Paeds Endo and metabolic Flashcards
What are the common causes of hyponatraemia?
High water intake
Water retention
Excessive sodium losses (dehydration)
SIADH (meningitis, sepsis, post surgery etc)
Raise Na+ by no more than 8mmol/day
What are the common causes of hypernatraemia?
Loss of water in excess of sodium (diarrhoea, diabetes insipidus etc)
Excessive sodium intake (poisoning, wrong rehydration fluids etc)
Lower Na+ 0.5mmol/hr
What are the common causes of hypokalaemia?
Acute diarrhoea
Inadequate intake
Alkalosis
Volume depletion
Salbutamol use
Diuretics
Primary hyperaldosteronism
What are the common causes of hyperkalaemia?
Renal failure
Ingestion/Poisoning
Trauma with Rhabdo/burns
Acidosis
Hypoaldosteronism
Hypoadrenalism
What are the common causes of hypocalcaemia?
Sepsis
Renal failure
Rickets
Pancreatitis
Rhabdomyolysis
Hypoparathyroidism
What are the common causes of hypercalcaemia?
Hyperparathyroidism
Hypervitaminosis D or A
Idiopathic hypercalcaemia of infancy
Skeletal disorders
What are some examination findings associated with pituitary insufficiency and adrenal insufficency?
Midline defects (hereditary pituitary hypoplasia)
Small genitalia (reduced hormones)
Hyperpigmentation (adrenal insufficiency)
What is the difference between bedside glucometer and laboratory tested BSL?
BSL <3.0 on glucometer is unreliable
Consider BSL <3.0 on glucometer to be critically low
On laboratory tests/blood gas <2.6mmol is critically low
What are the key differentials for hypoglycaemia in children/infants?
Sepsis
Vomiting/Diarrhoea
Hormone deficiencies
Hyperinsulinism (ie macrosomia at birth, insulinoma)
Liver disease
Metabolic disorders
Drug overdose (ie insulin)
ETOH/Illicit drugs in adolescents
Ketotic hypoglycaemia (idiopathic, toddlers and young chidlren)
Malignancy
When should urine be tested for ketones and metabolic screen in hypoglycaemic children?
Straight away
The first urination after a hypoglycaemic episode is the key as this will have the highest yield for the metabolic screen
ketones will gradually clear from the urine over 24hrs post hypoglycaemia
What will be the effect on urine and serum ketone levels in hyperinsulinism states?
Both will be low or absent
Insulin utilises ketones so an absence of ketones in the context of low BSL suggests a hyperinsulin state
What is the morbidity of DKA?
The leading cause of both morbidity and mortality in T1DM
Morality mainly due to cerebral oedema in 0.3-1% of patients
How is DKA severity determined on laboratory testing?
Mild: pH <7.3 or bicarb <15
Moderarte: pH <7.2 or bicarb <10
Severe: pH <7.1 or bicarb <5
When should a fluid bolus be given in DKA in children?
10-20ml/kg N.Saline
Only if patient is shocked, higher risk of cerebral oedema than adults from this
IV fluids cause rapid falls in BSL due to dilution and increased GFR with glucosuria, these rapid fluid/electrolyte shifts are a potential cause of cerebral oedema
What is the clinical grading of dehydration and what is the maximum accepted in DKA?
Mild: 3%, barely clinically detectable
Moderate: 5%, Dry mucous membranes and skin turgour
Severe: 8%, sunken eyes and poor cap refill
8% should be considered the maximum dehdration for rehydration dosing purposes, overcorrection with fluids is dangerous and leads to cerebral oedema
How should vomiting and per oral status be managed in DKA?
Moderate to severe DKS should remain NPO until substantial improvement (ie BSL <15 and norm al GCS)
Consider placing NGT
Treat N/V with IV fluids first, then antiemetics 2nd line
How should fluid be given to DKA patients who are not shocked?
Maintenance + (Deficit - fluid bolus already given) over 48hrs
Maximum 8% deficit, don’t include urinary losses in assessment of dehydration
0.9% Saline + 5% dextrose + 40mmol KCL
Potassium should be removed from solution if anuric or K+ >5.5
What is the calculation for osmolality? what is it for corrected Na+?
Osmolality = 2x (Na+K) + BSL, >310 is elevated
Na corrected = Na + [2x(glucose -5.5)]/5.5]
Use the corrected serum sodium for the osmolality calculation
What is the dose of insulin infusion in DKA? when should it be altered?
0.1units/kg/hr
Can be decreased to 0.05units/kg/hr under certain conditions
- interhospital transfer
- <5yo
- BGL <15mmol/L at time of commencement
Goal is to clear ketones and resolve acidosis, not to significantly lower the BSL
What are the risk factors for cerebral oedema in DKA?
Can occur at any time but usually at the 4-12hr mark of treatment
New onset T1DM
Elevated urea
Severe dehydration
Severe DKA (low pH, low bicarb)
Age <5
Reduced GCS
Corrected sodium is hypernatraemic
Overzealous fluid (develops hyponatraemia, osmolarity rapidly drops)
What is the most common cause of recurrent hypoglycaemia in childhood?
18months to 5yrs = Idiopathic ketotic hypoglycaemia (akaaccelerated starvation)
<2yo = congenital hyperinsulinism (not ketotic)
Accelerated starvation- After prolonged fast, usually mild illness, low BGL + ketonaemia/uria, Diagnosis of exclusion
What are the basics of hyperammonaemia?
Hyperventilation
VBG- resp alkalosis, normal anion gap
Bloods- high ammonia
Stop feeds (NPO), give IV glucose, keep hydrated
Urea cycle defects etc
What are the basics of energy deficiency disorders?
Mitochondrial disorders
Make NPO, give IV glucoses
What is Kussmaul breathing
Hyperventilation from deep breathing as opposed to rapid breathing (although may be rapid as well)
Most commonly associated with DKA, but can be seen in any patient with a metabolic acidosis as this is the underlying cause (respiratory compensation)
What is the triad of metabolic derangements in congenital adrenal hyperplasia?
low sodium
high potassium
low glucose
17- hydroxyprogesterone is the definitive test
Mx: IV hydrocortisone 2-4mg/kg
IV fluids
correct electrolytes and glucose
What is the definition of DKA?
pH <7.30 or HCO3- <15
+
Ketonaemia >0.6mmol/L OR moderate/Large ketones in urine
+
Hyperglycaemia >11mmol/L
What is the treatment for paediatric hyperkalaemia?
IV calcium gluconate 10% 0.5mls/kg
+
Salbutamol nebs 2.5mg <25kg and 5mg if >25kg
+
Sodium bicarbonate 8.4% 1ml/kg if concurrent metabolic acidosis
+
IV insulin 0.1U/kg bolus + Dextrose 10% 5ml/kg bolus
+
Dialysis, resonium etc
Do not give bicarb and calcium simultaneously
