A woman with palpitations

Published on 10/04/2015 by admin

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Last modified 10/04/2015

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Problem 49 A woman with palpitations

A 63-year-old female retired administrative assistant attends your preoperative assessment clinic prior to a diagnostic left knee arthroscopy after several months of unexplained left knee pain. In passing, she mentions palpitations and you note her to have an irregular pulse with a rate of 130/minute with a pulse deficit of 20/minute.

You also note a small asymmetric and slightly irregular goitre. She has no personal history of thyroid disease or other medical conditions although she admits to recent stress and anxiety. Her sister had surgery for an ‘enlarged thyroid’ many years ago.

Q.1

What is the likely diagnosis? What other symptoms should be enquired about?

She describes a 10 kg weight loss over 2 months, heat intolerance, excess sweating, anxiety, sleep disturbance (although she has attributed this to her knee pain), infrequent but mild palpitations and tremulousness. She denied any change in appetite, has had no diarrhoea and no ocular symptoms.

Q.2

What signs should be looked for on examination and how useful are they?

Physical examination reveals a slim lady of 59 kg, height 164 cm. She has warm sweaty palms. There is no palmar erythema. She has a goitre with the thyroid approximately 5× its normal size. It is irregular and nodular. She has thyroid stare due to lid retraction and lid lag but no exophthalmos. She has atrial fibrillation.

Q.3

What investigations would you like to arrange and how would they assist in your management?

An ECG (Figure 49.1) shows atrial fibrillation.

Figure 49.1

Laboratory investigations include the following:

Investigation 49.1 Summary of results

Free T4	64.8 pmol/L	(10–25 pmol/L)
Free T3	12.8 pmol/L	(3.1–5.4 pmol/L)
TSH	<0.01 mIU/L	(0.5–3.7 mIU/L)

A thyroid technetium scan (Figure 49.2) shows an enlarged thyroid with generally increased tracer uptake in a patchy distribution consistent with a multinodular goitre.

Figure 49.2

Q.4

What treatment should be started? How might the treatments for the thyroid and heart problems interact? What are the risks of the thyroid treatments and how should the patient be counselled?

The patient is treated with carbimazole 20 mg bd and propranolol 20 mg bd. Warfarin is started and titrated to an INR of 2–2.5. She is seen with thyroid function tests initially at 3-weekly intervals to check that the thyroid hormone levels are falling and to allow reduction of the carbimazole dose.

After 3 weeks, she reports the resolution of most of her symptoms, particularly reduced anxiety. Her heart rate is 60 and irregularly irregular consistent with atrial fibrillation. Blood tests are as follows:

Investigation 49.2 Summary of results

Q.5

What do these blood tests indicate?

The dose of carbimazole was reduced to 15 mg bd and 3 weeks later to 15 mg daily.

Six weeks later her free T4, free T3 and TSH are all normal although she remains in atrial fibrillation.

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