This is a general Endo post which attempts to tie together a few different interesting aspects of thyroid management. It touches on examination + presentation of findings in a thyroid disease patient, giving a technique for examination – followed by a brief presentation of some of the major thyroid diseases, common dosing regimens for T4 and management of thyroid storm.
Advanced Examination Technique of the Thyroid
- Inspect goitre from both sides. Note hair & eye changes if any. Eyebrows, Proptosis (can be measured with a Hertel Exophthalmometer or, if not available, a general comment can be made), Diaphoresis, Nail changes, Facial changes, Pulse (?Atrial Fibrillation/Tachy)
- (Brief reminder for describing a Lump/Mass) Size, Site, Shape, Surface, Surrounding Skin, Edge, Erythematous, Mobile vs Immobile,Nodular, Local Lymph nodes.
- Give the patient a glass of water. Ask them to take a sip, but not to swallow it, this avoids the patient blocking your view when they take a drink.Ask them to swallow and see if the visible mass moves w/ swallow (Ddx: Thyroglossal duct cyst/Malignancy)
Ask patient to place head in neutral position (many patients will extend neck upwards intuitively to let you examine them, however this causes flexion of neck musculature making it more difficult to palpate). Palpate with the patient sitting on an examination table if you are much taller than the patient to ensure they are not arching their neck up towards you!
Many endocrinologists will argue (mostly amongst themselves…) about how to properly palpate a thyroid. Most endocrine experts (in my experience) will agree with facing the patient directly – rather than palpating from behind as described in many textbooks. It makes sense to be able to see what you are looking at/palpating. Nobody palpates the abdomen from behind the patient! Further, it is best to palpate with the thumbs due to their larger surface area. Ask the patient if there is any neck pain before starting palpation (?thyroiditis)
- Sternal Notch (Manubrium)
- Tracheal Cartilage
- Cricoid Cartilage
- Thyroid Gland (L & R)
- Cricothyroid Membrane
- Thryroid Cartilage
- Thyrohyoid membrane
- Hyoid Bone
- Palpate Lymph nodes
Followed by palpation of lymph nodes:
- Submental, Submandibular, Superficial Jugular, Deep Cervical, Pre-auricular, Post Auricular, Occipital, Post Cervical Chain, Supraclavicular lymph nodes.
- Experienced Endocrinologists/ENT surgeons will particularly focus in on Neck Zones 2 & 3 along the sternocleidomastoid (the most common site for metastatic disease from thyroid malignancies) for palpation of lymphadenopathy.
Note that if the Thyroid Isthmus is palpable between the two lobes of the thyroid – it feels like a little lump you can roll your finger over in the midline of the trachea – this is a good indicator of an enlarged thyroid
Who is the ‘at risk patient’ for thyroid storm
Patients with a known thyroid disease, recent thyroid surgery, trauma, infection (esp lung), acute iodine load or recent birth (parturition), recent medication changes to thyroid medication are the typical patients who are at risk for thyroid storm.
- Confusion and altered mental status
- Chest pain/Anxiety
- High output heart failure
Orders to get immediately once ‘Thyroid Storm is suspected’:
- TSH, free T4, total T3, LFT’s, CBC, Electrolytes, may need to get TSI (thyroid-stim immunoglob) or TRab
- Note: (TSH-receptor antibody) to confirm Graves disease. The TSH-receptor ab is more sensitive than TSI. Note that thyroid antibodies take a few days to come back, so your diagnosis should be made clinically. The antibody test is expensive, so should be reserved for cases where it is not clear what is going on.
- ECG +/- Tele
- Uptake/scan of the thyroid is very helpful, but you CANNOT do it if they have gotten IV or PO iodinated contrast within the preceding 4-6 weeks. This is obviously useful after the initial stabilization of the patient.
- Thyroid ultrasound can help show increased vascular flow and if there are nodules, but may not help that much in your ultimate diagnosis – as described below, the diagnosis should ideally be clinical.
Diagnostic Criteria for Thyroid Storm
To make your clinical diagnosis, use the criteria in UpToDate for thyroid storm – it’s a scoring scale with points assigned to heart rate, temperature, LFT abnormalities, sx of heart failure, altered mental status etc. This is KEY! If they meet criteria, you must treat.
Treatment (link) is usually PTU given q8h, definitely beta-blockade (unless contraindicated) plus/minus steroids and SSKI.
- PTU q8h
- Beta Blockade – will require close monitoring + pre-blockade ECG
- +/- Steroids
- Continue to monitor ECG, bloods and patient vitals closely until clinically stabilizing.
You will eventually switch to methimazole, once they are no longer thyrotoxic. Thyroid storm is a clinical dx, so these patients and their labs should obviously always be seen same-day
Thyroid Replacement Therapy (important!)
Full dose replacement for PO is 1.6 mcg/kg/day, use 80% of the PO dose to get the IV dose.(Your pharmacy may tell you it’s a 50% conversion, but that’s not true). For example, if their total PO dose should be 100 mcg daily, you will give 80 mcg IV daily. (Please check this in your local hospital and ensure that you stick to local T4 replacement guidelines)
Check free T4 every 2-3 days until it normalizes
Do not recheck TSH for at least 7 days to be sure it’s coming down. But WHY?
The reason for waiting a few days before checking the TSH is as follows. The half-life of TSH is approximately 7 days, which is why we wait 6 weeks before re-checking TSH after making dose adjustments in outpatient clinic patients (Theoretically, if you have a high TSH and make a dose adjustment, the TSH will fall by 50% every 7 days and you will have steady-state in 6 weeks).
Convert back to PO levothyroxine when their free T4 is normal and they are taking PO.
Further workup – in patient with new Thyroid disease diagnosis
Supportive of Graves: Younger patient, smooth goiter, eye findings (obviously), T3-predominant thyrotoxicosis (not always true!)
Supportive of Thyroiditis: Some kind of prodrome (viral symptoms), offending medication (IL-2 or some chemotherapies can do it), neck tenderness (will obviously not be present in painless thyroiditis)
Other diagnoses which may be missed: Think about thyroid abscess in your Ddx too, in the right patient – esp. IVDU/Endocarditis/Immunocompromised
A brief bit on Myxedema coma management…
TSH is usually over 50 or even higher (we’ve seen 120s, I saw a 212 last month!) free T4 is always low. They will also have signs like delayed deep-tendon reflexes, hyponatremia, hypothermia, etc.
You MUST ensure that they are not adrenally insufficient before you start thyroid hormone! if you give thyroid hormone and they’re adrenally insufficient, you could increase metabolic rate and trigger an adrenal crisis. When in doubt, give stress-dose steroids before the first dose of thyroid hormone.
There can be gut edema (and usually they have very poor PO intake) so you can use intravenous LT4 (Levothyroxine)
Get out there palpating some necks!
Last updated (October 16)