Test your knowledge by answering this question in 12 minutes

A 50 year old female presented to the emergency department with anxiety, palpitations and feeling generally unwell.  She had no past medical history and was on no medications.  She had, however, seen her GP the week before complaining of 2 weeks of palpitations, anxiety and weight loss.  Her GP had checked her thyroid function tests and started her on carbimazole 3 days previously.  However, since then her symptoms had worsened.  In particular, she was having palpitations, sweats, anxiety, and diarrhoea.
On examination, she looked anxious and jittery

• T 37.1
• heart rate of 115,
• respiratory rate of 22
• BP 122/65
• She had a fine tremor and the examination was otherwise unremarkable.  There was no signs of goitre, proptosis or oedema.  There was no clinical evidence of heart failure and her ECG showed sinus tachycardia.

The Patient’s Thyroid Function tests are shown below
TSH <0.01 (0.3-4.5 mU/L)
T3 9.6 (3.0-7.2 pmol/L)
T4 15 (7-17 pmol/L)

​1. Briefly discuss the patient’s thyroid function tests in light of her symptoms (6 marks)
2. List a minimum of 4 clinical features of thyrotoxicosis(4 marks)
3. List a minimum of 4 clinical features that may be present in Thyroid Storm(4 marks)
4. What is the medical Management of thyroid storm?(6 marks)

Once you have answered all questions or when the 4 minutes is up scroll down to look at the answers

ANSWERS

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Question 1

Very low TSH
High T3
Normal to higher normal range T4

Thyrotoxicosis is the diagnosis.
​Remember that T3 is more potent than T4
Most of the T3 is converted from T4, only 10-20% is released as T3 from the thyroid.
T3 Thyroiditis is an entity

Question 2

• Exophthalmos
• Diplopia
• Pretibial Myxoedema
• Acropachy
• Tremor
• Tachycardia

Question 3

• Fever – must have in answer
• Tachycardia- must have in answer
• Abnormal conscious state(occurs in >90%) and may include:
  • Agitation
  • Delirium
  • Coma
• Atria Fibrillation
• Myocardial Infarction
• Heart Failure
• Shock

Question 4

Thyroid Storm is one of those questions that can easily come up in the exam. It is a low time investment, high yield question.

1. Inhibit TSH production
   1. Propylthiouracil 900-1200mg PO loading dose
      1. Blocks new hormone production but has no effect on stored hormone
      2. Decreases T4 to T3 conversion peripherally
   2. Lugol’s Iodine
      1. BEWARE do not give before Propylthiouracil, or for 30-60 minutes following administration as it will form a substrate generation of new thyroid hormone
2. Inhibit Peripheral effects
   1. Propranolol
      1. Blocks cardiac and other peripheral effects
      2. up to 120mg PO or 1mg/minute to 10 mg total IV
3. Corticosteroids
   1. Hydrocortisone 100mg IV 6/24
   2. decreases peripheral conversion of T4 to T3
4. Supportive Measures
   1. IV fluids
   2. Oxygen
   3. Temperature reduction: Beware NO aspirin as it displaces T4 from thyroglobulin.