Case 7 - Thyroid Disease Flashcards
What are the causes of primary hyperthyroidism?
- Graves’ disease
- Toxic multinodular goitre (MNG)
- Toxic adenoma: single nodule
- Drugs – Amiodarone, Interferon
- De Quervain’s (subacute) thyroiditis
- Sub clinical hyperthyroidism
What are the causes of secondary hyperthyroidism?
- TSH secreting pituitary tumor
- Ectopic thyroid tissue
What is De Quervain’s (subacute) thyroiditis?
- Painful swelling of the thyroid gland triggered by a viral infection.
- Common in women aged 20 to 50.
- Causes fever and pain in the neck, jaw or ear.
- 2 phases: second phases = hypothroidism
What are the signs and symptoms of hyperthyroidism?
- Heat intolerance
- Excessive sweating
- Weight loss despite increased appetite
- Frequent bowel movements
- Weakness
- Fatigue
- Hyperflexia
- Tachycardia
- Palpitations
- Fine tremor
- Myopathy
- Oligo/amenorrhoea
- Onycholysis: loosening of nail from nail bed
What the signs and symptoms of Graves’s eye disease?
- Signs of hyperthyroidism
- Exophthalmos/proptosis: bulging eyes
- Upper eye lid retraction
- Peri-orbital oedema
- Lid lag
- Chemosis
- Ophthalmoplegia – paralysis of the muscles within or surrounding the eye
- Acropachy
- Pretibial myxodeama: non-pitting oedema on shins
- Bruit: may be heard due to increased vascularity of the gland
How to diagnose hyperthyroidism?
- TFT: low TSH, raised T3 and T4
- Serum thyroid antibodies: Graves’ disease
- Ultrasound: nodules, diffuse enlargement, nodules
- Thyroid scintigraphy
What is thyroid scintigraphy and when is it/isn’t used?
- Uptake of radioactive iodine
- Graves’ disease: increase RAI uptake
- Toxic MNG: hot and cold
- Toxic adenoma: hot nodule
- Not used pregnant or breast feeding women
What is the 1st line treatment for hyperthyroidism?
Radioactive iodine ablation:
- Destroys thyroid with radioactive iodine 131 across 6 weeks.
- Worsen Graves’ eye disease, esp smoking. Needs prednisolone.
- Not given to pregnant women, breast feeding women and women shouldn’t get pregnant for 4-6 months after
- Likely to have hypothyroidism so need levothyroxine
What is the 2nd line treatment for hyperthyroidism?
- Anti-thyroid drugs: carbimazole and propylthiouracil
- Low risk of hypothyroidism
- Agranulocytosis
- Propylthiouracil used in 1st trimester of pregnancy, shorter half life, works faster
- Carbimazole used in 2nd + 3rd trimester of pregnancy
What is agranulocytosis?
- Very low WCC
- Seek medical advice if signs of infection, low fever, sore throat, rigors after taking medication.
- Need FBC to rule out agranulocytosis
What are the different ways to take carbimazole?
- Block and replace: high dose with levothyroxine to bring TFTs under control, Takes 6-24 months.
- Titration: Start moderate dose, then reduce. Takes 18-24 months. Only in pregnancy.
What is the 3rd line treatment for hyperthyroidism?
- Thyroidectomy
- Hypothyroidism inevitable: need thyroxine
- Scarring of neck
- Possible voice changes if recurrent laryngeal nerve damaged
- Haematoma: respiratory distress and stridor
- Hypocalcaemia: damage to parathyroid glands
How are symptoms of hyperthyroidism controlled?
Beta blockers
What is Graves’ disease?
- Autoimmune condition: TSH receptor antibodies stimulate thyroid
- Most common type of hyperthyroidism (75% affected)
- Mainly affects females
What are the investigations for Graves’ disease?
- TFTs
- Autoantibodies: raised TSH receptor autoantibody (TRAbs), anti-TPO and anti-Tg (thyroglobulin)
What is thyroid storm (thyrotoxic crisis)?
- Exacerbation of hyperthyroidism
- Due to a spontaneous excessive release of thyroid hormones.
How to treat thyroid storm?
BAIS
- Beta blockers – propranolol
- ATDs – Propylthiouracil
- Potassium iodide: Lugol solution
- IV steroids: glucocorticoids
What is the biggest risk factor for Graves’ disease?
Smoking
What is the complication of hyperthyroidism?
- Heart failure (thyroid cardiomyopathy)
- Atrial fibrillation
What are thyroid nodules?
Fibrous changes to thyroid, not visible.
How to test for nodules?
- Radionuclide test.
- Hot = producing more hormone than usual. Benign/tumour.
- Warm = producing normal amounts. Benign/swelling, normal.
- Cold = producing lower amounts. Malignant
What rules to follow after radioactive iodine treatment?
- Avoiding close contact
- Sleep alone
- Wash your clothes separate
- Flush the toilet twice
- Radioiodine still in blood, urine, poo, saliva
How to treat hyperthyroidism in pregnancy?
- Propylthiouracil: 1st trimester of pregnancy, shorter half life, works faster
- Carbimazole: 2nd + 3rd trimester of pregnancy
- Beta blocker: symptom control
What is euthyroid sick syndrome?
– Systemic illness in which serum levels of all thyroid hormones (T3, T4 and TSH) are low.
What is a goitre?
Enlarged thyroid due to a swelling which is visible.
What are the different types of goitre?
- Diffuse: iodine deficiency, Hashimotos, Graves’
- Multi nodular: Toxic multi nodular goitre, toxic adenoma, carcinoma
What is a thyroglossal cyst?
- Fibrous structure resulting from incomplete closure of the thyroglossal duct
What moves on swallowing AND sticking tongue out?
