Thyrotoxicosis is a state of thyroid hormone excess. Hyperthyroidism is excessive thyroid function. Hyperthyroidism or thyrotoxicosis defines a spectrum of clinical findings consistent with thyroid hormone excess.

THYROTOXICOSIS Causes, Symptoms and Diagnosis

Causes of Thyrotoxicosis

• Primary hyperthyroidism
• · Grave’s disease
• · Toxic multinodular goitre
• · Toxic adenoma
• · Thyroid carcinoma
• · Iodine excess (Jod-Basedow phenomenon)
• · Subacute thyroiditis
• · Drugs like amiodarone
• · Radiation
• ·ThyrotoxicO~is factitia. Secondary hyperthyroidism
• · Pituitary adenoma
• · Thyroid hormone resistance syndrome
• · Gestational thyrotoxicosis.

Physical Exam of Thyrotoxicosis

• •Adults:
  • Cardiovascular: Tachycardia, atrial fibrillation, cardiomegaly
  • Endocrine: Increased sweating, heat intolerance, goiter
  • Gynecomastia, decreased libido, and spider angiomata in males
  • HEENT: Exophthalmos, lid lag
  • Musculoskeletal: Skeletal demineralization, osteopenia, osteoporosis, fractures
  • Neurologic: Tremor, proximal muscle weakness, nervousness, emotional lability, brisk deep tendon reflexes
  • Skin: Warm, moist, pretibial myxedema (GD only)
• •Children:
  • Linear growth acceleration
  • Ophthalmic abnormalities more common

Etiology of Thyrotoxicosis

• GD: Autoimmune disease
• excessive exposure to iodine, and excessive ingestion of thyroid hormones all may cause thyrotoxicosis.
• Toxic multinodular goiter: 60% TSH receptor gene abnormality; 40% unknown
• Postpartum thyroidits: Autoimmune thyroiditis that lasts up to 8 weeks,
• Graves’ disease, overactive thyroid nodules, toxic multinodular goiter, thyroiditis,
• Toxic adenoma: Point mutation in TSH receptor gene with increased hormone production and no TSH stimuli
• Drug-induced thyroditis: Amiodarone produces an autoimmune reaction and a destructive process.

Signs and Symptoms of Thyrotoxicosis

• · Hyperactivity and irritability
• · Heat intolerance
• · Sweating
• · Palpitations
• · Weakness and fatigue
• · Weight loss
• · Diarrhoea
• · Polyuria
• · Oligomenorrhoea
• · Tachycardia and atrial fibrillation
• · Tremors and Goiter
• · Warm moist skin and Muscle weakness
• · Lid retraction and lid lag
• · Gynaecomastia.

Diagnostic Tests for Thyrotoxicosis

• TSH, free T₄, T₄, T₃, TSI
• T₃: Elevated especially in T₃ toxicosis or amiodarone-induced thyrotoxicosis
• Thyroxine:triiodothyronine ratio: The T₄:T₃ ratio may be a useful tool
• 95% have suppresed TSH and elevated free T₄
• Drugs that may alter lab results: Estrogens, heparin, iodine-containing compounds,
• Free thyroxine index (FTI): Usually calculated from T₄ and thyroid hormone–binding ratio.

Thyrotoxicosis Differential Diagnosis

• Anxiety,
• menopause,
• pheochromocytoma
• malignancy,
• diabetes mellitus,
• pregnancy,