Hypothyroidism is the clinical result of the impaired production of LT4 and LT3 which are essential for growth, development and metabolism.
When to refer:
· Suspect uncommon cause for hypothyroidism (ie. medications- amiodarone)
· Persistently raised TSH despite adequate treatment where reversible causes ( poor adherence, malabsorption, drug interactions) have been excluded
· Persistent symptoms despite treatment ( following consideration of alternative causes of symptoms)
· Suspect associated endocrine disease ie. Addisons
· Pregnancy- if profoundly hypothyroid.
If previously uninvestigated, unexplained palpable neck lump- REFER 2WW Head and Neck
Investigations prior to referral:
Primary care management:
Overt hypothyroidism – treat with levothyroxine
DO NOT PRESCRIBE COMBINATION THERAPY (LT4 and LT3) in primary care.
Aim to adjust dose to resolve symptoms and normalise TSH.
Once TSH stable, check levels 4-6monthly then annually.
If elderly remember to start at lower dose.
During pregnancy increase the patient’s normal dose by 25mcg and aim for a TSH below 2
If TSH>10miu/L and fT4 in normal range:
If 70yrs or younger start treatment with LT4
If 70yrs+ consider watch and wait, if decide to treat with LT4, recheck TSH after 2months and adjust accordingly
If TSH 4-10miu/L and fT4 normal:
If <65yrs and symptomatic, consider trial LT4 assess response to treatment 3-4months after TSH in reference range.
If older (esp >80yrs), watch and wait
In asymptomatic patients, observe and repeat TFTs in 6months.
Clinical knowledge summary-NICE : Hypothyroidism, April 2016
Personal communication with Dr Duncan Browne, Consultant Endocrinologist, Treliske Hospital, November 2016