Hypothyroidism

Terms

Adult hypothyroidism Myxoedema Cretinism

Cretinism

Fetal or infantile hypothyroidismEndemic and sporadic Sporadic –agenesis ,dyshormonogenesis Hoarse cry , macroglossia , umbilical

herniaImmediate diagnosis and treatment

Adult type

• bradycardia• cold extremities• dry skin and hair• periorbital puffiness• hoarse voice• bradykinesis, slow movements• delayed relaxation phase of ankle jerks.The symptoms are:• tiredness• mental lethargy• cold intolerance• weight gain• constipation• menstrual disturbance• carpal tunnel syndrome.

Myxoedema

Classification of hypothyroidism

Autoimmune thyroiditis (chronic lymphocytic thyroiditis

1) Non-goitrous: primary myxoedema2) Goitrous: Hashimoto’s disease

Classification

IatrogenicAfter thyroidectomyAfter radioiodine therapyDrug induced (antithyroid drugs,para-

aminosalicylic acid and iodides in excess)

Classification

DyshormonogenesisGoitrogensSecondary to pituitary or hypothalamic

diseaseThyroid agenesisEndemic cretinism- Often goitrous and

due to iodine deficiency

Dyshormonogenesis

Deficient enzymes Autosomal recessiveYoung patients , thyromegaly , euthyroid

statePendred syndrome – TPO deficiency goitre , sensorineural deafness ,

abnormal bony labyrinth

Investigations and management

TFT- low T3 , T4 and high TSHHigh titres of TPO antibodies Oral thyroxine (0.1 to 0.2 mg/day) or

triiodothyronine (20mcg tds)Myxoedema – bolus 500mg of T4 or 10

mcg of T3 oral or IV 4-6 hourly Corticosteroids and broad spectrum

antibiotics