Parathyroid Gland Dysfunction - PowerPoint PPT Presentation

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Parathyroid Gland Dysfunction

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Title: Parathyroid Gland Dysfunction


1
Parathyroid Gland Dysfunction
  • Excela Health School of Anesthesia

2
Parathyroids
3
Parathyroid Hormone
  • Released into circulation by negative feedback
  • PTH release stimulated by hypocalcemia
  • PTH maintains normal serum calcium levels

4
Hyperparathyroidism
  • PTH level elevated
  • Serum calcium levels may be increased, decreased,
    or unchanged
  • Classified as primary, secondary, or ectopic

5
Primary Hyperparathyroidism
  • Excessive secretion PTH from benign parathyroid
    adenoma, carcinoma of parathyroid, or hyperplasia
    of parathyroid glands
  • Benign adenoma responsible for 90 primary
    carcinoma for 5
  • Hyperplasia usually involves all 4 parathyroids

6
Primary Hyperparathyroidism
  • Diagnosis
  • serum calcium gt5.5 mEq/L ionized calcium
  • concentration gt2.5 mEq/L
  • Measurement of serum parathyroid hormone
    concentration is not always sufficiently reliable
    to confirm the diagnosis of primary
    hyperparathyroidism

7
Primary Hyperparathyroidism
  • Signs Symptoms
  • early sedation, vomiting
  • others skeletal muscle weakness, hypotonia
    that may mimic myasthenia gravis
  • persistent increases in plasma calcium
    concentration can interfere with urine
    concentrating ability with resulting polyuria
  • Oliguric renal failure in advanced cases of
    hypercalcemia (see handout)

8
Primary Hyperparathyroidism
  • Treatment Initially by medical means followed by
    surgical removal of diseased area(s)
  • Medical Saline infusion (150ml/hour) for pts.
    with symptomatic hypercalcemia
  • Loop diuretics (furosemide 40-80mg IV q 2-4
    hours
  • Do not administer thiazide diuretics for
    hypercalcemia

9
Primary Hyperparathyroidism
  • Medical Treatment for Life Threatening
    Hypercalcemia Use of Bisphosphonates such as
    disodium etidronate
  • binds to hydroxyapetite and acts as potent
    inhibitor of osteoclastic bone reabsorption
  • Hemodialysis can also be considered

10
Primary Hyperparathyroidism
  • Surgical Management Normalization of serum
    calcium levels within 3-4 days
  • postoperative potential complication is
    hypocalcemic tetany
  • a hypomagnesemia may occur postop that will
    aggravate the hypocalcemia and may render it
    refractory to treatment

11
Primary Hyperparathyroidism
  • Anesthetic Management No specific drugs or
    techniques
  • Maintain hydration and urinary output
  • If somnolent preop anesthestic requirements
    decreased
  • If coexisting renal dysfunction use of
    sevoflurane is questionable
  • Careful use of muscle relaxants and
    monitoring
  • Careful positioning

12
Secondary Hyperparathyroidism
  • A disease process produces hypocalcemia and
    parathyroids compensate by secreting more
    parathyroid hormone (ex. Chronic renal disease)
  • Since secondary hyperparathyroidism is adaptive,
    rather than autonomous, it seldom produces
    hypercalcemia
  • Treatment Treat underlying disease

13
Ectopic Hyperparathyroidism
  • Due to secretion of parathyroid hormone by
    tissues other than the parathyroid glands
  • (ex. Humoral hpercalcemia of malignancy,
    cancer of lung, breast, pancreas, kidney)
  • Likely to be associated with anemia

14
Hypoparathyroidism
  • PTH absent or deficient, or peripheral tissues
    are resistant to the effects of PTH
  • Absence or deficiency of PTH almost always
    iatrogenic (inadvertent removal)
  • Diagnosis Measurement of serum calcium
    concentrations and the ionized fractions of
    calcium is best indicator
  • Signs Symptoms Depend of the rapidity of the
    onset of hypocalcemia

15
Acute Hypocalcemia
  • Can occur after accidental removal
  • Likely to manifest as perioral paresthesias,
    restlessness, neuromuscular irritability, as
    evidenced by a positive Chvosteks sign or
    Trousseaus sign
  • Treatment Infusion of calcium (10 ml of 10
    calcium gluconate IV) until signs of
    neuromuscular irritability disapper

16
Chronic Hypocalcemia
  • Associated with complaints of fatigue and
    skeletal muscle cramps
  • Prolonged QT
  • Neurological lethargy, cerebration deficits,
    personality changes
  • CRF is most common cause of chronic hypocalcemia

17
Anesthesia Management
  • Management of anesthesia in presence of
    hypocalcemia is designed to treat any further
    decreases in serum calcium and to treat adverse
    effects of hypocalcemia on the heart so avoid
    iatrogenic hyperventilation
  • rapid infusions of blood (500 ml q 5-10 min) as
    during CPB or liver transplantation can decrease
    ionized calcium concentration
  • when metabolism or elimination of citrate is
    impaired as with hypothermia, cirrhosis, renal
    dysfunction
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