Thyroid Pathology Flashcards by Shauneen Kiernan

What is the function of thyroid hormone?

>Cell Basal Metabolic Rate

>CO

>Bone Resorption

Activates sympathetic nervous system

How well did you know this?

Not at all

Perfectly

What hormone is thyroid hormone permissive to?

Adrenalin

How well did you know this?

Not at all

Perfectly

Describe the pathophysiology of Grave’s disease

Antibodies are produced which mimic TSH and continually activates the thyroid gland

This increased TH production switches off TSH release and so plasma concentration is low

Thyroid gland may be 2-3X normal size due to hyperplasia and hyperactive cells may also be apparent

How well did you know this?

Not at all

Perfectly

What sex is hyperthyroidism more common?

F>M

How well did you know this?

Not at all

Perfectly

What are the causes of hyperthyroidism?

Graves

Thyroid Adenoma

Toxic Multinodular Goitre

Secondary: Pituitary adenoma

Drugs

Struma Ovarii: Rare ovarian cancer

(Initial De Quervain’s)

How well did you know this?

Not at all

Perfectly

What drugs can cause hyperthyroidism?

Amiodarone

Lithium

How well did you know this?

Not at all

Perfectly

What is the most common cause of hyperthyroidism?

Graves (70% causes)

How well did you know this?

Not at all

Perfectly

How does hyperthyroidism present?

Tremor

Weight loss

Palpitations

Hair loss

Poor concentration

Amenorrhea/oligomennnorhoea

Bowel frequency

Sweaty

Heat Intolerance

Exophthalmos/Proptosis

Pretibial myxoedema

Muscle weakness

Clubbing

Anxiety/irritability

Hyperreflexia

>HR/Tachycardia

Goitre

How well did you know this?

Not at all

Perfectly

What is a goitre?

Enlargement of the thyroid gland that can accompany hypo and hyperthyroidism

How well did you know this?

Not at all

Perfectly

What investigations are used in hyperthyroidism diagnosis?

TSH

Increased unbound T3/T4

Radioactive Iodine Uptake Test and Thyroid Scan

Patchy uptake suggests toxic multinodular goitre

Antibodies

Thyroid Peroxidase Antibodies
TSH Receptor Antibodies, present in 90-100% Graves patients

How well did you know this?

Not at all

Perfectly

When is TSH high for hyperthyroidism?

Secondary/pituitary causes of hyperthyroidism

How well did you know this?

Not at all

Perfectly

When is TSH low for hyperthyroidism?

Primary causes of hyperthyroidism

How well did you know this?

Not at all

Perfectly

Give complications of hyperthyroidism

Atrial fibrillation

Osteoporosis

How well did you know this?

Not at all

Perfectly

How is hyperthyroidism managed?

Anti-thyroid drugs

Radio-iodine therapy: For patients >45

Partial thyroidectomy

B-Blockers: Symptomatic relief

How well did you know this?

Not at all

Perfectly

Give an example of an anti-thyroid drug?

Carbimazole

How well did you know this?

Not at all

Perfectly

What is thyroid storm?

Hypermetabolism when individual causing exacerbation of symptoms

How well did you know this?

Not at all

Perfectly

Describe the pathophysiology of Hashimoto’s

Autoimmune destruction of thyroid epithelial cells, involving T cells, cytokine and antibody mediated destruction (circulating antibodies to thyroglobulin and thyroid peroxidase)

This results in diffuse enlargement of the thyroid and then the eventual shrinkage and gradual failure

How well did you know this?

Not at all

Perfectly

How common is hypothyroidism?

Most common endocrine condition after diabetes

How well did you know this?

Not at all

Perfectly

What sex is hypothyroidism most common?

F>M

How well did you know this?

Not at all

Perfectly

What are the primary causes of hypothyroidism?

Hashimoto’s Disease

Deficiency in dietary iodine

Milk, seafood, seaweed

Iatrogenic

External radiation
Post-operative/post-radioactive iodine

Congenital

Post-subacute Thyroiditis/De Quervain’s

Post-infection

How well did you know this?

Not at all

Perfectly

What is Hashimoto’s disease?

Autoimmune attack of thyroid gland

How well did you know this?

Not at all

Perfectly

What are the secondary causes of hypothyroidism?

Pituitary tumour

Craniopharyngioma

Post pituitary surgery or radiotherapy

Sheehan’s Syndrome

Isolated TRH Deficiency

How well did you know this?

Not at all

Perfectly

What is Sheehan’s Syndrome?

Postpartum pituitary gland necrosis

How well did you know this?

Not at all

Perfectly

How does hypothyroidism present?

Weight gain

Cold intolerance

Depression

Dry and thin hair/skin, brittle nails: Disrupted protein synthesis

Constipation

Menorrhagia

Hoarseness: Severe

Lethargy

Hyporeflexia: Altered nervous system

Bradycardia

Goitre: If Hashimoto

Puffy face, large tongue: Severe

Coma: Severe

How well did you know this?

Not at all

Perfectly

What investigations are used in hypothyroidism diagnosis?

TSH Anti Thyroid Peroxidase antibodies FBC * Macrocytic anaemia \>ESR in De Quervain's Iodine uptake scan * Reduced iodine uptake in De Quervain's

When is TSH high for hypothyroidism?

Primary

When is TSH low/normal for hypothyroidism?

secondary

How is hypothyroidism managed?

