Endocrine

Question 1

Preparation for Glucose Tolerance Test

Answer 1

• overnight fast of 8-14 hours
• 3 days of unrestricted diet + exercise
• evening meal as normal

Question 2

What happens during the glucose tolerance test?

Answer 2

• fasting blood in the morning
• Drink 75 g of anhydrous glucose in 250-300ml water over 5 mins
• blood sample 2 hours later
• no smoking during the test

Question 3

Diagnosis of diabetes using GTT

Answer 3

• random venous plasma glucose = 11.1 mmol/l
• fasting venous plasma glucose = 7.0 mmol/l
• 2 hr post = 11.1 mmol/l

Question 4

What is HbA1c?

Answer 4

• percentage of glycosylated haemoglobin

- estimate for 90 days

Question 5

Diagnostic value of Diabetes using HbA1c

Answer 5

• Pre-diabetes
  
  • > 42 - 47 mmol/mol
  • fasting plasma glucose 6 - 7 mmol
• Diabetes
  
  • > 48 mmol/mol
  • fasting plasma glucose > 7 mmol

Question 6

T2DM diagnosis using HbA1c

Answer 6

1. HbA1c > 48 mmol + symptomatic

2. HbA1c > 48 mmol + asympotamtic –> repeat within 2 weeks —> HbA1c > 48 mmol

Question 7

When can you not use HbA1c to diagnose diabetes?

Answer 7

1. Under 18yrs
2. Possible Type 1
3. Where glucose may rise rapidly e.g.: steroids, antipsychotics.
4. Reduced red cell survival e.g. haemolytic anaemia
5. Gestational Diabetes
6. Pancreatic damage/surgery
7. Anaemia/Haemoglobinopathy

Question 8

Define hypoglycaemia?

Answer 8

1. Development of neurogenic or neuroglycopenic symptoms
2. Low blood glucose (<4 mmol/L if on insulin or secretagogue)
3. Response to carbohydrate load

Question 9

What are neurogenic symptoms?

Answer 9

Trembling
Palpitations
Sweating
Anxiety
Hunger
Nausea

Question 10

What are neuroglycopenic symptoms?

Answer 10

Difficulty Concentrating
Confusion
Weakness
Drowsiness
Vision Changes
Difficulty Speaking
Dizziness

Question 11

Define severe hypogylcaemia

Answer 11

1. Requires the assistance of another person
2. Unconsciousness may occur
3. Plasma glucose is typically <2.8 mmol/L

Question 12

Clinical indications for TFTs (hyper)

Answer 12

1. Rapid-onset malaise, fever, and thyroid pain (may suggest subacute thyroiditis).
2. Compression symptoms of breathlessness, hoarse voice, dysphagia, neck pressure (may be caused by a toxic multinodular goitre).
3. Agitation, emotional lability, insomnia, irritability, anxiety, palpitations.
4. Exercise intolerance, fatigue, muscle weakness.
5. Heat intolerance, increased sweating.
   Increased appetite with unintentional weight loss, diarrhoea.
6. Subfertility, oligomenorrhoea, amenorrhoea.
7. Polyuria, thirst, generalized itch.
8. Reduced libido, gynaecomastia in men.
9. Deterioration in blood glucose control and hyperglycaemia in people with diabetes mellitus

Question 13

Interpret TFTs

Answer 13

Primary hypothyroidism:

1. Low T3/T4
2. High TSH

Primary hyperthyroidism:

1. High T3/T4
2. Low TSH

Secondary hypothyroidism:

1. Low T3/T4
2. Low/Normal TSH

Secondary hyperthyroidism:

1. High T3/T4
2. High TSH

Question 14

Subclinical thyroid

Answer 14

Hypo:
Normal T3/T4
High TSH

Hyper:
Normal T3/T4
Low TSH

Question 15

1st line for thyroid nodules

Answer 15

USS

- follow-up dependent on US appearances

Question 16

USS classification of thyroid nodules

Answer 16

U1  = normal
U2 = benign
U3 = indeterminate
U4 = Suspicious
U5 = malignanct

Question 17

Which thyroid nodule require fine-needle biospy (FNAB)?

Answer 17

1. U3-U5 = USS guided FNAB
2. FNA of abnormal lymph nodes
3. Incidental nodules on CT
4. PET-CT positive nodules

Question 18

THY classification: cytology + action

Answer 18

Thy 1:
Cyt = Non-diagnostic US
Action = +/- repeat FNA

Thy 2:
Cyt = Non-neoplastic
Action = Correlate with clinical and US
findings

Thy 3a:
Cyt =  Neoplasm possible (atypical features)
Action = Further US +/- FNA
MDT discussion if Thy3a on repeat
sample

Thy 3f
Cyt = Follicular neoplasm Action = Diagnostic hemi-thyroidectomy

Thy 4:
Cyt = Suspicious of malignancy
Action = Diagnostic hemi-thyroidectomy

Thy 5:
Cyt = Diagnostic of malignancy
Action = Therapy appropriate to tumour
type: usually surgery

Question 19

When is synacthen test requested?

