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Medicine Notes Medicine and Surgery Notes

Endocrinology Notes

Updated Endocrinology Notes

Medicine and Surgery Notes

Medicine and Surgery

Approximately 143 pages

Theses are my latest set of notes for my first year as a clinical medic, complementing the 3rd year curriculum perfectly. Each topic is briefly but thoroughly covered with clear headings and colour co-ordination.

The notes use a great mix of words and diagrams in an eye-pleasing layout making revision easier for you with plenty of space to annotate.

Each system is clearly marked and most of the core diseases are covered and broken down into prevalence, aetiology, clinical features, managemen...

The following is a more accessible plain text extract of the PDF sample above, taken from our Medicine and Surgery Notes. Due to the challenges of extracting text from PDFs, it will have odd formatting:

Disorders of the Pituitary

Causes of Pituitary Disorders

Hypersecretion – functioning tumours or drugs

Symptoms Deficient Hormone
Growth retardation in children, excessive tiredness, muscle weakness GH
Hypogonadism – reduced body hair, low libido, impotence in men, amenorrhoea, dyspareunia and hot flushes in women FSH/LH
Weight gain, decreased energy, sensitivity to cold, constipation, dry TSH
Pale appearance, weight loss, low BP, dizziness, tiredness ACTH
Thirst and polyuria VP

Hyposecretion – craniopharyngeoma, non-functioning pituitary tumours, radiotherapy, trauma, empty sella syndrome

Hypopituitarism

Deficiency of hypothalamic releasing hormones

Isolated deficiency of GH, LH, ACTH, TSH & vasopressin

Growth Failure

Short Stature

  • Thyroid function test – hypothyroidism

  • GH status

  • IGF-1 – GH undersecretion

  • Assessment of bone age

  • Karyotyping female – turner’s syndrome

Treatment

Hypothyroidism – levothyroxine

GH insufficiency – somatrophin injections

Acromegaly & Giantism

GH excess due to a pituitary tumour

  • Changes in appearance

  • Visual fields defects/headaches

  • Sweating

Investigations

GH levels

Glucose tolerance test – diagnostic if there is no suppression of GH

IGF-1 – almost always raised

Visual field exam – bitemporal hemianopia

MRI scan – pituitary adenoma

Prolactinaemia

Management & Treatment

Surgery - trans-sphenoidal

Pituitary radiotherapy after surgery

Medical therapy

  • Somatostatin receptor agonist – octreotide

  • Dopamine agonists

  • GH antagonists – normalises IGF-1 levels

Hyperprolactinaemia

Caused by a small prolactin producing tumour , PCOS, primary hypothyroidism

Applies pressure on the optic nerve resulting in bitemporal hemianopia

Amenorrhea, breast milk production, loss of libido, headaches, oesteoporosis due to hypoestrogenism

Investigations

Visual fields

Hypothyroidism must be excluded

Anterior pituitary function – tumours

MRI scan of pituitary

Treatment

Must be treated to avoid the long term effects of oestrogen deficiency

  • Medical

    • Dopamine agonist – cabergoline/bromocriptine

  • Trans-sphenoidal surgery

  • Radiotherapy

    • Controls the growth but is slow in effect

Thyroid Disease

Produces thyroxine, T4 and triiodothyronine, T3

These regulate the rate of metabolism and affect growth and rate of function of many systems

Iodine and tyrosine are both used to for T3 and T4

T4 is converted to T3 and reverse T3 by de-iodination

T3 is rapidly excreted due to poor binding and further de-iodination

Regulation

Regulated by TRH from the hypothalamus

TSH stimulates the enlargement of follicular cells and increases all steps in hormone production: iodine uptake, formation of reactive iodine, production of thyroglobulin colloid, endocytosis of colloid and liberation of T4 & T3

TSH is stimulated by TRH

Negative feedback of T4 and T3 on the pituitary switch of TSH production

Actions

T4 & T3 operate through nuclear receptors regulating gene transcription

Genes concerned with cell differentiation and metabolism

Most tissues respond to T3/T4 and require thyroid hormones for normal development

Main effects:

  • Respiratory – maintains normal hypoxic & hypercapnic drive

  • Metabolism of proteins, carbohydrates, lipids – increases

  • Cardiovascular effects – heart rate & cardiac output

  • Neuromuscular effects – increases speed of muscle contraction, relaxation & protein turnover

  • Function of sympathetic nervous system – increases sensitivity

  • Higher functions of CNS

  • GI tract – motility

  • Skeletal – increased turnover & resorption

  • Growth and development

Hypothyroidism

Primary hypothyroidism -1% prevalence in women 0.1% in men

Causes

AUTOIMMUNE

  • Atrophic (autoimmune) hypothyroidism

    • Antithyroid antibodies

    • Lead to lymphoid infiltration and atrophy/fibrosis

  • Hashimoto’s thyroiditis

    • Autoimmune

    • Atrophy with regeneration leading to goitre formation

    • Levothyroxine may shrink the goitre

  • Postpartum thyroiditis

    • Due to modifications of the immune system in pregnancy

DEFECTS OF HORMONE SYNTHESIS

  • Iodine deficiency

  • Dyshormonogenesis

    • Genetic defects

    • Goitre

Clinical features

Slow, dry-haired, thick-skinned, deep-voiced, weight gain, cold intolerance

Children: slow growth velocity

Investigations

Serum TSH

Normocytic anaemia

Increased serum creatinine kinase

Hypercholesterolaemia

Hyponatraemia

Treatment

  • Replacement therapy

    • Levothyroxine for life

  • Monitoring

    • Up to 6 months for full resolution of Sx

Hyperthyroidism

2-5% of all females affected

Grave’s Disease

Autoimmune process

IgG antibodies bind to TSH receptors in the thyroid, stimulating thyroid production

These antibodies can be measured in serum TSHR-Ab

Thyroid eye disease accompanies Grave’s

Relapse & remission is common

Only 40% will experience one episode

  • Toxic multinodular goitre

  • Amiodarone-indiuced toxicosis

Clinical features

Eye signs

Pretibial myxoedema

Thyroid acropachy

Atrial fibrillation in the elderly

Children: excessive height, hyperactivity

Weight loss

Increased appetite

Irritability

Heat intolerance

Tremor

Goitre

Investigations

Serum TSH is suppressed in hyperthyroidism

Raised T4/T3

Treatment

  • Antithyroid drugs

    • Carbimazole – inhibit formation of thyroid hormones

    • Beta-blockers provide rapid relief

    • 50% will relapse within 2 years

  • Radioactive iodine

    • Not during pregnancy

    • Destroys the gland by radiation

    • May take months

  • Subtotal thyroidectomy

    • Risks: laryngeal nerve palsy, hypoparathyroidism, hypothyroidism

Glucocorticoids

CRH ACTH Cortisol

Negative feedback control

DEXAMETHASONE Measure Normal test result Use & explanation
Overnight 0900 Cortisol<100nmol/L Outpatient screening test
Low-dose 0900 +2 days Cortisol <50nmol/L Diagnosis of Cushing’s syndrome
High-dose 0900 +2 days Cortisol on day 2 <50% of day 0 suggests pituitary dependent disease Differential of Cushing’s syndrome

Addison’s disease – hypoadrenalism

Destruction of the adrenal cortex

Glucocorticoid, mineralocorticoid and sex steroid production are all reduced

Reduced...

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