hyperthyroidism, hypothyroidism and thyroiditis Flashcards
what does primary thyroid disease mean?
-a disease affecting the thyroid gland itself
what are the levels of T4, T3 and TSH like in primary hypothyroidism?
T4/T3= too low TSH= high
what are T3, T4 and TSH levels like in primary hyperthyroidism?
T3 + T4= high
TSH= low
what are T3, T4 and TSH like in secondary hypothyroidism?
T3 + T4= low
TSH= low (or ‘normal’)
what are T3, T4 and TSH like in secondary hyperthyroidism?
T3 + T4= high
TSH= high (or normal)
what is myxoedema?
-severe hypothyroidism and is a medical emergency
what is pretibial myxoedema?
a rare clinical sign of Graves’ disease (an autoimmune disease which results in hyperthyroidism)
who is hypothyroidism more common in?
- women
- white population
- incidence is higher in areas of high iodine intake
what is the most common cause of hypothyroidism in western world?
autoimmune (hashimotos)
what increases risk of getting hashimotos?
-family history of autoimmune or thyroditis
what most common antibodies found in Hashimoto’s?
thyroid peroxidase antibodies
what can occur to hair and skin in hypothyroidism?
- coarse, sparse hair
- dull, expressionless face
- periorbital puffiness
- pale cool skin that feels doughy to touch
- vitiligo may be present
- hypercarotenaemia
how may a patients tolerence to temperature change if they have hypothyroidism?
-they may develop cold intolerance
what are some cardiac clinical features of hypothyroidism?
- reduced heart rate
- cardiac dilatation
- pericardial effusion
- worsening of heart failure
what affect does hypothyroidism have on lipidaemia?
it can cause hyperlipidaemia
what affect does hypothyroidism have on appetite and weight?
- decreased appetite
- increased weight gain
what are some GI clinical features of hypothyroidism?
- constipation
- megacolon and intestinal obstruction
- ascites
what are some resp clinical features of hypothyroidism?
- deep hoarse voice
- macroglossia
- obstructive sleep apnoea
what are some neurological/CND clinical features of hypothyroidism?
- decreased intellectual and motor activities
- depression, psychosis and neuro psychiatric
- muscle stiffness, cramps
- peripheral neuropathy
- prolongation of the tendon jerks
- carpal tunnel syndrome
- decreased visial acuity
what are some gynae/reproductive clinical features of hypothyroidism?
- menorhagia
- later oligo or amenorrhoea
- hyperprolactaemia
what causes hyperprolactaemia?
high TRH (once TRH is lowered it can be reversed)
what is treatment for hypothyroidism in younger patients?
-start levothyroxine (T4) at 50-100 micrograms daily
check TSH 2 months after any dose change and once stabilised check TSH every 12-18 months
what is treatment for hypothyroidism in older patients?
in elderly patients with a history of IHD:
-start levothyroxine (T4) at 25 to 50 micrograms daily, adjust every 4 weeks according to response
-TSH should be checked 2 months after any dose change and once stabilised TSH should be checked every 12-18 months
when should levothyroxine (T4) be taken?
- before breakfast (on empty stomach)
- doesn’t work if taken with PPI, iron tablets and calcium tablets as they impair the absorption
what should happen to dose of levothyroxine to a pregnant patient with hypothyroidism?
dose of levothyroxine should be increased by 25-50%
who does myxoedema coma usually affect?
-elderly women with long standing but frequently unrecognized or untreated hypothyroidism
what are the signs of a myxoedema coma?
ECG: bradycardia, low voltage complexes, varying degrees of heart block, T wave inversion, prolongation of the QT interval
Type 2 respiratory failure: hypoxia, hypercarbia, respiratory acidosis
In 10% of patients there is co existing adrenal failure
what is the treatment for myxoedema coma?
- ICU
- passive rewarm (aim for slow rise in body temp)
- cardiac monitoring for arrhythmias
- close monitoring of urine output. fluid balance, central venous pressure, blood sugars, oxygenation
- broad spectrum antibiotics
- thyroxine cautiously (hydrocortisone)
what is thyrotoxicosis?
-a clinical, physiological and biochemical state arising when tissues are exposed to excess thyroid hormone
what are cardiac signs/symptoms in thyrotoxicosis?
- palpitations
- AF
- cardiac failure (very rare)
- tremor
- sweating
what are CNS signs/symptoms in thyrotoxicosis?
- anxiety
- nervousness
- irritability
- sleep disturbances
what are GI signs/symptoms in thyrotoxicosis?
-frequent, loose bowel movements
what are vision signs/symptoms in thyrotoxicosis?
- lid retraction
- double vision
- proptosis
what are hair and skin signs/symptoms in thyrotoxicosis?
brittle, thing hair
rapid fingernail growth
what are reproductive signs/symptoms in thyrotoxicosis?
-menstrual cycle changes (including lighter bleed and less frequent periods)
what are the changes in muscles in thyrotoxicosis?
