Thyroid Gland anatomy and physiology. Disorders of thyroid gland and managements.

1. THYROID GLAND
THYROID GLAND – largest endocrine organ; produces thyroid
hormones (T4 and T3) and calcitonin.
ANATOMY AND PHYSIOLOGY
I. THYROID HORMONE
Thyroid gland  composed of follicles  filled with colloid
 consists of thyroglobulin  contains 140 tyrosine amino
acids thyroid synthesis  produces T4 and T3 stored
until needed for release into the bloodstream.
A.Thyroid Hormone Synthesis
T4 = 90% and T3 = 10%released in the blood.
B. Thyroid Hormone Regulation
Hypothalamic-Pituitary-Thyroid Feedback System
C. Thyroid Hormone Function
 Increases metabolic rate
 Increases body temperature in response to an elevated
metabolism, which produces body heat.
 Increases the use of oxygen as metabolism increases.
 Aids in the development of the neural and skeletal systems
in fetuses.
 Affects respiratory rate: too much thyroid hormone
increases respiratory rate, and too little decreases
respiratory rate.
 Aids in normal growth and development.
II. CALCITONIN–↓es serum calcium level
↑ed serum Cal  signals thyroid gland (C cells)  release of calcitonin
in blood ↓es Cal resorption; ↓es osteoclast activity in the bone;
↓es intestines’ ability to absorb Cal.
ASSESSMENT AND DIAGNOSTIC FINDINGS
I. PHYSICAL EXAMINATION(palpate and auscultate)
Isthmus – firm and of a rubber-band consistency.
Lateral lobes – 2 thin, smooth and nontender lobes.
Enlarged thyroid – auscultate for a bruit sound indicating an
increased bloodflow.
II.LABORATORY AND DIAGNOSTIC PROCEDURES
1. Serum Thyroid-Stimulating Hormone – used to
distinguishsubclinical thyroid disease from euthyroid states
in patients with low or high normal values.
2. Serum Free T4–used for direct measurement of free
(unbound) T4; NR: 0.9 – 1.7 ng/dL
3. Serum T3 andT4– used to measure the total T3 andT4; NRT4: 4.5
– 11.5 ng/dL and NRT3: 70 – 220 ng/dL.
4. T3 Resin Uptake Test– used to determine the amount of
thyroid hormone bound to TBG; NR: 25% - 35%.
5. Thyroid Antibodies – test the presence of antithyroid antibodies:
NR: 5% - 10%.
6. Radioactive Iodine Uptake – measures the rate of iodine uptake
by the thyroid gland; NR vary with the intake of iodine.
7. Fine-Needle Aspiration Biopsy – safe and accurate test for
malignancy; results: (-) benign; (+) malignant; (indeterminate)
suspicious; (inadequate) nondiagnostic.
8. Thyroid Scan, Radioscan, or Scintiscan – used to determine the
location, size, shape, and anatomic function.
9. Serum Thyroglobulin – used to detect persistence of thyroid
carcinoma.
DISORDERS OF THYROID GLAND
A. HYPOTHYROIDISM (myxedema)
I. DEFINITION:
 Hyposecretion of the thyroid hormone characterized by
decreased rate of body metabolism.
 Myxedema Coma is are but serious d/o which result from
persistently low thyroid hormone precipitated by acute illness,
rapid withdrawal of thyroid meds, use of sedatives & narcotics. It
is used to describe extreme symptoms of severe hypothyroidism
II. CLASSIFICATION:
 Primary or thyroidal hypothyroidism – refers to dysfunction of
the thyroid gland itself.

2.  Central hypothyroidism – the cause of thyroid dysfunction is
failure of the pituitary gland, the hypothalamus, or both.
 Pituitary or secondary hypothyroidism - the cause of thyroid
dysfunction is entirely a pituitary disorder
 Hypothalamic or tertiary hypothyroidism – the cause is a
disorder of the hypothalamus resulting in inadequate secretion of
TSH due to decreased stimulation of TRH.
