Paediatrics: Hyperthyroidism (thyrotoxicosis)

2021-03-03 12:00 AM

Thyrotoxicosis: refers to the clinical, physiological, and biochemical findings that result when the tissues are exposed to excess thyroid hormones.

Hyperthyroidism (thyrotoxicosis)

  • Thyrotoxicosis: refers to the clinical, physiological, and biochemical findings that result when the tissues are exposed to excess thyroid hormones.
  • Hyperthyroidism: denotes those conditions resulting in hyperfunction of the thyroid gland leading to a state of thyrotoxicosis.

Causes of thyrotoxicosis

Due to hyperthyroidism

  • Excessive thyroid stimulation:
  • Graves’s disease
  • Hashimoto’s disease
  • neonatal (transient) thyrotoxicosis
  • pituitary thyroid hormone resistance (excess TSH)
  • McCune–Albright syndrome
  • hCG-secreting tumours
  • Thyroid nodules (autonomous):
  • toxic nodule/multinodular goitre
  • thyroid adenoma/carcinoma

Not due to hyperthyroidism

  • Thyroiditis:
  • subacute
  • drug-induced
  • Exogenous thyroid hormones

Clinical features (all causes)

Thyrotoxicosis may be associated with the following symptoms:

  • hyperactivity/irritability;
  • poor concentration; altered mood; insomnia;
  • heat intolerance/fatigue/muscle weakness/wasting;
  • weight loss despite increased appetite;
  • altered bowel habit—diarrhoea;
  • menstrual irregularity;
  • sinus tachycardia; increased pulse pressure;
  • hyperreflexia; fine tremor;
  • pruritis.

Investigations

  •  Thyroid function tests (serum): raised T4 and T3; suppressed TSH.
  • Thyroid antibodies: antithyroid peroxidase; anti-thyroglobulin; TSH receptor antibody (stimulatory type).
  • Radionucleotide thyroid scan: increased uptake (Graves’s disease); decreased uptake (thyroiditis).