2.3-3.7 mg/dL
C. > 60 F 2.8-4.1 mg/dL
5. Serum albumin
6. ↓ Urinary calcium
7. Serum magnesium
8. Alkaline phosphatase WNL
A. M 38-126 U/L
B. F 70-230 U/L


What is the emergency treatment for severe hypocalcemia/hypoparathyroid tetany?

1. Airway
2. Telemetry
3. IV (central) Calcium gluconate for tetany
A. Phlebitis in periph IV
4. Oral Calcium for post-op hypoparathyroidism
5. Oral calcitriol for acute hypocalcemia
6. IV Mg sulfate if hypomagnesemia
7. Injections of recombinant human PTH (Natpara) if indicated (1/2015)
A. Risk of osteosarcoma