 Cretinism – thyroid deficiency is present at birth
III. CAUSES:
 Autoimmune disease (Hashimoto’s thyroiditis, Post Graves’
disease)
 Atrophy of thyroid gland with aging
 Therapy for hyperthyroidism: radioactive iodine, thyroidectomy
 Medications: lithium, iodine compounds, antithyroid medications
 Radiation to head & neck for treatment of head & neck cancers,
lymphoma
 Infiltrative diseases of the thyroid (amyloidosis, scleroderma,
lymphoma)
 Iodine deficiency & iodine excess
IV. SIGNS AND SYMPTOMS:
 Hypotension
 Bradycardia
 Hypothermia
 Hyponatremia
 hypoglycemia
 respiratory failure
 death
V. MANAGEMENTS:
1. Medical Management:
a. Synthetic levothyroxine (Synthroid or Levothroid) is the
preferred preparation for treating hypothyroidism a
suppressing nontoxic goiters.
2. Nursing Management:
a. Provide for comfort and safety
b. monitor for infection or trauma
c. provide warmth
d. prevent heat loss & vascular collapse
e. administer thyroid meds as ordered
f. Monitor HR including rhythm.
g. Instruct patient re: thyroid replacement therapy.
h. Instruct on low-calorie, low-cholesterol, low-saturated fat
diet.
i. Assess for constipation & provide roughage.
j. Provide for warm environment.
k. Monitor for overdose of thyroid meds.
l. Patent airway
m. Keep patient warm & check V/S frequently
n. Administer IV fluids & levothyroxine Na (Synthroid)
o. Give IV glucose & corticosteroids
p. Health teaching:
 Diet: low calorie, high protein
 S/Sx of hypothyroidism & hyperthyroidism
 Lifelong meds, dosage, desired effects, side effects.
 Stress-management techniques
 Exercise program
B. HYPERTHYROIDISM
I. DEFINITION:
 Hypersecretion of the thyroid gland.
 It is a type of thyrotoxicosis, a hypermetabolic clinical syndrome
which occurs when there are elevated serum levels of T3 and/or
T4.
 The most common underlying cause of hyperthyroidism is
“Graves' disease”,an autoimmune disesase.
 In its most severe form, untreated hyperthyroidism may result in
"thyroid storm," a condition involving high blood pressure, fever,
and heart failure. (S/Sx: fever, tachycardia, hypotension, marked
respiratory distress, pulmonary edema, irritability,
apprehension, agitation, restlessness, confusion, seizures.)
II. SIGNS AND SYMPTOMS:
V/S: increased systolic BP, widened pulse pressure, tachycardia
Excessive sweating
Heat intolerance
Increased bowel movements
Tremor (usually fine shaking)
Nervousness; agitation
Rapid heart rate
Weight loss despite of increased appetite
Fatigue
Enlarged thyroid
Irregular and scant menstrual flow
dyspnea
exophthalmos
In older patients, irregular heart rhythms and heart failure can
occur.
III. DIAGNOSTIC FINDINGS:
blood tests that show a decreased thyroid-stimulating hormone
(TSH) level and elevated T4 and T3 levels
radioactive iodine uptake test and thyroid scan
Thyroid scintigraphy
IV. MANAGEMENTS:
1. Medical Management:
 Antithyroid drugs(carbimazole, methimazole,
propylthiouracil) - drugs that inhibit the production of thyroid
hormones.
 Beta-blockers (Propranolol (Inderal), atenolol (Tenormin),
metoprolol (Lopressor)- used to treat high blood pressure, are
a class of drugs that offset this effect, reducing rapid pulse
associated with the sensation of palpitations, and decreasing
tremor and anxiety.
 Radioactive Iodine Therapy-destroy the overactive thyroid
cells; treat toxic adenomas,multinodular goiter and
thyrotoxicosis.
 Iodine preparations (SSKI, Lugol’s Solution) - decrease size &
vascularity of the thyroid gland; palatable if diluted with
water, milk or juice; give through straw tp prevent staining of
teeth; takes 2-4 weeks before results are evident.
