Hyperthyroidism: Causes, Symptoms, and Diagnosis

• Hyperthyroidism is a common endocrine disorder and a form of thyrotoxicosis resulting from excessive thyroid hormone synthesis and secretion.

Basic Concepts of Hyperthyroidism

• Increased metabolic rate due to hypersecretion of T3 hormone.
• Increased body heat production due to hypersecretion of T4 hormone.
• Hypocalcemia due to hypersecretion of thyrocalcitonin.

Etiology

• Toxic multinodular goiter
• Toxic adenoma
• Autoimmune disorder (Graves disease)
• Thyroiditis

Clinical Manifestations

• Related to increased metabolic rate and oxygen consumption.
• Patient may appear anxious, restless, and irritable.
• Fine tremors of the hands.
• Tachycardia and palpitations.
• Heat intolerance with increased perspiration.
• Increased appetite and diarrhea.
• Weight loss and thin skin.
• Graves disease may present with exophthalmos and reduced blinking and lid retraction.
• Women may experience changes in menstruation, including oligomenorrhea.

Investigations

• Enlarged thyroid gland that is soft and may pulsate. A thrill often can be palpated, and a bruit is heard over the thyroid arteries.
• Decreased serum TSH.
• Increased free T4.
• Increased radioactive iodine uptake.

Management

• Directed toward reducing thyroid hyperactivity to relieve symptoms and preventing complications.
• Radioactive iodine is the most common treatment for Graves disease.
• Beta-adrenergic blocking agents (e.g., propranolol, atenolol, metoprolol) are used for symptomatic relief, particularly in transient thyroiditis.
• Complications of treatments include relapse or recurrent hyperthyroidism and permanent hypothyroidism.

Pharmacologic Therapy

• Irradiation by administration of the radioisotope 131I for destructive effects on the thyroid gland.
• Antithyroid medications interfere with the synthesis of thyroid hormones.

Surgical Management

• Thyroidectomy (removal of thyroid gland).
• Subtotal thyroidectomy
• Total thyroidectomy

Pre-operative Care

• Promote euthyroid state to control thyroid disturbance and stabilize vital signs.
• Administer iodides as ordered to reduce the size of the thyroid gland.
• ECG monitoring to check for heart failure.

Post-operative Care

• Position: Semi-Fowler's position with head and neck erect.

• Prevent hemorrhage by applying an ice collar over the neck.

• Keep tracheostomy set available for the first 48 hours.

• Assess laryngeal nerve damage by asking the patient to speak every hour.

• Monitor body temperature, as elevation may indicate thyroid crisis.

• Monitor blood pressure.

• Steam inhalation to soothe irritated airway.

• Advise supporting the neck when getting up from bed.

• Observe for potential complications such as hemorrhage, airway obstruction, thyroid crisis, and myxedema.

• Hypothyroidism results from suboptimal levels of thyroid hormone, affecting all body functions. It can range from mild to severe (myxedema).

Causes

• Autoimmune thyroiditis (Hashimoto disease, post-Graves disease).
• Atrophy of thyroid gland with aging.
• Infiltrative diseases of the thyroid (amyloidosis, scleroderma, lymphoma).
• Iodine deficiency, iodine excess, and iodine compounds.
• Medications (e.g., Lithium)
• Radioactive iodine (131I) therapy for hyperthyroidism.
• Thyroidectomy.
• Radiation to head and neck in treatment for cancers and lymphoma.

Basic Concepts

• Decreased metabolic rate (hyposecretion of T3).
• Decreased body heat production (hyposcreation of T4).
• Hypercalcemia (hyposecretion of thyrocalcitonin).

Clinical Manifestations

• Reflect decrease in metabolism
• Fatigue and lethargy.
• Weight gain without increased calorie intake.
• Cold intolerance.
• Dry skin.
• Bradycardia.
• Changes in electrical conduction of the heart (noted on ECG).
• Menstrual cycle changes in women.

Management

• Restore normal metabolic state by replacing the missing hormone.
• Prevent disease progression and complications.

Pharmacologic Therapy

• Synthetic levothyroxine is the drug of choice.

Supportive Therapy

• Maintain vital functions.
• Fluids should be given cautiously.
• Passive rewarming with a blanket.

