Thyroid Function Tests - Interpretation and Common Findings

Question 1

Introduction

Answer 1

I have the thyroid function tests of (patient name, DOB), taken on (time, date) having presented with a (Hx)

I will take you through my findings

Question 2

Presentation of hypothyroidism

Answer 2

Fatigue
Weight gain
Cold intolerance
Constipation
Hair loss
Dry skin
Depression
Bradycardia
Heavy periods

Question 3

Presentation of hyperthyroidism

Answer 3

Anxiety
Weight loss
Heat intolerance
Diarrhoea
Tremor
Sweating
Tachycardia
Oligo/amenorrhea

Question 4

Presentation of Graves disease

Answer 4

Exopthalmos/proptosis
Watery eyes
Goitre
Pretibial myxedema
Other AI conditions
Thyroid bruits

Question 5

Primary hypothyroidism

• TFT results
• possible causes

Answer 5

High TSH
Low T3,4
-if T4 normal - subclinical hypothyroidism

Possible causes

• AI (Hashimotos)
• I2 def
• thyroidectomy, radioactive treatment
• medications

Management
-Levothyroxine => repeat test in a few weeks

Question 6

Secondary hypothyroidism

• TFT results
• possible causes

Answer 6

Low TSH
Low T3,4

Pituitary, hypothalamic causes
MOST COMMON - adenoma
-surgery, RT => pituitary/hypothalamus damaged

Management
-Levothyroxine => repeat test in a few weeks

Question 7

Primary hyperthyroidism

• TFT results
• possible causes

Answer 7

Low TSH
High T3,4

Graves
Toxic multinodular goitre/adenoma
Iodine induced

Management
-carbimazole, propiouracil

Complications

• thyroid storm
• AF
• HF
• Graves

Question 8

Secondary hyperthyroidism

• TFT results
• possible causes

Answer 8

High TSH
High T3,4

TSH secreting tumour

Question 9

Investigations to consider

Answer 9

Bedside

• Hx
• vital signs

Bloods

• FBC - anemic from menorrhagia
• anti TPO, anti TSH
• glucose, lipids - CV risk increases with hyper/hypo

Question 10

Describing
-hypothyroidism
-hyperthyroidism
to patients

Answer 10

Your thyroid is a small organ at the front of your neck which produces a hormone called thyroxine.

Thyroxine controls many aspects of your metabolism like heat control, weight and energy levels

When your thyroid produces too much/too little thyroxine, it results in the symptoms you’ve been experiencing

Question 11

Dosing and monitoring

Answer 11

Levothyroxine is taken once a day
-30mins before breakfast as food and coffee can reduce the absorption

It it likely that you will need to take levothyroxine for the rest of your life

If you miss a dose, take it as soon as you remember but please do not double dose

Don’t suddenly change the dose or number of tablets taken without talking to your doctor first

As your needs are unique, initially we will need to check your thyroid hormone levels 2-3wks after starting treatment to see if we need to adjust your dose. We will recheck your thyroid hormone levels every 2-3months until your levels are stable. Then we will check them once a year

Question 12

SE of levothyroxine

Answer 12

Too much => hyperthyroid symptoms

Not enough => hypothyroid symptoms