Endocrine

Question 1

Hyperthyroidism causes

Answer 1

Primary: Graves, toxic multinodular goitre, toxic neoplasm
Secondary: pituitary hyperfunction

Question 2

Hypothyroidism causes

Answer 2

Primary: Hashimoto (most common in SG), iatrogenic, cretinism, dietary iodine deficiency
Secondary: Pituitary failure

Question 3

Signs of hyperthyroidism and hypothyroidism

Answer 3

Hyperthyroidism: thin, staring gaze, lid lag, exophthalmos (graves), warm sweaty skin, tachycardia and atrial fibrillation, proximal myopathy, pretibial myxoedema

Hypothyroidism: mildly obese, swollen and puffy face, dry cool skin, bradycardia, pericardial effusion, proximal myopathy

Question 4

Symptoms of hyperthyroidism and hypothyroidism

Answer 4

Hyperthyroidism: Weight loss, heat intolerance, oligomenorrhea, diarrhoea, irritable mental state and increased appetite

Hypothyroidism: Weight gain, cold intolerance, menorrhagia, oligomenorrhea, constipation, mental slowness, may have poor appetite

Question 5

Biochemical symptoms of hyperthyroidism and hypothyroidism

Answer 5

Hyperthyroidism: High T4, T3, low TSH (primary hyper), Graves’ autoantibodies

Hypothyroidism: Low T4, T3, high TSH (primary hypo) or low TSH (secondary hypo), Hashimoto autoantibodies

Question 6

What is Graves disease

Answer 6

Autoantibodies bind to and activate TSH receptors, releasing T3 and T4, and increases cellularity and causes hyperplasia of the thyroid gland (goitre)

Question 7

What is Hashimoto thyroiditis

Answer 7

Immune mediated cytotoxic destruction of follicular epithelial cells

Question 8

Gross features of Graves thyroid

Answer 8

Diffuse enlargement
Reddish meaty cut surface with high cell density
Smooth and soft gland with intact capsule
Histologically, follicular cells are tall, columnar and crowded, forming pseudopapillae with inflammatory cells

Question 9

What are the thyroid cancers

Answer 9

Follicular adenoma
Anaplastic carcinoma
Medullary carcinoma (MEN syndrome, FMTC if hereditary)
Follicular carcinoma (capsular/vascular invasion, metastasis to lungs, bone, liver via blood)
Papillary carcinoma (metastasis to lymph nodes, diagnosis based on nuclear features: finely dispersed chromatin, nuclear grooves, pseudo inclusions, classical features: papillae with fibrovascular cores, psammoma bodies)

Question 10

Gene mutations in MEN

Answer 10

MEN 1: MENIN gene
MEN 2: RET gene

Question 11

MEN 1 clinical features

Answer 11

Prolactinoma: excess breast milk formation
Hyperparathyroidism: hypercalcemia
Adrenal adenoma: cushing’s syndrome
Insulinoma: hypoglycemia
Gastrinoma: gastric ulceration

Question 12

MEN 2B clinical features

Answer 12

Mucosal neuroma syndrome: growth around nerves of mucous membranes
Marfanoid habitus: long limbs, loose joints, curved spine

Question 13

Causes of hyperparathyroidism

Answer 13

Primary:
Parathyroid adenoma, most common
Parathyroid carcinoma
Parathyroid hyperplasia (more than 1 gland enlarged)

Secondary:
Renal failure (kidney reabsorbs too much phosphate, forming insoluble CaPO4, reducing Ca ion levels, stimulating increased PTH)

Question 14

Effects of hyperparathyroidism

Answer 14

Renal and urinary calculi
Osteitis fibrous cystica
Hypertension
Pancreatitis
Peptic ulcers
Metastatic calcification

Question 15

Causes of adrenal hyperfunction

Answer 15

Primary:
Adrenal adenoma/carcinoma
Adrenal hyperplasia

Secondary:
Pituitary adenoma (increased ACTH causing increased cortisol)

Others:
Iatrogenic: steroids
Paraneoplastic: SCLC producing ACTH

Question 16

Clinical features of Cushing’s syndrome (hyperfunction of adrenal gland)

Answer 16

Adrenal tumor/hyperplasia
Enlarged sella turcica (base of skull, location of pituitary)
Emotional disturbances
Moon face, buffalo hump, obesity
Thin wrinkled skin, abdominal striae
Poor wound healing, skin ulcers
Muscle weakness
Hypertension
Hyperglycemia
Osteoporosis
Amenorrhea (no period)
Immune suppression and opportunistic infections
GI bleeding
Posterior subcapsular cataracts
Euphoria, depression, psychosis