Endocrinology: Thyroid Disease Flashcards
Which symptom would differentiate between a patient is suffering from thyrotoxicosis as opposed to malignancy? [1]
Increase in appetite
Thyrotoxicosis symptoms:
General? [3]
CVS? [3]
Abdominal? [3]
GU? [1]
CNS? [3]
General symptoms
* tired, anxious, sweating
CVS
* palpitations, atrial fibrillation, heat intolerance
Abdo
* weight loss, frequency, appetite
GU
* Oligomenorrhoea
CNS
* tremor, eye problems, nuscle weakness, emotional / agitated
Name and explain drugs may you suspect of a patient’s DH, who is displaying symptoms of thyrotoxicosis [3]
Amiodarone (treats afib): high levels of iodine
Lithium: can mimic iodine
ARVs
What are T3/4 and TSH levels likely to be with a ptx suffering from thyrotoxicosis? [2]
TSH: low
T3/4: High
When can you only make a diagnosis of thyrotoxicosis? [1]
Can only make diagnosis of thyrotoxicosis if TSH levels are undetectable
State the main causes of thyrotoxicosis [5]
Graves Disease
Toxic Multinodular Disease
Toxic adenoma
Ectopic thyroid tissue
Exogenous (Lithium excess)
What type of Ig are the anti TSH receptor antibodies? [1]
IgG
Which cause of a goitre causes a painful goitre? [1]
Subacute (De Quervains)
State 4 diffuse causes of goitre [4]
State 3 nodular causes of goitre [4]
Diffuse:
- Graves
- Hashimotos
- Subacute
Nodular:
- TMG
- Adenoma
- Carcinoma
Which antibodies are present in Graves disease? [1]
Thyroid-stimulating hormone receptor antibodies (TSHR-Ab): these antibodies mimic the action of TSH causing excessive stimulation of the gland.
Asides from TSHR-Ab, which other antibodies would you potentially test for in a ptx presenting with thyrotoxicosis? [1]
Thyroid Stimulating Immunoglobulin (TSI)
Cardinal signs of Graves disease? [3]
Opthalmopathy
Pre-tibial myxoedema
Acropachy
Describe basic overview of toxic multinodular goitre [1]
Multiple autonomous nodules develop that are capable of producing and secreting thyroid hormones.
Describe the structure of the goitre seen in Grave’s disease [1]
Diffuse smooth goitre with a bruit
Which cardiac sign / symptom is the consequence of advanced/long-term action of excess TH on the heart? [2]
AF
Increase in ANP
State 5 risk factors for Graves Disease
FEMALE - biggest risk factor (onset is common postpartum)
- Genetic - association with HLA-B8, DR3 & DR2
- E.coli and other gram-NEGATIVE organisms contain TSH-binding sites so may initiate pathogenesis via ‘molecular mimicry’
- Smoking
- Stress
- High iodine intake
- Autoimmune disease:
- Vitiligo (pale white patches on skin)
- Addison’s disease
- Pernicious anaemia
Which autoimmune diseases are commonly associated with Graves disease? [5]
- Vitiligo (pale white patches on skin)
- Addison’s disease
- Pernicious anaemia
- Myasthenia gravis
- Type 1 DM
What specifically does Graves opthalmology occur from? [1]
Describe the features of Graves opthalmology [6]
Results in retro-orbital inflammation and swelling of the extrocular muscles
- Eye discomfort, grittiness, increased tear production, photophobia, diplopia, reduced acuity
- Exophthalmos - appearance of protruding eye and proptosis - eye protrudes beyond orbit
- Conjunctival oedema
- Corneal ulceration
- afferent pupillary defect
- Ophthalmoplegia - paralysis of eye muscles Eyes are examined via CT/MRI of orbit
What is the main risk factor for Grave’s eye disease? [1]
Smoking
Which sign of Graves ophthalmology indicates that optic nerve is compressed? [1]
afferent pupillary defect
How do you manage Graves opthamology? [3]
- Most individuals with mild disease however can be treated symptomatically: artificial tears, sunglasses, avoid dust, sleep inclined to reduce periorbital oedema.
