Transcript Hyperthyroidism

Hyperthyroidism
TRH –Thyrotropin-releasing
hormone
Produced by Hypothalamus
Release is pulsatile
Downregulated by T3
Travels through portal venous system
to adenohypophysis
 Stimulates TSH formation




TSH – Thyroid-stimulating hormone
Produced by Adenohypophysis
Upregulated by TRH
Downregulated by T4, T3
Travels through portal venous system
to cavernous sinus, body.
 Stimulates:




 Iodine uptake
 Growth of thyroid gland
Thyroid Hormone
 Majority of circulating hormone is T4
 98.5% T4
 1.5% T3
 Total Hormone load is influenced by
serum binding proteins
 Albumin 15%
 Thyroid Binding Globulin 70%
 Transthyretin 10%
Hyperthyroidism
 Primary hyperthyroidism
 Secondary hyperthyroidism (TSH)
 Tertiary hyperthyroidism (TRH)
Hyperthyroidism
 Normal Thyroid
 Inactive Thyroid
 Hyperactive
Thyroid
Hyperthyroidism
 1. Graves’ disease
 Toxic multinodular goiter
 Toxic adenoma
Graves’ disease
 Most common cause of thyrotoxicosis
 Autoimmune condition with anti-TSH
antibodies
 Onset of disease may be related to
severe stress which alters the
immune response
Graves’ disease
Etiology:
 Is most often seen in women 20-40
years of age
 Toxic nodular goiter
 Toxic adenomas
 Subacute thyroiditis
Graves’ disease - History







Weight loss
Increased appetite
Heat intolerance, increase sweating
Nervousness
Weakness
Increased bowel frequency
Menstrual abnormalities
Graves’ disease – Clinical features






Warm, moist skin
Goiter
Sinus tachycardia or atrial fibrillation
Thyroid bruit
Tremor
Hyperactive reflexes
Graves’ disease - Exophthalmos
Proptosis and lid retraction
results from:
1) lymphocytic infiltration
2) edema of the extraocular muscles
Graves’ disease - Evaluation






Suppressed TSH
Elevated Total T4
TRH
Increased free T3, T4
Thyroglobulin
Antibodies: Anti-TSH
Graves’ disease - Treatment
1. Beta blockers for symptoms
2. Thionamide medications
 May re-establish euthyroidism in 6-8
weeks
 40% - 60% incidence of disease
remission
3. Radioiodine ablation
 10% incidence of hypothyroidism at 1
year
 55% - 75% incidence of
hypothyroidism at 10 years
Graves’ disease - Treatment
Surgery
 Used for compressive symptoms
 Hypothyroidism occurs in up to 70% of
subtotal thyroidectomy patients
 Pre-surgical stabilization with
thionamide medications
Hyperthyroidism - Treatment
Antithyroid drugs:
 Methimazole
 Carbimazole
 Propylthiouracil
Complications
Thyroid storm – extreme
hyperthyroidism
Symptoms include:
high fever,
dehydration,
tachycardia
high-output cardiac failure
coma
Complications
Treatment of a thyroid storm:
B-blocker (propranolol)
Propylthiouracil (PTU)
Iodine
Cooling measures
Toxic Adenoma
Treatment
 Radioiodine
 Surgery
 Preferred for children and adolescents
 Preferred for very large nodules when
high I131 doses needed