Thyroid Disorders

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HYPERTHYROIDISM IN ADULTS

Clinical Description

  • Metabolic disorder resulting from excessive circulating thyroid hormones

Causes

  • Graves’ disease, toxic multinodular goitre, toxic solitary nodule

Clinical Features 

SIGNS AND SYMPTOMS

  • Fatigue, nervousness or anxiety, weight loss, palpitations, heat intolerance, irregular menses/sub infertility.
  • Tachycardia (may be irregular if atrial fibrillation), warm moist hands.
  • Goitre (smooth if Grave’s disease) and tremor.
  • Diarrhoea, jaundice or heart failure symptoms and signs (if in thyroid storm).
  • If Graves’ disease: thyroid eye signs: lid retraction, proptosis, lid lag, chemosis, ophthalmoplegia.

INVESTIGATIONS

  • Thyroid function tests
  • Full blood count
  • Thyroid antibodies (TSH-receptor antibody, Thyroperoxidase antibody)
  • Thyroid gland ultrasound
  • Random blood sugar
  • ECG and echocardiogram

Treatment 

  • Treatment objectives are to reduce thyroid hormone levels in the blood to normal, reduce symptoms associated with thyrotoxicosis, and prevent or treat complications e.g., heart failure, atrial fibrillation and ophthalmopathy.

PHARMACOLOGICAL 

  • Management should be supervised by a doctor
  • Refer to tertiary level

Treatment:

  • Give Propranolol 40-120mg q8h to control symptoms, especially tachycardia
  • Give Carbimazole 40mg od or in divided doses for approximately 2 months then reduce dose according to symptoms improvement and improved thyroid function tests. Monitor side effects of carbimazole (neutropenia with infection, hepatitis)
  • In Graves’ disease continue for 12 to 18 months then stop and monitor TSH every 3 months for a year, then once a year (In large percentage, hyperthyroidism will be resolved)
  • If patient pregnant or breast-feeding, use Propylthiouracil instead of carbimazole
  • For persistent hyperthyroidism on treatment in Grave’s disease, and relapsed hyperthyroidism after remission following treatment, consider total thyroidectomy (or radioactive iodine once it becomes available in the country)
  • In other causes continue Carbimazole and refer for surgery or radioactive iodine once it becomes available in the country which might be soon; these patients should be considered for radioiodine first before surgery unless it not suitable in their case)

 

HYPERTHYROIDISM IN CHILDREN

Clinical Description

Metabolic disorder resulting from excessive circulating thyroid hormones

Causes:

  • Diffuse toxic goitre/ Graves’ disease
  • Thyroiditis
  • TSH induced
    • TSH producing tumour
    • Inappropriate secretion of TSH

Clinical Features

SIGNS AND SYMPTOMS

  • Weight loss, sweating, palpitations, tremor, muscle weakness and hypertension 

INVESTIGATIONS

  • Thyroid function test
  • Thyroid antibodies
  • Radionuclide thyroid scan

Treatment

  • The aim is to Induce remission and Improve symptoms of thyrotoxicosis

PHARMACOLOGICAL

  • Carbimazole 0.5-1mg/kg/day in 3 divided doses (maximum dose not to exceed 30mg/day)
  • Propranolol 0.5 – 1 mg PO 2 -3 times a day
  • If unresponsive consider radioactive iodine

Complications

  • Thyroid crisis
  • High output cardiac failure

REFERRAL

  • All patients with suspected hyperthyroidism

If a patient develops a fever or sore throat while taking Carbimazole, neutropenia should be urgently excluded. If present, then stop Carbimazole and treat with antibiotics.

 

HYPOTHYROIDISM (MYXOEDEMA)

Clinical Description

Hypothyroidism is a condition associated with reduction in thyroid hormone production. Thyroid hormone is required for normal metabolism and growth. Its deficiency has major consequences on fetal development as well as intellectual and physical development in infants and children (cause of cretinism). In adults, it may be the cause of several problems.

Causes:

  • Antibody-related thyroid gland destruction (Hashimoto thyroiditis)
  • Subtotal thyroidectomy
  • Pituitary surgery or lesions
  • Congenital
  • Severe iodine deficiency
  • Drug induced (e.g., radioiodine therapy, amiodarone etc.)

Clinical Features

SIGNS AND SYMPTOMS

  • Cretinism in infants: Poor growth, development, and poor school performance in children
  • Signs Neonate: Prolonged neonatal jaundice, Excessive sleep, Feeding problems
  • Cretinism in Children: mental sub-normality, short stature, large tongue, dry skin, sparse hair, protuberant abdomen, umbilical hernia, abnormal facies)
  • Adults: menstrual irregularity and infertility, mental health conditions and dementia.
  • General fatigue, constipation, cold intolerance, dry and coarse skin, hoarse voice, weight gain, bradycardia (slow heart rate, slow relaxing reflexes, hyperlipidaemia, goitre (+/-), dementia, pallor, puffy face, hair loss and eyebrow loss

INVESTIGATIONS

  • Thyroid function tests T3, T4, TSH.
  • Fasting blood lipids (for elevated cholesterol level)
  • Full blood count

Treatment 

  • Treatment objectives are to correct blood level of thyroid hormones and to maintain lifelong normal levels of thyroid hormones

PHARMACOLOGICAL

  • Start treatment with a low dose of Levothyroxine, especially in the elderly, those with heart disease and Children (e.g., 25-50 microgram), and adjust dose as appropriate every 2-8 weeks until TSH levels are within normal reference range. Treatment is often life-long.

Adults 

  • 25-200 microgram daily (can start with dose 25 to 100mcg daily)

Children

  • > 12 years; 25 micrograms daily (max. 200 micrograms) 2-12 years; 25 micrograms daily (max. 100 micrograms)
  • < 2 years; 25-75 micrograms daily.

Monitor thyroid function tests where possible to avoid over or under treating

REFERRAL CRITERIA

  • All cases need to be managed by a doctor/specialist

 

CONGENITAL HYPOTHYROIDISM

Clinical Description

Congenital hypothyroidism is one of the common treatable causes of preventable mental retardation in children. Congenital hypothyroidism must be treated as early as possible to avoid intellectual impairment.

Clinical Features

SIGNS AND SYMPTOMS

  • Prolonged jaundice, feeding difficulties, hypotonia, wide open fontanelles, oedema, constipation, enlarged tongue, dry skin, bradycardia, lethargy etc.

INVESTIGATIONS

  • Thyroid function test

Treatment 

  • Give Levothyroxine 10-15 mcg/kg od orally for neonates and infants and 100 mcg/kg od
  • Requires urgent referral for confirmation of diagnosis.

 

IODINE DEFICIENCY DISORDERS (ENDEMIC GOITRE)

Clinical Description

  • More common in highland areas
  • Much less likely since the introduction of iodized salt
  • Only consult surgeons for treatment if large goitre causing obstructive problems or cosmetically unacceptable

Clinical Features

SIGNS AND SYMPTOMS

  • Goitre, Fatigue, If hypothyroid: Constipation and cold intolerance

INVESTIGATIONS

  • Thyroid function test
  • Thyroid gland ultrasound

Treatment 

Prevention

  • Use of Iodised Salt

Prophylaxis:

  • Give Aqueous Iodine Oral Solution 130mg/ml single dose
  • Repeat every 2 years