Levothyroxine: T4 tablets Liothyronine: T3 tablets

When is subclinical hypothyroidism treated?

Treat if TSH\>10 or \>5 with positive thyroid antibodies Trial therapy if TSH elevated with symptoms

What is Myxoedema Coma?

Severe life-threatening form of hypothyroidism affecting those with poorly controlled hypothyroidism in a physiological stressful situation

Describe how levothyroxine is given

T4 tablets, initial dose of 50cmg/day Increase after 2 weeks to 100mcg and continue until TSH is normal

What are the classifications of thyroid tumour?

Papillary carcinoma Follicular carcinoma Anaplastic carcinoma Medullary carcinoma Lymphoma

What is the most common thyroid tumour?

Papillary carcinoma, most common at 75-80%

Give side effects of Carbimazole

Agranulocytosis Hair loss Headaches Nausea Stomach pains Itchy skin Rashes Muscle and joint pain

What is the most serious side effect of Carbimazole?

Bone marrow suppression (neutropenia/agranulocytosis) resulting in immune system suppression Sore throat is the most common symptom of this

What is the mechanism of action of Carbimazole?

Blocks thyroid peroxidase from coupling and iodinating the tyrosine residues on thyroglobulin, therefore reducing thyroid hormone production

How is Carbimazole given?

High doses for 6 weeks until patient becomes euthyroid before being reduced

What group of patients is papillary carcinoma most common in?

Young females

What is the prognosis of papillary carcinoma?

Excellent

What is associated with medullary carcinoma?

MEN2

What does medullary carcinoma secrete?

Calcitonin This used as an alternative to thyroglobulin in medullary carcinoma for recurrence screening

How are thyroid tumours managed?

Total thyroidectomy followed by radioiodine

What histological sign is seen in papillary thyroid cancer?

Orphan annie cells

What levels are measured yearly to detect early recurring thyroid tumours?

Thyroglobulin

What sign is only seen in Graves disease?

Exopthalamos/Proptosis

Give complications of Hashimotos

MALT Lymphoma Addisons Graves Type 1 diabetes Pernicious anaemia Lupus Erythematosus RA Thrombocytopenic Purpura Vitiligo

How do thyroid tumours present?

**PAID DUET** Pain in the neck Asymmetry in the thyroid Increased risk for women Difficulty swallowing Dyspnoea Unexplained hoarseness Enlarged lymph nodes in neck Thyroid nodule/lump

Can Carbimazole be used in pregnancy?

Contraindicated in first trimester as can cross placenta and cause aplasia cutis

How does myxoedema coma present?

Confusion Hypothermia Hypotension Bradycardia

How is myxoedema coma managed?

IV thyroid replacement IV corticosteroids, until the possibility of coexisting adrenal insufficiency has been excluded IV fluids Electrolyte imbalance correction Rewarming

What are the features of thyroid eye disease?

Proptosis Lagophthalamos, inability to fully close eyelids Lid retraction Opthalmoplegia

What is the first line therapy for toxic multinodular goitre?

radio-iodine therapy

How can thyroid eye disease be prevented?

stop smoking (this is a risk factor for Graves)

How much should levothyroxine dose be increased in pregnancy?

Up to 50% as early as 4-6 weeks

When should levothyroixine be adjusted?

Higher dose for pregnancy and lower in ischaemic heart disease

Give causes of thyroid storm

Stops treatment Infection Surgery Trauma Acute iodine load

How does thyroid storm present?

Fever over 38.5ºC Tachycardia Confusion and agitation N&V Hypertension HF Abnormal LFT/jaundice

How is thyroid storm managed?

Symptomatic treatment, paracetamol Treatment of underlying precipitating event B blockers, typically IV propranolol Anti-thyroid drugs, methimazole Lugol's iodine Dexamethasone, blocks the conversion of T4 to T3

What is first line management of thyroid storm?

IV B blocker

What blood test is used to measure response to treatment in Hashimotos?

TSH

What is the most common cause of hypothyroidism

Iodine deficiency worldwide Hashimotos in countries were iodine consumption is adequate

How does goitre presentation differentiate in hypothyroidism?

Hashimotos is associated with non tender goitre De Quervain's is associated with a painful goitre

Describe the TFT results in non thyroidal illness/sick euthyroid syndrome

TSH low (sometimes this is normal) and free T4 low Common in elderly hospital inpatients Changes are reversible upon recovery from the systemic illness and hence no treatment is usually needed

Describe the TFT results in subclinical hypothyroidism

TSH high and free T4 normal

Describe the TFT results in patients with poor compliance with levothyroxine

TSH high and normal free T4

How can steroid therapy affect TFT results?

TSH low and normal free T4

What group of patients is anaplastic thyroid carcinoma most common in?

Elderly females

What drug interactions can occur with levothyroxine?

Iron and calcium carbonate Absorption of levothyroxine reduced, give at least 4 hours apart

Give side effects of thyroxine therapy

Hyperthyroidism Osteoporosis Worsening angina AF

Give complications of thyroidectomy

Recurrent laryngeal nerve damage Bleeding and therefore haematomas due to comfined space, rapidly leading to respiratory compromise due to laryngeal oedema Parthyroid damage and hypocalcaemia

How is hyperthyroidism managed in pregnancy?

Propylthiouracil

Thyroid Pathology Flashcards

(71 cards)