Transcript Unusual Thyroxine Requirements

5 Thyroid cases
Simon Pearce
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
– 5/01
– 8/02
– 10/02
– 1/03
TSH
11.3
16.0
13.3
17.7
Daily T4 dose
200µcg
250µcg
300µcg
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
• FT4 18.0
(0.3-4.7 mU/l)
(9.5-21.5 pmol/l)
• 79 year old woman
• Palpitations
• Weight loss
• Sinus rhythm
• TSH <0.05
• FT4 18.0
• FT3 9.4
(0.3-4.7 mU/l)
(9.5-21.5 pmol/l)
(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