Simon Pearce

5 Thyroid cases

RVI, Endocrine Unit

Unusual Thyroxine Requirement

• 39 year old woman• Congenital hypothyroidism• Required up to 200µcg thyroxine daily in childhood and adolescence

• High TSH despite high thyroxine dose

– Date TSH Daily T4 dose– 5/01 11.3 200µcg– 8/02 16.0 250µcg– 10/02 13.3 300µcg– 1/03 17.7 400µcg

What to do now?

• Talk about compliance– Should involve some mention of LT4 half-life

• Explore drug interactions– Ferrous salts– Calcium carbonate (eg. calcichew, rennie)– Gaviscon etc.– PPIs– Cholestryamine etc.

• Think about malabsorption (Coeliac Abs)

Actions

• Prescribe dosette box

• Re-iterate taking thyroxine before breakfast on an empty stomach

• Suggest that thyroxine taken at bedtime

• Review 8 weeks to recheck TSH

• Remember, they’re probably not taking their other medication either

Next steps

• Refer

• Peak dosage effects (tachy, headache)– Suggest split dose (eg. 50 mcg bd)– Try thyroxine liquid solution

• Supervised dosing– Eg. 1000 mcg once per week

• Thyroxine absorption test

Palpitations

• 79 year old woman• Palpitations• Weight loss

• Sinus rhythm

• TSH <0.05 (0.3-4.7 mU/l)• FT4 18.0 (9.5-21.5 pmol/l)

• 79 year old woman• Palpitations• Weight loss

• Sinus rhythm

• TSH <0.05 (0.3-4.7 mU/l)• FT4 18.0 (9.5-21.5 pmol/l)• FT3 9.4 (3.5-6.5 pmol/l)

What to do now?

Actions

• Prescribe beta blocker– Eg. Propranolol LA 80 mg od or bd

• Refer

• Indications for urgent referral– Atrial fibrillation– Worsening angina– Heart failure

• Consider starting Carbimazole 20mg od or bd– Need to warn about agranulocytosis risk

Next steps

• For mild-moderate Graves’ disease– Carbimazole therapy– Block & replace for 12 months

• Discuss radioiodine therapy with patient– Permanent hypothyroidism risk (50% or 95%)– Short-term radiation protection measures (11 d)– No cancer risk, no fertility risk, no alopecia

• In the case of AF, angina, heart failure:– Warfarin– Early RAI– May cover with carbimazole for 4-6 months post RAI

Oh Baby!

• 34 year old woman• On thyroxine for 12 years for hypothyroidism

• Period 10 days late• Boots pregnancy test positive• Stopped thyroxine yesterday, worried about

effect of drugs on her baby• Second pregnancy; miscarriage at 10 weeks in

first pregnancy

• Last recorded TSH 6 months ago = 3.9 mU/l

What to do now?

Actions

• Check TSH urgently

• Recommend increase dose LT4 of 25 mcg/d pending TSH result

• Explain fetal thyroid hormone synthesis doesn’t start until 10-12 years

• Thyroxine critical for brain development

• Thyroxine is the same as natural thyroid hormone

Next steps

• Low or suppressed TSH is normal in first trimester

• 4 to 8 weekly TFT monitoring throughout pregnancy

• Increased thyroxine dose very likely

• Refer joint medical obstetric clinic

Lump in my neck

• 28 year old F• Sister noticed neck lump last

week

• No pain

• O/e– Anterior triangle neck lump 4x4 cm

What to do now?

Actions

• Ask about alarm features:– Airway compromise– Voice change

• Check TSH

• Refer (endocrine, endocrine surgery, ENT)

• We will generally see within 2 weeks

• We will see urgently if alarm features

Next steps

New onset anterior triangle lump

Check TSH & refer

FNA cytology

Management decision

If surgery, symptoms etc. then imaging

I’m tired and emotional

• 45 year old woman• Feels tired• Daytime somnolence• Forgetfulness & emotional lability

• TSH 6.2 mU/l• Hb 13.5 g/l• RBG 5.9 mmol/l

What to do now?

Actions

• Recheck TSH, with FT4 & TPO antibodies

• Assess symptoms

• If TSH persistently elevated, discuss trial of thyroxine therapy

• Close to full replacement dose (75 or 100mcg/d) for 3 or 4 months

• Continue if symptoms are improved

Next steps

• Symptoms are worse on thyroxine– ? Addison’s disease– ? Hypopituitary

• Consider other diagnoses– Depression, mood disturbance, alcohol etc.– Sleep apnoea– Vitamin D deficiency– Iron deficiency– B12 deficiency– Many other possibilities