Pharmacotherapy

• Proloid (Thyroglobulin)
• Synthyroid (Levothyroxine)
• Dessicated thyroid extract
• Cytomel (Liothyronine)

Nursing Responsibility

• Monitor blood pressure and pulse rate before administration.
• Start with low dose and gradually increase the dose.

Complication

• Myxedema coma is a severe stage of hypothyroidism where the client is hypothermic and unconscious.

Management of Myxedema Coma

• Administer I/V thyroid hormone.

• Correction of hypothermia.

• Maintenance of vital functions.

• Treat the cause.

• Hyperpituitarism is defined as an excessive secretion or production of one or more hormones produced by the pituitary gland. Also referred to as Acromegaly and Gigantism

Acromegaly

• Oversecretion of growth hormone from the pituitary gland starting between the ages of 20 and 40 years.

Gigantism

• Excess amounts of growth hormone secreted from the pituitary gland during childhood, before the epiphyseal plates fuse.

Causes

• Benign tumor of pituitary gland.
• 60% to 80% of tumors cause hyperpituitarism.

Treatment

• Surgery: Transsphenoidal hypophysectomy or pituitary microsurgery.

• Medicine: Bromocriptine, which inhibits GH synthesis.

• Octreotide: Medicine which shrinks tumor.

• Diet: Salt-restricted diet.

• Hypopituitarism is a rare condition in which the pituitary gland doesn't make one or more hormones.

Characteristics

• Dwarfism
• Metabolic dysfunction
• Sexual immaturity
• Growth retardation

Causes

• Pituitary tumors
• Inadequate blood supply to the pituitary
• Infections
• Inflammatory disorders (such as sarcoidosis)
• Inflammation of the pituitary due to anticancer monoclonal antibody medications
• Irradiation
• Surgical removal of pituitary tissue
• Autoimmune disorders
• Surgical damage to the pituitary

Types

• Panhypopituitarism (Simmond’s disease): Total absence of all pituitary secretions.
• Sheehan’s Syndrome: Postpartum pituitary necrosis due to severe bleeding.

Management

• Hormone Replacement Therapy (HRT): Thyroid and cortisol hormone replacement.

• Radiation

• Surgery: Hypophysectomy (removal of the pituitary gland).

• Diabetes Insipidus (DI) is a condition in which abnormally large volumes of dilute urine are excreted due to deficient vasopressin production (ADH secretion from the pituitary gland).

Causes

• Insufficient secretion of Anti-diuretic hormone (vasopressin).
• Surgical treatment of a brain tumor.
• Non-surgical brain tumors.
• Traumatic brain injury.
• Infections of the nervous system.
• Post hypophysectomy.
• Failure of renal tubules to respond to ADH.
• Use of specific medications.

Clinical Manifestations

• Enormous daily output (>250 mL per hour) of very dilute urine with a specific gravity of 1.001 to 1.005.
• Urine contains no abnormal substances such as glucose or albumin.
• Intense thirst, drinking 2 to 20 L of fluid daily and craving cold water.
• Insidious or abrupt onset.

Diagnostic & Management

• Plasma and urine osmolality studies and urine for specific gravity.
• Medical Management objectives:
• Replace ADH
• Ensure adequate fluid replacement
• Identify and correct the underlying intracranial pathology

Pharmacologic Therapy

• Desmopressin (DDAVP): Synthetic vasopressin without vascular effects (nasal sprays twice a day).
• Chlorpropamide (Diabinese) and thiazide diuretics: Potentiate the action of vasopressin in mild forms.
• Thiazide diuretics, mild salt depletion, and prostaglandin inhibitors (ibuprofen, indomethacin, and aspirin): Used to treat the nephrogenic form of DI.

Nursing Management

• Review the patient history and physical assessment.
• Educate the patient, family, and other caregivers about follow-up care, prevention of complications, and emergency measures.
• Specific instructions should include the dose, actions, side effects, and administration of all medications and the signs and symptoms of hyponatremia.
• Demonstrate medication administration to ensure that the patient received the prescribed dosage.
• Advise the patient to wear a medical identification bracelet and carry required medication and information about DI at all times.