02: Clinical Cases

Question 1

Discuss the clinical presentation and biochemical diagnosis of pituitary hyperfunction syndromes (acromegaly, Cushing’s disease and prolactinoma)

Answer 1

HYPERFUNCTION SYNDROMES commonly caused by tumours

ACROMEGALY

• soft tissue overgrowth, wide feet, coarse facial features, thick lips tongue
• carpal tunnel syndrome
• syndrome
• CHIASMAL COMPRESSION complication
• screening: igf-1 ELEVATED?
• OGT: glucose load suppressed
• pituitary MRI

CUSHING’S SYNDROME

• xs ACTH, tissue breakdown and sodium retention = HT and HF, insulin antagonism = DM
• skin atrophy, spontaneous purpura + bruising, flushed
• 8 typical striae 1cm+, central obesity thin limbs
• ACTH-independent: tumour or CORTICOSTEROID THERAPY
• ACTH-dependent: pituitary tumour or ectopic ACTH secretion

PROLACTINOMA

• 1º, pituitary lesions
• pregnancy, lactation, stress
• Iatrogenic: dopamine antagonists (neuroleptics/anti-emetics), DA-depleting agents, oestrogens, antidepressants

Question 2

Describe the clinical features of hypopituitarism in adults and children.

Answer 2

Tiredness, weight gain, depressed functions and symptoms, reduced growth delayed puberty

Question 3

Describe the consequences of a space occupying lesion in the pituitary region (imaging techniques, visual field assessment).

Answer 3

• often BITEMPORAL HEMIANOPIA d/t chiasm involvement (pituitary masses)
  • via suprasellar extension: tumour extending into the chiasm

Question 4

Discuss the clinical management of patients with pituitary disease (pituitary surgery, radiotherapy, medical therapy and pituitary hormone replacement

Answer 4

HYPERSECRETION MGMT
- dopamine agonists (prolactinoma)
• microprolactinoma, macroprolactinoma 
• nausea
• impulse control disorders
- somatostatin analogues (acromeg.): can induce tumor shrinkage
•monthyl injections
•sfx: nausea etc., therefore slow release preparations
- GH receptor antagonist (acromegaly)

HYPOSECRETION

• cortisol, T4, sex steroids, GH
• desmopressin

TUMOUR
-sx (transsphenoidal) = often first line of treatment for functioning pituitary syndromes
- RADIOTHERAPY
• causes hypopituitarism

Question 5

Diabetes Insipidus

Answer 5

Water deprivation test diagnostic: urine cannot be concentrated; POLYURIA
*vasopressin deficiency

*cranial origin: post-trauma/surgery, metastatic carcinoma, benign, SARCOIDOSIS, IDIOPATHIC (AuIm?)

Question 6

Describe the normal anatomy and physiology of the thyroid and its regulation through the hypothalamic pituitary thyroid axis.

Answer 6

Found at base of neck

TRH (hypothal.) > TSH (ant pit.) > Thyroxine (thyroid) > T3

negative feedback of T3

1º disease @ Thyroid, 2º disease @ pituitary

Question 7

Describe the principles underlying tests of over and under production of Thyroid hormones

Answer 7

TFTs = TSH and free T4

HYPO: low hormones + ⇧TSH (d/t NO NEG FEEDBACK)
HYPER: high hormones + ⇩TSH (too much neg feedback)
• TSH only altered in SUBCLINICAL respectively •

T4 is produced in large quantities by the thyroid. However, TSH is a far superior screening test because small changes in T4 cause large TSH spikes. Usually when a person has hypothyroidism, TSH levels become very high way before T4 levels fall below normal.

Question 8

State the common tests of thyroid function and their interpretation, and the methods available for thyroid imaging

Answer 8

TFTs = TSH and free T4
+FBC
+HbA1c

Question 9

State the common presentations of hyperthyroidism and hypothyroidism and their associated physical signs.

Answer 9

HYPOTHYROIDISM
• depressed features + presentation, Wt gain
• oedema, hoareness, goitre, bradycardia, carpel tunnel syndrome = paraesthesia

HYPERTHYROIDISM
• Wt loss
• anxiety, irritability
• heat intolerance, sweat intolerance, palpitations

Question 10

Discuss the identification and management of hypothyroidism in the newborn

Answer 10

Newborns are screened in the UK for CONGENITAL DYSHORMONOGENESIS

A heel prick blood sample is tested to look for: low levels of T4 (thyroxine)

Question 11

Describe the pathogenesis of different types of hyperthyroidism and hypothyroidism, and the rational use of investigations in formulating a diagnosis.

