Hypothyroidism Flashcards
(55 cards)
What is hypothyroidism?
Insufficient production of thyroid hormones, leading to metabolic slowdown
What head and neck features are seen in hypothyroidism?
(1) Macroglossia
= tongue is abnormally large compared to the mouth
(2) Puffy face
(3) Possible goitre
(depending on the cause)
What are the peripheral features of hypothyroidism?
(1) Dry, thick skin
(2) Brittle hair
(3) Scanty secondary sexual hair
(4) Queen Anne’s sign
(loss of outer 1/3 of eyebrows)
(5) Cold intolerance
What are the cardiac manifestations of hypothyroidism?
Bradycardia and cardiomegaly
How does hypothyroidism affect the nervous system?
(1) Carpal tunnel syndrome
(2) Slow relaxing reflexes
(3) Cerebellar ataxia
(4) Peripheral neuropathy
(5) Difficulty concentrating
What are the menstrual abnormalities in hypothyroidism?
Menorrhagia
(heavy menstrual bleeding)
What bedside test findings might suggest hypothyroidism?
(1) Bradycardia
(2) Goitre
(3) Dry skin
(4) Loss of outer 1/3 of the eyebrows
What blood tests are used to diagnose hypothyroidism?
(1) Thyroid function tests (TFTs)
= Raised TSH and low T3/T4
(2) Antibody testing
= Anti-TPO, Anti-thyroglobulin, Anti-TSH receptor
(to check for autoimmune causes)
(3) Iodine levels
= To determine if deficiency or excess is a factor
What imaging studies are used for hypothyroidism?
- Ultrasound scan (USS) of the neck
- Thyroid biopsy - not done unless necessarily
What is the primary treatment for hypothyroidism?
Levothyroxine (LT4) replacement therapy
How often should TSH levels be monitored in non-pregnant patients?
Every 3 months initially, then annually once stable
What specialist referral is required for hypothyroidism?
All patients with overt or subclinical hypothyroidism should be followed up by an endocrinology specialist
How does pregnancy affect levothyroxine dosing?
The dose is usually increased by 25-50 mcg due to increased metabolic demands
When should TFTs be checked during pregnancy?
Immediately upon confirmation of pregnancy, and results should be interpreted using the pregnancy-specific reference range
What are the foetal/neonatal complications of hypothyroidism?
(1) Low birth weight & growth restriction
(2) Neurodevelopmental delay
(3) Congenital hypothyroidism
= if iodine deficiency or maternal autoantibodies are present
When should TFTs - thyroid function tests be checked before conception?
Before attempting pregnancy, ensure the patient is in a euthyroid range.
If abnormal, conception should be delayed until TSH stabilises with levothyroxine treatment
What do thyroid function tests include?
TSH (Thyroid-Stimulating Hormone)
= (1) Elevated in primary hypothyroidism
(2) Low in secondary hypothyroidism
Free T4 (Thyroxine)
(1) Low in hypothyroidism
Free T3 (Triiodothyronine)
(1) May be low or normal in hypothyroidism
What are the bone complications of an early menopause?
Osteoporosis
What are the most common causes of hypothyroidism?
(1) Autoimmune thyroiditis =Hashimoto’s
(2) Iodine deficiency
(3) Post-thyroidectomy
(4) Congenital hypothyroidism, and certain medications (eg, lithium, amiodarone)
What is the most common cause of hypothyroidism worldwide?
Iodine deficiency
What does the loss of the lateral third of the eyebrow relate to?
Hashimoto’s thyroiditis
= Queen Anne’s sign
A 68-year-old woman is brought to the emergency department after being found unresponsive at home. She has a background of osteoarthritis, hypothyroidism, hypertension, depression and vascular dementia. Her regular medications include paracetamol, codeine, levothyroxine, ramipril, sertraline and amlodipine. Her family have expressed concerns about her adherence to medications because of a decline in her memory.
The patient’s observations are: temperature 33.2°C, HR 42, BP 106/64, RR 12, oxygen saturations 96% on air. On examination, she is unresponsive. Periorbital oedema is noted. She has bibasal lung crackles and pitting oedema to the ankles. Blood results are pending.
What is the best next step in management?
IV hydrocortisone or IV levothyroxine
When is Tinel’s sign positive?
When tapping over a nerve causes tingling, pain, or paresthesia in its distribution
Difficulty concentrating, hair loss and joint pain are all associated with what disease?
Hypothyroidism
