THYROID HORMONES Flashcards
Thyroid Hormone is regulated by
Thyroid-Stimulating Hormone
Thyroid Hormone is synthesized and secreted by
Thyroid Gland
The essential amino acids of thyroid gland
Thyrosine
The 3 Thyroid Hormones
Thyroxine (t4)
Tri-iodothyronine (T3)
Thyrocalcitonin
Whats the behind reason on why the thyroid hormone is produced?
Thyroid Hormone is produced because of the combination of iodide and thyrosine
Functions of T3 and T4
Basal Metabolic Rate
Blood Sugar
Breakdown of Lipids
Brain Maturation
Bone Growth
B-adrenergic effects
Balls and Baby Bumps
Everything is high, fast, and dry
Hyperfunction
Everything is low, wet, and slow
Hypofunction
It stores calcium in the bones
Thyrocalcitonin
Results from suboptimal levels of thyroid hormones
Hypothyroidism
In hypothyroidism, it commonly affects
Women than men
The 3 types of Hypothyroidism
Primary Hypothyroidism
Secondary Hypothyroidism
Cretinism
It is a type of Hypothyroidism that is hypofunction of the thyroid gland
Primary Hypothyroidism
It is a type of Hypothyroidism that dysfunction originates from the pituitary gland
Secondary Hypothyroidism
Hypothyroidism in children
Cretinism
What are the causes of Primary Hypothyroidism?
-Hashimoto’s thyroiditis (most common cause)
-Atrophy (common in elderly)
-Thyroidectomy
-Iodine Therapy
- Drugs: Lithium, Anti-Thyroids
Comparisons of Laboratory Findings In Primary vs. Secondary Hypothyroidism
Primary Hypothyroidism
-Elevated TSH
-Decreased free T4
-Elevated cholesterol, triglycerides, and LDL
-Hashimoto (+) Thyroid peroxidase antibodies
Secondary Hypothyroidism
- Decreased TSH
-Decreased free T4
-Elevated cholesterol, triglycerides and LDL
Clinical Manifestations of Hypothyroidism
- Hypothermia
- Cold Intolerance
- Weight Gain
- Fatigue
- Bradycardia
- Thickened skin
- Hoarseness of voice
- Myxedema (Subcutaneous)
- Hyperlipidemia
- Decreased Perspiration
- Dry Skin
- Constipation
Other Manifestations
* depression
* somnolence
* abnormal menses
* infertility
Decreased metabolic rate can also decreased glandular secretion in skin and Decreased GI motility . What manifestations that decreased GI motility?
Constipation
Medical Management of Hypothyrodism
Thyroid Replacement Therapy
Levothyroxine (Synthroid)
-Synthetic form of T4
- Treatment of Choice
Liothyronine (Cytomel)
- Synthetic form of T3
- Used as second line treatment
-Given more frequent
- Has better GI absorption than T4 but has a short duration of action
Nursing Responsibilities of Hypothyroidism
-Administer on an empty stomach (30 mins to 1 hour) before breakfast with a full glass of water
-Avoid eating strawberry, peaches, cabbage, grapefruit juice while while on thyroid replacement
-Facilitate dose titration (to prevent hyperthyroidism)
- Thyroid replacement is safe for pregnant or lactating mothers. Dose is higher in these situations
- WOF: chest pain as drug may precipitate angina. Discontinue if noted.
Is a rare life-threatening condition presenting as a decompensated state of severe hypothyroidism
Myxedema Coma
Common among undiagnosed hypothyroidisms
Myxedema Coma
What triggers myxedema coma?
