Hyperthyroidism Flashcards
What are the causes of Hyperthyroidism?
Common – Graves (Autoimmune), Toxic Multinodular Goitre (multiple T4 secreting nodules caused by hyperplasia of thyroid), Toxic Adenoma (Benign T4 secreting tumour), Subacute Thyroiditis (aka De Quervain’s Thyroiditis – Inflammatory process causes thyroid hormones to be released)
Others – Ectopic Thyroid Production (metastatic follicular/ovarian cancer), Too much levothyroxine, secondary/tertiary (Pituitary/Hypothalamic lesion)
What will you find on a histroy taking of hyperthyroidism?
Symptoms:
Systemic - Weight loss, Weakness, Fatigue, Sweating., Tremor, Heat intolerance
GI - Increased or decreased appetite, Diarrhoea
Neuro – Anxiety, Psychosis, Irritability
Repro - Loss of libido, Oligomenorrhoea or amenorrhoea
Cardio – Palpitations, Tachycardia, Atrial Fibrillation
Graves specific symptoms – Thyroid Eye disease (Eye discomfort, Grittiness, Tearful, Photophobia, Diplopia, Staring eyes) and Pretibial myxoedema
Thyroid Storm - Very high temperature (>41), Sweating, Tachycardia, Hypotension, Heart Failure, Nausea and vomiting/Diarrhoea, Abdominal Pain, Neurological symptoms (confusion/coma)
Risk Factors: Female Middle Aged Family history Smoking
Specific Questions to ask:
Personal or family history of any other autoimmune conditions (Pernicious anaemia, Addison’s, Type 1 diabetes) – Predisposes to increased likelihood of autoimmune Graves’ disease
Any recent viral infection or flu like symptoms – Indicate sub-acute thyroiditis
Painful Thyroid - indicates sub-acute thyroiditis
Differentials:
Phaeochromocytoma – Raised urinary catecholamines
Thyroid Carcinoma – Will present with goitre but rarely has an effect on thyroid levels
What are the signs of Hyperthyroidism?
Hands:
Sweaty and warm palms
Palmar erythema
Fine tremor
Tachycardia - may be atrial fibrillation and/or heart failure (common in the elderly)
Brisk reflexes
Proximal myopathy - muscle weakness ± wasting
Neck:
Goitre - Graves, Toxic Multinodular Goitre, Carcinoma
Face:
Hair thinning or diffuse alopecia
Lid lag - Eyes lag the as they follow your finger descending
Thyroid eye disease (Specific to Graves’ Disease) -Exophthalmos or Proptosis, Conjunctival oedema, Corneal Ulceration, Papilledema, Colour Blindness, Red eyes
Periorbital puffiness (Specific to Graves’ Disease)
Chest:
Gynaecomastia
Legs:
Brisk reflexes
Proximal myopathy (muscle weakness ± wasting)
Pretibial myxoedema (Specific to Graves’ Disease)
What investigations will you order in Hyperthyroidism?
Bedside:
ECG if any palpitations or indications of AF
Bloods:
Thyroid function tests - T4/T3 (Raised), TSH (Low in primary hyperthyroidism, Raised in secondary)
Autoantibodies for graves - Antimicrosomal, Antithyroglobulin, TSH-receptor antibodies
ESR/CRP - raised in subacute thyroiditis
Imaging:
US Goitre – If person has thyroid goitre or nodule use 2-week referral to see a specialist as may be cancerous (Thyroid cancer normally has normal thyroid levels)
Thyroid uptake scan – (Diffuse uptake = Graves) (Single hot spot = Toxic Adenoma) (Multiple Hot spots = Toxic Multinodular Goitre)
MRI Pituitary/Hypothalamus - If Secondary cause suspected
Investigations to order in a suspected Thyroid Storm:
ECG – Looking for a precipitating MI or for any arrhythmias caused by the thyroid storm (specifically AF)
Blood Glucose – Ruling out Ketoacidosis or Hyperosmolar Hyperglycaemic State
TFT’s – Raised T3/T4 (They do not have to be abnormally raised for it to be a thyroid storm)
FBC – Looking for raised WCC that may indicate precipitating infection or low Hb that may indicate precipitating bleed
ESR/CRP – Will be raised
U&E – Increased body stress can precipitate or be precipitated by Renal Failure
LFT – Increased body stress can precipitate or be precipitated by Liver Failure
Serum Calcium – Can be raised due to hyperthyroidism
CXR – Looking for a precipitating Pneumonia or heart failure
ABG – Patient will be very unwell and may have abnormal pH
Head CT may be needed to exclude other causes of coma
What is the treatment of hyperthyroidism?
Requires referral to endocrine specialist
Medical:
B blockers for rate control while awaiting referral
Graves – Carbimazole, can either titrate up to correct dose or give lots and then use levothyroxine to adjust levels. 50% of people remit after 18 months so trial without the Carbimazole at this point
Toxic Multinodular Goitre – Radioiodine, kills off thyroid leading to hypothyroidism and then treat with levothyroxine
Subacute de Quervain’s Thyroiditis – NSAIDS and supportive treatment as it is normally self-limiting (no new hormones are being made, just released in an inflammatory process and so Carbimazole has no effect).
Thyroid Eye Disease – Artificial tears and Prednisolone. In severe cases consider IV hydrocortisone or surgery for sight loss
Surgical:
Thyroidectomy - Risks recurrent laryngeal nerve, hypoparathyroidism, and will lead to hypothyroidism requiring lifelong levothyroxine, not regularly used
Removal of any pituitary/hypothalamic tumours may be indicated with specialist review
How will you grade thyroid eye disease?
Staging – NOSPECS
Class 0 - No signs/symptoms
Class 1 - Only Signs (Lid Lag, stare, upper lid retraction)
Class 2 - Soft Tissue involvement causing symptoms
Class 3 - Proptosis >22mm (Eyes protrude over orbit; severe proptosis is referred to as exophthalmos)
Class 4 - Extraocular muscle involvement (Weakness in movement, Diplopia, Eye normally looking upwards)
Class 5 - Corneal involvement e.g. ulceration
Class 6 - Sight Loss (Due to optic nerve being compressed)
What is the treatment of a Thyrotoxic Storm?
Resuscitation:
A-E approach
Get IV Access/Give O2 to maintain sats of 94+ /Attach 12 lead ECG
Assessment with AMPLE history and brief examination
Get help - Medical reg on call
Frequent Observations - Constant or 15 minutely
Medical:
Oral Carbimazole
IV beta blocker to reduce heart rate
IV Hydrocortisone - block T4 conversion to T3 (the more active form) and will also treat any associated Addisonian crisis
What is hyperthyroidism?
Hyperthyroidism is the clinical syndrome brought about by elevated levels of Thyroid hormones T3/T4. Thyroid hormones usually increase basal metabolic rate.
Patients with Graves’ disease can get thyroid eye disease, this occurs in flare ups where the extraocular muscles and orbital fat swells, causing the eyes to bulge out (proptosis). These flare ups are normally self-limiting but can cause permanent proptosis (Due to tissue stretching) or in extreme cases vision loss (due to optic nerve compression)
Patients with hyperthyroidism are at risk of a Thyrotoxic Storm. This is effectively a state of severe hyperthyroidism triggered by acute illness/stress.
