Endocrinology

Question 1

DKA: diagnostic criteria

Answer 1

1. BSL >11 (unless euglycaemic DKA)
2. pH <7.3
3. HCO3 <15
4. Ketones >3mmol/L

Question 2

DKA: Treatment targets and rate

Answer 2

1. Ketones - reduce by 0.5mmol/L per hour
2. Bicarb - increase by 3.0mmol/L per her
3. BSL - reduce by 5mmol/L per hour
4. Potassium - Maintain between 4.0-5.0

Question 3

DKA - Fluid management, adults

Answer 3

Volume resus:
- Stat 1L if very dehydrated/hypotensive
- then 1L over first hour
- then 1L over 2 hours
Target UO 0.5mL/kg/hr

Fluid choice:
Can use NS 0.9%
Preference for Hartmann’s or Plasmalyte (acidosis resolves ~25% more rapidly)
Can use 0.45% saline if Na+>150 or osmolarity >320 mosm/L

When BSL <15, commence 5% glucose 125mL/hr

Question 4

DKA: Fluid management, paeds

Answer 4

• 20mL/kg 0.9% NS if shocked
• +10mL/kg over 1 hour if significantly dehydration
• or 5mL/kg/hr until lab results available
• Give replacement (% dehydration x Wt) and maintenance fluids evenly over 48 hours

Question 5

DKA: Insulin management

Answer 5

May not be needed in mild DKA
Commence after 1 hour in paeds
Delay if serum K+ <3.5mmol/L
Loading dose should be avoided

Bolus 0.2U/kg SC basal long-acting (controversial)
Infusion:
- 50U in 50mL NS0.9%
- 0.05-0.1U/hr (lower preferred), max 5U/hr
- Titrate to BSL, aiming decrease 5mmol/L per hour
- Continue until ketosis clears and patient tolerating oral intake

Question 6

DKA: potassium management

Answer 6

Commence in second hour if K+<5.0
- <3, 40mmol/hr
- 3-4, 30mmol/hr
- 4-5, 10mmol/hr
- >5, cease infusion

Question 7

DKA management: other concerns

Answer 7

1. NGT if ileus
2. ECG monitoring if significant electrolyte abnormalities
3. VTE prophylaxis (high risk VTE)
4. NBM

Question 8

Euglycaemic DKA management differences

Answer 8

As per DKA but start 5% dextrose infusion at BSL <20 (earlier than usual 15)

Question 9

DKA: paeds differences

Answer 9

1. No insulin in first hour
2. 10-20mL/kg NS 0.9% bolus - be more cautious
3. Rehydration w/ 0.9% +/- 40mmol/L K+ +/- 5% dextrose
   - K+ as per potassium level
   - Dextrose once BSL <15
   - Rehydration over 48 hours (deficit [usually 5%]+maintenance)
4. Liaise with NETS/paeds/ICU
5. If hypo:
   - 2mL/kg 10% dextrose bolus
6. Other:
   - Nurse head up
   - Cardiac monitoring
   - 30-60min VBGs
   - IDC

Question 10

Paeds DKA: cerebral oedema RFs and management

Answer 10

First presentation
Long history of poor control
Age <5

Reduce IVF rate by 50%
Mannitol 20% 0.5g/kg over 20 mins
OR 3mL/kg 3% NaCl

Question 11

HHS diagnostic criteria

Answer 11

Osm >320mosm/L
BSL >33
pH >7.3
HCO3 >15
Ketones <3

Hypovolaemia
+
Hyperglycaemia
+
Hyperosmolar state

Question 12

HHS treatment aims

Answer 12

1. Replace fluid deficit over 48hrs (up to 6-10L common)
2. Reduce osmolality by:
   - 3-8mosm/L in first hour
   - 3-5mosm/L/hr after that

