Week 11: Chp 43: Hypoparathyroidism Flashcards
Can be classified as?
idiopathic (unknown), acquired, or reversible
What is the most common cause of acquired hypoparathyroidism?
secondary to the removal of the parathyroid glands during total thyroidectomy or bilateral resection for cancer of the head and neck
Reversible hypoparathyroidism may develop when?
secondary to iodine therapy for hyperthyroidism and with metastasis of malignant tumors
What is suspected in patients who present with a spontaneous presentation of hypoparathyroidism with no identifiable cause?
an autoimmune disease
What is the primary disorder associated with hypoparathyroidism?
Hypocalcemia
- because of the lack of parathyroid hormone (PTH), calcium is not mobilized from the bones, conserved in the kidneys, or absorbed in the small intestines
- vitamin D enters the body in an inactive form through dietary intake or ultraviolet rays and is activated in the kidneys based on actions of the PTH; it is activated vitamin D that leads to calcium absorption in the intestines
Calcium plays a major role in what?
membrane potential and neuronal excitability and is needed for cardiac, skeletal, and smooth muscle contractions
Clinical manifestations of Hypoparathyroidism
decreased serum calcium levels, numbness and tingling around the mouth or in the hands and feet, severe muscle cramps, spasms of the hands and feet, and tetany
- Chvostek signs
- Trousseau sign
Two specific assessments that are observed in hypocalcemia
-Chvostek Signs
-Trousseau sign
>are associated with an increased risk of tetany that can result in laryngospasm and airway compromise
What is a medical emergency when associated with tetany and laryngospasm?
hypocalcemia because this complicates placement of the endotracheal tube
-a tracheostomy tray (set up) is often placed at the bedside of patients at risk as a result of thyroid surgery or severe hypocalcemia
Diagnostic Results consistent with hypoparathyroidism
low serum calcium levels, high serum phosphate levels, and low serum PTH levels
- serum magnesium levels are often evaluated to rule out hypomagnesemia as the cause of hypoparathyroidism, as low serum magnesium levels inhibit synthesis of PTH
- serum albumin levels are monitored because the majority of serum calcium is plasma protein bound; in the patient with both low calcium and albumin, an ionized (free) calcium evaluation is required to determine the extent of the hypocalcemia
Hypoparathyroidism treatment is based on what?
whether the presentation is acute or insidious and focuses primarily on raising serum calcium levels
Treatment for Acute hypocalcemia
Intravenous calcium (usually calcium gluconate or calcium chloride) is administered to the patient with acute hypocalcemia and then followed up with oral calcium and vitamin D supplementation
With a history of cardiac disease, how should you administer IV?
IV administration should be slow to minimize hypotension and bradycardia
Chronic Hypoparathyroidism is treated with?
oral calcium and vitamin D based on close monitoring of serum calcium levels
The nurse correlates a positive Chvostek sign to hyposecretion of which hormone?
parathyroid hormone (PTH)
The clinical signs of hypoparathyroidism is primarily linked to what?
the effects of low serum calcium levels
- decreased serum calcium levels
- tetany (spasms of the hands and feet; cramps), muscle cramps, carpopedal spasm (frequent and involuntary muscle contractions of the hands and feet)
- positive Chvostek’s Signs
- paresthesias of the hands and feet
- tingling of circumoral areas
- seizures
- prolonged QT interval
- resistance to digitalis linked to loss of inotropic effect
- hypotension and cardiac dysrythmias
- bone pain and skeletal deformities
Nursing Diagnoses
- high risk for ineffective airway clearance r/t laryngospasm secondary to hypocalcemia
- decreased cardiac output r/t suppressed myocardial contractility secondary to hypocalcemia
Nursing Assessments
- vital signs
- cardiac monitoring
- ionized calcium levels
- serum magnesium levels
- acid-base status
- neuromuscular activity
Assessment: Vital Signs
hypotension may occur secondary to decreased myocardial contractility and cardiac dysrythmias
Assessment: Cardiac monitoring
hypocalcemia may cause cardiac dysrythmias secondary to effects on cardiac automaticity
Assessment: Ionized calcium levels
ionized calcium is the free and active form of calcium
-lets us see the severity of the hypocalcemia
Assessment: Serum Magnesium Levels
hypomagnesemia interferes with PTH synthesis and contributes to hypocalcemia
Assessment: Acid-base status
an alkaline pH increases binding of calcium to protein and results in decreased ionized calcium
Assessment: Neuromuscular activity
insufficient free, ionized calcium at the neuromuscular junction results in excessive neuronal firing
Nursing Actions
- administer calcium replacements
- administer vitamin D
Actions: administer calcium replacements
raise serum calcium levels
-IV calcium is usually administered over 10 to 15 minutes
Actions: administer vitamin D
vitamin D is needed for calcium absorption from the bowel
Nursing Teaching
- medication regimen
- eat foods high in calcium but low in phosphorus
- signs of hypocalcemia and hypercalcemia
Nursing Teaching: Medication Regimen
lifelong supplementation with calcium is necessary secondary to decreased synthesis or secretion of PTH
Nursing Teaching: eat foods high in calcium but low in phosphorus
foods high in calcium assist in raising serum calcium levels
-foods high in phosphorus are to be avoided because phosphorus can bind with calcium in the serum, further decreasing calcium levels
Evaluating Care Outcomes
compliance with the medication regimen, particularly calcium supplements, usually results in stable serum calcium levels
-because of intake of calcium supplements, it is important to ensure that the patient maintains adequate hydration
High Calcium Foods used in the treatment of hypoparathyroidism
>Fruits and Fruit Juices: -calcium and vitamin D-fortified orange juice -rhubarb -stewed figs >Dark Green, Leafy Vegetables: -collard greens -kale -mustard spinach >Soy Products
Laboratory Tests for Parathyroid Disorders
- Calcium
- Ionized Calcium
- Magnesium
- Phosphorus
- Vitamin D
Lab Test: Calcium
> Normal Range: 8.2- 10.2 mg/dL
>Significance: decreased in hypoparathyroidism, increased in hyperparathyroidism
Lab Test: Ionized Calcium
> Normal Range: 4.6- 5.3 mg/dL
>Significance: decreased in hypoparathyroidism, increased in hyperparathyroidism
Lab Test: Magnesium
> Normal Range: 1.6- 2.2 mg/dL
>Significance: decreased in hypoparathyroidism; low serum magnesium levels inhibit synthesis of PTH
Lab Test: Phosphorus
> Normal Range: 2.5- 4.5 mg/dL
Significance: increased in hypoparathyroidism,
decreased in hyperparathyroidism
(phosphorus can bind with calcium in the serum, further decreasing calcium levels)
