Hyper/Hypothyroidism and Thyroiditis Flashcards
What is primary hyper/hypothyroidism?
Affects the gland itself
+/- goitre
Autoimmune is the most common cause
What is secondary hyper/hypothyroidism?
Hypothalamic or pituitary related
NO thyroid gland pathology
What is another word used in TSH?
Thyrotropin
What kind of cells release TSH and from where?
Thyrotroph cells
Anterior pituitary gland
What are the blood results in primary hypothyroidism?
fT3/4 low
TSH high
What are the blood results in primary hyperthyroidism?
fT3/4 high
TSH low
What are the blood results in secondary hypothyroidism?
fT3/4 low
TSH low or normal
What are the blood results in secondary hyperthyroidism?
fT3/4 High
TSH High
What is myxoedema?
Severe hypothyroidism
Medical emergency
What is pretibial myxoedema?
Clinical sign of graves disease
Hyperthyroidism
What are causes of primary hypothyroidism with goitre?
Chronic thyroiditis- Hashimotos
Iodine deficiency
Drug induced - amiodarone
Maternally transmitted
What are the causes of primary hypothyroidism without a goitre?
Atrophic thyroiditis
Post ablative therapy
Post radiotherapy
Congenital development failure
What are some causes of self limiting hypothyroidism?
Withdrawal of antithyroid drugs
Subacute thyroiditis
Transient hypothyroidism
Post partum thyroiditis
What are some causes of secondary hypothyroidism?
Infiltrative Infectious Malignant Traumatic Cranial radiotherapy Drug induced
What is the antibody specific in Hashimotos thyroiditis?
Thyroid peroxidase
TPO antibodies
What happens in hashimotos thyroiditis?
Antibodies destroy the thyroid
T cell infiltration in inflammation
How sensitive are TPO antibodies in Hashimotos thryoiditis?
95% sensitivity
Why does hypothyroidism result in hyperprolactinaemia?
Increased TRH causes an increase in prolactin
What is TRH?
Thyrotropin releasing hormone
Clinical signs of hypothyroidism
Coarse sparse hair Dull expressionless doughy face Periorbital puffiness Pale cool skin Vitiligo Deep hoarse voice Sleep apnoea Muscles aches and cramps
Cardiac signs of hypothyroidism
Reduced heart rate
Cardiac dilation
Pericardial effusion
Heart failure
Metabolic signs of hypothyroidism
Hyperlipidaemia
Decreased appetite
Weight gain
Reproductive signs of hypothyroidism
Menorrhagia
Hyperprolactinaemia
In the lab what will hypothyroidism look like?
Macrocytosis
Increased Creatine Kinase
Increased LDL cholesterol
What is the drug of choice in hypothyroidism?
Levothyroxine
What is rule with starting hypothyroidism drugs?
Especially in the old start low and incrementally increase.
Too high a does can lead to arrhythmias and death
In the young what is the usual dose of levothyroxine?
50-100 μg
In the old what is the usual dose of levothyroxine?
25-50 μg
How is the treatment plan slightly different in secondary hypothyroidism?
Titrate the dosage according to fT4 not the TSH levels
In pregnancy how is the dose affected?
As soon as pregnancy is suspected increase dosage by between 25-50%
What is a myoexedema coma?
Severe hypothyroidism resulting in coma and medical emergency
60% mortality
What is present on ECG in myoexedema coma?
Bradychardia
Low voltage complexs
T wave inversion
Prolonged QT
What type of respiratory failure does someone with myoexedema present with?
Type 2 respiratory failure
What is type 2 respiratory failure?
Hypoxia
Hypercapnia
Respiratory acidosis
How else can someone in a myoexedema coma be affected?
Can have adrenal failure
What is mainstay of treatment for a myoexedema coma?
ABC Passively rewarm Cardiac monitor IV thyroxine slowly infused Hydrocortisone if adrenal failure
What is thyrotoxicosis?
Clinical and physiological state when tissues exposed to too many thyroid hormones
Cardiac signs off hyperthyroidism?
Palpitations
Atrial fibrillations
Tachycardia
Sympathetic affect of hyperthyroidism
Tremor
Sweating
CNS affect of hyperthyroidism
Anxiety
Nervousness
Irritability
Sleep disturbances
Vision affects of hyperthyroidism
Lid Lag and retraction
Proptosis (bulging eyes)
Double vision
Hair and skin affects of hyperthyroidism
Brittle thin hair
Rapid fingernail growth
Reproductive affects of hyperthyroidism
Lighter less frequent periods
What antibodies are involved in graves disease?
TRAb
TSH receptor antibodies
Is graves genetically or environmentally driven?
Susceptible genes with environmental factors
If an old patient presents with thyrotoxicosis what is the most likely cause?
Toxic multi nodular goitre
What do blood tests usually show in graves?
Reduced TSH Increased fT3/4 Hypercalcaemia Increased alkaline phosphatase Leucopenia
Clinical presentation in graves?
Pretibial myxoedema
Thyriod acropachy - Clubbing
Thyroid bruit - only seen in graves
What is the cause of the bruit in graves?
Increased vascularity of the thyroid
What is the driving force behind eye pathology in graves?
TRAb
Smoking consolidates damage
In mild eye disease associated with graves what is the treatment?
Lubrication
In severe eye disease associated with graves what is the treatment?
Steroid
Radiotherapy
Surgery
In multi nodular goitre what do blood tests show?
Increased fT3/4
Reduced TSH
TRAb negative
What is a thyroid storm?
Severe hyperthyroidism
Usually triggered by infection or surgery with concordant hyperthyroidism
What happens in a thyroid storm?
Respiratory and cardiac collapse
Hyperthermia
Exaggerated reflexes
What is the 1st line drug in hyperthyroidism?
Carbimazole
What is used in pregnancy?
Propylthiouracil
Why is carbimazole 1st line?
As it has less risk of side effects
What is used in symptomatic treatment of hyperthyroidism?
B2 Antagonist
Propanolol
If drug treatment fails what is next step in treatment of hyperthyroidism?
Radioiodine
No increased risk of cancer
When in radio iodine treatment avoided?
If eye disease is present
If patient is pregnant
What is the main risk of radioiodine treatment?
Hypothyroidism
What can amiodarone cause?
Hyper and hypothyroidism
What is amiodarone?
Anti arrhythmic drug
If all else fails what can be used to treat hyperthyroidism?
Thyroidectomy
What are the risks associated with surgery in hyperthyroidism?
Hypothyroidism
Hypoparathyroidism
Damage to recurrent laryngeal nerve