- High dose steroids
- Consideration of radiotherapy / surgical decompression if medical management is unsuccessful.
(The hyperthyroidism should also be dealt with if not already)
Describe the management for hyperthyroidism [4]
Anti-thyroid drugs:
- PROPYLTHIOURACIL (PTU) stops the conversion of T4 to T3
- ORAL CARBIMAZOLE which blocks thyroid hormone biosynthesis and also has immunosuppressive effects (which will affect Graves’ disease process
Radioactive iodine:
- RADIOACTIVE I(131) is given: contraindicated in pregnancy and breast feeding
Surgery: subtotal thyroidectomy only in those who have been rendered euthyroid (normal functioning thyroid gland); total thyroidectomy
AEs of carbimazole? [3]
AGRANULOCYTOSIS - results in a severely low white blood cell count (leukopenia) - most commonly neutropenia: can lead to sepsis
Rash
Arthralgia
Hepatitis
Vasculitis
State 3 AEs of thyroid surgery [3]
- Tracheal compression from postoperative bleeding
- Laryngeal nerve palsy resulting in hoarse voice
- Transient hypocalcaemia - due to removal of parathyroid gland too
Signs of hypothyroidism?
BRADYCARDIC:
* Bradycardia
* Reflexes relax slowly
* Ataxia (cerebellar)
* Dry, thin hair/skin
* Yawning/drowsy/coma
* Cold hands +/- temperature drop * Ascites
* Round puffy face
* Defeated demeanour
* Immobile +/- Ileus (temporary arrest of intestinal peristalsis)
* Congestive cardiac failure
Describe 5 causes of hypothyroidism [5]
Iodine deficiency: (most common cause in developing world):
* GOITRE FORMATION due to TSH stimulation causing thyroid enlargement
Autoimmune/atrophic hypothyrodisim:
* antithyroid autoantibodies leading to lymphoid infiltration of the gland and eventual atrophy and fibrosis - since there is atrophy there is NO GOITRE
Hashimoto’s thyroiditis:
- GOITRE FORMATION due to lymphocytic and plasma cell infiltration but with regeneration.
- Thyroid peroxidase antibodies (TPO-Ab) are present in HIGH TITRES
Post-partum thyroiditis:
- usually a transient phenomenon observed following pregnancy. Thought to result from modifications to the immune system necessary in pregnancy and histologically is a lymphocytes thyroiditis (AUTOIMMUNE)
Iatrogenic (caused by treatment or examination):
- Thyroidectomy - for treatment of hyperthyroidism or goitre
- Radioactive iodine treatment or external neck irradiation for head and neck cancer;
- too much of carbimazole; lithium; amiodarone
How do you investigate for hypothyroidism? [4]
Thyroid function tests:
- High TSH; low T3/T4 (primary)
- Low TSH; low T3/T4 (secondary)
Thyroid antibodies (e.g. anti-TPO-Ab in Hashimotos)
Cortisol to ensure patient has a normal ACTH/cortisol reserve.
- Sometimes profound hypothyroidism can infiltrate tissues such as the adrenal gland and disrupt cortisol reseves. If thyroxide is given in these conditions it may trigger Addinsonian Crisis
Anaemia:
- Usually normochromic and normocytic
- May be macrocytic (sometimes due to pernicious anaemia)
- Or microcytic (in women, due to menorrhagia or undiagnosed coeliac disease)
What is the standard treatment length of carbimazole of propylthiouracil? [1]
Maintain for 12-18 months then withdraw
What are TFT results for:
Primary Hypothyroidism [2]
Secondary Hypothyroidism [2]
Primary Hypothyroidism:
- TSH high; T3/4 low
Secondary Hypothyroidism:
- TSH low; T3/4 low (v rare)
Treatment for hypothyroidism?
