Medicine (6)

Question 1

DKA

• triad (biochemical)
• predisposing factors

Answer 1

Biochemical triad of:

• ketonaemia (ketosis)
• hyperglycaemia
• acidaemia

Precipitating factors:

• Infection
• Missed insulin
• MI

Question 2

Presentation of pt with DKA

Answer 2

• abdominal pain
• polyuria, polydipsia, dehydration
• Kussmaul respiration (deep hyperventilation)
• Acetone-smelling breath (‘pear drops’ smell)

Question 3

Diagnostic criteria of DKA

Answer 3

• glucose > 11 mmol/l or known diabetes mellitus
• pH < 7.3
• bicarbonate < 15 mmol/l
• ketones > 3 mmol/l or urine ketones ++ on dipstick

Question 4

Management of DKA

Answer 4

• fluid replacement: most patients with DKA are deplete around 5-8 litres. Isotonic saline is used initially
• insulin: IV infusion 0.1 unit/kg/hour. Once blood glucose is < 15 mmol/l an infusion of 5% dextrose should be started
• correction of hypokalaemia
• long-acting insulin should be continued, short-acting insulin should be stopped

Question 5

The differential diagnosis for goitre

Answer 5

• Physiological (puberty/pregnancy)
• Thyroid disease (autoimmune)
• Simple colloid/Multinodular goitre
• Thyroiditis
• Tumours
• Infiltrative (TB/sarcoidosis)

Question 6

Clinical features being specific for Grave’s (3)

Answer 6

Question 7

Investigations for hyperthyroidism

Answer 7

• Bedside – ECG (tachycardia/AF)
• Bloods – TFTs (low TSH, high T3), Autoantibodies (anti-TSH), FBC (anaemia), HbA1c (associated diabetes), lipids
• Imaging – USS Scan thyroid (if lump)

Question 8

Management of hyperthyroidism

Answer 8

Question 9

Causes of hypothyroidism

Answer 9

Question 10

Digoxin MoA

Answer 10

• Inhibits the Na/K ATPase pump
• Positively inotropic

Question 11

Digoxin toxicity

• presentation
• predisposing factors
• management

Answer 11

Presenting features:

• generally unwell
• anorexia
• yellow-green vision
• fatigue/nausea + vomiting
• arrhythmias
• gynaecomastia

Precipitating factors:

• ↓K+
• renal failure
• ↑Ca2+
• loop diuretics

Management:

• Digibind
• correct arrhythmias
• monitor potassium

Question 13

Symptoms of hypercalcaemia

Answer 13

bones, stones, groans, thrones and psychic moans

• Bones (bone pain)
• Stones (renal calculi)
• Groans (abdominal pain, tiredness/weakness)
• Thrones (polydipsia, constipation)
• Psychic moans (confusion)

Question 14

Causes of hypercalcaemia

Answer 14

• Malignancy (breast/myeloma/lung) - 90% causes
• Primary hyperparathyroidism - 90% causes
• Sarcoidosis
• Vitamin D toxicity
• Thyrotoxicosis
• Lithium
• Tertiary hyperparathyroidism
• Milk-Alkali syndrome
• Familial benign hypocalcinuric hypercalcaemia

Question 15

Management of hypercalcaemia

Answer 15

Correct dehydration:

• Fluids
• Bisphosphonates
• Treat underlying cause

Question 16

Causes of prolonged and shortened QT interval

Answer 16

Question 17

What’s that ECG suggestive of?

