If a thyroid condition is described as Primary, what is actually affected by the disease process?
affecting thyroid gland itself
Can thyroid disease occur both WITH and WITHOUT a goitre?
goitrous or non-goitrous
What type of disease process is usually responsible for types of thyroid disease?
If there is a problem in the hypothalamus or pituitary gland, what is this referred to in terms of thyroid disease?
Secondary Thyroid disease
What is the other name for Thyroid Stimulating Hormone (TSH)?
Where is TSH or Thyrotropin released from?
Thyrotroph cells in anterior pituitary
Released in response to Thyrotropin Releasing Hormone (TRH)
Describe the levels of Free T3/T4 and TSH found in Primary Hypothyroidism?
Free T3/4 low TSH high (body's reaction to low circulating hormone)
Describe the levels of Free T3/T4 and TSH found in Primary Hyperthyroidism?
Free T3/4 high
What is the difference in the level of TSH between primary and secondary Hypothyroidism?
TSH low (or ‘normal’) in secondary hypothyroidism
Due to problem being in pituitary/hypothalamus
=> less able to sense body’s required response
What is the difference in the level of TSH between primary and secondary Hyperthyroidism?
TSH high (or ‘normal’) in secondary hyperthyroidism
What name is given to the condition which is a severe form of hypothyroidism causing a medical emergency?
What disease does Pretibial Myxoedema usually indicate?
rare clinical sign of Graves’ disease
Incidence of thyroid disease is higher in White Caucasian populations than in ethnic minorities. TRUE/FALSE?
higher in areas of high iodine intake
What conditions could cause Goitrous Primary Hypothyroidism?
- Chronic thyroiditis (Hashimoto’s)
- Iodine deficiency
- Drug-induced (e.g. amiodarone, lithium)
- Maternally transmitted (e.g. antithyroid drugs)
What conditions can cause Primary Hypothyroidism that presents without a goitre?
- Atrophic thyroiditis
- Post-ablative therapy (e.g. radioiodine, surgery)
- Post-radiotherapy (e.g. for lymphoma treatment)
- Congenital developmental defect
What forms of Primary Hypothyroidism can be self-limiting?
- Following withdrawal of antithyroid drugs
- Subacute thyroiditis with transient hypothyroidism
- Post-partum thyroiditis
What are the usual characteristics in Hashimoto’s Thyroiditis?
- Antibodies against thyroid peroxidase (TPO)
- microscopic T-cell infiltrate and inflammation
What clinical signs of Hypothyroidism can occur in the skin?
- Coarse, sparse hair
- Periorbital puffiness
- Pale cool skin that feels doughy to touch
- Hypercarotenaemia (Yellowing Skin)
Patients experiencing hypothyroidism become intolerant to the heat. TRUE/FALSE?
They become cold all the time
Patients with HYPERthyroidism become intolerant to the heat
What cardiac symptoms and complications can a patient with Hypothyroidism experience?
- Reduced heart rate
- Cardiac dilatation
- Pericardial effusion
- Worsening of heart failure
Patients with hypothyroidism find it easy to put on weight. TRUE/FALSE?
can cause easy weight gain
Describe the GI symptoms experienced in both hypothyroidism and hyperthyroidism
HYPO = Constipation HYPER = Diarrhoea
What respiratory symptoms can be experienced in hypothyroidism?
- Deep hoarse voice
- Macroglossia (unusally large tongue)
- Obstructive sleep apnoea
What neurological symptoms can arise from Hypothyroidism?
- Muscle stiffness, cramps
- Peripheral neuropathy
- Prolongation of the tendon jerks
- Carpal tunnel syndrome
Does Hypothyroidism cause heavier or lighter periods?
- Menorrhagia (heavier periods)
- Patients can also experience irregular periods or no periods at all
What is the starting dose for hypothyroid patients beginning on levothyroxine?
Younger patients = 50-100 μg daily
Elderly with Hx of IHD: start 25-50 μg daily, adjusted every 4 weeks according to response
How long after a dose change should a patient’s TSH levels be checked?
2 months after any dose change
Once TSH is stabilised, how often should it be checked?
TSH should be checked every 12-18 months
Why is T3 therapy not often used in hypothyroidism?
T3 effects develop within a few hours and disappear within 24-48 hours of discontinuation
Dose requirements in hypothyroidism may increase in pregnancy. TRUE/FALSE?
Due to increased TBG
What group of people are most affected by Myxoedema coma?
Elderly females with frequently unrecognized or untreated hypothyroidism
What symptoms of a myxeoedema coma can be found on an ECG?
- low voltage complexes
- varying degrees of heart block
- T wave inversion
- prolongation of the QT interval
What respiratory symptoms can be seen in myxoedema coma?
Type 2 respiratory failure:
=> hypoxia, hypercarbia, respiratory acidosis
What percentage of patients with myxoedema coma also experience adrenal failure?
10% of patients
How should myxoedema coma be treated and monitored?
