Thyroid Disease Flashcards by raniya robb

If a thyroid condition is described as Primary, what is actually affected by the disease process?

affecting thyroid gland itself

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Can thyroid disease occur both WITH and WITHOUT a goitre?

Yes

goitrous or non-goitrous

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What type of disease process is usually responsible for types of thyroid disease?

Autoimmune

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If there is a problem in the hypothalamus or pituitary gland, what is this referred to in terms of thyroid disease?

Secondary Thyroid disease

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What is the other name for Thyroid Stimulating Hormone (TSH)?

thyrotropin

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Where is TSH or Thyrotropin released from?

Thyrotroph cells in anterior pituitary

Released in response to Thyrotropin Releasing Hormone (TRH)

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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)

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Describe the levels of Free T3/T4 and TSH found in Primary Hyperthyroidism?

Free T3/4 high

TSH low

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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

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What is the difference in the level of TSH between primary and secondary Hyperthyroidism?

TSH high (or ‘normal’) in secondary hyperthyroidism

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What name is given to the condition which is a severe form of hypothyroidism causing a medical emergency?

Myxoedema

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What disease does Pretibial Myxoedema usually indicate?

rare clinical sign of Graves’ disease

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Incidence of thyroid disease is higher in White Caucasian populations than in ethnic minorities. TRUE/FALSE?

TRUE

higher in areas of high iodine intake

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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)

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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

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What forms of Primary Hypothyroidism can be self-limiting?

Following withdrawal of antithyroid drugs
Subacute thyroiditis with transient hypothyroidism
Post-partum thyroiditis

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What are the usual characteristics in Hashimoto’s Thyroiditis?

Antibodies against thyroid peroxidase (TPO)

- microscopic T-cell infiltrate and inflammation

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What clinical signs of Hypothyroidism can occur in the skin?

Coarse, sparse hair
Periorbital puffiness
Pale cool skin that feels doughy to touch
Vitiligo
Hypercarotenaemia (Yellowing Skin)

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Patients experiencing hypothyroidism become intolerant to the heat. TRUE/FALSE?

FALSE
They become cold all the time
Patients with HYPERthyroidism become intolerant to the heat

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What cardiac symptoms and complications can a patient with Hypothyroidism experience?

Reduced heart rate
Cardiac dilatation
Pericardial effusion
Worsening of heart failure
Hyperlipidaemia

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Patients with hypothyroidism find it easy to put on weight. TRUE/FALSE?

TRUE

can cause easy weight gain

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Describe the GI symptoms experienced in both hypothyroidism and hyperthyroidism

HYPO = Constipation
HYPER = Diarrhoea

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What respiratory symptoms can be experienced in hypothyroidism?

Deep hoarse voice
Macroglossia (unusally large tongue)
Obstructive sleep apnoea

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What neurological symptoms can arise from Hypothyroidism?

Depression/psychosis/neuro-psychiatric
Muscle stiffness, cramps
Peripheral neuropathy
Prolongation of the tendon jerks
Carpal tunnel syndrome

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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?

TRUE | 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?

- bradycardia - 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 Monitor: - urine output - fluid balance - central venous pressure - blood sugars - O2

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?

Tremor | Sweating

What CNS symptoms can be caused by thyrotoxicosis?

Anxiety nervousness irritability sleep disturbance

Constipation can be a sign of thyrotoxicosis. TRUE/FALSE?

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’) Double vision 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?

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?

FALSE | can experience weight loss regardless of increased appetite

Are patients with thyrotoxicosis usually intolerant to the heat or to the cold?

Heat intolerant

What causes of thyrotoxicosis are related to hyperthyroidism?

Excessive thyroid stimulation => Grave's DIsease => Hashitoxicosis => Cancer 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?

Younger (20-50yrs)

Smoking is an important factor in Grave's Disease. TRUE/FALSE?

TRUE | 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?

Hypercalcaemia ↑Alkaline phosphatase Leucopenia (↓white cell count) TSH receptor antibody (TRAb)

What clinical signs are extremely specific to Grave's Disease?

Pretibial Myxoedema Thyroid acropathy (severe finger clubbing) Thyroid Bruit (Associated only with large goitres) Grave's Opthalmopathy

A nodular goitre is more likely to present in younger people. TRUE/FALSE

FALSE | older patients

A nodular goitre usually has an insidious onset. TRUE/FALSE?

TRUE

What type of Goitre may be seen in nodular disease?

Assymetrical

Will nodular thyroid disease be TRAb positive or negative?

Negative

What is Thyroid Storm? (also known as Thyroid Crisis)

Severe hyperthyroidism! - Respiratory and cardiac collapse - Hyperthermia - 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?

Carbimazole

What anti-thyroid drug is used in the first trimester of pregnancy and why?

Propylthiouracil (PTU) Risk of Carbimazole causing aplasia cutis in early pregnancy

What are the differences between giving Carbimazole and Propylthiouracil?

Carbimazole: Once daily dosing Less side effects 10x more potent Propylthiouracil: 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 Agranulocytosis

What drugs provide immediate relief from thyrotoxic symptoms?

Beta Blockers | Propanolol preferred

If a patient is asthmatic and cannot tolerate Beta Blockers, what drug should be given instead to manage Thyrotoxic symptoms?

Calcium Channel Blockers | e.g. Diltiazem

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 Hypothyroidism/ Hypoparathyroidism Anaesthetic Risk Permanent Scar

What are the most common causes of thyroiditis?

- Hashimoto’s - De Quervain’s/subacute (viral) - Post-partum - Drug-induced (e.g. amiodarone) - Radiation - Acute suppurative thyroiditis (bacterial)

Who is most likely to get Subacute thyroiditis?

Females | Ages 20-50 years

Is subacute thyroiditis usually self limiting?

Yes | 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