Thyroid

Thyrotoxicosis

Pathology:                    IncreasedT3 and/or T4 (usually both) due to excess production causing increased basalmetabolic rate and multiple end-organ effects

Aetiology:                     Primary: Autonomous thyroid inmultinodular goitre or autoimmune

hyperthyroidism (Graves’ Disease)

Secondary: Thyrotrophpituitary tumour, thyroiditis from drugs (e.g.

amiodarone),infections, post-partum, radiation, inappropriate use  

of thyroxinemedications

Symptoms:                   Anxiety,hyperactivity, sweating, heat intolerance, palpitations, weakness, weight loss,increased stool frequency, pruritus, oligo/amenorrhoea

Signs:                              Finetremor, tachycardia, warm moist skin, palmar erythema, hair loss, musclewasting/ weakness, brisk reflexes, signs of congestive cardiac failure

Graves’Disease: May have neck swelling and eye signs, proximalmyopathy,

pre-tibialmyxoedema, thyroid acropachy

                                          Eye Signs: Exophthalmos, proptosis,ophthalmoplegia

Investigations:          Bloods: Thyroid function tests (TFTs): Increased T₄, Increased T₃, Decreased

TSH , Antithyroidperoxidase (TPO) antibodies, TSH receptor (TRAb)

antibodies (Graves’ Disease)

Imaging: ultrasound thyroid, thyroid uptake scan

Treatment:                  Medical: Symptomatic treatment with beta blockers (Propranolol) and

  anti-thyroid drugs(Carbimazole, Propylthiouracil)

Radiation: Radioiodinetherapy

Surgery: Thyroidectomy

Complications:          Atrialfibrillation, heart failure, osteoporosis

Prognosis:                    Usuallygood. Can cause exacerbation of pre-existing heart failure or arrhythmias

Hypothyroid

Pathology:                    Relativeor absolute lack of thyroid hormones or resistance to thyroid hormone

Aetiology:                     Endemic (iodine deficiency),autoimmune (Hashimoto’s thyroiditis), congenital, drugs (e.g. lithium, amiodarone),thyroiditis (atrophic, post-partum), following thyroidectomy or radioiodinetreatment, hypopituitarism

Symptoms:                   Lethargy,weight gain, cramps, constipation, cold intolerance, peri-orbital oedema,menorrhagia, ataxia, confusion (elderly), psychosis, depression

Signs:                              Dryskin, hoarse voice, hair loss, hypothermia, bradycardia, macroglossia, slowedreflexes, heart failure, serous effusions (e.g. pleural, pericardial)

Investigations:          Bloods: TFTs: Decreased T₄,decreased T₃, increasedTSH, thyroid antibodies –

Autoantibodiesagainst thyroid peroxidase thyroglobulin in Hashimoto’s

Thyroiditis

UltrasoundScan: Thyroid

Treatment:                  Replacewith daily Levothyroxine for life and regular monitoring of thyroid function

Complications:          Heartfailure, ischaemic heart disease, delayed development and mental retardation(if congenital)

Prognosis:                    Usually good

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