Hypothyroid Part II Module 7

Main Causes: Primary (direct and 95% of cases) Destruction of thyroid tissue –Radioactive Iodine –Hashimoto’s –Surgical removal/radiation –Untreated Graves’ disease (which eventually destroys gland) Defective hormone synthesis –Iodine deficiency Secondary (indirect and 5% of cases) Pituitary/hypothalmic neoplams Congenital hypopituitarism

What role does Iodine have? The Iodine we ingest from salt intake is the precursor for thyroid hormones T3 and T4.

Iodine and Hypothyroidism Iodine is needed for production of T3, T4. Without Iodine T3/T4 production decreases Decreased T3 and T4 stimulates TSH TSH stimulates the thyroid gland causing it to enlarge (which may result in a goiter) Low TH in body Decreased Feedback To Pituitary Pituitary keeps Sending TSH Thyroid grows to try And respond to Pituitary signal

What is the link between the pituitary gland, hypothalmus and thyroid gland?

Secondary Cause of Hypothyroidism Hypothyroidism can be a result of decreased function of the anterior pituitary gland This results in decreased TSH production and lower T3/T4 levels

Hashimoto’s disease Destruction of the glandular tissue by circulating antibodies Autoimmune disease Familial More common in women Diagnosis: –Presence of circulating thyroid antibodies –Thyroid hormone levels –Radioactive iodine uptake –Symptoms –Presence of Goiter Dr. Hashimoto

Hypothyroidism Clinical Manifestations Weight gain Decreased heat production Low BMR Cold intolerance Lethargy Tiredness Constipation Slightly lowered body temperature Increased TSH which may lead to goiter Altered thought processes Which of these symptoms did the patient you interviewed have? Stop and compare these symptoms with those of Bill Loney

Untreated hypothyroidism causes Myxedema (“mucous swelling”) Decreased metabolism causes Build up of metabolites (proteins/sugars: glycosaminoglycans) Metabolites accumulate in the tissues which in turn increases mucous and water in the tissue Cellular/tissue edema which is mucinous: myxedema

Myxedema See also Fig 48-6 on pp Dull, puffy skin with mask-like expression, prominent tongue and edema around the eyes, thin/sparse hair

Hypo vs. Hyper Compare and contrast the clinical manifestations for hyper vs. hypo thyroidism (see Table 48-4, pp. 1313) Keep in mind the two main reasons these symptoms occur…what are they? (Discuss and then click when you are done) 1. Alterations in metabolism 2. Alterations in tissue sensitivity to sympathetic nervous system responses

Just like Bill External replacement of the thyroid hormone is the treatment of choice –Given orally, once a day –Dosage regulated by patient response and monitoring of patient’s lab values Surgery to remove goiter if it is large and doesn’t decrease with hormone therapy

Patient Teaching Review Table pp in your text and the Nursing Care Plan on pp Are there any other interventions or teaching items would you add as the nurse caring for a patient with hypothyroidism?