Answer 11

1º HYPOTHYROIDISM:
• CONGENITAL: developmental, dyshormonogenesis
• ACQUIRED: common;
AuIm. (Hashimotos)
Iatrogenic: RT head and neck, post-op/post radioactive iodine
Chronic I2 def.
Post-subacute thyroiditis - post partum thyroiditis

2º: Pituitary / hypothalamic damage
• tumour

1º HYPER
• Grave's Disease (AuIm.) F>M
- thyroid peroxidase Ab., TSH receptor Ab.
• Toxic Multinodular Goitre
• Toxic Adenoma
2º
• Pituitary adenoma secr. TSH
• Iatrogenic

+ SUBACUTE THYROIDITIS (nil hyperthyroid): VIRAL, YOUNGER, painful goitre fever,
•⇧ESR
• thyrotoxicosis followed by hypothyroid
> STEROID and NSAIDS

Question 12

Discuss the common treatment options for, and the possible complications of the treatment of hyperthyroidism.

Answer 12

HYPERTHYROIDISM/ THYROTOXICOSIS
+beta blockers, +

> ANTI-THYROID DRUGS: CARBIMAZOLE, PROPYLTHIOURACIL
• replace with thyroxine
• titration regime common, maintain lowest dose (12-18mos)
!rash, hypothyroidism > FBCs
!hepatotox for PROPYLTHIOURACIL (prego)
consider risk of relapse = extend titration range

> RADIOIODINE: ablative,
!recurrent hyperthyroidism, !risk of hypo
!teratogenic
+ steroids

> Sx

Question 13

Discuss the principles of treatment of hypothyroidism

Answer 13

<65y/o
=>LEVOTHYROXINE, daily, altered based on monitoring every 3mos

> 65y/o or with pre-existing cardiac disease
=>LEVOTHYROXINE

• first thing in the morning; empty stomach (avoid food 30mins)
- sfx: palpations and angina
- TEST ANTIAB THYROID PEROXIDASE ONCE
! overtreatment: AF, fracture

PREGNANT
=> PRECONCEPTION REPLACEMENT > DOSE INCREASE IN EARLY PREG.
\+ regular monitoring
> reduce LEVOTHYROX. to PRE-PREG. DOSE
> recheck 2-3mos post preg.

Question 14

Discuss the presentation, investigation and management of thyroid cancer.

Answer 14

TSA tumour ADENOMA: secretes TSH = discordant bloods
• MRI

> somatostatin analogue (LANREOTIDE)

THYROID CANCER

• Differentiated papillary: commonest, multifocal, spread, good prog.
• Follicular: single lesion, mets to lung/bone
• ANAPLASTIC: do not take up radioiodine therefore Sx
  poor prog
• Lymphoma: rare, preexisting hashimotos,
  >external RT
• Medullary thyroid cancer (parafollicular C cells) ⇧Calcitonin > Total thyroidectomy

> Total thyroidectomy
radioiodine
• LT suppressive doses of thyroxine
• Thyroglobulin: whole body I2 scanning + USS = risk stratification and monitoring

Question 15

Significance of subclinical

Answer 15

subclinical hyperthyroidism: AF 3fold increase risk in 60+

fracture risk

Question 16

Causes of Goitre

Answer 16

physiological, 
AuIm: graces, hashimoto
Thyroiditis: acute de Quervains, chronic fibrotic
Iodine def.
Dyshormogenesis

Question 17

Goitre Types

Answer 17

MULTINODULAR

DIFFUS: colloid, simple,

CYSTS

TUMOURS

SOLITARY NODULE THYROID
• MALIGNANCY RISK, large dominant nodule, prev H&N irradiation, pain,

• TFT, USS: benign vs malignant, FNA

Question 18

Bloods Workup for Grave’s Disease

Answer 18

Increased T3 and T4
Decreased TSH

anti-TSHR antibodies
+ anti-thyroid-peroxidase (anti-TPO) (HASHIMOTO)
+ anti-thyroglobulin (anti-Tg) antibodies.