Thyroglossal cyst
What moves on swallowing but NOT sticking tongue out?
Goitre
How do goitres expand?
- Limited
- Superiorly, inferiorly and laterally
What are the differentials for hyperthyroidism?
- Anxiety
- Bipolar
- Atrial fibrillation
- Toxic multinodular goitre
- Graves’
What are congenital causes of hypothyroidism?
Thyroid dysplasia or aplasia
What are the acquired causes of hypothyroidism?
- Primary: Hashimotos thyroiditis (
- Secondary: Sheehans syndrome, post-patrum thyroiditis, pituitary adenoma
- Drugs: Amiodarone, Lithium, Iodine, anti-thyroid drugs
- De Quervains thyroiditis (second phase)
- Subclinical hypothyroidism
What are the signs and symptoms of hypothyroidism?
- Tired/lethargic
- Cold intolerance
- Low mood
- Weight gain
- Constipation
- Menorrhagia
- Hoarse voice
- Decreased memory/cognition
- Myalgia
- Cramps
- Weakness
- Bradycardia
- Dry/Thin hair and skin
- Puffy face with peaches and cream complexion
- Slow reflexes
What are the risk factors for hypothyroidism?
- Female
- Iodine deficiency
- Middle age
- Family history of autoimmune thyroiditis or other auto immune disorders
What investigations are done in hypothyroidism?
- Primary hypo: Raised TSH, reduced T4
- Secondary hypo: Decreased TSH and T4
- Radioactive iodine: decreased uptake
What are the associated conditions with hypothyroidisms?
- Hypercholesterolemia
- Give levothyroxine and if hypercholesterolemia doesn’t resolves, add statins
How to treat hypothyroidism?
- Long term Levothyroxine (T4)
- Start at 75 mcg. increase in 25 mcg
- In elderly or cardiac patients start with 25 mcg to prevent AF
What is myxoedema coma?
- Severe hypothyroidism
- Triggered by infections, surgery, and trauma.
What are the features of myxoedema coma?
- Typical hypothyroid features +
- Low temperature
- Decreased reflexes
- Low blood glucose
- Bradycardia
- Coma
- Seizures
- HF
- Cyanosis
- Hypotension
How to treat myxoedema coma?
IV T4 + T3
Which antibodies are associated with Hashimoto’s thyroiditis?
- Anti-TPO
- Anti-Tg
What problems can hypothyroidism cause in pregnancy?
- Eclampsia
- Anaemia
- Prematurity
- Low birth weight
- PPH
- Stillbirth
When does post partum thyroiditis occur?
1-8 months after delivery
How doe post partum thyroiditis present?
- Transient thyrotoxicosis followed by hypothyroidism
- Weight loss, palpitations, heat intolerance and anxiety
- T4 increased to a greater degree than T3 and TPO autoantibodies.
What are the signs of post partum thyroiditis?
- Tremor, tachycardia, warm and moist skin, muscle weakness, lid retraction, lid lag
What is Sheehan’s syndrome?
- Postpartum necrosis of the pituitary gland occurs following post-partum haemorrhage.
How does Sheehan’s syndrome affect women?
- Affects breastfeeding
- No periods
How to treat Sheehan’s syndrome?
- No TSH so monitor T3/4
- Life long hormone replacement
What are the 5 different types of thyroid cancer?
- Papillary
- Follicular
- Medullary
- Anaplastic
- Lymphoid
What is the typical presentation of papillary thyroid cancer?
- Young woman with lymph node metastases
- Raised thyroglobulin
In which thyroid cancer would serum calcitonin be raised and CEA present?
Medullary carcinoma
What is the typical presentation of anaplastic thyroid cancer?
Elderly women, rapid growth and local invasion
What the typical presentation of follicular thyroid cancer?
- Middle aged, solitary thyroid nodule, may have spread to lung and bone
- Raised thyroglobulin
What are the 5 possible FNAC results of thyroid biopsy?
Thy 1 - non diagnostic Thy 2 - benign Thy 3 - intermediate Thy 4 - suspicious Thy 5 - malignancy
What are the 6 anterior pituitary hormones?
FLAT (cause more hormone release) PEG:
- FSH
- LH
- ACTH
- TSH
- Prolactin
- Endorphins
- Growth hormones
What are the 2 hormones released by posterior pituitary gland?
ADH and oxytocin (made by hypothalamus)
Describe the pathway for thyroid hormone release (HPT)
- Hypothalamus releases TRH
- Anterior pituitary releases TSH
- Thyroid releases T4
- T4 converted to T3 in periphery and bound to thyroxine binding globulin
- T4/3 release inhibits pituitary gland
- Less TSH released, less T4/3
When does raised TSH, T4 and T3 occur?
Non compliance hypothyroidism - Meds taken just few days before blood test
- Doesn’t allow TSH to decrease
What is lymphoma thyroid cancer associated with?
Hashimoto’s thyroiditis
Which inherited condition is medullary carcinoma most likely to be associated with?
- MEN 2
- Pheochromocytoma
- Hyperparathyroidism
- What is MEN condition?
- What are the different types?
- MEN - multiple endocrine neoplasia. Hereditary disease.
- Type 1 affects parathyroid, pituitary, and pancreas.
- Type 2 causes medullary thyroid cancer and pheochromocytomas
What is a typical exam question for medullary carcinoma?
A patient is diagnosed with a thyroid tumour. Her family history is positive for diabetes, hypertension, and her brother has been treated for a pheochromocytoma, what type of tumour is she likely to have?
What cells does medullary carcinoma arise from?
Calcitonin-producing (C-cells) in the thyroid