2. Surgical Management:
Thyroidectomy-removal of thyroid tissue that was producing
the excessive thyroid hormone.
PRE-OPERATIVE CARE:
 Assess V/S, weight, electrolyte & glucose level
 Teach DBE & coughing as well as how to support neck in
post-op period when coughing & moving
 Administer antithyroid meds etc. to prevent thyroid storm
POST-OP CARE:
 Monitor for respiratory distress & have tracheostomy set,
O2 & suction machine at bed side
 Maintain semi-Fowler’s position to reduce edema
 Immobilize head with pillows/sandbags; prevent flexion &
hyperextension of neck
 Check surgical site for edema & bleeding

3.  Limit client talking & assess for hoarseness
 Assess for laryngeal nerve damage…high-pitched voice,
stridor, dysphagia, dysphonia & restlessness
 Monitor for signs of hypocalcemia & tetany & have calcium
gluconate at bed side
3. Nursing Management:
 Protect from stress: private room, restrict visitors, quiet
environment.
 Promote physical & emotional equilibrium:cool, quiet, cool
well ventilated environment; eye care: sunglasses to protect
from photophobia, protective drops (methylcellulose) to
soothe cornea; diet: high calorie, protein, vit. B; avoid
stimulants
 Prevent complications: give medications as ordered.
 Monitor for thyroid storm.
 Health teaching: stress reduction techniques; importance of
medications; methods to protect eyes from environment; s/sx
of “Thyroid Storm”.
 Measure neck circumference daily to check for progression of
thyroid enlargement.
 Weigh patient.
C. THYROIDITIS
I. DEFINITION: The inflammation of the thyroid gland.
II. TYPES
a.Acute thyroiditis
Definition: Is a rare disorder caused by infection of the thyroid
gland by bacteria, fungi, mycobacteria, or parasites
Causes: Staphylococcus aureus are the most common
S & Sx: Anterior neck pain and swelling, fever, dysphagia,
dysphonia, pharyngitis, or pharyngeal pain
Examination: Reveals warmth, erythema (redness), and
tenderness of the thyroid gland
Treatment: Antimicrobial agents and fluid replacement,
surgical incision and drainage may be needed if an abscess
is present
b.Subacute Thyroiditis
Definition: May be of two kinds: Subacute granulomatous
thyroiditis and painless thyroiditis
Subacute Granulomatous Thyroiditis
Definition: Is an inflammatory disorder of the thyroid gland
that predominantly affects women between 40-50 ages of
years. It is also associated with a viral respiratory infection
and has a summer peak incidence that coincides with
coxsackievirus groups A and B and echovirus infections.
Causes: Virus
S & Sx: Myalgias, pharyngitis, low-grade fever, and fatigue,
painful swelling at the anterior neck, symmetric
enlargement of the thyroid, difficulty of swallowing
Treatment: NSAIDs to relieve neck pain, Acetylsalicylic acid
(aspirin) is avoided if Sx of hyperthyroidism occur, oral
corticosteroids, follow up monitoring
Painless thyroiditis (Subacute Lymphocytic Thyroiditis)
Definition: Often occurs in the postpartum period and is
thought to be an autoimmune process
S & Sx: Sx of hyperthyroidism and hypothyroidism
Treatment: Directed at symptoms, and a yearly follow-up is
recommended
c. Chronic Thyroiditis
Definition: Also known as Hashimoto’s disease or chronic
lymphocytic thyroiditis, it occurs most frequently in
women between 30-50 ages of years.Cell mediated
immunity may play a significant role in the pathogenesis of
chronic thyroiditis and there may be a genetic
predisposition to it.
Cause: Unknown
S & Sx: initially the Sx of hyperthyroidism, such as restlessness,
tremors, chest pain, increased appetite, diarrhea, moist
skin, heat intolerance, and weight loss.
