1. Hyperthyroidism / Thyrotoxicosis - 10 marks

Definition

• Hyperthyroidism is a state of increased synthesis and secretion of thyroid hormones by the thyroid gland.
• Thyrotoxicosis is the clinical syndrome due to excess circulating thyroid hormones (T3/T4), whether produced by the gland or received from outside.
• It causes a hypermetabolic, hyperadrenergic state.

Etiology

1. Graves' disease - most common cause; autoimmune stimulation of TSH receptors.
2. Toxic multinodular goitre.
3. Toxic adenoma.
4. Thyroiditis - subacute, painless, postpartum.
5. Excess intake of thyroid hormone.
6. Iodine-induced or amiodarone-induced thyrotoxicosis.
7. Rarely, TSH-secreting pituitary adenoma.

Clinical features

• Weight loss despite increased appetite
• Heat intolerance and excessive sweating
• Weakness, fatigue and increased thirst
• Fine tremors

• Nervousness, irritability, anxiety
• Insomnia, hyperactivity and poor concentration
• Hyperreflexia

• Palpitations, tachycardia
• Systolic hypertension
• Atrial fibrillation, especially in elderly patients
• Heart failure in severe untreated disease

• Increased bowel frequency or diarrhoea
• Oligomenorrhoea/amenorrhoea and infertility in females
• Reduced libido and erectile dysfunction in males

• Staring look, lid retraction and lid lag
• Graves' orbitopathy: exophthalmos, diplopia
• Warm, moist skin; fine hair
• Pretibial myxoedema in Graves' disease

• Diffuse goitre in Graves' disease, sometimes with bruit
• Nodular goitre in toxic multinodular goitre

Investigations

1. Serum TSH: suppressed or low, best initial screening test.
2. Free T4 and/or T3: raised.
3. TSH-receptor antibody: supports Graves' disease.
4. Radioactive iodine uptake scan:
   • Diffuse increased uptake: Graves' disease
   • Focal uptake: toxic adenoma
   • Low uptake: thyroiditis or exogenous hormone intake
5. ECG: tachycardia or atrial fibrillation.
6. CBC and liver function tests before antithyroid medication.

Management

1. General measures
   • Rest, avoid excess iodine and stimulants.
   • Treat precipitating factors.
2. Symptomatic treatment
   • Beta-blocker, such as propranolol, for tremor, tachycardia and palpitations.
3. Antithyroid drugs
   • Methimazole/carbimazole are commonly used.
   • Propylthiouracil is preferred during the first trimester of pregnancy and in thyroid storm.
   • Monitor for agranulocytosis and hepatotoxicity.
4. Definitive treatment
   • Radioactive iodine ablation.
   • Thyroidectomy in large goitre, suspicion of malignancy, compressive symptoms, or selected Graves' disease cases.
5. Graves' orbitopathy
   • Smoking cessation, eye protection and specialist management.
   • Severe disease may need corticosteroids or other therapy.

Complications

• Thyroid storm
• Atrial fibrillation and thromboembolism
• Heart failure
• Osteoporosis and fractures
• Infertility and adverse pregnancy outcomes

Ayurvedic correlation and principles

• There is no exact single classical Ayurvedic equivalent of hyperthyroidism.
• It may be understood as a Pitta-Vata predominant condition with tikshnagni, dhatu-kshaya, kampa, daha, sweda, hrid-drava and anidra.
• Chikitsa principles:
  • Nidana parivarjana
  • Pitta-Vata shamana
  • Mridu langhana where appropriate
  • Manasika shanti, adequate sleep and avoidance of excessive ushna, tikshna, amla and katu ahara
  • Any Ayurvedic treatment should be adjunctive and must not delay endocrine evaluation, especially in severe disease.