-Systemic illness
-Opioids
-Exposure to cold
- Bleeding
Essential Concept of Myxedema Coma
-Hypothyroid patients maintains a homeostasis through chronic neurovascular compensatory mechanisms
-Chronic vasoconstriction
-Diastolic hypertension (Narrowed PP)
-Diminised blood volume
Clinical Manifestations of Myxedema Coma
-Decreasing mental status (initial sign)
- Hypothermia (best indicator of prognosis)
- Hypoventilation
- Bradycardia
-Hypotension
- Hypoglycemia
Medical Management of Myxedema Coma
Priority: Airway Management
-Mechanical Ventilation (initially)
-Respiratory support with non-invasive oxygen therapy
Thyroid Replacement
Intravenous T4 and T3 during acute stages, then shifted to ORAL form once able to take medications by mouth
Medical Emergency
Myxedema Coma
Supportive Measures for Myxedema Coma
-Passive rewarming using ordinary blankets and a warm room
- Monitor core temperature via the rectal route
- Treat associated infection using broad-spectrum antibiotics, as ordered
For hyponatremia:
-Saline Infusion
-Free water restriction
For hypoglycemia
-D50 Water
Is a set of disorders that involve excess synthesis and secretion of thyroid hormones by the thyroid gland, which leads to the hypermetabolic condition of thyrotoxicosis
Hyperthyroidism
Is a condition characterized by increased thyroid hormone levels with or without increased thyroid hormone synthesis
Thyrotoxicosis
Hyperthyroidism and Thyrotoxicosis are both characterized
both characterized by hyperfunction of thyroid hormones leading to hypermetabolism
3 forms of Hyperthyroidism
-Grave’s Disease
- Toxic Nodular Goiter
-Toxic Adenoma
An organ-specific autoimmune disorder characterized by circulating thyroid-stimulating antibodies which act as TSH receptor agonist in the thyroid gland
Grave’s Disease
-A form of goiter characterized by thyroid hormone-releasing nodules
- Commonly affects the elderly
Toxic Nodular Goiter
Presence of a hyperfunctioning follicular thyroid adenoma
Toxic adenoma
Causes of Thyrotoxicosis
-Excessive intake of Thyroid Hormone
- Subacute Thyroiditis
Causes of Thyrotoxicosis
-Overdosing
- Incorrect Dosage Prescription
Excessive Intake of Thyroid Hormone
Causes of Thyrotoxicosis
A self-limited thyroid condition associated with a triphasic clinical course of hyperthyroidism, hypothyroidism, and return to normal thyroid function
Subacute Thyroiditis
Clinical Manifestations of Hyperthyroidism and Thyrotoxicosis (REVERSIBLE MANIFESTATIONS)
Increased B receptor responsiveness to catecholamines
-Nervousness (most common presenting symptom)
- Tachycardia
- Hypertension
- Fine Tremors
- Diaphoresis
Increased glycogenolysis
- Hyperglycemia
Increased metabolic rate
-Heat intolerance
- Increased appetite
- Weight loss
Hypocalcemia
- Diarrhea
- Pllable nails
-Fine, silky hair
Clinical Manifestations of Hyperthyroidism and Thyrotoxicosis
-Ophthalmopathy
-Exophthalmos
-Dalyrimple’s sign (thyroid stare)
Most frequent extrathyroidal involvement in Grave’s Disease
Ophthalmopathy
Protrusion of eyeballs resulting from fluid accumulation at the fat pads behind the eyelids
Exophthalmos
Bright-eyed stare and infrequent blinking
Dalyrimple’s sign (Thyroid stare)
Nursing Care for Hyperthyroidism and Thyrotoxicosis
- Artificial tears to prevent excessive dryness
- Tinted and well- fitting eyeglasses at all times
Laboratory and Diagnostic Tests for Hyperthyroidism and Thyrotoxicosis
TSH Level
Radioactive Iodine Uptake (Thyroid Scan)
Thyroid Hormone (T3 and T4) Level
Laboratory and Diagnostic Tests for Hyperthyroidism and Thyrotoxicosis
The most reliable method of assessing thyroid function and SUPPRESED in hyperthyroidism
TSH Level
What is the normal level of TSH level?
0.4-4.0 mlU/L
Laboratory and Diagnostic Tests for Hyperthyroidism and Thyrotoxicosis
Done if etiology of thyroid hormone elevation remains unclear after physical exam and standard laboratory test
Radioactive Iodine Uptake (Thyroid Scan)
Laboratory and Diagnostic Tests for Hyperthyroidism and Thyrotoxicosis
Uses Iodine-123 as an isotope
Radioactive Iodine Uptake (Thyroid Scan)
Laboratory and Diagnostic Tests for Hyperthyroidism and Thyrotoxicosis
Elevated in hyperthyroidism and thyrotoxicosis
Thyroid Hormone (T3 and T4) Level
Nursing Responsibilities of the Radioactive Iodine Therapy
Before the procedure:
-Assess for allergies to iodine or shellfish
- NPO for 8-12 hours
- Determine LMP in women. Facilitate pregnancy test if necessary
-Explain that test does not pose any radioactive hazard
After the Procedure:
- Isolate patient x 24 hours
- Institute safety precautions (DTS)
- No pregnant caregivers allowed
- Encouraged increased oral fluid intake
- Flush the toilet twice after using
What is DTS?