Answer 19

Suspecting addison’s disease:

Crisis:
1. hypotension, hypovolaemic shock, delirium, reduced consciousness, acute abdominal pain, vomiting, headache, low-grade fever, and muscle weakness.

2. Hypoglycaemia can also occur (in particular in children).

Persistent, non-specific clinical features:
1. Fatigue

2. Hyperpigmentation
3. GI: weight loss, loss of appetite and premature satiety, nausea and vomiting, abdominal pain, and/or cravings for salt.
4. MSK: muscle weakness (difficulty getting up from sitting or carrying weights), muscle cramps (due to electrolyte derangement), and joint pain.
5. CVS: postural dizziness due to hypotension (blood pressure decrease of 20 mmHg between sitting and standing measurements).
6. Other: headache, low-grade fever, increased thirst or urination, loss of axillary or pubic hair in women, and anxiety or depression.

Question 20

How is synacthen test carried out?

Answer 20

• Get baseline level
• Inject 250mg of Tetracosactrin(IV or IM)
• Measure plasma cortisol level in 60 minutes
• Excluded if basal or test level is > 525 nmol/L

Plasma cortisol levels between 8am-9am

• Level <83 nmol/Llikely
• Level >525 nmol/L rules OUT

Question 21

When should you suspect adrenal crisis?

Answer 21

Unexplained hyponatremia and hyperkalemia in the setting of hypotension unresponsive to catecholamine and fluid administration

Question 22

What is the diagnostic test for acromegaly?

Answer 22

first line: Serum IGF-1 levels

Oral Glucose tolerance to confirm diagnosis

pituitary MRI may show pituitary tumour

Question 23

Clinical features of hyperprolactinemia

Answer 23

• Infertility
• Changes in menstruation.
• Galactorrhoea.
• Women who are not pregnant or nursing may begin producing breast milk.
• Loss of libido
• Gynaecomastia
• impotence
• Headaches or eye problems caused by the enlarged pituitary pressing against nearby eye nerves.

Question 24

Diagnostic test for prolactinoma

Answer 24

MRI

Question 25

Investigation for diabetes insipidus

Answer 25

water deprivation test

Question 26

Signs and symptoms of pheochromocytoma

Answer 26

Classic triad:

• headache
• sweating
• palpitations

Question 27

Diagnostic test for pheochromocytoma

Answer 27

24 Hour Urine Studies

- Catecholamines and Metabolites

Question 28

Values for hypercalcaemia

Answer 28

Mild = 2.5 mmol/L
Moderate = 3 mmol/L
Crisis = 4 mmol/L

Question 29

Acute hypocalcaemia value

Answer 29

2.20 - 2.60mmol/l

Symptoms of hypocalcaemia typically develop when adjusted serum calcium levels fall below ~ 1.9 mmol/L

Question 30

Investigation for hypocalcaemia

Answer 30

1. Serum calcium (adjusted for albumin)
2. Phosphate
3. PTH
4. U+E
5. Vitamin D
6. Magnesium

Question 31

Features of b12 deficiency

Answer 31

Haematological (in increasing order of severity)
o Isolated red cell macrocytosis
o Macrocytic anaemia (esp. if MCV >110fl)
o Pancytopenia (esp. if MCV >120fl)

Neurological or psychiatric
o Peripheral neuropathy
o Cognitive change e.g. dementia
o Optic neuritis
• Gastrointestinal

Investigation of possible malabsorptive process
• Other (rare)
o Angular cheilosis
o Sore beefy red tongue

Question 32

Ix for vitamin b12 deficiency

Answer 32

1. Anti-intrinsic factor (anti-IF) antibodies
2. Anti-gastric parietal cell (anti-GPC) antibodies
3. Thyroid function tests and anti-thyroid antibodies
4. Test for celiac disease
   - Tissue transglutaminase (tTG)
5. Tests for generalised malabsorption (if symptoms are suggestive) – we suggest that the
   faecal tests are only requested by a Gastroenterologist
6. Serum
   calcium and vitamin D
   folate
   ferritin
7. Faecal
   fats
   elastase
8. Schilling test

Question 33

What is thyroid fine needle aspiration?

Answer 33

A thyroid fine needle aspiration biopsy is a procedure that removes a small sample of tissue from your thyroid gland. Cells are removed through a small, hollow needle.