• Credits

  • Section Writer: Dr. Om J Lakhani
  • Section Editor: Dr. Om J Lakhani

• Q. Is it required to perform a thyroid scan in patients patients with thyrotoxicosis ?

  • While etiological evaluation for thyrotoxicosis is required in all cases, Graves' disease is the most common cause of thyrotoxicosis

  • Patients can be clinically diagnosed to have Graves' disease when they have the following:

    • Long duration of symptoms
    • Thyroid associated orbitopathy
    • Diffuse goiter (with bruit)

  • It is prudent to perform a thyroid scan in the following group of patients

    • Recent onset of thyrotoxicosis (short duration of symptoms)
    • Absence of thyroid associated orbitopathy
    • Presence of a nodular goiter

  • !WhatsApp Image 2021-04-28 at 15.14.55.jpeg

    • Smooth diffuse goiter in a patient with Graves' disease

• Q. Which clinical features are characteristic of Graves’ disease over other hyperthyroidism causes?

  • Eye signs
    • Exophthalmos
    • Periorbital edema
    • Conjunctival edema
  • Pretibial myxedema
  • Thyroid acropachy

• Q. What are the causes of T3 toxicosis (high T3, Normal T4, low TSH)?

  • Graves’ disease
  • Toxic MNG/ Toxic adenoma in iodine-deficient region
  • T3 ingestion

• Q. What are the causes of isolated T4 toxicosis- increase T4, normal T3, and Low TSH?

  • Amiodarone induced thyrotoxicosis
  • Thyrotoxicosis with Non-thyroidal illness
  • Exogenous T4 administration

• Q. How the diagnosis of Graves’ disease as a cause of hyperthyroidism established?

  • Any one of the following
    • Clinical features classical Graves’ disease - Graves ophthalmopathy, pretibial myxedema, or thyroid acropachy
    • Increase Radioactive iodine uptake
    • TRAb antibody positive
    • Increase blood flow in Doppler ultrasound of the thyroid gland

• Q. What ratio of T3/T4 helps differentiate Graves’ disease from other causes of hyperthyroidism?

  • T3/T4 > 20
  • Free t3/t4 >0.3

• Q. What are the causes of Low TSH without hyperthyroidism?

  • Subclinical hyperthyroidism
  • Central hypothyroidism
  • Cushing’s syndrome- TSH suppression
  • Non-thyroidal illness
  • Pregnancy – because of HCG
  • Elderly – may have changed in set point of TSH

#Updates

• Date: Sunday, 18 April 2021
• Source: YouTube video: Thyrotoxicosis management issues by Dr. Om J Lakhani

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