ORAL LEVOTHYROXINE (T4)
- Aim is normal TSH conc. which will be achieved by levothyroxine - but don’t give too much so as to completely suppress TSH as this carries risk of AF and osteoporosis
Describe what a thyroid crisis is [1], how it occurs [1], and features? [3]
Rare, life threatening condition in which there is a rapid deterioration of thyrotoxicosis (RAPID T4 INCREASE)
Features include hyperpyrexia, tachycardia, extreme restlessness
and eventually delirium, coma and death
Usually precipitated by stress, infection, surgery or radioactive
iodine therapy in an unprepared patient
Treatment for thyroid crisis / storm? [4]
- ORAL CARBIMAZOLE
- ORAL PROPRANOLOL
- ORAL POTASSIUM IODIDE (to block acutely the release of thyroid hormone from gland)
- IV HYDROCORTISONE (to inhibits peripheral conversion of T4 to T3)
Label A
TSH: low
T3/T4: high
Label B
TSH: high
T3/T4: high
Label C
TSH: high
T3/T4: low
Label D
TSH: low
T3/4: low
Name a complication of longstanding untreated hypothyroidism? [1]
Myxoedema coma
Describe the features of a myxoedema coma [5]
- hypothermia
- cardiac failure (bradycardia)
- hypoventilation
- hypoglycaemia
- hyponatraemia
- myxoedema (thickened, swelling of skin)
How do you treat a patient presenting with myxoedema coma? [3]
- IV/ORAL T3
- IV fluid
- IV corticosteroids (until the possibility of coexisting adrenal insufficiency has been excluded)
- Glucose infusion
- Gradual rewarming
Explain the 5 main types of thyroid carcinoma [5]
Papillary (70%):
* Most common, well differentiated
* Young people, local spread and good prognosis
* Arise from thyroid epithelium
* Lymph node metastasis predominate
* Usually contain a mixture of papillary and colloidal filled follicles
* Histologically tumour has papillary projections and pale empty nuclei
Follicular (20%):
* Middle age, spread to lung/bone, usually good prognosis
* 3x more likely in women
* Well differentiated, arise from thyroid epithelium
- Follicular adenoma: Usually present as a solitary thyroid nodule. Malignancy can only be excluded on formal histological assessment.
- Follicular carcinoma: Capsular invasion seen microscopically, and without this finding the lesion would be a follicular adenoma. Vascular invasion predominates unlike papillary which is lymph-node predominant
Anaplastic (< 5%):
* Very undifferentiated and arise from thyroid epithelium
* Aggressive, local spread but poor prognosis
Lymphoma (2%)
* Can be associated with Hashimoto’s
Medullary cell (5%):
* C cells derived from neural crest and not thyroid tissue
* Serum calcitonin levels often raised
* Both lymphatic and haematogenous metastasis are recognised, nodal disease is associated with a very poor prognosis.
Which is the most common type of thyroid carcinoma? [1]
Papillary (70%)
Raised calcitonin levels would indicate which type of thyroid cancer? [1]
medullary thyroid cancer (arise from calcitonin C cells of thyroid gland)
Which types of thyroid cancers are differentiated? [2]
Which types of thyroid cancers are undifferentiated? [1]
Differentiated:
- papillary
- follicular
Undifferentiated:
- anaplastic
General treatment of thyroid carcinomas? [4]
- Administer lots of LEVOTHYROXINE (T4) to keep TSH reduced as this is a growth factor for the cancer!
- Iodine 131 ablation
- Thyroidectomy
- Chemotherapy helps to reduce risk of spread and treats micro-metastases that have been undetected
What are the three stages of De Quervain’s thyroiditis? [3]
De Quervain’s thyroiditis, also known as subacute thyroiditis, is a condition causing temporary inflammation of the thyroid gland. There are three phases:
Thyrotoxicosis
Hypothyroidism
Return to normal
De Quervain’s thyroiditis usually occurs after what? [1]
A viral infection
Describe the initial thyrotoxic phase of De Quervain’s thryoiditis [3]
- Excessive thyroid hormones
- Thyroid swelling and tenderness
- Flu-like illness (fever, aches and fatigue)
- Raised inflammatory markers (CRP and ESR)
Which thyroid carcinomas respond to iodine-131 ablation? [2]
Which do not? [2]
Ablative radioactive iodine:
- Papillary and follicular carcinomas
Anaplastic carcinomas and lymphomas:
- DO NOT respond to radioactive iodine
TOM TIP: The MHRA issued a warning in 2019 about the risk of [] in patients taking carbimazole.
