Hyperthyroidism

In station 5 you may be asked to assess a patient with palpitations/weight loss/tremor/anxiety etc.

HISTORY (3 minutes)

  • Thyroid History
    • weight loss, appetite, anxiety, irritable, mood, fidgety, restlessness, insomnia, sweating, diarrhoea, feeling hot, tremor, periods, hair loss, palpitations, breathlessness, weakness eg. going up stairs
    • Eye Questions- change in appearance of eyes, redness, swelling of eyelids, pain on movement/at rest/gritty/watering/itch/photophobia/dry, double vision, blurred vision, change in colour vision, eye bulge, loss of vision, bumping into things. 1 or both eyes
    • Neck Questions- neck swelling, any problems with breathing, swallowing. Any change in voice, any snoring, early morning headache, daytime sleepiness (obstructive sleep apnoea).
    • Previous thyroid history and treatment- dose of thyroxine, change in dose, last blood test, radioactive iodine, surgery.
    • Other autoimmune disorders – rheumatoid arthritis, T1 diabetes, vitiligo, pernicious anaemia, addisons, alopecia, lupus
    • Timing of symptoms- when did they start
  • PMH
  • Fx: thyroid +/- autoimmune
  • Dx
  • Sx: pregnancy plans/children, smoking

 

EXAMINE (3 minutes)

Thyroid exam:

  1. Observe- relaxed/restless, thin/overweight, clothes, hair, neck, eyes
  2. Hands- feel (warm/sweaty), tremor (set piece of paper on outstretched hands), nails (thyroid acropachy), palmar erythema, pulse (tachy/AF)
  3. Eyes- observe for red/swollen conjunctiva/caruncle, observe for exophthalmos and proptosis from front and side and above, observe for periorbital swelling/redness and lid retraction, check eye movements and ask re. pain/double vision, check for lid lag, check convergence, check eye closure, VA, VF, RAPD, colour, fundoscopy
  4. Neck- swallow and observe from front and side, stick out tongue, look for scars, palpate from behind and get patient to swallow, feel for lymphadenopathy, feel trachea, percuss sternum, auscultate over goitre.  Is the swelling diffuse or nodular, tender or nontender?
  5. Look at shins for rash/oedema/pretibeal myxoedema
  6. Stand from sitting (proximal myopathy)
  7. Reflexes (brisk)

ICE+EXPLANATION (2 minutes)

A suggested explanation is as follows:

“Your symptoms could be consistent with an overactive thyroid gland. It could be making too much thyroid hormone causing the bodily functions to speed up. Graves’ disease is the most common cause. When I examined you I found that your thyroid gland was enlarged and your eyes are more prominent. This is seen in Graves’ disease.

I’d like to do some blood tests to check your thyroid function, thyroid antibodies and do an ultrasound of your neck and a tracing of your heart.

If I find you to have an overactive thyroid we can treat with medication to reduce level of thyroid hormone. A drug called carbimazole stops production.  It can take 4-8 weeks to get the level down but it should help your symptoms within 2 weeks. Most patients take this for 1-1.5 years.  There is a 50% chance of cure/50% chance of relapse.  You can take carbimazole again in the future if it flares again or other options are available such as radioactive iodine or surgery. Carbimazole has side effects- rash, effect on the liver, white cell count drops therefore you must be vigilant for sore throat/fever and if this happens you need to stop treatment and see GP/hospital immediately for blood test. We can also give you a betablocker to cover the first 4-8 weeks to reduce palpitations etc. Stopping smoking is important for your eye disease. I’ll refer you to a hormone doctor and an eye doctor.”

A bit more on eye disease…

“Antibodies to the fatty tissue behind the eye push the eye forward and cause redness and swelling. It usually burns itself out in 1-2 years. Management is to stop smoking, use eye drops for redness/irritation and sleep on an extra pillow/raised head of bed for swelling. We also need to reverse your hyperthyroidism (see above).  I’ll refer you to an eye doctor who will perhaps do a scan of your eyes. It’s important that you stop driving if you have problems with your vision. Worrying signs are blurred vision/reduced colour vision, not being able to shut your eyes and double vision and you should seek help immediately if you develop these symptoms. For treatment of severe eye disease we can give you a steroid injection into the vein weekly for 6 weeks. If not settling, we can give other medication or perform surgery or radiation.  It’s preferable to perform surgery once the eye disease has burnt out. I know it is distressing for you, some people cope by growing fringe/ wearing tinted glasses. I can put you in touch with other people who also have eye disease and who can share coping strategies. I can refer you to counselling. You may feel self conscious but it is less obvious to others than it is to yourself”