-muscle weakness (especially in thigha and upper arms)
what are the changes in weight in someone with thyrotoxicosis?
weight loss even though there’s increased apetite
what is a patients with thyrotoxicosis tolerance to temperature like?
-they have an intolerance to heat
who does Grave’s disease usually affect?
younger 20-50 years
what are some clinical signs/features of Grave’s?
- pretibial myxoedema
- thyroid acropachy
- thyroid bruit
- Grave’s eye disease
who does nodular thyroid disease typically affect?
-older patients
what tests are done if a patient has suspected nodular thyroid disease?
- increase T4/3
- decrease TSH
- antibody negative (TRAb)
- thyroid US
- scintigraphy: high uptake
what is the first line treatment for hyperthyroidism?
1st line= Carbimazole once daily
what is the first line treatment for someone in their first trimester of pregnancy?
Propylthiouracil (PTU) twice daily
side effects of using carbimazole in pregnancy?
-risk of aplasia cutis in early pregnancy
side effects of propylthiouracil (PTU)
1:10,000 risk of liver failure
what type of drug is carbimazole?
ATD (antithyroid drug)
what are side effects of ATDs (carbimazole)?
- 1 to 5% will develop allergic reaction (rash, urticaria, arthralgia)
- cholestatic jaundice, increase liver enzymes, fulminant hepatic failure (PTU)
- agranuloytosis
what is agranulocytosis?
-a life-threatening blood disorder when the body cannot make enough of a type of white blood cell called neutrophils
what should the patient be warned about and how before starting carbimazole?
- warned about the side effect of agranulocytosis
- warn patient verbally and in writing to stop drug and have urgent FBC checked in event of fever, oral ulcer or oropharyngeal infection
when should a patient get an urgent FBC and stop taking carbimazole?
in event of :
- fever
- oral ulcer
- oropharyngeal infection
when is risk of getting agranulocytosis highest when on carbimazole?
-in first 6 weeks
what treatment is good for immediate symptomatic relief of thyrotoxic symptoms in patients with hyperthyroidism?
BB (propanolol)
what is 1st line treatment of relapsed Graves’ disease ?
radioiodine
what is 1st line treatment of nodular thyroid diseases?
radioiodine
when is radioiodine contraindicated?
- in pregnancy
- relatively in active thyroid eye disease
what is a high risk when treating Grave’s patients with radioiodine?
-high risk of hypothyroidism
when is a thyroidectomy the choice of treatment in hyperthyroidism?
-when radioiodine is contraindicated
what risks does a thyroidectomy bring?
- recurrent laryngeal nerve palsy
- hypothyroidism
- hypoparathyroidism
what is thyroiditis?
inflammation of the thyroid
who is subacute thyroiditis typically found in?
-females ages 20-55
what may trigger subacutre thyroitisis?
-viral infection
what are some associated symptoms of subacute thyroiditis?
- neck tenderness
- fever
- and/or other viral symptoms
what are the investigations for subacute thyroiditis?
scintigraphy scan (low uptake throughout)
what are some causes of thyroiditis?
- hashimotos
- de quervain’s/subacute
- post partum
- drug induced (amiodarone, lithium)
- radiation
- acute suppurative thyroiditis (bacterial)
what is the treatment for subacute thyroiditis?
-its usually self limiting (few months)
what is subclinical al thyroid disease?
-abnormal TSH with normal thyroid hormone levels
what would T3, T4 and TSH be like in subclinical hypothyroidism?
TSH= increase T4/T4= the same
what would T3, T4 and TSH be like in subclinical hyperthyroidism?
TSH= lower T3/T4= the same
when is treatment advised in subclinical hypothyroidism?
- when TSH>10
- if pregnancy
when is treatment advised in subclinical hyperthyroidism?
- when TSH<0.1
- or if there’s coexisting osteoporosis/fracture or AF
what increases risk of getting sunclinical hypothyroidism?
-if TPO antibody positve
what increases risk of getting sunclinical hyperthyroidism?
- multinodular goitre
- if patient has Afib or osteoporosis
what is non thyroidal illness also known as?
sick euthyroid syndrome
who is non thyroidal illness commonly seen in?
-unwell, hospitalised patients
what are TSH levels like in non thyroidal illness ?
TSH typically supressed initially and then rises during recovery
who os postpartum thyroiditis more common in?
-type 1 diabetic women
how does postpartum thyroiditis present?
- temporary overactive thyroid and after a few weeks becomes under active
- occurs after birth
- however not all women with postpartum thyroiditis will go through both phases
what is De Queverain’s thyroiditis?
-thyroiditis caused by a viral infection such as mumps or flu
how does De Queverain’s thyroiditis present?
- initially hyperthyroidism and then after a couple weeks can become hypo
- this can resolve spontaneously or hypothyroidism may become permenant
- fever
- pain in neck, jaw or ear
