3. Management of Patients With Thyroid Disorders
The thyroid gland is a butterfly-shaped organ located in the lower
neck anterior to the trachea.
It consists of two lateral lobes connected by an isthmus.
The gland is about 5 cm long and 3 cm wide and weighs about 30 g.
The blood flow to the thyroid is very high (about 5 mL/min per gram
of thyroid tissue), about five times the blood flow to the liver.
4. This reflects the high metabolic activity of the thyroid gland. The
thyroid gland produces three hormones: thyroxine (T4),
triiodothyronine (T3), and calcitonin.
Thyroxine and triiodothyronine are referred to collectively as thyroid
hormone.
5. Hyperthyroidism
Hyperthyroidism is the second most prevalent endocrine disorder,
after diabetes mellitus.
Graves’ disease, the most common type of hyperthyroidism, results
from an excessive output of thyroid hormones caused by abnormal
stimulation of the thyroid gland by circulating immunoglobulins.
It may appear after an emotional shock, stress, or an infection.
Graves' disease is an autoimmune disorder that can cause
hyperthyroidism, or overactive thyroid.
6. Patients with well-developed hyperthyroidism exhibit a characteristic
group of signs and symptoms
(sometimes referred to as Thyrotoxicosis).
The presenting symptom is often nervousness.
These patients are often emotionally hyperexcitable, irritable, and
apprehensive; they cannot sit quietly; they suffer from palpitations;
and their pulse is abnormally rapid at rest as well as on exertion.
7. They tolerate heat poorly and perspire unusually freely.
The skin is flushed continuously, with a characteristic salmon color,
and is likely to be warm, soft, and moist.
(Salmon is a range of pinkish-orange to light pink colors)
Elderly patients, however, may report dry skin and diffuse pruritus.
A fine tremor of the hands may be observed.
Patients may exhibit exophthalmos (bulging eyes), which produces a
startled facial expression.
8. Other manifestations include an increased appetite and dietary intake,
progressive weight loss, abnormal muscular fatigability and weakness
(difficulty in climbing stairs and rising from a chair), amenorrhea, and
changes in bowel function.
9. The pulse rate ranges constantly between 90 and 160 beats/min; the
systolic, but characteristically not the diastolic, blood pressure is
elevated; atrial fibrillation may occur; and cardiac decompensation in
the form of heart failure is common, especially in elderly patients.
Osteoporosis and fracture are also associated with hyperthyroidism.
Atrial fibrillation-Atrial fibrillation is a heart condition that causes
an irregular and often abnormally fast heart rate.
10. Cardiac effects may include sinus tachycardia or dysrhythmias,
increased pulse pressure, and palpitations
Myocardial hypertrophy and heart failure may occur
Symptoms of hyperthyroidism may occur with the release of excessive
amounts of thyroid hormone
Long-standing use of thyroid hormone in the absence of close
monitoring
It may result in premature osteoporosis
11. Assessment and Diagnostic Findings
The thyroid gland invariably is enlarged to some extent.
It is soft and may pulsate; a thrill often can be palpated, and a bruit is
heard over the thyroid arteries.
In advanced cases, the diagnosis is made on the basis of the symptoms
and an increase in serum T4 and an increased 123I or 125I uptake by
the thyroid in excess of 50%.
12. Medical Management
Treatment of hyperthyroidism is directed toward reducing thyroid
hyperactivity to relieve symptoms and remove the cause of important
complications.
PHARMACOLOGIC THERAPY
Two forms of pharmacotherapy are available for treating hyperthyroidism
and controlling excessive thyroid activity:
(1) use of irradiation (exposure to radiation) by administration of the
radioisotope 123I or 131I for destructive effects on the thyroid gland and
(2) Antithyroid medications that interfere with the synthesis of thyroid
hormones and other agents that control manifestations of hyperthyroidism.
13. Radioactive Iodine Therapy.
The goal of radioactive iodine therapy (123I or 131I) is to destroy the
overactive thyroid cells.
Use of radioactive iodine is the most common treatment in elderly
patients.
The patient is observed for signs of thyroid storm; propranolol is
useful in controlling these symptoms.
Thyroid hormone replacement is necessary; small doses are usually
prescribed, with the dose gradually increased over a period of months
(up to about 1 year) until the FT4 and TSH levels stabilize within
normal ranges.
14. Thyroid storm, also referred to as thyrotoxic crisis, is an acute, life-
threatening, hypermetabolic state induced by excessive release of
thyroid hormones (THs) in individuals with thyrotoxicosis.
Cretinism, a congenital disease due to absence or deficiency of
normal thyroid secretion.
Exophthalmic goiter, enlargement of the thyroid gland accompanied
by exophthalmos, usually due to hyperthyroidism.
15. Antithyroid medications are contraindicated in late pregnancy because
they may produce goiter and cretinism in the fetus.
Thyroid hormone is occasionally administered with antithyroid
medications to put the thyroid gland at rest.
Thyroid hormone is available as thyroglobulin (Proloid) and
levothyroxine sodium (Synthroid).
16. SURGICAL MANAGEMENT
Surgery to remove thyroid tissue was once the primary method of
treating hyperthyroidism
Surgery for treatment of hyperthyroidism is performed soon after the
thyroid function has returned to normal (4 to 6 weeks).
The surgical removal of about five sixths of the thyroid tissue (subtotal
thyroidectomy) practically ensures a prolonged remission in most
patients with Exophthalmic goiter.
17. Before surgery, propylthiouracil is administered until signs of
hyperthyroidism have disappeared.
A beta-adrenergic blocking agent (propranolol) may be used to reduce the
heart rate and other signs and symptoms of hyperthyroidism
Patients receiving iodine medication must be monitored for evidence of
iodine toxicity (iodism), which requires immediate withdrawal of the
medication.
Symptoms of iodism include swelling of the buccal mucosa, excessive
salivation, coryza, and skin eruptions.
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