D-Distance
T- Time (30 mins)
S- Sheild (Lead Apron)
Medical Management of Hyperthyroidism and Thyrotoxicosis
Radioactive Iodine Therapy
-Most common treatment for Grave’s Disease
- Effects are less rapid than antithyroid medications for thyroidectomy
-Isotope: Iodine 131
Contraindications: Pregnancy and lactation
- Pre-treatment with Methimazole is CONTROVERSIAL
Special Nursing Considerations:
-Check female patients for pregnancy prior to treatment
- Institute radiosafety precautions
Anti-Thyroid Medications
Methimazole (Tapazole)
-First line drug for hyperthyroidism
- Has longer duration of action
-Contraindications:
-First trimester pregnancy
-Thyroid Storm
Propylthiouracil (PTU)
-Drug of choice for severe thyrotoxicosis
- May be given to pregnant women in the first trimester of pregnancy
Adjunct Medications for Symptomatic Relief
-Beta-Blockers
- DOC: Metoprolol (Neobloc), Propranolol (Inderal)
-Decreases HR, systolic blood pressure, and anxiety
Enough to kill tissues that is very hyperactive
Iodine 131
Anti-Thyroid Mechanism of action
Prevents formation of thyroid hormones by blocking iodine utilization
Adverse Effect of Anti-Thyroid Medications
Agranulocytosis
WOF: fever and sore throat
Nursing Responsibilities of Anti-Thyroid Medications
-Instruct to take medication early in the morning on an empty stomach 30 minutes before eating to avoid decrease in absorption
-Advise patient that it may take weeks until symptom relief occurs
Surgical Removal of the Thyroid Gland
Thyroidectomy
Removal of about 5/6 of the thyroid gland
Subtotal Thyroidectomy
The remaining portion can still produce and secret thyroid hormones
Subtotal Thyroidectomy
Removal of both lobes and isthmus
Total Thyroidectomy
What’s the indication of Thyroidectomy?
-Pregnant women who are allergic to antithyroid medications
- Large goiters
- Patients who are unable to take anti-thyroids
Subtotal Thyroidectomy Iodine Compounds
Iodine Compounds
-Lugol’s solution, saturated solution of potassium iodide (SSKI)
-Administer with milk or fruit juice to increase palatability
-Administer using a straw to prevent staining of teeth
Post-Operative Care of Subtotal Thyroidectomy
-Position: semi-fowler’s with head, neck and shoulders erect (support with a pillow)
- Monitor surgical site for bleeding and edema
-Check for dressing and back of neck
- WOF: respiratory distress
-Prepare at bedside:
-Tracheostomy set, oxygen, and suction equipment
Respiratory distress manifestation
Grasping for air, cyanosis
If someone is having a respiratory distress, what is the EMERGENCY INTERVENTION to do?
Perform Tracheotomy or Stab PT Windpipe
Tracheostomy set, oxygen, and suction equipment among these three which is the most important?
Tracheostomy set
A form of severe, life-threatening hyperthyroidism
Thyroid Storm
What causes thyroid storm?
-Stress
-Infection
Clinical Manifestations of Thyroid Storm
-Hyperpyrexia (T>38.5C)
- Extreme tachycardia (HR > 130 bpm)
-Exaggerated symptoms of hyperthyroidism
-Altered mental status (delirium, psychosis, coma)
Management of Thyroid Storm
-Propylthiouracil (PTU), as ordered
-Ice packs, paracetamol (to lower temperature)
-Supplemental oxygen (provide for increased oxygen demands)
- IV fluids with dextrose (D5LR or PNSS)- Hypertonic solutions
Secreted by the Parathyroid Gland
Parathyroid Hormone
Increases serum calcium level, but decreases phosphorus level
Parathyroid Hormone
Vitamin D enhances the effects of the hormone
Parathyroid Hormone
Regulates PTH effects by depositing serum calcium into the bones, thus reducing its serum level
Calcitonin counter
Is characterized by overproduction of PTH causing hypercalcemia
Hyperparathyroidism
Types of Hyperparathyroidism
-Primary Hyperparathyroidism
-Secondary Hyperparathyroidism
-Parathyroid adenoma (most common)
- Long-term lithium therapy
Primary Hyperparathyroidism
-A compensatory response to conditions that induce hypocalcemia
- CKD, Vitamin D deficiency
Secondary Hyperparathyroidism
Basic Concept of Hyperparathyroidism
-PTH decalcifies the bone, making it fragile and prone to fractures
- The kidneys will try to excrete excess calcium via the urine. However, this causes precipitation which forms kidney stones
How to prevent precipitation?