In your exams, look out for a patient on carbimazole presenting with symptoms of []
TOM TIP: The MHRA issued a warning in 2019 about the risk of acute pancreatitis in patients taking carbimazole.
In your exams, look out for a patient on carbimazole presenting with symptoms of pancreatitis (e.g., severe epigastric pain radiating to the back).
TOM TIP: Both carbimazole and propylthiouracil can cause agranulocytosis, with a dangerously low white blood cell counts. Agranulocytosis makes patients vulnerable to severe infections.
[] is a key presenting feature of agranulocytosis. In your exams, if you see a patient with a sore throat on carbimazole or propylthiouracil, the cause is likely agranulocytosis. They need an urgent full blood count and aggressive treatment of any infections.
TOM TIP: Both carbimazole and propylthiouracil can cause agranulocytosis, with a dangerously low white blood cell counts. Agranulocytosis makes patients vulnerable to severe infections.
A sore throat is a key presenting feature of agranulocytosis. In your exams, if you see a patient with a sore throat on carbimazole or propylthiouracil, the cause is likely agranulocytosis. They need an urgent full blood count and aggressive treatment of any infections.
How do you adapt a pregnant women’s dose of levoythroxine due to their pregnancy? [1]
In pregnancy, anyone already on levothyroxine treatment should increase their dose. Thyroid doses should be adjusted in steps of 25-50mcg. In pregnancy, the increase in thyroid replacement is typically 20-50%, which normally equates to 25mcg-50mcg increase.
You suspect an underlying thyroid malignancy and send her for further imaging which confirms a malignancy, likely thyroid in origin. Her case is brought up at the next multi-disciplinary team meeting (MDT) and her prognosis is considered to be excellent.
What is the most likely diagnosis?
Anaplastic thyroid cancer
Follicular lymphoma
Follicular thyroid cancer
Medullary thyroid cancer
Papillary thyroid cancer
You suspect an underlying thyroid malignancy and send her for further imaging which confirms a malignancy, likely thyroid in origin. Her case is brought up at the next multi-disciplinary team meeting (MDT) and her prognosis is considered to be excellent.
What is the most likely diagnosis?
Anaplastic thyroid cancer
Follicular lymphoma
Follicular thyroid cancer
Medullary thyroid cancer
Papillary thyroid cancer
Papillary Prognosis is Perfect
Which of the following often has lymph node metastasis?
Anaplastic thyroid cancer
Follicular lymphoma
Follicular thyroid cancer
Medullary thyroid cancer
Papillary thyroid cancer
Which of the following often has lymph node metastasis?
Anaplastic thyroid cancer
Follicular lymphoma
Follicular thyroid cancer
Medullary thyroid cancer
Papillary thyroid cancer
Which of the following does not respond very well to treatment?
Anaplastic thyroid cancer
Follicular lymphoma
Follicular thyroid cancer
Medullary thyroid cancer
Papillary thyroid cancer
Which of the following does not respond very well to treatment?
Anaplastic thyroid cancer
Follicular lymphoma
Follicular thyroid cancer
Medullary thyroid cancer
Papillary thyroid cancer
Anaplastic is Awful (not treatment responsive usually)
How do the following types of thyroid cancer spread?
- Papillary [1]
- Follicular [1]
PL - premier league = papillary + lymphatic spread
FH - follicular + haematogenous spread
PAINFUL goitre
Raised ESR (caused by inflammation to thyroid)
Hyperthyroidism features
Subacute thyroiditis occurs after an infection from which type of organism? [1]
Post-viral infection
Describe the uptake of iodine in subacute thyroiditis [1]
No increase uptake: thyroid is inflammed due to infection.
Lots of T4 released, but it is acutely damaged and not producing any more during period
