Endocrinology Flashcards

1
Q

Treatment of acute severe hypercalacemia

A
  1. REHYDRATION
  2. LOOP DIURETICS - to increase calcium excretion (if fluid overloaded because hypercalcemia causes osmotic diuresis)
  3. IV BISPHOSPHONATES (e.g. zoledronate, takes 3-5 days to work)
  4. IV CALCITONIN - if aggressive presentation
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2
Q

Visual defect assocaited with pituitary tumour?

A

Bitemporal hemianopia
(pressure on optic chiasm)

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3
Q

Ocular palsy associated with pituitary tumour?

A

Oculomotor nerve palsy most common due to location in cavernous sinus (CN III)

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4
Q

Hormones released from the anterior pituitary

A

TSH
ACTH
LH/FSH
Prolactin
GH

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5
Q

Hormones released from the posterior pituitary

A

Oxytocin
ADH

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6
Q

Describe the growth axis

A
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7
Q

Describe te adrenal axis

A
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8
Q

Describe the gonadal axis

A
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9
Q

Describe the thyroid axis

A
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10
Q

Describe the prolactin axis

A
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11
Q

Types of pituitary tumours

A

PITUITARY ADENOMA = BENIGN

  1. Microadenoma <1cm
  2. Macroadenoma >1cm
    - Functioning (secretes hormones)
    - non-functioning (not secretory)
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12
Q

Most common functional pituitary adenoma types

A

Prolactinoma (35%) –> hyperprolactinaemia

GH-secreting (20%) –> acromegaly / gigantism

ACTH-secreting –> cushings disease

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13
Q

Treatment of prolactinoma

A

Dopamine agonist
- carbergoline
- bromocriptine

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14
Q

Describe the Insulin stress test and what is it used for?

A

Used to test for ACTH deficiency

Given insulin –> drop in blood glucose
Hypoglycaemia should stimulate ACTH release
No increase in ACTH suggests a deficiency

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15
Q

Decribe the oral glucose tolerance test and what is it used for?

A

Used to test for GH suppression/acromegaly

Glucose should result in GH impression

No suppression suggests acromegaly (check IGF-1 levels

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16
Q

Describe the synacthen test and what is it used for?

A

Tests for adrenal insufficiecny

Synacthen = artificial ACTH –> should stimulate adrenal gland to produce cortisol

measure cortisol at baseline, 30 mins, and 60 mins. Cortisol should double every 30 mins

17
Q

Causes of raised prolactin levels

A

PITUITARY
- Prolactinoma
- Non-functioning adenoma / other causes of hypopituitarism

HYPOTHALAMUS
- Tumours

SECONDARY
- renal failure
- primary hypothyroidism
- adrenal insufficiency
- PCOS

PHYSIOLOGICAL
- Pregnancy
- Breast stimulation
- stress

MEDICATIONS
- Antipsychotics
- antiemetics
- antihypertensive
- oestrogen

18
Q

What is the Water deprivation test?

A

Prevent patient drinking water
ask the patient to empty their bladder
hourly urine and plasma osmolalities

19
Q

Primary/psychogenic polydipsia: what is it and what would the water deprivation test show?

A

Primary polydipsia = the patient drinks excessive amounts of water, causing dilution of the serum and urine, leading to low serum osmolality and low urine osmolality.

Following water deprivation, the urine becomes more concentrated, and osmolality rises to >750mOsmol/kg.

This show the kidneys are able to concentrate urine and rules out diabetes incipidus

20
Q

Nephrogenic vs Cranial Diabetes incipidus

A

Nephrogenic DI - results from renal insensitivity to anti-diuretic hormone (ADH), preventing the concentration of urine (even if a patient is hypovolaemic)

Cranial DI = insufficient ADH release from posterior pituitary –> inability to concentrate urine even if a patient is hypovolaemic. Low urine osmolality even during water deprivation. BUT kidneys are unaffected - so will respond to desmopressin (synthetic ADH) to produce concentrated urine.

21
Q

Causes of Nephrogenic DI

A

Inherited
Metabolic - low potassium, high calcium
Drugs: lithium
CKD
Post-obstructive uropathy

22
Q

Causes of cranial DI

A

Idiopathic
Congential (defects in ADH gene)
Tumours - craniopharyngioma, pituitary
Brain trauma
Hypophysectomy (removal of pituitary)
Haemorrhage
Infection

23
Q

What is Sick euthyroid syndrome?

A

non-thyroidal illness) it is often said that everything (TSH, thyroxine and T3) is low.

In the majority of cases however the TSH level is within the >normal range (inappropriately normal given the low thyroxine and T3).

Changes are reversible upon recovery from the systemic illness and hence no treatment is usually needed.

24
Q

How often should insulin-dependent diabetics check their glucose when driving?

A

every 2 hours

25
Q

DVLA driving rules for diabetics (group 1 drivers)

A

They can drive a car as long as they have hypoglycaemic awareness + not >1 episode of hypoglycaemia requiring the assistance within the preceding 12 months and no relevant visual impairment.

If diet controlled alone then no requirement to inform DVLA

26
Q

Drug used to treat Thyrotoxicosis in pregnancy

A

propylthiouracil

27
Q

Drug used to treat Thyrotoxicosis in pregnancy

A

First trimester: propylthiouracil
After 1st trimester: carbimazole

28
Q

Most common cause of thyrotoxicosis in pregnancy

A

Grave’s disease (autoimmune)

29
Q

Signs of thyroid crisis / storm

A

fever > 38.5ºC
tachycardia
confusion and agitation
nausea and vomiting
hypertension
heart failure
abnormal liver function test

30
Q

Management of thyroid crisis

A
  1. beta-blockers (IV propranolol)
  2. anti-thyroid drugs: e.g. methimazole or propylthiouracil
  3. dexamethasone - e.g. 4mg IV qds - blocks the conversion of T4 to T3
31
Q

Antibodies associated with Hashimoto’s thyroiditis

A
  1. antithyroid peroxidase (anti-TPO) antibodies
  2. antithyroglobulin antibodies
32
Q

Lithium affect on thyroid gland

A

Lithium inhibits the production of thyroid hormones in the thyroid gland and can cause a goitre and hypothyroidism

33
Q

Amiodarone affect on thyroid gland

A

interferes with thyroid hormone production and metabolism, usually causing hypothyroidism but it can also cause thyrotoxicosis.

34
Q

Define primary hypothyroidism

A
35
Q

Define secondary hypothyroidism

A
36
Q

Two most common causes of hyperthyroidism

A
  1. Autoimmune / Graves disease (70%)
  2. Toxic multinodular goitre (15%)
37
Q

Signs specific to Graves disease (autoimmune)

A
  1. Goitre
  2. Pre-tibial myxoedema
  3. Acropachy
  4. Thyroid eye disease - exophthalmos, lagophthalmos, periorbital oedema