Answer 17

Question 18

Causes, signs and management of hypocalcaemia

Answer 18

Question 19

Causes and levels of (Ca, PTH, phosphate) of hypoparathyroidism (3)

Answer 19

Question 20

Ix in Cushing’s syndrome

Answer 20

Confirmation tests
• Overnight dexamethasone suppression test
• 24hr urinary free cortisol

Localization tests
• Plasma ACTH
• If low: CT adrenals (look for adrenal tumour)
• If high: perform high-dose dexamethasone suppression test (if cortisol low →
cushings disease, if high → look for ectopic ACTH source)

Question 21

Causes of Cushing’s syndrome

Answer 21

ACTH dependent causes

• Cushing’s Disease
• Ectopic secretion from tumour (e.g. lung ca)

ACTH independent causes

• Iatrogenic: steroids
• Adrenal adenoma
• Adrenal carcinoma

Question 22

Dexamethasone suppression test results

Answer 22

Question 23

Ix for Addison’s disease

Answer 23

ACTH stimulation test

(short Synacthen test)

• Plasma cortisol is measured before and 30 minutes after giving Synacthen 250ug IM
• If an ACTH stimulation test is not readily available (e.g. in primary care) then sending a 9 am serum cortisol can be useful:
• > 500 nmol/l makes Addison’s very unlikely
• < 100 nmol/l is definitely abnormal
• 100-500 nmol/l should prompt a ACTH stimulation test to be performed

Question 24

Causes of adrenal insufficiency

Answer 24

Primary (Addison’s disease)

Autoimmune, Tuberculosis, metastases (e.g. bronchial carcinoma),

meningococcal septicaemia (Waterhouse-Friderichsen syndrome), HIV, antiphospholipid syndrome

Secondary

pituitary disorders (e.g. tumours, irradiation, infiltration)

Tertiary (stopping exogenous steroid)

Question 25

Treatment of adrenal insufficiency (Addison's)

Answer 25

Combination of: * **hydrocortisone:** usually given in 2 or 3 divided doses. Patients typically require 20-30 mg per day, with the majority given in the morning dose * **fludrocortisone** **Patient education** is important: * emphasise the importance of not missing glucocorticoid doses * consider MedicAlert bracelets and steroid cards * discuss how to adjust the glucocorticoid dose during an intercurrent illness Management of **intercurrent illness** * in simple terms the glucocorticoid dose **should be doubled**

Question 26

Causes of Addisonian crisis

Answer 26

Causes: * **sepsis** or **surgery** causing an acute exacerbation of chronic insufficiency (Addison's, Hypopituitarism) * **adrenal haemorrhage** eg Waterhouse-Friderichsen syndrome (fulminant meningococcemia) * **steroid withdrawal**

Question 27

Management of Addisonian crisis

Answer 27

* **hydrocortisone 100 mg** IM or IV * **1 litre normal saline** infused over 30-60 mins or with **dextrose** if hypoglycaemic * continue hydrocortisone 6 hourly until the patient is stable. No fludrocortisone is required because high cortisol exerts weak mineralocorticoid action * oral replacement may begin after 24 hours and be reduced to maintenance over 3-4 days

Question 28

Electrolyte imbalance in hyperaldosteronism (Conn's)

Answer 28

Question 29

(3) structures of the adrenal cortex and what they produce

Answer 29

Question 30

**Primary hyperaldosteronism** - features - investigations - causes - management

Answer 30

Question 31

Causes of hypernatraemia

Answer 31

* Reduced fluid intake * Fluid loss without replacement * Diabetes insipidus * Primary hyperaldosteronism

Question 32

Causes of hyperkalaemia

Answer 32

* AKI * Drugs (ACEi, K+ diuretics, NSAIDs) * Adrenal insufficiency (e.g. Addison’s) * Rhabdomyolysis

Question 33

Causes of hypokalaemia

Answer 33

* Vomiting and diarrhoea * Drugs (e.g. diuretics) * Primary hyperaldosteronism * Cushing’s syndrome

Question 34

Causes of hyponatraemia

Answer 34

* Fluid loss * Adrenal insufficiency (e.g. Addison’s) * Drugs (thiazide diuretics) * SIADH * Organ failure

Question 35

Tests for phaeochromocytoma

Answer 35

* 24 hr urinary collection of metanephrines * this has replaced a 24 hr urinary collection of catecholamines

Question 36

Management of phaeochromocytoma

Answer 36

Surgery is the definitive management. The patient must first however be stabilized with medical management: * alpha-blocker (e.g. phenoxybenzamine), given before * beta-blocker (e.g. propranolol)