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,



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