Hyperthyroidism is the second most prevalent endocrine disorder, after diabetes mellitus. The most common type of hyperthyroidism is Graves’ disease, results from an excessive secretion of thyroid hormones caused by abnormal stimulation of the thyroid gland. The thyroid gland is a butterfly-shaped organ located in the lower neck, anterior to the trachea. The thyroid gland produces three hormones: thyroxine (T4), triiodothyronine (T3), and calcitonin. The thyroid gland regulates the metabolism through the release of these Hormones. The condition occurs when the thyroid produces an excessive amount of T4, T3 or both. Diagnosis of hyperactive thyroid and management of underlying cause can relieve symptoms and prevent complications from it.
The disorder affects women eight times more frequently than men, with onset usually between the 40-50 years of age. The disorder may appear as an emotional shock, stress, or an infection. However, the exact significance of these relationships is not understood.
Thyroid storm (thyrotoxic crisis) is a form of severe hyperthyroidism, usually of abrupt onset. Untreated, it is almost always fatal but with proper treatment, the mortality rate is reduced substantially. The patient with thyroid storm or crisis is critically ill and requires astute observation and aggressive and supportive nursing care during and after the acute stage of illness.
What are the causes of hyperthyroidism?
The causes of hyperthyroidism include:
- The excessive amount of iodine, a key among in T3 and T4.
- Inflammation or infection such as Thyroiditis, which causes T3 and T4 to leak out of the gland.
- Ovarian or testicular tumors.
- Benign (non-malignant) tumors of thyroid and pituitary gland.
- Intake of a large amount of tetraiodothyronine through medications or dietary supplements.
- Tends to run in families, suggesting a genetic link.
Those patients with well-developed hyperthyroidism exhibit a characteristic group of signs and symptoms sometimes referred to as thyrotoxicosis.
- Nervousness (emotionally hyper excited), irritability, apprehensiveness; inability to sit quiet, palpitations, rapid pulse on rest and exertion.
- Poor tolerance of heat; excessive perspiration; skin that is flushed with a characteristic salmon color, and likely to be soft, warm and moist.
- Dry skin and pruritus.
- Fine tremors of hands.
- Exophthalmos (bulging eyes) in some patients.
- Increased appetite and dietary intake, progressive loss of weight, abnormal muscle fatigability, weakness, amenorrhoea, and changes in bowel function (constipation or Diarrhoea).
- Pulse rate ranges between 90 to 160 beats per minute; systolic but not diastolic blood pressure elevation (increased blood pressure).
- Arterial fibrillation; cardiac decompensation in the form of congestive heart failure, especially in elderly.
- Osteoporosis and fracture are also associated with hyperthyroidism.
- Cardiac effects may include tachycardia or dysrhythmias, increased pulse pressure, and palpitations; myocardial hypertrophy and heart failure may occur if the hyperthyroidism is severe and untreated.
- May include remissions and exacerbations, terminating with spontaneous recovery in a few months or years.
- May progress relentlessly causing emaciation, intense nervousness, delirium, disorientation and eventually may lead to heart failure or death.
Diagnostic findings of Hyperthyroidism
- The thyroid gland invariably is enlarged to some extent; it is soft and may pulsate; a thrill may be felt and a bruit heard over thyroid arteries. These are the signs of greatly increased blood flow through the thyroid gland.
- In advanced cases, the diagnosis is made on the basis of the symptoms.
- Laboratory tests show a decrease in serum TSH, increased free T4 and an increase in radioactive iodine uptake.
Elderly patients commonly present with vague and nonspecific signs and symptoms. The only presenting manifestations may be anorexia and weight loss, an absence of ocular signs, or isolated fibrillation. New or worsening heart failure or angina is more likely to occur in elderly than in younger patients. Spontaneous remission of hyperthyroidism is rare in the elderly. Symptomatic treatment must be done before radioactive iodine is used because radiation may be precipitate thyroid storm, which has a mortality rate of 10% in the elderly.
The treatment of hypothyroidism is directed toward reducing thyroid hyperactivity to relieve symptoms and prevent complications from it. The treatment is based on three therapeutic approaches:
1. Radioactive iodine
- It is given to destroy the overactive thyroid cells (most common treatment in the elderly).
- It is contraindicated in the pregnancy and nursing mothers because radioiodine crosses the placenta and is secreted in breast milk.
2. Antithyroid Medications
- The objective of the pharmacologic therapy is to inhibit hormone synthesis or release and reduce the amount of thyroid tissue.
- The most commonly used medications are propylthiouracil (propacil, PTU) and methimazole (Tapazole) until the patient is euthyroid.
- Maintenance dose is established, followed by gradual withdrawal of the Medication over the next several months.
- An antithyroid drug is contraindicated in late pregnancy because of a risk for goitre and cretinism in the fetus.
- Thyroid hormone may be administered to put the thyroid to rest.
3. Adjunctive Therapy
- Potassium iodine, Lugol’s solution and a saturated solution of potassium iodide (SSKI) may be added.
- Beta-adrenergic agents may be used to control the sympathetic nervous system effects that occur in hyperthyroidism; for example, propranolol is used for nervousness, tachycardia, tremor, anxiety and the heat intolerance.
- Surgical intervention (reserved for special circumstances) removes about five-sixths of the thyroid tissue.
- Surgery to treat hyperthyroidism is performed after thyroid function has returned to normal (4 to 6weeks).
- Before surgery, a patient is given propylthiouracil until signs of hyperthyroidism have disappeared.
- Iodine is prescribed to reduce thyroid size and vascularity and blood loss. A patient is monitored carefully for evidence of iodine toxicity (swelling buccal mucosa, excessive salivation, and skin eruption).
- Risk of relapse and complications necessities long-term follow-up of a patient undergoing treatment of hyperthyroidism.
- Encourage on self-care
- Should have a complete knowledge about the use of prescribed medication and its effects.
- Have an individualized written plan of care for use at home.
- Should report to the doctor if any adverse effects of medications are seen or experienced.
- Stress long-term follow up care because of the possibility of hypothyroidism after thyroidectomy or treatment with antithyroid drugs or radioactive iodine.
- Emphasis on the importance of health promotion activities and recommended health screening.
- Preventive measures to avoid complications related to the disorder.