A bit more on treatments…

“Radioactive iodine kills thyroid cells.  90% of patient’s respond, 1 in 10 need a 2nd dose. It can take 6 months to work. Risks involved include low thyroid hormone level and need replacement for life, it can worsen eye disease (but can cover with steroid), you can’t have children for 6 months, you can’t hold children/pets afterwards- keep at 1 yard away, you can’t have contact with pregnant women, you’d need at least a week off work, there is a risk of lymphoma/leukaemia in the future.”

“Surgery to remove thyroid gland offers 90% chance of cure. Risks include nerve damage causing hoarse voice, removal of parathyroids causing low calcium, low thyroid hormone level- need replacement tablet for life.”

 

VIVA

Comment to the examiner whether the patient is clinically hyper/hypo/euthyroid.  Remember that the patient may have thyroid eye disease but no features of hyperthyroidism if on treatment.

Graves’ disease

  • Autoimmune, antibody to TSH receptor. Most common cause of thyrotoxicosis, relapsing and remitting, F>M, 1% of population
  • Thyroid eye disease, pretibeal myxoedema, thyroid acropachy
  • Tests: TFT (low TSH, high free T4 and/or T3), autoantibodies (thyroid peroxidase, thyroglobulin, TSH-receptor Abs), USS, radioactive iodine uptake scan.
  • Also FBC, U+E, LFT, CRP, ECG +/- echo (if evidence of high output heart failure), pregnancy test
  • Management: medical, radioactive iodine, surgery
  • Treat medically first for 18 months to 2 yrs. If relapse, consider radioactive iodine or surgery.
  • Medical Management: beta-blocker for symptomatic relief (e.g. propranolol), carbimazole or propylthiouracil (during 1st trimester).
  • Indications for surgery: relapse after stopping antithyroid drugs, poor compliance with meds, intolerance of meds, cosmesis, compression, symptomatic and planning pregnancy, uncontrolled on meds, suspicious nodules
  • Complications of surgery: hypoparathyroidism, damage to recurrent laryngeal nerve, hypothyroidism, recurrence of hyperthyroidism

Thyroid eye disease

  • Up to 50% with Graves’ disease, smokers, F, 90% bilateral
  • Autoimmune against TSH Receptor on orbital tissue
  • Oedema and inflammation of extraocular muscles and retroorbital tissues causes eye to be pushed forward – risk of exposure keratitis
  • Fibrosis tethers muscles- risk of opthalmoplegia
  • Increased pressure on optic nerve- risk of reduced visual acuity
  • Can occur before/during/after diagnosis
  • Worrying signs:
    • Optic neuropathy- Visual acuity and colour vision
    • Exposure keratopathy
    • Double vision
  • Can do CT/MRI orbits
  • Calculate clinical activity score: if ≥3 consider iv methylpred 500mg weekly for 6 weeks. 88% effective, SE: hepatitis, diabetes. Ciclosporin is steroid sparing agent if necessary for severe eye disease. Other options after failed steroid are orbital decompression surgery and radiotherapy
  • Be familiar with NOSPECS scoring system
  • Can do orbital decompression/squint surgery/lid lengthening surgery once disease is inactive and burnt out.
  • Refer to joint endocrine-opthalmology clinic
  • Differential diagnosis for proptosis: orbital tumour/met/granuloma, caroticocavernous fistula, orbital cellulitis, AVM, cavernous sinus thrombosis

Other causes of thyrotoxicosis:

  • Hashimotos disease (often a period of hyperthyroidism prior to patients becoming hypothyroid)
  • Toxic adenoma
  • Toxic multinodular goitre
  • Excess levothyroxine replacement
  • Ectopic
    • pituitary adenoma
    • hypothalamic mass
    • ovarian teratoma, hydatidiform mole, choriocarcinoma
  • Thyroiditis of any cause
    • De Quervain’s thyroiditis
    • Radiation thyroidits
    • Postpartum thyroiditis
    • Drug-induced thyroiditis –e.g. amiodarone

 

Written by Dr Sarah Kennedy

Resources used to write this document include those listed in the references section of this webpage