- Intensive care ( A, B, C, D, E )
- Passively rewarm (slow rise in body temp.)
- Cardiac monitoring for arrhythmias
- Broad spectrum antibiotics
- Thyroxine cautiously
- urine output
- fluid balance
- central venous pressure
- blood sugars
What is the definition of thyrotoxicosis
Clinical, physiological and biochemical state arising when the tissues are exposed to excess thyroid hormone
Describe the difference between Hyperthyroidism and thyrotoxicosis
Hyperthyroidism = conditions where overactivity of the thyroid gland leads to thyrotoxicosis
What are the potential cardiac symptoms of thyrotoxicosis?
Palpitation, atrial fibrillation (AF) Cardiac failure (very rare)
Thyrotoxicosis causes what effect on the sympathetic nervous system?
What CNS symptoms can be caused by thyrotoxicosis?
Constipation can be a sign of thyrotoxicosis. TRUE/FALSE?
Thyrotoxicosis usually results in frequent, loose bowel movements
What are the common features of thyrotoxicosis which present in the eye?
Lid retraction (not specific to Graves’)
Proptosis (Eyes bulging forward - only really seen in Grave’s)
What hair and nail changes can be noticed in thyrotoxicosis?
brittle, thin hair
Rapid fingernail growth
Patients with thyrotoxicosis usually experience heavier periods. TRUE/FALSE?
lighter bleeding and less frequent periods
In what areas do patients with thyrotoxicosis experience muscle weakness?
thighs and upper arms
Patients with thyrotoxicosis usually gain weight easily. TRUE/FALSE?
can experience weight loss regardless of increased appetite
Are patients with thyrotoxicosis usually intolerant to the heat or to the cold?
What causes of thyrotoxicosis are related to hyperthyroidism?
Excessive thyroid stimulation
=> Grave’s DIsease
Thyroid nodules with autonomous function
=>Toxic solitary nodule
=> Toxic multinodular goitre
What causes of thyrotoxicosis are NOT associated with hyperthyroidism?
Thyroid inflammation (thyroiditis)
=> Sub acute (de Quervains)
=> Post partum
Exogenous thyroid hormones
=> overtreatment with levothyroxine
Ectopic thyroid tissue
=> Metastatic thyroid cancer
What age do patients usually develop Grave’s Disease?
Smoking is an important factor in Grave’s Disease. TRUE/FALSE?
major risk factor especially for developing Grave’s related thyroid disease
Aside from TSH and free T3/T4 levels, what other lab results can be seen in a patient with Grave’s disease?
Leucopenia (↓white cell count)
TSH receptor antibody (TRAb)
What clinical signs are extremely specific to Grave’s Disease?
Thyroid acropathy (severe finger clubbing)
Thyroid Bruit (Associated only with large goitres)
A nodular goitre is more likely to present in younger people. TRUE/FALSE
A nodular goitre usually has an insidious onset. TRUE/FALSE?
What type of Goitre may be seen in nodular disease?
Will nodular thyroid disease be TRAb positive or negative?
What is Thyroid Storm? (also known as Thyroid Crisis)
- Respiratory and cardiac collapse
- Exaggerated reflexes
- May require mechanical ventilation
How should Thyroid Storm/crisis be treated?
Lugol’s Iodine, glucocorticoids Propylthiouracil (PTU) β-blockers fluids
When does thyroid storm/crisis usually occur?
Hyperthyroid patients with:
- acute infection/illness
- Recent thyroid surgery
What is the 1st line anti-thyroid drug?
What anti-thyroid drug is used in the first trimester of pregnancy and why?
Risk of Carbimazole causing aplasia cutis in early pregnancy
What are the differences between giving Carbimazole and Propylthiouracil?
Once daily dosing
Less side effects
10x more potent
Twice daily dosing
10x less potent
Side effects more common (e.g. liver failure)
What are the main side effects of anti-thyroid drugs?
allergic type reactions – rash, urticaria, arthralgia
Cholestatic jaundice/ Liver failure
What drugs provide immediate relief from thyrotoxic symptoms?
If a patient is asthmatic and cannot tolerate Beta Blockers, what drug should be given instead to manage Thyrotoxic symptoms?
Calcium Channel Blockers
What is Radioiodine used for?
1st choice treatment for relapsed Graves’ disease and nodular thyroid disease
can cause Patient to have HYPOthyroidism
When would a thyroidectomy be indicated?
If radioiodine was contraindicated
What complications can arise during a thyroidectomy?
recurrent laryngeal nerve palsy
What are the most common causes of thyroiditis?
- De Quervain’s/subacute (viral)
- Drug-induced (e.g. amiodarone)
- Acute suppurative thyroiditis (bacterial)
Who is most likely to get Subacute thyroiditis?
Ages 20-50 years
Is subacute thyroiditis usually self limiting?
Over a few months
What is meant by non-thyroidal illness?
impact of intercurrent illness (e.g. severe infection) on the Hypothalamic-Pituitary axis
TSH = suppressed initially then rises during recovery