III. DIAGNOSTIC TESTS:Immunofluorescent assay, a test that detects
antigens on cells using an antibody with a fluorescent tag, detects
antithyroid antibodies. TSH is elevated, while (T3) and (T4) levels
are low. A thyroid scan is also done.
IV. TREATMENT: The objective is to reduce the size of the thyroid
gland and the prevent hypothyroidism, thyroid hormone therapy
D.THYROID TUMORS
Tumors are classified on the basis of:
 Being benign or malignant
 The presence or absence of thyrotoxicosis
 The diffuse or irregular quality of glandular enlargement.
If the enlargement is sufficient to cause a visible swelling in the
neck, the tumor is referred to as GOITER.
Grades of goiter:
Barely visible and producing disfigurement.
Symmetric and diffuse
Nodular
Accompanied by hyperthyroidism
Toxic or non-toxic
I. ENDEMIC (IODINE-DEFICIENT) GOITER
SIMPLE OR COLLOID GOITER
Most common type of goiter encountered chiefly in geographic
regions where the natural supply of iodine is deficient. (e.g., Great
Lakes areas of the United States)
May be caused by an intake of large quantities of goitrogenic
substance in patients with unusually susceptible glands. These
substances include excessive amounts of iodine or lithium, which
is used in treating bipolar disorders.
Represents a compensatory hypertrophy of the thyroid gland,
caused by stimulation by the pituitary gland. Its production
increases if there is subnormal thyroid activity, as when
insufficient iodine is available for production of the thyroid
hormone.
Such goiters usually cause no symptoms, except for the swelling in
the neck.
SSKI, a supplementary iodine which is prescribed to suppress the
pituitary’s thyroid-stimulating activity
Ensuring a preoperative euthyroid state through treatment with
antithyroid medication and iodide will minimize the risk of
postoperative complications.
Providing children in iodine-poor regions with iodine compounds
can prevent simple or endemic goiter.
The introduction of iodized salt has been the single most effective
means of preventing goiter in at-risk populations.
II. NODULAR GOITER
 Some thyroid glands are nodular because of areas of hyperplasia
(overgrowth)
 No symptoms may arise as a result of this condition, but not
uncommonly these nodules slowly increase in size, with some

4. descending into the thorax, where they cause local pressure
symptoms.
 Some nodules become malignant
 Some are associated with a hyperthyroid state
III. THYROID CANCER
 Much less prevalent than other forms of cancer; however it
accounts for 90% of endocrine malignancies
 According to American Cancer Society, such cases are more
occurring to men than the women.
 Types:
 Papillary adenocarcinoma 70%- most common, least aggressive,
asymptomatic, starts in childhood or early adult life/ more
aggressive in adults life, metastasizes along the lymphatics if
untreated
 Follicular adenocarcinoma 15%- appears after 40 yrs. of age,
encapsulated, feels elastic or rubbery on palpation, spreads
through the blood stream to bone, liver and lung, prognosis is
not as favorable as papillary adenocarcinoma
 Medullary 5%- after 50 yrs. of age, occurs as part of multiple
endocrine neoplasia (MEN), hormone producing tumor causing
endocrine dysfunction symptoms, metastasizes by lymphatics
and bloodstream, moderate survival rate
 Anaplastic 5%- after 60 yrs. of age, hard, irregular mass that
grows quickly and spreads by direct invasion to adjacent tissues,
may be painful or tender, survival is usually less than 6 months
 Thyroid lymphoma 5%- after 40 yrs. of age, may have history of
goiter, hoarseness, dyspnea, pain and pressure, good prognosis
External radiation of the head, neck or chest in infancy and
childhood increases the risk of thyroid carcinoma.
Appears to increase 5 to 40 years after
Consequently, people who underwent radiation treatment or
were otherwise exposed to radiation as children should
consult a physician and request an isotope thyroid scan as part
of the evaluation.
Assessment and Diagnostic Findings
Single, hard, and fixed lesions on palpation suggest malignancy usually
associated with cervical lymphadenopathy.
