Thyroid Disease Flashcards
Suggest 4 drugs of abuse that can potentially lead to significant weight loss
- Alcohol
- Cocaine
- Amphetamines
- Cannabis
Give 8 potential physical signs that are commonly associated with hyperthyroidism
- Tremor
- Agitation
- Acropachy
- Conjunctival oedema
- Opthalmoplegia
- Pretibial myxoedema
- Proximal myopathy
- Hyperreflexia
Define and describe the position of the thyroid gland
A soft endocrine gland found in the lower neck, anterior to the trachea, below the thyroid cartilage of the larynx
Which cell type produce thyroglobulin?
Thyroid follicular cells
Which thyroid cell type produces calcitonin?
Thyroid C-Cells
What hormones are produced by the hypothalamus and pituitary gland respectively as part of the hypo-pituitary-thyroid axis
Hypothalamus - TRH
Pituitary - TSH
Give 2 scenarios that can lead to an artificially elevated levels of thyroid binding globulin (TBG)
- Pregnancy
2. OCP
Name a drug that can lead to deranged TFT results
Amiodarone as it contains high levels of iodine
What are the 3 main causes of thyrotoxicosis?
- Grave’s disease
- Multinodular goitre
- Solitary toxic nodule
What is the pathophysiology of Grave’s disease?
Antibody stimulation of the TSH receptors
Name 2 drugs that can potential cause thyrotoxicosis
- Amiodarone
2. Interferon
Name the 3 potential forms of eye disease that can be precipitated by thyrotoxicosis
- Exophthalmos
- Chemosis
- Peri-orbital oedema
What are the 3 main risk factors associated with thyroid eye disease?
- Raised intraocular pressure
- Optic nerve damage
- Corneal ulceration
Symptoms control of thyrotoxicosis can be achieved by which drug class?
Beta-adrenergic blockers
What are the 3 main treatment options for thyrotoxicosis?
- Antithyroid drugs
- Radioactive iodine
- Surgery
Give 2 examples of anti-thyroid drugs
- Carbimazole
2. Propylthiouracil
Name the 2 possible drug regimes for the treatment of thyrotoxicosis
- Titration
2. Block and replace
What are the 5 main side effects associated with antithyroid drugs?
- Rash/ itching
- Arthralgia
- Nausea and vomiting
- Mild leukopenia
- Agranulocytosis
Define agranulocytosis
Severe acute deficiency in neutrophil production as a result of damage to the bone marrow by toxic drugs/chemicals
What is the main consequence of treatment with radioactive iodine?
Permanently damages the thyroid follicular cells and thus the patient becomes at risk of developing hypothyroidism.
What are the 4 main risks of thyroid surgery that a patient should be informed of?
- Damage to the parathyroid glands
- Damage to the recurrent laryngeal nerve
- Bleeding
- Keloid scaring
Give 4 clinical features often seen in hyperthyroidism due to Grave’s disease
- Opthalmoplegia
- Exopthalmos
- Pretibial Myxoedema
- Thyroid acropachy
What triad of symptoms are associated with acropachy?
- Digital clubbing
- Soft tissue swelling of the hands and feet
- Periosteal new bone formation
What is the mechanism in neonatal hyperthyroidism?
Thyroid stimulating antibodies (in Grave’s disease) can cross the placenta and excessively stimulate the thyroid gland of the foetus
Name the thyroid cell type that secretes calcitonin
Parafollicular C cells
What is the ratio of T4 to T3 released by the thyroid gland?
Approximately 10 times as much T4 is released
In what state is 99% of circulating thyroid hormone found in?
Inactively bound to plasma proteins
Name 2 peripheral tissues that deiodinate T4 to T3
- Liver
2. Kidneys
What is the blood supply to the thyroid gland?
Superior and inferior thyroid arteries; branches of the External carotid artery and thyrocervical trunk respectively.
Which intracellular structure within the thyroid follicular cells produce thyroglobulin?
Endoplasmic reticulum
Where does the synthesis of thyroid hormones occur?
Within the colloid lobules that are surrounded by follicular cells
Name the transported that transports iodide from the follicular cell into the colloid
Pendrin transporter
Name 2 possible early complications of radioactive iodine therapy
- Grave’s opthalmopathy
2. Neck discomfort
Give 4 symptoms that can help identify hypothyroidism
- Hoarse voice
- Constipation
- Myalgia and muscle weakness
- Cold intolerance
What is the most common cause of primary hypothyroidism in the UK?
Hashimoto’s thyroiditis
Outline the TFT results one would expect to see in cases of secondary hypothyroidism
Low levels of TSH and low free T4
Give 2 possible consequences of thyroid hormone over-replacement
- Atrial Fibrillation
2. Osteoporosis
List 5 red flag symptoms when investigating a new onset neck swelling
- Dysphagia
- Neck pain
- Hoarseness
- History of radiation to the neck
- Family history of thyroid cancer
What is the investigations of choice for a neck lump?
Ultrasound followed by a fine needle aspirate
What are the main histological types of thyroid carcinoma?
- Papillary carcinoma (70%)
- Follicular carcinoma (20%)
- Anaplastic carcinoma (3%)
- Lymphoma (2%)
- Medullary cell carcinoma (5%)
From which cell type do medullary cell carcinomas of the thyroid gland arise from?
Calcitonin producing C cells
What are the 4 main potential causes of a diffuse goitre?
- Grave’s disease
- Hypothyroidism (e.g. Hashimoto’s)
- Colloid goitre (euthyroid)
- Iodine deficiency
Name a drug that can cause a diffuse goitre
Lithium
Outline the 4 ‘pressure symptoms’ to consider when assessing a goitre
- Mobility
- Skin tethering
- Lymphadenopathy
- Recurrent laryngeal nerve palsy
Name 2 other conditions that are commonly associated with medullary cell carcinoma
- Phaeochromocytoma
2. Hyperparathyroidism
Briefly define Sheehan syndrome
A form of secondary hypothyroidism due to pituitary infarction postpartum.
In addition to hypothyroidism, give 3 other hormones that a patient with Sheehan syndrome is likely to be deficient in
- ACTH
- Gonadotrophins
- Prolactin