2. Hypothyroidism - 10 marks

Definition

• Hypothyroidism is a clinical state caused by deficient production or action of thyroid hormones.
• It leads to slowing of metabolic processes.
• It may be:
  1. Primary: disease of thyroid gland
  2. Secondary: pituitary TSH deficiency
  3. Tertiary: hypothalamic TRH deficiency

Etiology

1. Hashimoto thyroiditis - common cause in iodine-sufficient regions.
2. Iodine deficiency.
3. Post-thyroidectomy or post-radioactive iodine therapy.
4. Drugs: amiodarone, lithium and some immunotherapies.
5. Postpartum thyroiditis.
6. Infiltrative disease of thyroid.
7. Congenital thyroid dysgenesis or dyshormonogenesis.
8. Pituitary or hypothalamic disease causing central hypothyroidism.

Clinical features

• Fatigue, lethargy and weakness
• Weight gain despite poor appetite
• Cold intolerance
• Reduced sweating

• Dry, coarse, cold skin
• Coarse, brittle hair and hair loss
• Puffy face and periorbital puffiness
• Non-pitting oedema: myxoedema

• Slow speech and slow mental activity
• Poor memory, depression and drowsiness
• Muscle cramps and proximal muscle weakness
• Delayed relaxation of deep tendon reflexes
• Carpal tunnel syndrome

• Bradycardia
• Low cardiac output
• Diastolic hypertension
• Pericardial effusion in severe cases

• Constipation
• Menorrhagia, infertility and recurrent miscarriage
• Decreased libido and erectile dysfunction

• Hoarse voice
• Goitre may be present in Hashimoto thyroiditis or iodine deficiency
• In children: growth retardation and delayed development

Investigations

1. Serum TSH
   • Increased in primary hypothyroidism.
   • Low or inappropriately normal in central hypothyroidism.
2. Free T4
   • Reduced in overt hypothyroidism.
3. Subclinical hypothyroidism
   • Increased TSH with normal free T4.
4. Anti-thyroid peroxidase antibodies:
   • Often positive in Hashimoto thyroiditis.
5. Additional tests where indicated:
   • Lipid profile: hypercholesterolaemia may occur.
   • CBC: anaemia may occur.
   • ECG: sinus bradycardia.
   • Ultrasound when structural thyroid disease is suspected.

Management

1. Levothyroxine replacement
   • Treatment of choice.
   • Usually taken once daily, preferably on an empty stomach.
   • Dose is individualized based on age, body weight, cardiac disease, pregnancy and laboratory values.
2. Monitoring
   • Check TSH after starting or changing dose, generally after about 6-8 weeks.
   • In central hypothyroidism, monitor free T4 rather than relying only on TSH.
3. Special situations
   • Elderly persons and patients with coronary artery disease: start with a low dose and titrate slowly.
   • Pregnancy: thyroid hormone requirement often rises, so early monitoring and dose adjustment are required.
   • Correct iodine deficiency where relevant.
4. Avoid
   • Unsupervised use of T3 or thyroid extracts.
   • Taking levothyroxine together with iron, calcium, antacids or certain foods that impair absorption.

Complications

• Myxoedema coma: hypothermia, bradycardia, hypotension, altered sensorium and hypoventilation
• Hyperlipidaemia and atherosclerotic cardiovascular disease
• Infertility and poor pregnancy outcomes
• Pericardial effusion
• Growth and intellectual impairment in untreated congenital hypothyroidism

Ayurvedic correlation and principles

• Hypothyroidism also has no exact one-to-one classical Ayurvedic diagnosis.
• It can be interpreted as a Kapha-Vata predominant state, with mandagni, meda vriddhi, shotha, gaurava, alasya, sheetata and mala-sanga.
• Chikitsa principles:
  • Nidana parivarjana
  • Agni deepana and ama pachana according to patient assessment
  • Kapha-Meda hara ahara-vihara
  • Appropriate vyayama, pathya ahara and weight management
  • Shodhana or shamana only after proper Ayurvedic assessment
• Levothyroxine should not be abruptly stopped or replaced by Ayurvedic medicines without endocrinology supervision.

Important laboratory comparison