Thyroid Function Test- helpful in evaluating thyroid nodules and
masses.
Needle Biopsy- used as an outpatient procedure to make a diagnosis
of the thyroid Cancer
- Procedure is safe and usually requires only a local anesthesia.
Large Bore needle- may be used when the result of the standard
biopsy are in convulsive or with rapidly growing tumors.
Additional Diagnostic Studies
 Ultrasound
 MRI
 CT
 Thyroid Scan
 Radioactive iodine uptake test
 Thyroid Suppression Test
Medical Management
 Surgical Removal- Treatment of Choice for Thyroid Carcinoma
 Total or near-total Thyroidectomy
 Modified neck dissection- performed if there is lymph node
involvement
 Ablation Procedure- carried out with radioactive iodine to eradicate
residual thyroid tissue if the tumor is radiosensitive.
 Radioactive Iodine- also maximizes the chance of discovering
thyroid metastasis at a later date if total body scans are carried out.
After Surgery Administer;
 Thyroid Hormone- to prevent hypothyroidism
 Thyroxine
Several routes for administering radiation therapy to the thyroid or
tissue of the neck:
1. Oral Administration of radioactive iodine
2. External administration of radiation therapy
Nursing Management
Important preoperative goals are to gain the patient’s confidence and
reduce anxiety.
a. PROVIDING PREOPERATIVE CARE
 The nurse instructs the patient about the importance of eating a diet
high in carbohydrates and proteins.
 A high daily caloric intake.
 The patient is reminded to avoid tea, coffee, cola, and other
stimulants.
 The nurse also informs the patient about the purpose of
preoperative tests, if they are to be performed, and explains what
preoperative preparations to expect.
 Preoperative teaching includes demonstrating to the patient how to
support the neck with the hands after surgery.
b. PROVIDING POSTOPERATIVE CARE
 The nurse periodically assesses the surgical dressings and reinforces
them when necessary.
 When the patient is in a recumbent position, the nurse observes the
sides and the back of the neck as well as the anterior dressing for
bleeding.
 Difficulty in respiration occurs as a result of edema of the glottis,
hematoma formation, or injury to the recurrent laryngeal nerve.
 The intensity of pain is assessed and analgesic agents are
administered as prescribed for pain.
 Intravenous fluids are administered during the immediate
postoperative period.
 The patient is advised to talk as little as possible to reduce edema to
the vocal cords.
 An overbed table may be used to provide easy access to items that
are needed frequently, such as paper tissues, water pitcher and
glass, and a small emesis basin.
 The patient is usually permitted out of bed as soon as possible and is
encouraged to eat foods that are easily eaten.
c. MONITORING AND MANAGINGPOTENTIAL COMPLICATIONS
 Hemorrhage, hematoma formation, edema of the glottis, and injury
to the recurrent laryngeal nerve are common complications.
 Producing a disturbance in calcium metabolism.
 Tetany- this type is usually treated with intravenous calcium
gluconate.
d. PROMOTING HOME AND COMMUNITY-BASED CARE
Teaching Patients Self-Care.
 The patient may be discharged the evening of surgery or within 1 or
2 days.
 The patient and family need to be knowledgeable about the signs
and symptoms of the complications that may occur and those that
should be reported.
 The nurse explains to the patient and family the need for rest,
relaxation, and nutrition.
 The patient is permitted to resume his or her former activities and
responsibilities completely once recovered from surgery.
Continuing Care.
If indicated, a referral to home care is made.
 The home care nurse assesses the patient’s recovery from surgery.
 The nurse also assesses the surgical incision and reinforces
instruction about limiting activities that put strain on the incision
and sutures.

5.  Family responsibilities and factors relating to the home environment
that produce emotional tension have often been implicated as
precipitating causes of thyrotoxicosis.
 A home visit provides an opportunity to evaluate these factors and
to suggest ways to improve the home and family environment.
 The nurse gives specific instructions regarding follow-up visits to the
physician or the clinic, which are important for monitoring the
thyroid status.