Endocrinology - Thyrotoxicosis and Hypothyroidism

Question 1

-Thyrotoxicosis: aetiologies

Answer 1

• Grave’s disease
• Toxic multinodular goitre (Plummer’s disease)
• Toxic adenoma
• Thyrotoxic phase of thyroiditis
• Drugs

Question 2

-Thyrotoxicosis: Ix

Answer 2

• Bloods: low TSH/high T4 and T3
  
  • Serum antigens: TSH receptor and thyroid peroxidase
  • Raised Ca2+ and LFTs
• Isotope scan: raised in Graves, low in Thyroiditis
• Ophthalmopathy: acuity, fields, movements

Question 3

-Causes of thyrotoxicosis: Graves’ disease - features

Answer 3

• Diffuse goitre with increased iodine uptake
• ophthalmopathy and dermopathy
• triggers: stress, infeciton and child birth

Question 4

-Causes of thyrotoxicosis: Toxic multinodular goitre

Answer 4

• Plummer’s disease
• Functionally autonomous nodule develops on background multinodular goitre - produces thyroxine
• Elderly and iodine deficient areas
• iodine scan shows hot nodules

Question 5

-Causes of thyrotoxicosis: Toxic adenoma

Answer 5

• Solitary hot nodule which can produce T3/T4
• Most nodules are non functional

Question 6

-Causes of thyrotoxicosis: thyrotoxic phase of thyroiditis

Answer 6

• Hashimoto’s
• de Quervain’s
• Subacute lymphocytic thyroiditis

Question 7

-Causes of thyrotoxicosis: drugs

Answer 7

• thyroxine
• amiodarone

Question 8

Thyrotoxicosis Rx- medical

Answer 8

• Symptomatic control: Beta blocker (propanolol 40mg/6h)
• Anti-thyroid: Carbimazole (titrate, S/E agranulocytosis)

Question 9

Thyrotoxicosis Rx- radiological

Answer 9

• Radio-iodine Rx
  
  • most will become hypothyroidic
  • CI: pregnancy/lactation

Question 10

Thyrotoxicosis Rx- surgical

Answer 10

• Thyroidectomy
• S/E:
  
  • recurrent/external branch of sup laryngeal nerve palsies
  • hypoparathyroidism
  • hypothyroidism

Question 11

What is a thyroid storm? Features?

Answer 11

• Life threatening hyperparathyroidism
• Features:
  
  • raised temp
  • agitation/confusio/coma
  • tachycardia/AF
  • acute abdo
  • HF

Question 12

What are precipitants of a thyroid storm?

Answer 12

• Recent surgery/radio-iodine
• infection
• MI
• trauma

Question 13

Outline basic Mx for a patient in a thyroid storm

Answer 13

• Fluid restriction + NGT
• Bloods: TFTs and cultures in query infection
• propanolol (may need digoxin too)
• Carbimazole
• hydrocortisone
• Rx cause

Question 14

Hypothyoidism- causes

Answer 14

• Primary:
  
  • atrophic thyroiditis (most common in UK)
  • Hashimoto hypo
  • Subacute thyroiditis
  • Post de Quervain thyroiditis
  • iodine deficiency (most common woldwide)
  • Drugs: carbimazole, amiodarone, lithium
  • congenital: thyroid agenesis
• Post surgical
  
  • thyroidectomy
  • radio-iodine
• Secondary
  
  • hypopituitarism: v rare

Question 15

Causes of hypothyoidism- Atrophic (auto-immune) thyroiditis

Answer 15

• Body interprets thyroid gland and T3/T4 as threats
• Serum: +ve for anti thyroid and anti-TSH

Question 16

Causes of hypothyoidism- Hashimoto

Answer 16

• TPO +ve
• may go through initial thyroitoxicosis phase

Question 17

Hypothyroidism: Ix

Answer 17

• Blood:
  
  • raised TSH, low T3/T4
  • Raised MCV +/- normochormic anaemia
  • raised TAGs and cholesterol
  • Hyponatraemia: SIADH
  • Raised CK (if associated with myopathy)
  • Serum abs: TPO, THS

Question 18

What is a myxodema coma? What is the Mx for ti?

Answer 18

• Pt hypothermic, hypoglycaemic, HF, coma and seizures
• Mx:
  
  • Bloods: TFTs, FBC, U+E, glucose, cortisol
  • Correct hypoglycaemia
  • T3/T4 IV slowly
  • hydrocortisone 100mg IV
  • Rx hypothermia and HF