Patient handout

Hypothyroidism (overt / subclinical / central — standalone core)

PRODUCTION

1. Your condition

This handout is for hypothyroidism (overt / subclinical / central — standalone core). Your care team identified this based on: elevated tsh on screening / opportunistic testing (ata 2014 jonklaas; eta 2013 pearce).

Other reasons your team may use this plan: low free t4 with low / inappropriately-normal tsh — central pattern (ata 2014; central ch not always mild, jcem 2014); fatigue / cold intolerance / weight gain / constipation / dry skin (low-specificity cluster) (ata 2014 jonklaas); established iatrogenic hypothyroidism — post-thyroidectomy / post-rai titration visit (ata 2014 jonklaas).

2. Your medications

Take these medications exactly as prescribed. Do not stop or change a dose without talking to your provider.

Medication	Starting dose	How	When	What it does
glucocorticoid BEFORE levothyroxine if central + possible adrenal insufficiency	—	—	—	ATA 2014 — in central disease give hydrocortisone first; levothyroxine before cortisol can precipitate adrenal crisis; route to endo.hypopituitarism.core.v1
defer treatment and retest after recovery (non-thyroidal illness)	—	—	—	ATA 2014 — NTIS (low T3/FT4 + low/normal TSH in acute illness) is not primary hypothyroidism; do not treat, retest after recovery
remove / reassess thyroid-toxic drug and retest (transient vs permanent — quantified by agent)	—	—	—	ATA 2014 — drug-induced / post-partum thyroiditis may be transient; characterise before lifelong therapy. Agent-specific pre-test: lithium clinical hypothyroidism OR 5.78 (95% CI 2.00–16.67) vs placebo, mean TSH +4.00 mIU/mL (McKnight Lancet 2012, PMID 22265699) — usually requires LT4 not drug-stop; immune-checkpoint inhibitors PD-1/PD-L1 hypothyroidism ~8% incidence and OR 1.89 (1.17–3.05) vs ipilimumab, combination OR 3.81 (2.10–6.91) — often after a thyrotoxic phase, then permanent → replace, do NOT stop oncologic therapy (Barroso-Sousa JAMA Oncol 2018 PMID 28973656; de Filette Horm Metab Res 2019 PMID 30861560); amiodarone-induced hypothyroidism is more common in iodine-replete/TPO-Ab+ patients and usually does NOT require amiodarone withdrawal (ATA 2014 25266247); postpartum thyroiditis hypothyroid phase (2–12 mo) is frequently transient — retest off insult before lifelong commitment

Plan: Hypothyroidism levothyroxine ladder — exclude central / treat reversible → overt full replacement → subclinical threshold → titration & absorption → persistent-symptom T3 (experimental) → pregnancy → geriatric/CAD start-low (ATA 2014 Jonklaas; ATA 2017 Alexander; ETA 2013 Pearce)

3. Your action plan

Use these zones to know what to do based on how you feel.

GREEN — Stable, TSH at target

If you have:

TSH within your individual target range (ATA 2014 Jonklaas)
No new symptoms; stable dose ≥6 months
Taking levothyroxine consistently on an empty stomach

Do this:

Take levothyroxine every day at the same time on an empty stomach (ATA 2014 Jonklaas)
Separate it from antacids/PPI, calcium, iron and fiber by about 4 hours (ATA 2014 Jonklaas)
Keep your TSH check every 6–12 months (ATA 2014 Jonklaas)
Tell any prescriber you take thyroid hormone before starting estrogen or new medicines (ATA 2014 Jonklaas)
If you plan a pregnancy, contact your provider FIRST to optimise the dose (ATA 2017 Alexander)

YELLOW — Symptoms changing, dose recently changed, or newly pregnant

If you have:

Return of fatigue / cold intolerance / weight change
Palpitations, tremor or trouble sleeping (possible over-replacement)
A positive pregnancy test while on levothyroxine
New medicine that affects absorption started

Do this:

If you are newly pregnant, contact your provider NOW — your dose usually needs to go up about 20–30% immediately (ATA 2017 Alexander)
Do not change your own dose; arrange a TSH check (ATA 2014 Jonklaas)
Report palpitations/tremor — these can mean too much thyroid hormone (Circulation 29061566)
Bring an updated medication list to your visit (ATA 2014 Jonklaas)

Call your provider if:

Newly pregnant on levothyroxine (same day) (ATA 2017 Alexander)
New or worsening palpitations / chest symptoms (ATA 2014 Jonklaas)
Symptoms persist despite a normal TSH (ATA 2014 Jonklaas)

RED — Severe decompensation

If you have:

Profound lethargy / confusion / unresponsiveness
Feeling very cold with slow breathing or very slow heart rate
Severe weakness after stopping levothyroxine for a long period

Do this:

Call emergency services or go to the emergency department now
This can be myxedema coma — a medical emergency (ATA 2014 Jonklaas)
Bring your medication list including your levothyroxine dose

Call your provider if:

Always seek emergency care for confusion + hypothermia + slow breathing (myxedema decompensation) (ATA 2014 Jonklaas)

4. When to seek emergency care

Call 911 or go to the nearest emergency room right away if you have:

Hypothermia + depressed consciousness + hypoventilation/bradycardia ± hyponatremia in a hypothyroid patient — myxedema coma (ATA 2014 Jonklaas)(life-threatening)
Low/inappropriately-normal TSH + low FT4 suggesting central disease, especially with sellar mass / cranial RT / Sheehan / TBI and possible adrenal insufficiency (ATA 2014 Jonklaas; JCEM 2014 — central CH not always mild)
Hypothyroid (overt or subclinical, esp. TPO-Ab+) woman who is pregnant or planning pregnancy (ATA 2017 Alexander)

5. Follow-up

Lifelong replacement for permanent primary and central disease (transient may be weaned and retested). Reinforce adherence + consistent timing + absorption-interaction counselling; pre-conception planning for women of reproductive age (optimise pre-pregnancy, plan the ~20–30% bump); annual TSH once stable; reassess persistent-symptom patients (chronic-disease support, exclude associated autoimmune disease) before any combination trial (ATA 2014 Jonklaas; ATA 2017 Alexander; 2021 ATA/BTA/ETA combination consensus)

6. Sources

Guideline: ATA 2014 Guidelines for the Treatment of Hypothyroidism (Jonklaas, Thyroid 2014) + ATA 2017 Thyroid Disease in Pregnancy (Alexander) + 2013 ETA Subclinical Hypothyroidism (Pearce) + 2012 ETA / 2021 ATA-BTA-ETA LT4-LT3 combination consensus; reconciled with TRUST (Stott NEJM 2017) and Thyroid Studies Collaboration IPD meta-analyses