To prevent precipitation is to increase oral fluid intake
What delays sodium into the cell?
Hypercalcemia
Delayed sodium influx means
Slower neuromuscular impulse transmission
Hyperparathyroidism decreases:
-Decrease cognitive function (decreased mental status)
- GI function (constipation, nausea and vomiting)
-Decrease muscle activity (fatigue, muscle weakness)
- Decrease Myocardial depolarization (bradycardia, dysrhythmias, ECG changes)
- Decrease Osteoblastic Activity (pathologic fractures, bone pain, shortened height)
Diagnostics for Hyperparathyroidism
-Serum Calcium Level
-Normal: 8.5 to 10.5 mg/dl
-Hyperparathyroidism: ELEVATED
-Intact PTH
-Normal: 14-72 pg/ml
-Hyperparathyroidism: ELEVATED
-Serum phosphorous level
-Normal: 2.5 - 4.5 mg/dl
-Hyperparathyroidism: Decreased
-Bone Mineral Density
-Score of 2.5 or less at any site or previous fragility fracture
Medical and Surgical Management of Hyperparathyroidism
Hydration Therapy
-Increased fluid intake to 2,00 ml or more to prevent renal calculi
- PNSS IV- fluid of choice as sodium enhances excretion of calcium
Mobility
-Bones subjected to the normal stress of walking give up less calcium. Bed rest increases calcium excretion and the risk of renal calculi
-Ambulation prescribed
Parathyroidectomy
- Removal of one or more of the parathyroid glands
- Post-Operative Care:
Position: Semi-Fowler’s
-WOF respiratory distress, bleeding at post-operative site
-Prepare at bedside: tracheotomy set
Occurs with extreme elevation of calcium levels greater than 13 mg/dl
Hypercalcemic Crisis
What causes Hypercalcemic Crisis?
Dehydration
Management of Hypercalcemic Crisis?
-Rapid dehydration with large volume of isotonic fluid
-Loop diuretic (e.g., Furosemide) if with edema
- Calcitonin-promotes renal excretion of calcium
- Corticosteroids- promotes calcium deposition in bone
-Dialysis
Hyposecretion of Parathyroid Hormome
Hypoparathyroidism
Causes of Hypoparathyroidism
-Subtotal Thyroidectomy (Most Common)
- Abnormal Parathyroid Development
Very little calcium in the blood
Hypocalcemia
Clinical Manifestations of Hypoparathyroidism
TETANY
General muscle hypertonia, with tremor and spasmodic or uncoordinated contractions occurring with or without efforts to make voluntary movement
Tetany
TETANY
-Numbness, tingling, and cramps in the extremities
- Stiffness of hands and feet
Latent Tetany
Overt Tetany
(+) trousseau’s sign: carpopedal spasm resulting from occlusion of the blood flow to the arm for 3 minutes
(+) Chvostek’s sign: sharp tapping over the facial nerve causes spasm or twitching of mouth, nose, eye
-Photophobia
- Dysrhythmias
- Laryngospasm, bronchospasm
-Seizure
A contraction of the facial muscles elicited in response to light tap over the facial nerve in front of the ear
Chvostek sign
A carpopedal spasm induced by inflating a blood pressure cuff above systolic blood pressure for 3 minutes
Trousseau sign
Medical Management of Hypoparathyroidism
-Vitamin D3 (calciferol) ( to supplement calcium deficit)
- Hydrochlorothiazide (Hydrodiuril) (decreases urinary calcium excretion)
- Calcium gluconate very slow IVTT (if hypocalcemia is after thyroidectomy)
-Aluminum hydroxide gel (Amphojel) after meals to bind phosphate its excretion through GI tract
- Place patient on seizure precaution
- Have a tracheostomy set, oxygen, and suction available at bedside
-Provide a high- calcium, low phosphorus diet
-Broccoli, tomato, banana, kidney beans- Avoid cheese, milk and milk products, and egg yolk
-Avoid spinach which contains oxalate that forms insoluble calcium substances
- Avoid cheese, milk and milk products, and egg yolk