Question 13

HHS IVF management

Answer 13

• Large volumes usually necessary (6-10L deficits common)
• Replace over 48 hours i.e. 3-5L/day
• 0.9% NS
• 1L in first hour, then continue deficit replacement, aiming decrease in mosm by 5/hr
• Add 5% dextrose at 125mL/hr once BSL <15
• Add KCl if serum K+ <5.5: 10mmol/hr if K>4.0, 20mmol/hr <4.0

Hartmann’s avoided

Question 14

HHS insulin regime

Answer 14

Only added if targets not being met by IVF alone
OR ketones >1

Low dose, 0.05U/kg/hr, max 5U/hr
Titrated to BSL reduction 5mmol/hr

Question 15

Osmolality calculation

Answer 15

2Na + Glu + Urea

Question 16

Corrected sodium calculation

Answer 16

Na + (glucose-5)/3
OR
Na + glucose/4

Question 17

Hypoglycaemia: glucagon dose

Answer 17

<25kg - 0.5mg SC or IM
>25kg - 1mg SC or IM

Question 18

Hypoglycaemia: IV glucose dose

Answer 18

Paeds: 2mL/kg 10% over 15 mins
Adults:
- 250mL 10% glucose over 15 mins
- 50mL 50% glucose over 15 mins

Question 19

Hypoglycaemia: oral glucose dose

Answer 19

Paeds: 5-10g glucose gel
Adults: 15g glucose gel

Question 20

Adrenal insufficiency: investigations

Answer 20

1. EUCs
   - HypoNa, HyperK
2. BSL
   - Hypo, usually mild
3. VBG
   - NAGMA
4. FBC
   - Neutropaenia +/- eosinophilia/lymphocytosis
5. Antiphospholipid antibodies
   - May be first clinical manifestation of antiphospholipid antibody syndrome (35%)
6. Early morning cortisol
   - Diagnostic test, limitations of single sample
7. Plasma ACTH
   - High in primary adrenal disease, low in pituitary disease
8. ACTH (Synacthen) stimulation test
   - Performed if other tests non-diagnostic

Question 21

Adrenal insufficiency/crisis management

Answer 21

Resuscitation w/ IV NaCl0.9%
Hydrocort 250mg IV stat then 100mg q6hrly
Treat hypogylcaemia - 50mL 50% glucose
Treat hyperK if symptomatic
Seek and treat precipitating cause

Paeds:
<3 years: 25mg hydrocort then 6hrly lower dose
3-12 years: 50mg hydrocort then 6hrly lower dose
>12 years: as adult

Question 22

Adrenal insufficiency precipitating events

Answer 22

Steroid withdrawal
Major surgery
MI
GA
Hypogylcaemia
Major trauma
Hypothermia
Drugs incl. morphine, chlorpromazine

Question 23

CAH, classic form: clinical features

Answer 23

Females: ambiguous genetalia
Males may have minimal features
Subtle hyperpigmentation, slight penile enlargement

Salt losing form:
- Present day 7-14 of life
- Vomiting
- Weight loss
- Lethargy
- Dehydration
HypoNa, HyperK
Shock

Non-salt-losing form
- Present age 2-4 years
- Early virilisation

Question 24

CAH diagnostic investigations

Answer 24

17-hydroxyprogesterone
- Random level >242nmol/L on day 3 of life diagnostic of classic disease
- False positive with premature infants
- Can be normal in non-classic disease

Corticotropin stimulation test
- Used in borderline cases
- Measurement of 17-hydroxyprogesterone at 60 mins

Question 25

CAH, classic form management

Answer 25

Glucocoticoids - Suppressed adrenal androgen secretion without total suppression of HPA axis - Hydrocortisone in childhood - Pred + dex in adults Mineralocorticoids - Return electrolyte concentrations an plasma renin activity to normal - Fludricortisone 100-200microg daily NaCl - 1-2g/day, may be needed in salt-losing form in first 6mo Hydrocort + fludrocort +/- NaCl

