Goitre

Notes

## Basic introductiona,b

  • This is an enlarged thyroid gland that is clinically palpable
  • The two-lobed thyroid gland is located in the anterior neck below the cricoid cartilage.
  • The gland produces two chemical entities of thyroid hormones: Tetraiodothyronine (thyroxine, T4) and Triiodothyronine (T3)
  • The presence of thyroid nodules in men is likely to be malignant

## Functions of thyroid hormones (T3 & T4)

  • Increase cell metabolism
  • Facilitate normal growth
  • Facilitate normal mental development
  • Increase the local effects of catecholamines

## Pathophysiology of goitre

  • The function of thyroid gland is controlled by hypothalamus and pituitary glands
  • Hypothalamus produces the hormone Thyroid Release Hormone (TRH) in response to low plasma levels of T4
  • The TRH stimulates Pituitary gland to produce Thyroid Stimulating Hormone (TSH)
  • TSH stimulates thyroid gland to produce thyroxine, T4
  • A proportion of T4 is converted into T3 where it exerts its effect
  • High plasma level of the free T3 stimulates reduction of production of TRH while T3 and T4 stimulate reduction of production of TSH
  • TSH stimulates iodine uptake, endocytosis of colloids, and the growth of thyroid gland
  • In the presence of iodine deficiency, the synthesis of T3 and T4 is reduced HENCE the production of TRH is not inhibited. This results in stimulation of production of TSH that stimulates the growth of thyroid gland and hence goitre

## Causesa

  • The most common cause is iodine deficiency
  • Hashimoto’s thyroiditis (common cause in developed nations)
  • Infection related goitre (e.g. TB and syphilis)
  • Selenium deficiency
  • Thiocyanate toxicity
  • Unsuccessful thyroidectomy

## Classification of goitre based on the growth pattern

  • Goitre is broadly classified into nodular and diffuse goitre
  • Nodular goitre is further classified into uninodular and multinodular goitre
  • Uninodular goitre can be either a cyst, a benign thyroid neoplasm or a thyroid cancer
  • Multinodular goitre can either be due to iodine deficiency, thyroditis or sarcodoisis
  • Diffuse goitre can either be due to iodine deficiency, Grave’s disease (also known as toxic diffuse goiter, an autoimmune disease), hypothalamic disease, pituitary disease, or thyroid hormone insensitivity

## Classification of goitre based on the size of the gland

  • Type III: Invisible but palpable
  • Type II: Visible and palpable
  • Type I: Visible, palpable with retrosternal extension

## Classification of goitre based on the activity of the gland

  • Hypothyroidism
  • Hyperthyroidism

## Statistics

  • The Female-to-Male ratio is 4:1
  • 5% of circulating thyroid hormone is T4 while 1.5% is T3
  • T3 is the most active form in binding to the nuclear receptor
  • The half-life of T3 is about 24hrs while the half-life of T4 is about 7 days
Symptoms
  • Most cases are asymptomatic
  • Anterior neck swelling
  • Symptoms arising from compression of adjacent tissues by the swelling

_Dysphagia

_Stridor

_Hoarse voice

_Dyspnea

_Engorged neck veins

  • Symptoms of malignancy that include pain, inflammation, and hemorrhage
  • Symptoms of hyperthyroidism

_ Enlarged thyroid gland (goiter)

_Irritability and anxiety

_Insomnia

_Palpitation

_Bulging eyes

_Eye irritation

_Hair loss

_Increased appetite

_Weight loss

_Heat intolerance

_Hyperhidrosis (excessive sweating)

_Oligomenorrhea (Reduced menstrual flow)

_Fatigue

_Stare

_Increased bowel movement

_Thinning of the skin

_Tachycardia

_Atrial arrhythmia

_Hypertension

_ Muscle weakness

_Hand tremor

_Osteoporosis (after a long life with the disease)

  • Symptoms of hypothyroidism
  • Endemic cretinism
Diagnosis
  • Free T3 and T4
  • Total T3 and T4
  • TRH
  • TSH
  • Thyroperoxidase Antibody (Anti-TPO)

Anti-TRHr

  • Thyroglobulin
  • Radioactive iodine uptake test, (or RAIU test)

X-ray: AP and Lateral thoracic

  • Ultrasound - for size, consistency and nodularity
  • CT-Scan
  • Radionuclide isotope scanning to assess the function of thyroid
  • Biopsy: fine needle aspiration or core biopsy
  • Spirometry: useful in assessment of compressive goitre
Differential
  • Thyroid lymphomas
  • Thyroid lipoma
  • Lympadenopathy (or Bull’s neck)
  • Pseudogoitre
  • Thyroglossal cyst
  • Sublingual dermoid
Prevention
  • Use of iodized salt in diet
  • Eating sea food such as shrimp, shellfish, and seaweeds
  • Preventing overexposure to radiation: be it as a treatment, or in a working environment
  • Maintain healthy lifestyle and food.
Reference

1. Ogbera, A. O., & Kuku, S. F. (2011). Epidemiology of thyroid diseases in Africa. Indian journal of endocrinology and metabolism, 15(6), 82.

2. Kenyan Ministry of Health. Clinical guidelines for management and referral of common conditions at levels 4-6. Hospitals. 2009; 3:259-261.http://apps.who.int/medicinedocs/documents/s21000en/s21000en.pdf

3. Ministry of Health, Kenya. Kenya Essential Medicine List (2016). http://publications.universalhealth2030.org/uploads/KEML-2016Final-1.pdf

Management
'-Deoxy-" '-Difluorocytidine
Drug Index 2.0 is here
Our new update features a more powerful search feature and easier login. Having any issues? Contact us today. Contact Us