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