Question 26

Myxoedema coma management

Answer 26

Specifics: 3-2-1 Levothyroxine (T4) - 300mcg slow IV injection - Then 75-100mcg IV daily Liothyronine (T3) - 25-50mcg slow IV - Then 10-20mcg q8hrly Hydrocortisone - 100mg TDS + Supportive - Haemodynamic support - Slow re-warming - Treat hypogylcaemia - Treat hypoNa (fluid restriction) - Seek and treat precipitant e.g. infection

Question 27

Thyroid storm: precipitants

Answer 27

Undiagnosed or under-treated hyperthyroidism, usually Grave's Withdrawal of anti-thyroid drugs Infection, MI, DKA etc. Major surgery Iodine administration, radio-active or xray contrast Vigorous palpation of thyroid gland(!)

Question 28

Thyroid storm diagnostic criteria

Answer 28

Temp > 37.8 degC (up to 41) Tachycardia out of proportion to fever - usually 120-200 CNS disturbance (90%) - Agitation, psychosis, seizure, coma GI - N+V, abdo pain Cardiac - CCF, AF, HTN

Question 29

Thyroid storm management

Answer 29

Suppportive - IVF - Supplemental O2 (increased demand) - Cooling (avoiding aspirin) Propranolol 60mg QID OR metoprolol 5mg IV OR esmolol 500mcg/kg Propylthiouracil - 1g loading -> 200mg QID PO/NG Lugols iodine - 0.5mL TDS - give at least 1 hour after PTU Dexamethasone - 8mg BD IV

Question 30

How to differentiate thyroid storm from thyrotoxicosis

Answer 30

Burch-Wartofsky Point Scale Higher score = more likely thyroid storm Temperature HR CNS effects GI/hepatic dysfunction CCF AF Precipitating event

Question 31

Central DI treatment

Answer 31

Desmopressin 2mcg IM/IV OR Vasopressin 5-10U SC/IM

Question 32

Nephrogenic DI management

Answer 32

Fluid Na restriction Thiazide diuretic (HCT) Indometacin (50mg BD) Seek and treat underlying cause

Question 33

Primary hyperaldosteronism (Conn's) investigations and management

Answer 33

Vitals - hypertensive EUCs - hypoK, HyperNa (opposite of Addison's) CMP - HypoCa VBG - metabolic alkalosis Spironolactone 25mg daily

Question 34

Phaeochromocytoma associated conditions

Answer 34

MEN II (Multiple endocrine neoplasia) - 50% MEN IIb NF1 (neurofibromatosis) Von Hippel-Lindau disease Familiar paraganglionomas

Question 35

Phaeochromocytoma management

Answer 35

- ICU/HDU admission - Resuscitate (A, B, C) - Alpha blockade: phentolamine 5mg IV - +SNiP if refractory HTN - Then beta blockade: metoprolol 50mg BD - Other: calcium channel blockers, labetalol - MgSO4 - Screen for myocardial damage: Trop, ECG, TTE - Definitive: surgery

Question 36

Pituitary insufficiency

Answer 36

Resuscitation Emergent glucocorticoid replacement - IV hydrocort 100mg Thyroxine replacement (second most important) - IV levothyroxine 300mcg Seek and treat precipitants Seek and treat cardiovascular and electrolyte effects of hormone deficiencies IV hydrocort -> levothyroxine -> other

Question 37

Carcinoid syndrome features and investigations

Answer 37

Serotonin-secreting tumour Diarrhoea Facial flushing Bronchospasm Hypotension Tricuspid and pulmonary valvular disease + RHF Ix: - 24 hour urinary HIAA (serotonin breakdown) - TTE - Imaging to locate malignancy CT/MRI - Octreotide scan

Question 38

Carcinoid syndrome management

Answer 38

Anti-histmines Octreotide infusion Treat vasodilatory shock (e.g. norad) Treat RHF (e.g. inotropes + diuretics)

Question 39

Dose of IM glucagon - paeds

Answer 39

Neonate: 0.03-0.1mg/kg (max 1mg) <25kg: 0.5mg (1/2 vial/0.5mL) >=25kgL 1mg (1 vial/1mL)