Transcript PPT
Adult Medical-Surgical Nursing Endocrine Module: Hypersecretion of the Thyroid Secretions of the Thyroid Gland The thyroid secretes Thyroglobulin, the pre-cursor of: Thyroxine (T4) Tri-odothyronine (T3) (more potent) (under control of Hypothalamus → TSH from Anterior Pituitary) Also Calcitonin Functions of Thyroid Hormones T3 and T4: Energy metabolism and moderation of Basal Metabolic Rate (BMR): oxygen uptake and consumption at cellular level Cell replication and growth Brain and nervous development/ function Calcitonin: Regulation of serum calcium (lowers while Parathormone raises) Importance of Iodine for Thyroid Function Iodine is essential to the thyroid for synthesis of hormones (major uptake and use of iodine in the body) Iodine in fish, added to salt, mostly in H2O Iodine from diet + Tyrosine (amino acid)→ T3 and T4 ↓ iodine in diet leads to ↓ thyroid function Most important cause of hypothyroidism world-wide and enlargement (Goitre) Hyperthyroidism: Grave’s Disease (Thyrotoxicosis) Increased synthesis and release of thyroid hormones Affects metabolism increasing BMR Auto-immune condition Aetiology: Genetic tendency Unknown aetiology Exacerbated by stress, infection, ↓ iodine Hyperthyroidism (Auto-immune) Thyroid-stimulating antibodies act like TSH stimulating thyroid: Hyperplasia Hypersecretion Leads to gradual destruction of gland, and eventually to exhaustion, atrophy and hyposecretion, requiring HRT Hyperthyroidism: Pathophysiology Hyperplasia: thyroid enlargement (“toxic goitre” as hypersecretion) Hypersecretion: increased thyroid hormone → increased BMR ↑ tissue sensitivity to sympathetic stimulation (adrenoline/ noradrenaline) Ophthalmopathy: impaired venous drainage from the eye orbit (auto-immune effect), fat deposits and orbital oedema Hyperthyroidism: Clinical Manifestations (Thyrotoxicosis) Goitre with increased pressure on trachea Excitability, restlessness, nervousness, tremor Rapid weight loss Much increased appetite and thirst Fatigue from over-activity → muscle weakness and exhaustion Cannot tolerate heat, flushed, sweating Hyperthyroidism: Clinical Manifestations (cont) Tachycardia/ tachypnoea: bounding very rapid pulse (90 – 160/min) Increased resting pulse Palpitations (dysrhythmias) and increased pulse pressure ↑ peristalsis, diarrhoea, frequent stools Exophthalmos: staring, protruding eyes (vision not affected) Hyperthyroidism: Diagnosis History and clinical picture Immuno-assay or radio-assay of hormone levels: TSH, T3 and T4 and FT4 (free unbound thyroxine) Radio-active iodine uptake test Needle biopsy of thyroid Ulrasound scan ECG Hyperthyroidism: Medical Management Anti-thyroid medication (Carbimazole* or Propylthiouracil): inhibit synthesis of thyroid hormones by blocking utilisation of iodine until “euthyroid state” (non-toxic) Radio-active iodine (I131) gradually destroys some of thyroid cells. (Patient must be euthyroid prior. May need 2 treatments. Risks hypothyroidism) Hyperthyroidism: Surgical Management Sub-total thyroidectomy (small amount of tissue left to regenerate slowly) Leaves parathyroid glands intact Avoids damage to recurrent laryngeal nerve Pre-op: Patient must be in euthyroid condition prior to surgery, prepared with anti-thyroid drugs, iodine (↓ size / vascularity) and B - blockers (Propanalol) Sub-total Thyroidectomy: Risks related to surgery Airway obstruction from: Oedema and pressure on trachea or stridor (damage and oedema to recurrent laryngeal nerve) Bleeding and haematoma (very vascular) Damage/ removal of parathyroids → low blood calcium levels (Tetany) Thyroid crisis (hyperpyrexia, extreme tachycardia and dysrhythmias, delirium) Hyperthyroidism: Nursing Considerations Patient education Monitoring/ supervision during tests Pre- and post-operative care especially be prepared for any post-op emergency: At bedside, O2 and suction ready and clipremovers Semi-sitting position, well-supported with pillows Careful monitoring all vital signs, wound.