Endocrinology

Question 1

Management of long term complications of corticosteroids

Answer 1

Acknowledge:” I am concerned about the impact of corticosteroids on this patient’s general health. In particular, I am concerned about his future risk of developing glucocorticoid-induced diabetes, osteoporosis and proximal myopathy which may threaten his already vulnerable mobility”

Osteoporosis

• Rule out secondary causes: PTH, Vit D (osteomalacia), TFTs, ALP (+IEPG)
• Maintain Ca (>1.2g/d, otherwise supplement), Vit D >75
• Regular weight bearing exercises
• BMD baseline + 1 year post → antiresorptive if T-score
• Wean steroids ASAP
• Falls prevention, in light of HPA suppression - PT/OT…etc.

Steroid-induced diabetes

• Educate risk of DM - patient to check BGLs on day 3, then weekly (pre-breakfast, 2h post lunch + dinner)
• Aim = fasting <7, post-prandial <11
• Life-style measures: low sugar, avoid processed food with high-glycaemic index, exercise, the Mediterranean diet (proven to improve CV health)
• If off the target <15 → OHG
• If >15 → insulin
• This patient is on OD dosing - I expect that BGL would peak noon-8pm, so I would use intermediate-acting insulin (e.g. Protaphane)

Other aspects

• Infection: ensure vaccination UTD
• HPA axis suppression: if symptoms, I’d check fasting morning cortisol level (serum), if >300 effectively rules it out. If suspicious, then I would perform SynACTHen test, consider r/o secondary adrenal insufficiency (low ACTH)
• PPI cover for PUD

Question 2

Monitoring and surveillance for Thyroid malignancies?

Answer 2

• T4/TSH – goal is to maintain TSH low (suppression) - <0.1 to <2 dep on high-risk features
• Monitor with USS, TSH, Serum Tg
• Recurrence: surgery, RI, chemo, RTx

Question 3

Adrenal incidentaloma investigation? (i.e. lesion >1cm)

Answer 3

1. Are there high-risk features?

• >4cm, irregular border, >20 HU, slow contrast washout, calcification
• Otherwise likely to be benign → surveillance 12 monthly

2. Exclude Phaeochromocytoma & Cushing’s (usually sub-clinical) & Conn’s

• 24-hour urine for fractioned metanephrines, catecholamines, plasma metanephrines
• 1mg Dexamethasone suppression test (looking for serum cortisol >50 after 1mg dex over night) + baseline DHEA → proceed with 24h urine cortisol, serum ACTH, high-dose Dex (8mg)
• EUC - hypokalaemic, hypernatramic - do renin/aldosterone

3. If high-risk features or phaeo, sub-clinical Cushing’s who are good surgical candidate and are symptomatic - surgery is recommended

Question 4

Treatment principle for adreno-cortical carcinoma? (3)

Answer 4

1. Surgery +/- RTx
2. Adj Mitotane
3. Glucocorticoid replacement to prevent adrenal insufficiency

Question 5

Post-treatment surveillance for adrenocortical tumours?

Answer 5

CT CAP 3-6 monthly up to 5 years

PET scan (controversial)

Basically screen for all steroid metabolism associated hormones: Morning cortisol, DHEA, Androstenedione, Testosterone, Estradiol, Mineralocorticoid (Aldosterone) - these essentially serve as tumour markers - look for elevation.

Question 6

Phaechromocytoma diagnosis? (biochemical + radiologic)

Answer 6

Initial: 24h urine fractionated catecholamines + metanephrines

Plasma fractionated metanephrines

Followed by CT/MRI abdomen (99% sensitive, but only 70% specific, due to prevalence of incidentalomas [benign cortical tumour])

FDG-PET for ?metastasis

Question 7

Treatment principle for Phaeochromocytoma?

Answer 7

Optimise medical preparation (pre-op): alpha-blockade (phenoxybenzamine) then beta-blockade (e.g. metoprolol 12.5mg bd) thereafter. Remember, beta blockade → peripheral vasodilatation → unopposed alpha-adrenergic receptor stimulation → worsens HTN

Surgery thereafter

For malignant disease, can do RTx and Chemo

Question 8

MEN1?

Answer 8

Diamond (or 3 Ps)

• Pituitary adenoma
• Parathyroid: primary hyperparathyroidism
• Pancreatic (GI tumours or Islet cell): Zollinger-Ellison, Insulinoma or non-functioning

Question 9

Surveillance/Diagnosis/Screening for MEN1? (4)

Answer 9

Lack of quality data & debatable

1. PTH, Calcium, Prolactin
2. Consider more aggressive approach if clinical suspicion is high - fasting glucose, insulin, IGF-1, Chromogrannin-A, Gastrin
3. Imagings (MRI/CT/EUS) but no survival benefit in screening. Only do if clinical/biochemical suspicion is high.
4. Mutation testing confirms Dx - however, only 70% sensitive.

Question 10

MEN 2A?

Answer 10

Question 11

MEN 2B?

Answer 11

Oral: mucosal neuromas (and GI ganglioneuromas), often has Marfanoid

Phaeochromocytoma

Medullary Thyroid Carcinoma

Question 12

Surveillance/Diagnosis/Screening for MEN2?

Answer 12

1. RET mutation. If +ve, needs family screening in 1st-degree relative.
   - Important because identification of specific RET mutation predicts particular phenotypes (aggressiveness, age of onset, presence/absence of other endocrine neoplasms) - so guide surveillance
2. Fractionated plasma metanephrines
3. Serum Calcium
4. Serum Calcitonin
5. Neck USS ?MTC